INORGANIC NITROGEN METABOLISM AND PHYTOPLANKTON
PRIMARY PRODUCTIVITY IN A SUBARCTIC LAKE
A
DISSERTATION
Presented to the F a c u lt y o f the
U n i v e r s i t y o f A la s k a in P a r t i a l
Fulfillm ent
o f the Requirements
f o r the Degree o f
DOCTOR OF PHILOSOPHY
By
Vera Alexan der Dugdale B . A . , M.S.
C o l l e g e , A la sk a
May, 1965
INORGANIC NITROGEN METABOLISM AND PHYTOPLANKTON
PRIMARY PRODUCTIVITY IN A SUBARCTIC LAKE
APPROVED:
Department Head and Chairman
DATE:
Vice P r e s i d e n t f o r Research and
Advanced Study
ABSTRACT
The r e l a t i o n s h i p between ni t ro ge n u t i l i z a t i o n and primary
p r o d u c t i v i t y was s tu d i e d in a s u b a r c t i c lake, u s i n r the s t a b l e
is ot op e
to measure the uptake ra tes o f anv.iu;',i j , -; i ; y > v ;,,v<
m ol e c u la r n i t ro g e n .
the ^ C method.
Primary p r o d u c t i v i t y de te rm ina tio ns employed
A combination o f these methods with the q u a n t i t a t i v e
de ter mination o f n it r o g e n n u t r i e n t s du rin g two seasons provioeu
in f o rm a t io n on the r o l e o f these n i t ro g e n sou rce s in the p r o d u c t i v i t y
regime o f t h i s p a r t i c u l a r lake.
The st ud y lake was Smith Lake, located on the U n i v e r s i t y of
A la s k a campus.
I t s s h a l l o w depth, and l a c k o f i n l e t and o u t l e t
du ri n g much o f the p r o d u c t iv e season made i t i n t e r e s t i n g from the
p o i n t o f view of an i n t e r n a l
c y cl e study.
The lake i s ch a r a c t e r iz e d
by two major growth peri od s f o r p h o t o s y n t h e t i c organisms.
The
f i r s t takes place under the i c e , under low l i g h t c o n d i t i o n s , and i s
predominantly composed o f green algae and f l a g e l l a t e s .
n it r o g e n source at t h i s time i s ammonia.
The major
The major bloom takes
plac e in June, and the dominant al ga i s Anabaena f l o s - a q u a e .
Ammonia, n i t r a t e and m ol ec u la r n it r o g e n a l l pl ay a p a r t in the
n it r o g e n su p p ly f o r t h i s bloom.
Foll owi ng t h i s bloom, which
d e c l i n e s a b r u p t l y , a low and more steady p r o d uc t io n continues
through the summer, with ammonia p r o v i d i n g most o f the ni t ro g e n .
Pe rio ds o f very high p h o t o s y n t h e t i c ra tes are always accompanied
by high rates o f ammonia a s s i m i l a t i o n .
From the amount o f ammonia
iv
in the water, and the r ate o f removal, a very high rate o f tu rn ov er
f o r ammonia i s e s t a b l i s h e d .
D i r e c t measurement o f the rate of
ammonia su p pl y usi ng an is o t o p e d i l u t i o n technique supported t h i s
co n c l u s i o n .
ACKNOWLEDGMENTS
T h is work was made p o s s i b l e by the sup port and encouragement
o f Dr. K. M. Rae, to whom the author exp resses a p p r e c i a t i o n .
The
p u r s u i t of the work le a d in g to t h i s paper r e q u ir e d g r e a t patience
on the p a r t of my husband, Dr. R. C. Dugdale, who not only
t o l e r a t e d the r e s u l t a n t e r r a t i c l i f e , but a l s o pro vid ed a s s i s t a n c e
and su p p o r t in every p o s s i b l e way.
Many people provided te ch n ic a l
o f the work.
a s s i s t a n c e in v a r i o u s phases
In 1963, f i e l d a s s i s t a n c e was pro vid ed by Mr. Robert
C la s b y , and M i s s Linda Mc Vic ar a s s i s t e d with chemical de ter mi nat io ns.
In 1964, a s s i s t a n c e in both l a b o r a t o r y and f i e l d was provided by
Mr. W il l i a m Z o l l e r and M i s s J u d i t h Thompson.
S p e c ia l thanks are
due to Donald H. Rosenberg f o r h i s help w ith data p r o c e s s i n g .
To
Dr. R. J. Ba rs dat e, the auth or exp resses a p p r e c i a t i o n f o r a s s i s t a n c e
with the pr ep ar a ti on o f the 14C ampoules.
C r e d i t f o r an e x c e l l e n t
job o f ty pi n g the man us cri pt goes to M i s s D i x i e D or iu s.
F i n a n c i a l su p po r t was pro vided in pa rt by the Na tional
o f H e a lt h , under g r a n t s WP-00422-01 and WP-00422-02.
v
Institutes
TABLE OF CONTENTS
page
A B S T R A C T .....................................................................
iii
ACKNOWLEDGMENTS...............................................................................
v
INTRODUCTION ..................................................................................
1
Statement of the problem.................................................
.
1
A b i l i t y of phytoplankton to a s s i m i l a t e
v a r i o u s compounds o f i n o r g a n i c ni t ro ge n ..........................
3
Nitroge n f i x a t i o n ........................................................
3
Ammonia.........................................................................
5
N i t r a t e ............................................................................
6
P re v io u s work on n it r o g e n in the
e co lo gy of l a c u s t r i n e envi ron m ent s .......................................
7
Nitrogen f i x a t i o n ...........................................................
7
Ammonia and n i t r a t e u t i l i z a t i o n ..........................
9
A d d i t i o n a l components o f the n it r o g e n cy cle
to be con sid er ed in t h i s s t u d y ............................................... H
Experimental approach ........................................................
12
The l a k e ................
13
METHODS.........................................................................................
15
N i tr o g e n -1 5 t r a c e r methods..................................................
15
In cu b at io n p r o c e d u r e s .............................
I7
C a l c u l a t i o n s ...........................................................................
I7
Primary p r o d u c t i v i t y measurements .......................................
19
vi i
page
P a r t i c u l a t e n i t ro g e n d e t e r m i n a t i o n s .................................
. 20
C h l o r o p h y l l a_........................................................................... 20
Methods f o r the q u a n t i t a t i v e a n a l y s i s
o f n u t r i e n t s in the w a t e r .................................
22
N itr oge n compounds........................................................... 22
Phosphorus de termin atio ns ...........................................
Techniques used f o r ot he r ana ly se s
23
....................................
24
PHYTOPLANKTON ...............................................................................
25
RESULTS - PHYSICAL AND CHEMICAL BACKGROUND.............................
. 28
Thermal regime ...................................................................... 28
D i s s o l v e d oxygen ..................................................................
29
S p e c i f i c c o n d u c t i v i t y .............................................................. 30
p H ............................................................................................30
L i g h t ........................................................................................ 31
P a r t i c u l a t e n it r o g e n ............................................................ 31
C h l o r o p h y l l a_........................................................................... 32
N u t r i e n t chemistry ...............................................................
33
A m m o n ia ........................................................................... 33
N i t r a t e ........................................................................... 34
N i t r i t e ........................................................................... 35
P h o s p h o r u s ...............................................................................35
EXPERIMENTAL RESULTS.............................
37
Primary p r o d u c t i v i t y ............................................................ 37
vi i i
page
1A
Depth d i s t r i b u t i o n o f
C
uptake in Smith L a k e .............................................................. 39
Winter p r o d u c t i v i t y ..........................................
The e f f i c i e n c y o f p h o t o s y n t h e s i s
39
........................................ 40
Experimental r e s u l t s - n it r o g e n uptake ..............................
41
The e x c r e t io n o f n e w ly -f ix e d
n it ro ge n by p h y t o p la n k t o n ....................................................... 44
Determination o f the rate o f ammonia
sup pl y in Smith Lake w a t e r .................................................... 46
DISCUSSION........................................................................................ 48
The pro d uc ti on
under the i c e ................................................ 48
The Anabaena s p . b l o o m .......................................................... 50
The post-bloom
p r o d u c t i o n ...................................................... 56
N i t r a t e as a n i t r o g e n - s o u r c e in Smith L a k e ............................57
I n t e r r e l a t i o n s h i p s with microorganisms .............................. 59
A comparison o f Smith Lake and
Sanc tua ry Lake, P e nn s y lv a ni a ..............................................
60
CONCLUSIONS ..................................................................................... 62
LITERATURE CITED.............................................................................. 65
APPENDIX A ........................................................................................ 72
APPENDIX B ........................................................................................ 73
L IS T OF ILLUSTRATIONS
Figures
1.
O u t li n e map of Smith Lake, A l a s k a ................................. ->4
2.
The seasonal d i s t r i b u t i o n o f c h l o r o p h y l l
a_ and p a r t i c u l a t e ni t ro ge n c on ce nt r at io ns
in Smith Lake - 1563 .................................................. 32
3.
The seasonal d i s t r i b u t i o n o f c h l o r o p h y l l
a_ ar.d p a r t i c u l a t e n i t ro g e n c on ce nt r at io ns
in Smith Lake - 1 9 6 4 .................................................... 32
4.
Disappearance of n i t r a t e in Smith Lake
in the s p r i n g o f 1964.................................................. 34
5.
Primary p r o d u c t i v i t y r e s u l t s f o r Smith
Lake, 1963 ..................................................................
37
Su rf ac e p h o t o s y n t h e s i s measurements in
Smith Lake, 1963 ........................................................
37
R e su lt s of in s i t u
experiments in
Smith Lake, 1964 ........................................................
38
R e s u l t s of 14C experiments incubated
under con sta nt l i g h t at 20°C - Smith
Lake su r fa ce water, 1964 ...........................................
38
The depth d i s t r i b u t i o n o f p h o t o s y n t h e s i s
in Smith Lake - r e o r e s e n t a t i v e curves
f o r 1963 ......................................................................
39
6.
7.
8.
9.
10.
Nitroge n f i x a t i o n r a te s and the p a r t i c u l a t e
ni t r o g e n co n c e n tr a ti o n in Smith Lake s u r f a c e
water, 1963..................................................................... 41
11.
The uptake o f i n o r g a n i c n it ro g e n sou rces in
Smith Lake in 1964 - the r e s u l t s o f s t a b l e
i s ot op e t r a c e r experiments on s u r f a c e water,
incubated at 20°C and co n sta nt l i g h t .......................... 4i
12.
The t o t a l uptake o f i n o r g a n i c n i t ro g e n in
Smith Lake, 1 S 6 4 ........................................................... 44
ix
X
f o l l o w i n g page
ABLES
I ■ il,^/ , , U t f
2.
U ISSU i V C ^
Cj ^ I t
)
I J u vj ,
• ■ ■ •
m g / l i t e r d i s s o l v e d oxygen, Smith Lake, 1954..............
29
. 30
3.
S p e c i f i c c o n d u c t i v i t y - Micromhos..........................
4.
L i g h t p e ne tr at io n - percent reaching
each d e p t h ..................................................................... 31
5.
NH3 -N y g - a t o m s / l i t e r , Smith Lake,
1 9 63 -19 64 .............
33
6.
NO3-N y g - a t c m s / 1 it e r , Smith Lake,
19 6 3 -1 9 6 4 .............
34
7.
The r e l a t i o n s h i p between c h l o r o p h y l l _a and
p h o to sy n th e si s ............................................................ 40
8.
The uptake o f n i t r o g e n compounds.
Results of
t r a c e r experiments, Smith Lake, 1963, s u r fa c e
w a t e r ...............................................................................41
9.
The uptake o f n i t ro g e n compounds.
R e s u l t s of
tracer experiments, Smith Lake, 1964 .......................
10.
41
Tne e x c r e t i o n o f d i s s o l v e d n it ro g e n during
n it r o g e n f i x a t i o n ........................................................... 45
Algae must be s k i l l e d in o p er at io n al c a l c u l u s - i n a b i l i t y to
i n t e g r a t e simultaneous d i f f e r e n t i a l eq u a ti o n s, one f o r each
v a r i a b l e , then s o l v i n g f o r optimal growth.
Hutner and P r o v a s o l i , 1964
xi
INTRODUCTION
Statement o f the problem
The bi og eo c he mi c al
c y c l e s o f c e r t a i n elements are i n t i m a t e l y
i n v o l v e d i n c o n t r o l l i n g the p o t e n t i a l b i o l o g i c a l
an environment.
p ro d u ctiv ity of
These elements e i t h e r are r e q u i r e d d i r e c t l y as
m aj or n u t r i e n t s o r as q u a n t i t a t i v e l y mi no r components o f v i t a m i n s
o r enzymes.
and i t s
N i t r o g e n p r i m a r i l y b e lo ng s
complex c y c l e p l a y s
A lake i s
own i n t e r n a l
a role of great ecological
i mportance.
a d i s c r e t e e c o l o g i c a l system i n t h a t i t e x h i b i t s
its
c y c l e s , which a r e , however, a f f e c t e d by the i n f l u e n t s
and to some e x t e n t by the e f f l u e n t s .
ecological
to the former c a t e g o r y ,
T h i s concept o f a l a k e as an
e n t i t y was f i r s t i n t r o d u c e d by Forbes
( 1925).
In the
p a s t , a l a r g e number o f measurements have been made o f the abundance
o f v a r i o u s compounds o f n i t r o g e n i n lake w a t e r , s i n c e i t was assumed
t h a t such i n f o r m a t i o n gave a good i dea o f the amount o f n u t r i e n t
a v a i l a b l e , and t h e r e f o r e o f the f e r t i l i t y
o f the water.
The c u r r e n t
i n t e r e s t i n n u t r i e n t c y c l e s developed p a r t l y i n res pon se t o the
r e a liz a tio n that th is
assumpti on i s
concentration o f a n u t r ie n t i s
not v a l i d , and t h a t the s t a n d i n g
i n many cases l e s s
i m p o r t a n t than i t s
r a t e o f r e p l e n i s h m e n t by a d v e c t i o n and r e g e n e r a t i o n .
Furthermore,
the c o n c e n t r a t i o n o f a n u t r i e n t i n the wate r may have an i n v e r s e
r e l a t i o n s h i p with production, s in c e a high concentration i s
unlikely
to p e r s i s t when the s u b s t a n c e i s b e i n g removed r a p i d l y , b u t may
accumulate when i t i s not.
There i s evi d enc e, which l a r g e l y comes
1
2
from work on the o ceans , t h a t the r a t e o f r e g e n e r a t i o n i n s i t u
in
the w at e r column i s much more i m p or t an t than had p r e v i o u s l y been
c o n s i d e r e d (Ketchum,
th ere i s
Ryt he r, Y e nt sc h , and Corwin, 1958).
Since
no reason t o b e l i e v e t h a t marine and l a c u s t r i n e p r oc e s se s
are f u n d a m e n t a l l y d i f f e r e n t ,
t h i s may be e q u a l l y t r ue o f f r e s h water.
Al t ho ug h s t a n d i n g c o n c e n t r a t i o n s
al one cannot g i v e an under­
s t a n d i n g o f the a v a i l a b i l i t y o f a n u t r i e n t which undergoes a c y c l e
i n t r a n s p o r t , measurements o f the a c t u a l
r a t e s o f u t i l i z a t i o n can
do s o , because a r a t e o f u t i l i z a t i o n i m p l i e s a minimum r a t e o f s u p p l y .
Th i s d i s s e r t a t i o n i s
relationships
the r e s u l t o f an attempt to i n v e s t i g a t e the
between the u t i l i z a t i o n o f i n o r g a n i c n i t r o g e n s o u r ce s
and pri mary p r o d u c t i v i t y ,
and a t the same time t o o b t a i n i n s i g h t
i n t o the r o l e o f the i n t e r n a l
The p o p u l a t i o n s
n i t r o g e n c y c l e o f a l ake .
i n a wate r body are not s t a t i c t h r o u gh ou t a
y e a r , but tend to demonstrate s e a s o n a l
from y e a r to y e a r .
T h i s annual
changes which may be repeated
r e p e t i t i o n i s o n l y found where the
l ak e as a whole i s not c ha ng i ng s i g n i f i c a n t l y from one y e a r t o the
next.
These changes are b e l i e v e d to be i n r es p on s e t o p h y s i c a l
chemical f a c t o r s i n the w at e r and t o a l t e r a t i o n s
the o r ga ni s m s p r es e n t .
and
i n these f a c t o r s by
There are a v a i l a b l e i n the l i t e r a t u r e e x c e l l e n t
and d e t a i l e d d e s c r i p t i o n s o f s t u d i e s o f such changes i n terms o f the
co m po s i t i o n o f the p o p u l a t i o n s and the abundance o f the c o n s t i t u e n t
o r ga ni s ms
(Utermohl, 1925; S i I v e y and Roach, 1964; Prowse and T a i l i n g ,
1957; Hartman and G r a f f i u s ,
1960).
These changes i n p o p u l a t i o n
c o m p o s i t i o n are accompanied by f l u c t u a t i o n s i n the p r i m ar y p r o d u c t i v i t y
rates
i n the l a ke ( V e r d u i n ,
1960); in t u r n , p r o b a b l y , they are accompanied
3
by v a r i a t i o n s
i n the p a t t e r n s o f u t i l i z a t i o n and r e g e n e r a t i o n o f
n i t r o g e n compounds i n the water.
The i n t e r a c t i o n s r e s u l t i n g i n net p r o d u c t i o n are h i g h l y complex,
but u l t i m a t e l y a l g a e and b a c t e r i a i n t e r a c t in p r o d uc i ng f l u c t u a t i o n s
i n p r o d u c t i v i t y , which may r e s u l t in e f f i c i e n t u t i l i z a t i o n o f the
i n o r g a n i c re so u rc e s a v a i l a b l e .
In o r d er t o o b t a i n a r e a s o n a b l e
p i c t u r e o f the n u t r i e n t regime o f a l a k e , the s t u d y must be c a r r i e d
out t h ro ugh ou t a c o n s i d e r a b l e span o f time.
T h i s has been attempted.
A b i l i t y o f p h y t o pl a n kt o n to a s s i m i l a t e
v a r i o u s compounds o f i n o r g a n i c n i t r o g e n
The work d i s c u s s e d here w i l l
deal w i t h the r e l a t i o n s h i p between
the u t i l i z a t i o n o f n i t r o g e n and p ri mary p r o d u c t i v i t y .
The experi ment al
te chn iq ue s employed i n t h i s s t u d y d e r i v e from the c o n s i d e r a b l e i n f o r m a ­
t i o n a v a i l a b l e from l a b o r a t o r y s t u d i e s on the a b i l i t y o f a l g a e t o use
v a r i o u s s ou rc es o f n i t r o g e n .
A l g a e a r e , o f c o u r s e , the most i m p or t an t
a gents o f pri mary p r o d u c t i v i t y , both i n terms o f bi omass and i n t h e i r
c o n t r i b u t i o n o f p h o t o s y n t h e t i c a l l y reduced carbon i n p e l a g i c water.
Nitrogen f i x a t i o n .
M olecular nitrogen represents a v i r t u a l l y
i n e x h a u s t i b l e r e s e r v o i r f o r th os e o rgani s ms c a p a b l e o f c a r r y i n g out
its
r e d u c t i o n to ammonia and thus o f u s i n g i t as a n i t r o g e n source.
Nitrogen i s
one o f the maj or g a s e s i n the atmosphere, occup yi ng
78t 0.004 p e r c e n t o f i t s
volume ( B ye r , 1959).
The b i o l o g i c a l
p r oc e s s
o f u s i n g m o l e c u l a r n i t r o g e n i s termed n i t r o g e n f i x a t i o n , and c o n s i s t s
o f an energy-cons uming s e r i e s o f r e a c t i o n s .
I n a few organi sms the
p r o c e s s e s o f n i t r o g e n f i x a t i o n and p h o t o s y n t h e s i s are c l o s e l y coupled
s o th at the energy trapped by the p h o t o s y n t h e t i c apparatus i s a l s o
used d i r e c t l y or i n d i r e c t l y f o r the redu cti on o f m ol e cu la r n it ro ge n.
The two groups demonstrating t h i s r e l a t i o n s h i p are the p h o to sy n th e ti c
b a c t e r i a and the blu e-g ree n algae.
Both groups are found in lake
wate rs , but the b lu e- g re en alga e are more l i k e l y to make a s i g n i f i c a n t
c o n t r i b u t i o n to the ni t ro ge n economy o f the water.
P ho to sy n th e t ic
b a c t e r i a appear to occu r most abundantly i n environments where f i x e d
ni t r o g e n compounds are p r e se n t, and under these c o n d i t i o n s b a c t e r i a l
n i t r o g e n f i x a t i o n i s b e li e v e d to be suppressed.
Fogg (1956) t h er e­
f o r e b e l i e v e s t h a t although these b a c t e r i a may have had g r e a t import­
ance e a r l y i n the h i s t o r y o f the ea rth , t h e i r n i t r o g e n f i x i n g a b i l i t y
remains as a f a c u l t a t i v e but not often important r e l i c t .
A consider­
able amount o f in f o rm a t i o n i s now a v a i l a b l e on the p h y s i o l o g y and
mineral n u t r i t i o n o f n it r o g e n f i x i n g blu e-g ree n al ga e or Myxophyceae.
Molybdenum i s s p e c i f i c a l l y r eq u ire d in h ig h e r amounts f o r n it ro ge n
f i x a t i o n than f o r the r e du c ti on of n i t r a t e , although i t i s r eq u ire d
a l s o f o r the l a t t e r r e a c t i o n (Wolfe, 1954); pr es en t in fo rm at io n
i n d i c a t e s that ammonia a s s i m i l a t i o n i s independent o f molybdenum
co n c e nt r a ti o n.
I ro n and boron are a l s o re q u ir e d s p e c i f i c a l l y f o r
nitrogen fix a t io n .
Va rio us ot he r m i n e r a l s , i n c l u d i n g calcium,
sodium and c o b a l t , are r e qu ire d by n i t r o g e n - f i x i n g Myxophyceae f o r
general growth.
Among the requirements f o r n it r o g e n f i x i n g a c t i v i t y ,
Webster (1959) i n c l u d e s the need f o r a vi g o ro u s m et ab ol ic rate .
In
p h o t o s y n t h e t i c n it r o g e n f i x a t i o n t h i s im p li e s a high r ate o f photo­
s y n t h e s i s , s i n c e the energy f o r the f i x a t i o n proce ss i s de ri ve d from
the p h o t o s y n t h e t i c process
(Fogg and Than-Thun, 1960).
A high r ate
o f photosynthesis a ls o implies
n u t r i e n t s from the water.
a h i g h r a t e o f removal o f e s s e n t i a l
A s t e a d y s u p p l y o f phosphorus and t r a c e
met als s h o u l d be r e q u i r e d f o r s u s t a i n e d h ig h n i t r o g e n f i x a t i o n r a t e s .
The p h y s i o l o g y and e c o l o g y o f p h o t o s y n t h e s i c n i t r o g e n f i x a t i o n
by b l u e - g r e e n a l g a e has been d i s c u s s e d by A l l e n
detail
by Fogg (1956).
emphasizes b io c he mi c al
Ammonia.
( 19 5 6) , and a l s o in
A more rec ent review by Yocum (1960)
aspects of nitrogen f i x a t i o n .
Ammonia i s
r e a d i l y used by a l g a e , and p r o v i d e s the
opt imal s o u r c e from an e n e r g e t i c p o i n t o f view, s i n c e a l l
compounds are b r o u g h t t o the r e d u c t i o n l e v e l
nitrogen
o f ammonia b e f o r e a s s i m i
l a t i o n i n t o the m e t a b o l i c pathways o f the o rgani sm.
In c u l t u r e media
however, the u n f a v o r a b l e pH changes which accompany growth and the
c onco mi t ant removal o f ammonia from the medium f r e q u e n t l y p r ec l u de
its
use.
There i s
no evi de nce t h a t any a l g a e are unable t o use
ammonia i n a n a t u r a l s i t u a t i o n .
In the n i t r o g e n c y c l e , ammonia i s
c o n s i d e r e d an i n t e r m e d i a t e , s i n c e , a lt h o u g h i t i s
breakdown o f n i t r o g e n o u s o r g a n i c m a t e r i a l
by a n i m a l s , i t
Nitrate is
process.
is
r e l e a s e d upon the
and ex cr e te d i n a d d i t i o n
i n tu r n o x i d i z e d through n i t r i t e t o n i t r a t e .
t h e r e f o r e the more s t a b l e e n d - pr o d uc t o f the r e g e n e r a t i o n
This o xida tion process i s
c a r r i e d out i n s o i l
called n i t r i f i c a t io n ,
and i s
and f r e s h w at e r by b a c t e r i a b e l o n g i n g to
the genus N itrosomonas and the second s t e p to n i t r a t e by N i t r o b a c t e r
spp.
N itrite,
an i n t e r m e d i a t e s t e p i n t h i s p r o c e s s , very seldom
accumulates t o any s i g n i f i c a n t l e v e l s
in w a te r , and a lt h o u g h a l g a e
are a b l e to use i t as a n i t r o g e n s o u r c e , i t i s
abundant to be i mp or t ant .
seldom s u f f i c i e n t l y
Under p o l l u t e d c o n d i t i o n s , where l a r g e
6
amounts o f n i t r i t e may o c c u r , two f a c t o r s
is
that n i t r i t e
that i t w i l l
are o f importance.
One
i s t o x i c under c o n d i t i o n s o f h i g h c o n c e n t r a t i o n , s o
not be used.
S e c o n d l y , the o x i d a t i o n o f n i t r i t e
n i t r a t e i s prevented by a h ig h i n i t i a l
t h a t the h ig h c o n c e n t r a t i o n w i l l
(Aleem and A le xe nder ,
1960).
to
c o n c e n t r a t i o n o f n i t r i t e , so
tend to remain s t a t i c o r i n c r e a s e
In c o n t r a s t , n i t r a t e i s
o f t en p r e s e n t
i n s u f f i c i e n t l y l a r g e amounts t o be s i g n i f i c a n t .
Nitrate.
M os t a l g a e are b e l i e v e d t o be c a p a b l e o f u s i n g n i t r a t e
as a n i t r o g e n s ou rce.
The r e d u c t i o n o f n i t r a t e t o n i t r i t e i s
c a t a l y z e d by an enzyme termed n i t r a t e r e d u c t a s e , which i s
f l a v o p r o t e i n w i th molybdenum as the metal
constituent.
a metallo-
Nitrite
r ed u c t a s e then c a t a l y z e s the s ub se quent r e d u c t i o n o f n i t r i t e to
ammonia; here the metal
N i c h o l a s et a l . ,
components are i r o n and copper.
Recently
(1962) have i m p l i c a t e d c o b a l t i n n i t r a t e r e d u c t i o n ,
a l t h o u g h t h i s work was not done wi th a l g a e , but r a t h e r wi th Rhizobiurn.
Light is be neficial
to n i t r a t e r e d u c t i o n i n green p l a n t s , a l t h o u g h some
a l g a e are c ap ab le o f c a r r y i n g o ut the p ro c es s i n the dark.
reduction i s
f r e q u e n t l y coupl ed t o r e s p i r a t i o n .
Nitrite
K e s s l e r (1964) has
d i s c u s s e d the a s s i m i l a t i o n o f n i t r a t e by p l a n t s , m a i n l y from the
b i o c h e m i c a l p o i n t o f view.
I n a d d i t i o n t o the th ree s o u r c e s o f n i t r o g e n a l r e a d y mentioned
above, s e v e r a l o r g a n i c compounds may s e r v e as n i t r o g e n s o u r c e s f o r
algae.
Urea, u r i c a c i d and x a n t h i n e are o f t e n u s e f u l s o u r ce s
a c c o r d i n g to H utner and P r o v a s o l i
(1964).
However, t h i s a b i l i t y to
use o r g a n i c s o u r c e s i s very v a r i a b l e between d i f f e r e n t genera and
even between d i f f e r e n t s p e c i e s o f a l g a e , and w i th o n l y the p r e s e n t l y
7
a v a i l a b l e i n f o r m a t i o n i t i s d i f f i c u l t to e v a l u a t e i t s
significance.
possible
In t h i s r e s e a r c h , t h e r e f o r e , o n l y the th r ee mi nor
s o u r c e s d i s c u s s e d above were used.
P r e v i o u s work on n i t r o g e n i n the
e c o l o g y o f l a c u s t r i n e environments
Nitrogen f i x a t i o n .
B l u e - g r e e n a l g a e are w i d e l y d i s t r i b u t e d
and i n c l u d e s p e c i e s cap ab le o f s u r v i v i n g under r a t h e r extreme
environmental
conditions.
A c c o r d i n g to Hutner and P r o v a s o l i
( 19 6 4 ) ,
workers have found t h a t many b l u e - g r e e n a l g a e were a b l e to grow a f t e r
s t o r a g e f o r e i g h t to ni ne weeks a t -15°C.
They are a l s o h i g h l y
r e s i s t a n t to d e s i c c a t i o n , and t h e i r o ccurr ence in h ot s p r i n g s
at
temperatures a pp roac hi ng the upper l i m i t f o r l i v i n g s ystems completes
a p i c t u r e o f extreme v e r s a t i l i t y f o r t h i s group.
The p res ence o f
blooms o f Anabaena i n l a k e s has s u g g e s t e d t h a t t h es e a l g a e may
c o n t r i b u t e s u b s t a n t i a l l y to the n i t r o g e n budget o f l a k e s by f i x i n g
molecular nitrogen.
Hu tc h in so n (1957) made t h i s s u g g e s t i o n i n
c o n ne ct i o n wi th the Anabaena bloom in L i n s l e y Pond.
finds
Guseva (1941)
t h a t n i t r o g e n - f i x i n g Anabaena are i m p o r t a n t i n the b i o l o g y o f
the Ucha R e s e r v o i r .
In C r a t e r Lake, Oregon, a bloom o f Anabaena
has been s u g g e s t e d r e s p o n s i b l e f o r the n i t r o g e n s u p p l y o f the lake
( U t t e r b a c k , P h i f e r , and Ro bi ns on, 1947); the phosphate t o n i t r o g e n
r a t i o appears t o be very h ig h i n t h i s
l a ke .
Prowse and T a i l i n g
(1957) a t t r i b u t e t o n i t r o g e n f i x a t i o n by Anabaena a maj or r o l e in
d e t e r m i n i n g the s e a s o n a l s u c c e s s i o n o f a l g a e in a r e s e r v o i r on the
White N i l e .
Here, a bloom o f Anabaena d u r i n g a p e r i o d o f low n i t r o g e n
c o n te n t was f o l l o w e d by a l g a e which were a p p a r e n t l y u s i n g n i t r a t e .
I f t h i s were s o ,
i t would i n d i c a t e t h a t the n i t r o g e n f i x e d by the
a l g a e became a v a i l a b l e r a p i d l y a f t e r i t s
o f the c e l l s .
r e l e a s e f o l l o w i n g the death
In none o f t h es e cases was th ere any d i r e c t evi dence
t o s u p p o r t the n i t r o g e n f i x a t i o n theory.
I n d i r e c t l y , however, the
evi dence s t r o n g l y s up po rt ed the c o n c l u s i o n , s i n c e i n each case a
l a r g e number o f organi sms wi th a h i g h n i t r o g e n c o n te n t grew w i t h o u t
any ap parent s u p p l y o f n i t r o g e n .
D i r e c t experi ments to t r y to measure n i t r o g e n f i x a t i o n were
c a r r i e d out by Sawyer et a l . ( 19 4 1 ) ; he i n cu b a t e d l a k e water f o r
long p e r i o d s o f time and measured the i n c r e a s e i n n i t r o g e n by the
K j e l d a h l method.
Dug dale, Dug dal e, Neess and G oe r i n g (1959) made
p r e l i m i n a r y attempts to measure n i t r o g e n f i x a t i o n i n l a k e s by
measuri ng the i n c o r p o r a t i o n o f
l a b e l l e d n i t r o g e n g a s i n t o the
p a r t i c u l a t e f r a c t i o n i n samples o f lake water.
Subsequently stu d ie s
were c a r r i e d o ut u s i n g the same t e c h n i q u e , which showed t h a t n i t r o g e n
fixation
can be a major s o u r c e o f n i t r o g e n to the p h y t o p l a n k t o n i n an
e u t r o p h i c l a k e when b l u e - g r e e n a l g a e o f the genus Anabaena are dominant
( Du gd a le and Dug dal e, 1962).
in several
la ke s
A s tud y o f the r a t e s o f n i t r o g e n f i x a t i o n
in the v i c i n i t y o f M a d i s o n , W i s c o n s i n showed c o n s i d e r a b l y
v a r y i n g r o l e s f o r the p r o c e s s among l a k e s i n a r e s t r i c t e d g e o g r a p h i c a l
area ( G o e r i n g 1962, 1964).
In a l l
these s t u d i e s the b e h a v i o r o f the
p r o c e s s i n r e l a t i o n to l i g h t s t r o n g l y i n d i c a t e d t h a t p h o t o s y n t h e t i c
p r o c e s s e s were r e s p o n s i b l e f o r the n i t r o g e n f i x a t i o n e i t h e r d i r e c t l y
or i n d i r e c t l y .
I n each case when h i g h r a t e s o f n i t r o g e n f i x a t i o n were
measured, b l u e - g r e e n a l g a e were p r e s e n t in l a r g e numbers.
Fogg ( 19 5 6) ,
9
in h is
review d e a l i n g w i th n i t r o g e n f i x a t i o n by p h o t o s y n t h e t i c
o r g a n i s m s , mentions the p o s s i b i l i t y o f a major r o l e i n the n i t r o g e n
economy o f e u t r o p h i c la ke s f o r n i t r o g e n f i x a t i o n by b l u e - g r e e n a l g a e ,
but q u a l i f i e s
t h i s by addi ng t h a t many o f the bl oo m- for mi ng s p e c i e s
do not f i x n i t r o g e n .
Some s p e c i e s o f Anabaena have been t e s t e d i n
pure c u l t u r e and found t o f i x
n i t r o g e n , a l t ho ug h not many o f the
components o f the blooms d i s c u s s e d above have as y e t been i s o l a t e d
i n b a c t e r i o l o g i c a l l y pure c u l t u r e s .
As e a r l y as 1938, F r i t s c h
i n the f e r t i l i t y
and De, 1938).
(De, 1939).
and De r ec o g n i z e d the r o l e o f Nos toe
of rice fie ld s
as a n i t r o g e n f i x i n g a g ent ( F r i t s c h
De a l s o r e c o g n i z e d a s i m i l a r r o l e f o r Anabaena
Nos toe i s
also responsible fo r f ix in g
n i t r o g e n in
tu ndra ponds i n Northern A l a s k a ( Dugdale and T o e t z , 1961), whereas
i n the K odi a k, A l a s k a r e g i o n ,
a lake e x h ib i t i n g high rates of
n i t r o g e n f i x a t i o n had a l a r g e p o p u l a t i o n o f Anabaena f l o s - a q u a e
(R.
C.
Dug dale, p er s on a l
communicati on).
It is
apparent, th erefore,
t h a t s i g n i f i c a n t n i t r o g e n f i x a t i o n o ccurs i n wa te r s r a n g i n g from
tropical
t o the a r c t i c .
The h a r d i n e s s o f the b l u e - g r e e n a l g a e
does r e s u l t i n a wide g e o g r a p h i c a l
distribution.
Ammonia and n i t r a t e u t i l i z a t i o n .
A l a r g e p a r t o f the i n f o r m a ­
t i o n on n i t r o g e n u t i l i z a t i o n stems from an i n t e r e s t i n i t s
a lim itin g factor.
r o l e as
N i t r o g e n , i n combined form, i s o f t e n p r e s e n t i n
s u f f i c i e n t l y low amounts so t h a t the r a t e o f p h o t o s y n t h e s i s i s
d i r e c t l y c o n t r o l l e d by i t s
availability.
G e r l o f f and Skoog (1957)
have s t u d i e d the r o l e o f n i t r o g e n from t h i s p o i n t o f vi ew, u s i n g
10
a combination of l a b o r a t o r y and f i e l d methods.
from l a b o r a t o r y work that the c e l l
They e s t a b l i s h e d
n it ro ge n content o f algae could
be used as an index of the adequancy o f the combined n it r o g e n su p pl y
in the medium, and then used t h i s in fo rm a t io n in i d e n t i f y i n g i n s t a n c e s
o f n i t r o g e n l i m i t a t i o n in the f i e l d .
Hutchinson (1 94 1), found,
however,that even where a s i n g l e n u t r i e n t appeared to be l i m i t i n g
in L i n s l e y Pond, the s i t u a t i o n was not t h a t simple.
The a d d i t i o n
o f n it ro g e n and phosphorus to ge th e r in an enrichment experiment
in c r e a se d the growth r a te c o n s i d e r a b l y more than the a d d i t i o n o f
e i t h e r o f these n u t r i e n t s alon e, even though each had a s t i m u l a t i n g
e f f e c t a l s o by i t s e l f .
Goldman (1960) a t t r i b u t e s the c l i n e in
p r o d u c t i v i t y a c r o s s Brooks Lake, A la s k a to h i g h e r n i t r a t e l e v e l s
at one end than at the other.
U n fo r tu n a te ly he did not measure
n i t r a t e l e v e l s in the water in connection with t h i s work; such
measurements would have helped to confirm the h y p o t h e s i s .
Goldman's
work on C a s t l e Lake (1960) s i m i l a r l y i n d i c a t e s at l e a s t a p a r t i a l l y
l i m i t i n g r o l e f o r n i t ro g e n .
There would seem to be d i f f i c u l t i e s
in h e r e n t i n assuming th at one f a c t o r i s a c t u a l l y s o l e l y r e s p o n s i b l e
f o r c o n t r o l l i n g the rate o f p h o t o s y n t h e s i s .
A l a r g e number of
f a c t o r s , perhaps v a r i a b l y weighted in importance, would seem to be
responsible.
In the case o f n i t r o g e n , there sh o u ld never be any
l i m i t a t i o n when s u i t a b l e c o n d i t i o n s f o r n it ro g e n f i x a t i o n e x i s t .
At p r e se n t the c o n d i t i o n s f a v o u r i n g n i t ro ge n f i x a t i o n in nat ural
waters are not known.
Trace metals are probab ly important in a d d i t i o n
to c h e l a t o r s which would make these metals as well as phorphorus
readily available.
Additional
components o f the n i t r o g e n c y c l e
to be c o n s i d e r e d i n t h i s s tu d y
The p r o c e ss o f the r e g e n e r a t i o n o f i n o r g a n i c forms o f n i t r o g e n ,
ultim ately n itra te ,
from o r g a n i c m a t e r i a l was d i s c u s s e d b r i e f l y above
i n co n ne ct i on wi th the s u p p l y o f v a r i o u s forms o f n i t r o g e n a v a i l a b l e
to a l g a e .
The f a t e o f the n i t r a t e produced v a r i e s , and i t may under
some c i r c u m s t a n c e s be c o m p l et e l y l o s t to the b i o l o g i c a l
the p r o c e s s o f d e n i t r i f i c a t i o n .
of respiration,
a c c e p t o r , and i s
This b a c te r ia l
system by
process i s
a form
in which n i t r a t e s e r v e s as the u l t i m a t e hydrogen
reduced to n i t r o g e n g a s o r t o N2 O.
T h i s ta kes p l a c e
o n l y under a n o x i c c o n d i t i o n s , where the oxygen c o n t e n t i s below
0.1 m l / l i t e r (Koyama, p e r s o n a l
communication, R. C. D ug d a l e ) .
some c o n d i t i o n s the n i t r a t e i s
reduced o nl y to n i t r i t e ,
not c l e a r whether t h i s
ammonia.
type o f p r o c e s s ever r e s u l t s
Under
but i t i s
in r e d u c t i o n to
T h i s type o f r e d u c t i o n i s sometimes termed ' d i s s i m i l a t o r y '
i n c o n t r a s t t o a s s i m i l a t o r y p r o c e s s e s in which the n i t r a t e i s
and then used f o r b i o s y n t h e t i c p urp os es .
reduced
D e n itr ific a tio n results
l o s s o f n i t r o g e n to the b i o s p h e r e , and thus a c t s
in
i n an o p p o s i n g manner
to nitrogen f i x a t i o n .
A s o u r ce o f n i t r o g e n which has been i g n o r e d i n the above d i s c u s s i o n
is
the n i t r o g e n co n te n t o f the i n f l u e n t s .
The magni tude o f t h i s s u p p l y
can be e a s i l y e s t i m a t e d from the volume o f i n f l u e n t wate r and i t s
nitrogen concentration.
o f combined n i t r o g e n .
Rainfall w ill
a l s o b r i n g i n a s ma ll
Both o f these s ou r ce s w i l l
amount
be l a r g e l y i g n o r e d
12
h er e, s i n c e no attempt i s b ei ng
made to draw up any complete n i t r o g e n
budget f o r the l a k e , but r a t h e r
to s tud y one a s p e c t o f t h i s budget
the b i o l o g i c a l
utilization
o f n i t r o g e n compounds.
in
The nat ur e o f the
experi ments a l l o w s the e s t i m a t i o n o f uptake r a t e s w h i l e i g n o r i n g the
e f f e c t s o f a d v e c t i o n , s i n c e the samples are e n c l o s e d i n b o t t l e s
thus i s o l a t e d f o r the d u r a t i o n o f the experiment.
Overall
and
nitrogen
budget s t u d i e s have been made, as i n the s t u d y o f the n i t r o g e n budget
o f Lake Mendota ( R o h l i c h and Lea, 1949).
been s t u d i e d .
Ryt he r and G u i l l a r d
know v er y l i t t l e
c y c l e has not
(1959) have p o i n t e d out t h a t we
about the r a t e s o f r e g e n e r a t i o n in s i t u
s u r f a c e waters o f the sea.
equal
The i n t e r n a l
The
v a l i d i t y to our knowledge
same s ta t e m e n t can be a p p l i e d wi th
of lakes.
Experi mental
approach
The s t a b l e i s o t o p e o f n i t r o g e n ,
uptake f o r t h i s work.
i n the
15
N was used t o measure n i t r o g e n
P r e v i o u s l y "*^N was used f o r measuri ng r a t e s o f
n i t r o g e n f i x a t i o n by Neess et a l . ,
( 19 6 2 ) , and s u b s e q u e n t l y the
t e chn iq ue was extended to i n c l u d e measurements o f the uptake r a t e s
o f n i t r a t e and ammonia by Dugdale and Dugdale ( 1965) .
The use o f
i s o t o p e t echn ique s i n t h i s s t u d y was n e c e s s a r y i n o r de r to a t t a i n
s u f f i c i e n t l y h i g h s e n s i t i v i t y u s i n g s h o r t i n c u b a t i o n ti mes .
way an approach to meas uri ng an i n s t a n t a n e o u s
In th i s
r a t e can be made.
A
r a d i o a c t i v e i s o t o p e o f n i t r o g e n havi ng a s u f f i c i e n t l y l ong h a l f - l i f e
f o r f i e l d use i s no t a v a i l a b l e .
work on b a c t e r i a l
13
N has been used in p h y s i o l o g i c a l
n i t r o g e n f i x a t i o n , but i t s
i n a l a b o r a t o r y w i th the f a c i l i t i e s
use i s
only p r a c t ic a l
f o r p r o d uc i ng the i s o t o p e
(Nicholas
et a l . , 1961).
Measurements of the rate s of u t i l i z a t i o n of mole cu lar n i t r o g e n ,
ammonia and n i t r a t e were made p e r i o d i c a l l y in the lake du ring two
y e a r s.
S im u l t a n e o u s l y , primary p r o d u c t i v i t y was measured, usi ng the
14C method o f Steemann N ie ls e n (1952).
as an index o f p l a n t biomass.
C hl o r o p h y ll
a^ was used
P a r t i c u l a t e n it ro g e n was used in
a s i m i l a r way and a l s o was a necess ar y parameter f o r c a l c u l a t i o n s
o f the ab so lu te rates o f n i t ro g e n uptake.
Determinations were made
o f the n i t r a t e , n i t r i t e and ammonia content o f the water f o r each
experiment.
A na ly se s f o r phosphorus content were a l s o included.
The i nf o rm at io n obtain ed by the procedures d e sc r ib e d sho ul d
s u f f i c e f o r the purposes o f t h i s stud y.
However, r o u t i n e l i m n o l o g i c a l
o b s e r v a t i o n s were made in a d d i t i o n , so that a more complete i n t e r p r e ­
t a t i o n o f the environmental
be made.
These w i l l
i n f l u e n c e s on the n i t r o g e n regime could
be d e sc r ib e d below.
The lake
The lake s e l e c t e d f o r t h i s work i s small with a s u r f a c e area
o f about 30 a cr es , and i s loca te d on land b e lo ng in g to the U n i v e r s i t y
of Al a sk a .
The s u r r o u n d in g land i s
l a r g e l y a w i l d l i f e study area,
and t h e re f o re i s not used e x t e n s i v e l y f o r r e c r e a t i o n a l
the p u b l i c .
purposes by
Some areas o f the watershed are under c u l t i v a t i o n , and
i t i s p o s s i b l e th a t f e r t i l i z a t i o n o f these lands may a f f e c t the n u t r i e n t
content o f the lake du rin g the time o f y e a r when there i s co n s id e r a b le
ru no f f.
Smith Lake has a maximum depth o f three meters and an estimated
mean depth o f two meters.
However, the depth undergoes f l u c t u a t i o n s
F
14
s e a s o n a l l y , with a c o n s id e r a b l e l o s s o f water due to evap ora tio n
du rin g the summer.
The lake occupies a d e p r es si on in a re gi o n o f
spru ce , white b i r c h , aspen and a l d e r f o r e s t which i s dry during the
summer, but i s e s s e n t i a l l y a marsh du ring the s p r i n g thaw period.
There i s no permanent i n l e t , but du rin g the s p r i n g thaw much of
the incoming drain age water enters through two d i s t i n c t streams.
There i s a s i n g l e o u t l e t , a l s o f u n c t i o n a l on ly du rin g the Sp rin g.
During the summer, r a i n f a l l
pr ov id e s the on ly s i g n i f i c a n t source of
incoming water.
During the e a r l y part o f the season there i s very l i t t l e
ve ge ta ti o n.
rooted
In l a t e summer, the rooted and submerged sho re v e g e ta ti o n
assumes an i n c r e a s i n g r e l a t i v e importance.
The lake water shows a s t r o n g brown c o l o r which i s often c h a r a c t e r ­
i s t i c o f a r c t i c and s u b a r c t i c la k e s.
This ma ter ial appears to be
s i m i l a r to tha t d e sc r ib ed by S h a p ir o (1964).
I t i s very s t a b l e , not
r e a d i l y p r e c i p i t a t e d and i t absorbs s t r o n g l y in the s h o r t e r wave l e n g t h s ,
showing no peak, but on ly e nd -a b so r pt io n.
d i r e c t l y r e l a t e d to pH.
The i n t e n s i t y o f c o l o r i s
T h i n - f i l m chromatography o f t h i s material
r e s u l t e d i n a s e p a r a t i o n whereby a y e l l o w component separated and
moved ahead o f the ot he r components on the chromatogam.
F i g u r e 1 i s a sim ple o u t l i n e map o f Smith Lake which shows the
p o s i t i o n o f the buoy which was used f o r in c u b a t i n g samples and a l s o
as the major sampling s i t e .
•*
ACCESS
ROAD
SMITH LAKE
METHODS
N it r o g e n - 1 5 t r a c e r methods
The method f o r measuring the ra tes of n it r o g e n f i x a t i o n in
water samples i s
a simple a p p l i c a t i o n of the t r a c e r method used
f o r p r o t e i n metabolism s t u d i e s by Ri tt enb er g et a l . (1939) and
ap p l i e d to s t u d i e s o f b i o l o g i c a l
M iller
(1941).
n it r o g e n f i x a t i o n by B u r r i s and
The m o d i f i c a t i o n f o r lake water work has been
de s c r i b e d in d e t a i l by Neess et a l ., (1962).
A re p rin t of this
paper, which i n c l u d e s d e t a i l s o f the techniques and o f the s p e c i a l
gl a s s w a r e re q u ir e d , i s attached f o r reference (Appendix A).
are not repeated here.
Details
In b r i e f , the proce ss i n v o l v e s removing the
n i t r o g e n gas pr e s e n t from an enclo sed water sample by f l u s h i n g at
reduced p r e s s u r e with a helium-oxygen mixture ( 8 0 : 2 0 ) , and then
r e p l a c i n g the removed gas with n it ro ge n c o n t a i n i n g a known enrichment
of ^ N .
A f t e r i n c u b at io n f o r a p r e s c r ib e d pe ri o d o f time, the
p a r t i c u l a t e f r a c t i o n i s recovered and analyzed by mass spectrometry
f o r enrichment in
15
N.
The procedure f o r measuring the uptake r at es o f ammonia and
n i t r a t e i s based on a s i m i l a r p r i n c i p l e .
I t i s ne ce ss ar y to add
la b e l e d KN03 o r NH^Cl to the water sample, inc ub ate , and then i s o l a t e
the p a r t i c u l a t e f r a c t i o n and analyze i t f o r 15N content.
Ordinary
one l i t e r Pyrex reagent b o t t l e s are used f o r these experiments.
The
is o t o p e s o l u t i o n s are prepared in bu lk and di sp ens ed i n t o ampoules,
with each ampoule no rmally c o n t a i n i n g two y g - atoms
15
1R
l3N in one ml
solution.
These ampoules are autoclaved immediately a f t e r
pr e p a ra tio n.
The amount o f la be led subs tan ce added to a lake
water sample in an experiment i s u s u a l l y c l o s e to ten percent of
the amount o f the same form of n i t ro g e n pr es en t in the volume of
lake water used.
i m p r a c t ic a l
At very low co n ce nt ra ti o n in the water, i t i s
to f o l l o w t h i s ru le .
The p o s t - i n c u b a t i o n procedure c o n s i s t s of f i l t e r i n g
water through a H u r l b u r t g l a s s
Angel
the
f i l t e r (984-H u l t r a f i l t e r ;
and C o. ) , and then d r y i n g the f i l t e r .
Reeve,
In t h i s way samples
can be s t o r e d f o r a re asonable pe rio d o f time in a d e s s i c a t o r
w it ho ut d e t e r i o r a t i o n .
The mass spectrometry was c a r r i e d out
us in g a Bendix T i m e - o f - F l i g h t mass spectrometer (Model 17-210).
The hi gh s e n s i t i v i t y o f t h i s machine i s o f g r e a t value in han dl in g
samples o f v a r i a b l e n i t r o g e n content.
The i n l e t system o f the
machine was connected v i a a l i q u i d n i t r o g e n trap to a mod ified
Coleman ni t ro ge n a n a ly z e r , so tha t by us in g the Dumas combustion
in the a n a ly z e r , the evolved n i t ro g e n was in tro duc ed d i r e c t l y i n t o
the mass spectrometer.
D e t a i l s of t h i s m o d i f i c a t i o n can be found
in Dugdale and Barsdate ( i n p r e s s ) .
The samples are ground up with
a small amount o f c u p r i c oxide , with no e f f o r t made to sep arate
out the g l a s s f i l t e r , s i n c e these f i l t e r s
have been found to
con tain only a small and c o n s i s t e n t amount o f n i t ro g e n .
The
sample i s then int rod uce d i n t o the combustion tube o f the n it ro ge n
a na ly zer .
17
I n c ub at io n procedures
During the f i r s t y e a r of the s tu d y , i n cu b at io n was g e n e r a l l y
c a r r i e d out in s i t u , with the b o t t l e s suspended in the lake from
a buoy.
During the second y e a r , a v a r i e t y of methods were employed.
I n c ub a ti on in a co n sta nt temperature room at 20°C under standard
l i g h t c o n d it io n s became the usual method, with a d d i t i o n a l
bottles
incubated in a tank on the r o o f o f the b u i l d i n g , under natural
l i g h t c o n d i t i o n s , but with r a t h e r v a r i a b l e ambient temp er atu re s.
Ni tr oge n f i x a t i o n f l a s k s were in a d d i t i o n incubated in the lake
whenever p o s s i b l e , s i n c e n i t r o g e n f i x a t i o n was found to be more
s e n s i t i v e to d i f f e r e n c e s in l i g h t and temperature than were n i t r a t e
o r ammonia uptake.
Calculations
The i s ot op e r a t i o s c a l c u l a t e d from the mass 29 and mass 28
peaks are converted in t o atom percent values ac cor di ng to the
formula:
Af = 100R
T
2 + R
where A - i s the atom percent of the p a r t i c u l a t e m at er ia l at the
i
end o f the experiment.
From t h i s the atom percent o f normal
unenriched n i t r o g e n i s sub tra ct ed .
This value i s determined from
18
iso to pe r a t i o blanks run on unenriched f i l t e r e d lake water samples.
The atom percent o f the n it ro g e n s u p p l i e d at the be gin ni ng of
the experiment must be known ir. order to c a l c u l a t e the amount of
n it r o g e n taken up.
where a l l
In the case of n it ro g e n f i x a t i o n experiments,
the unlabeled n it ro g e n i s removed, i t i s sim pl y the
enrichment in the s u p p l i e d gas.
For n i t r a t e and ammonia experiments,
the amount o f unlabeled n i t r a t e or ammonia in the water must be
inc lu de d in the c a l c u l a t i o n .
The atom percent o f the a v a i l a b l e
n it r o g e n at the be gin ni ng o f the experiment w i l l
be desig nat ed A.,-.
The amount o f n it ro g e n taken up during the experiment i s then:
Nf =
N- Af
i '
At
where Nj- i s the t o t a l p a r t i c u l a t e n it r o g e n in the sample.
This
method o f c a l c u l a t i o n i s v a l i d as long as the change in Nt du ring
the experiment i s very small.
In p r a c t i c e the change in N- during
an experiment very seldom exceeds 1%.
r a t e , the t o t a l
In order to c a l c u l a t e the
uptake i s d i v i d e d by the i n c u b a ti o n time.
P r o p o r t io n a l
uptake i s sometimes used:
Fractional
uptake =
Af
Ai
The formula f o r c a l c u l a t i n g percent uptake i s :
Percent uptake = 100
Af
i
All
these methods o f c a l c u l a t i o n w i l l be used below.
Primary p r o d u c t i v i t y measurements
1f
Primary p r o d u c t i v i t y was measured by the 1
method of
Steemar.n N i e l s e n (1952), u s i n g s i m i l a r in cu b at io n procedures
to those de scr ib ed f o r the n it ro ge n uptake experiments above.
However, in s i t u depth s e r i e s were inclu ded p e r i o d i c a l l y .
and l i g h t 125-ml b o t t l e s
Dark
were used, and the "^C was added from
a m p e r e s , with reasonable pr e c a u ti o n s to s h i e l d the b o t t l e s from
d i r e c t l i g h t when t h i s was done in the f i e l d .
tained 5
Each ampoule con­
c in one ml o f s o l u t i o n , and the a b so lu te counts per
minute per ampoule was obtained on the Tr a ce r la b s c a l e r (Model
Sc-33A with SC-10A sample h o l d e r and TGC-2 end-window Gei ge r tube)
used f o r sample counting by the BaC 03 p r e c i p i t a t i o n methods de scr ib ed
by S t r i c k l a n d and Parsons
(I960).
Follo wing in c u b a t i o n , the samples
were f i l t e r e d through an HA Mi 11ipore f i l t e r d r i e d and counted.
A
d i l u t e HC1 r i n s e was used a f t e r f i l t r a t i o n to remove any i n o r g a n i c
carbon pre c ip at e d as carbonate.
The f o l l o w i n g formula was used to
c a l c u l a t e the amount o f carbon f i x e d :
v ^
_ Fin al counts per minute ( l i g h t - d a r k )
Mg C a s s i m i l a t e d = ----------------------1:-----------------i— 2-----------Counts per minute s u p p l i e d
x 1>06 x
Where 1.06 i s the c o r r e c t i o n f o r the iso to pe e f f e c t which fa vo r s
the uptake o f ^2C, and Ca i s the t o t a l a v a i l a b l e carbon in mg per
u n i t volume in the water, c a l c u l a t e d from the a l k a l i n i t y and pH
i nf o rm at io n.
T h i s r e s u l t i s then d i v i d e d by the in c u b a t io n time
in hours to ob tai n an h o u r l y rate.
20
P a r t i c u l a t e n it r o g e n det er min ati on s
P &r t i c u i a i,e ni orogen was measureo using a ooieman ni tr o ge n
analy ze r.
A known volume of the sample was f i l t e r e d through a
g l a s s f i l t e r ( s i m i l a r to th a t used in the is o t o p e experiments),
the f i l t e r was d r i e d and then introduced i n t o the ni tro ge n a n a ly z e r
in i t s e n t i r e t y a f t e r g r i n d i n g with cuprox (Coleman grade c u p r i c
ox id e ).
Blanks were determined on se ve r al
f i l t e r s f o r each batch
o f a na ly se s and t h e i r mean value was su b tr a c te d from the i n d i v i d u a l
sample values to compensate f o r the n it ro g e n content o f the f i l t e r s .
C h l o r o p h y ll a_
The method used f o r determining c h l o r o p h y l l
the water was a conventional
as the s o l v e n t .
micropore f i I t e r ,
chlorophyll
a_ l e v e l s in
e x t r a c t i o n u si n g acetone
The sample was f i l t e r e d through a Whatman g l a s s
the f i l t e r placed in a c e n t r i f u g e tube and 5 ml
o f a 90% acetone:water mixt ure was added.
The volume of water
f i l t e r e d was g e n e r a l l y one l i t e r ; however when there was a la r ge
amount o f p a r t i c u l a t e mat er ial
to i n s u r e r a pi d f i l t r a t i o n .
added du ring f i l t r a t i o n .
pr ese nt a s m a l l e r volume was f i l t e r e d
A few drops of a MgC03 su sp e n si o n was
The c e n t r i f u g e tube was then t i g h t l y s e a le d ,
and the e x t r a c t i o n was c a r r i e d out in a r e f r i g e r a t o r in the dark f o r
at l e a s t tw e n t y- f ou r hours.
The percentage t r a n s m i s s i o n of the e x t r a c t s obtained in t h i s
way were read in a Beckman DB re cor di n g spectrophotometer.
One-
F
2i
centimeter c e l l s were used, with a 90% acetone:water mixture in
the reference c e l l .
and recorded.
Wavelengths between 750 and 450 my were scanned
In t h i s way percentage t r a n s m i s s i o n curves were
ob tained, u s u a l l y f o r three depths, with each experiment.
Tnere has been d i s c u s s i o n r e c e n t l y about the r e l a t i v e mer its
of v a r io u s ways of c a l c u l a t i n g the r e s u l t s of c h l o r o p h y l l a n a l y s e s ,
ano a l o t o f c r i t i c i s m o f the conventional procedures in the
literature.
In p a r t i c u l a r , the v a l i d i t y o f the va lu es obtained
by the Richards with Thompson (1952) equations have been questioned
(see, f o r i n s t a n c e , R i l e y ,
1963).
S t r i c k l a n d and Parsons (1963)
have r e v i s e d these equations to c o r r e c t f o r low s p e c i f i c a b so r pt io n
c o e f f i c i e n t s used in the o r i g i n a l work and to c o r r e c t f o r an
o ve r e st im a ti o n o f c h l o r o p h y l l _c.
The r e s u l t s c a l c u l a t e d by these
r e v i s e d equations do not agree with those obtained by usi ng the
formula o f Arnon (19 49), whose equation f o r t o t a l
c h l o r o p h y l l has
in turn been r e v i s e d by Bruinsma (1961).
In t h i s work, the method of c a l c u l a t i o n uses the s p e c i f i c
a b so r p t io n c o e f f i c i e n t f o r c h l o r o p h y l l
a_ given by Bruinsma ( i b i d . )
The formula obtained i s :
P . P . 65 8 x 14.8 x volume o f s o l v e n t s r a g / m e r c h l . ,
volume f i l t e r e d
The o p t i c a l d e n s i t y at 750 my i s f i r s t su b t r a c t e d from the
optical
d e s i t y at 658 my,
out as above.
and then the c a l c u l a t i o n i s c a r r i e d
The r e s u l t s obtained in t h i s way are a l i t t l e lower
than those obtained by B r u in sm a 's c a l c u l a t i o n method f o r tot al
22
chlorophyll
using the same water sample.
Although t h i s almost
c e r t a i n l y dees not g i v e an exact r e s u l t in terms of c h l o r o p h y l l
i
c o n c e n t r a t i o n , the r e s u l t s o b t a i r o d in t h i s way appear to be
c o n s i s t a n t and to r e f l e c t the changes in c h l o r o p h y l l
a_ in the
water, and inceed are probably f a i r l y cl o se to the true concen­
tration.
F ur th er refinements in c a l c u l a t i o n do not seem j u s t i f i e o
f o r the purposes of t n i s work, e s p e c i a l l y in view o f the con fu sio n
and c o n tr o v e r s y in the c u r r e n t l i t e r a t u r e .
Methods f o r the q u a n t i t a t i v e a n a l y s i s
o f n u t r i e n t s in tne water
Nit rogen compounds.
N i t r a t e was measured by a m o d i f i c a t i o n of
the Mull in and R i l e y procedure (1955) s i m i l a r to t h a t d e sc r ib ed by
S t r i c k l a n d and Parsons (1960).
In t h i s method, n i t r a t e i s reduced
to n i t r i t e by hy dr a z in e s u l f a t e in tne presence o f copper as a
c a t a l y s t , and the r e s u l t i n g n i t r i t e i s measured s p e c t r o p h o t m e t r i c a l l y
a f t e r c ou pli ng with s u l f a n i l a m i d e to form an azo dye.
precau tion proved e s s e n t i a l
An a d d i t i o n a l
f o r t h i s p a r t i c u l a r s t u d y , s i n c e the
lake water had a high but v a r i a b l e complement of an o r g a n i c material
which made copper l e s s a v a i l a b l e as a c a t a l y s t f o r the redu ctio n.
I t was necess ar y to compensate f o r t h i s by adding an ex p er im en ta lly
determined a d d i t i o n a l
amount of the metal.
Mi t r i t e was determined us in g the same method, in t h i s case
om i t ti n g the r ed u cti on step.
For both n i t r a t e and n i t r i t e de te r­
m i n a t i o n s , compensation was made f o r the v a r i a b l e water c o l o r by
u s i n': i n t e r n a l stand ar ds r a t h e r than comparing the values with a
23
d i s r i l e c water stan dar d curve.
Such stand ar ds were run f o r each
i n d i v i d u a l samp 1e , so th a t v a r i a b i l i t y from sample to sample would
not af f a c t the r e s u l t s .
A Beckman .1J spectrophotometer was used
t o r tnese o e t e r m i n a t i c n s c e < is witn a ; i g n t patn ot
iO cm Wc‘ 'fc usee as r e ^ u i r s c f o r accuracy.
\ , s or
The samples f o r tnese
c.nc,yses were in. crcpore-T i i ter ec immeG>a^e iy a f t e r co> iSCoiOn and
s t o r e c in po lye th yl e ne b o t t l e s in a f r e e z e r p r i o r to a n a l y s i s .
The samples f o r ammonia de terminations were frozen u n f i l t e r e d
in po ly e t hy le ne b o t t l e s .
No s i g n i f i c a n t changes in ammonia concentra­
tio n were found when samples were st o re d frozen f o r pe rio ds of time
up to s i x months.
Vacuum d i s t i l l a t i o n
or d i f f u s i o n methods were
used to concentrate the ammonia in the samples, with ap par ent ly good
recovery.
The a n a l y s i s f o r ammonia, which was c o l l e c t e d in .01 N HC1,
was done by the sodium phenate method of R i l e y (1953).
developed oy Richards and Kie t s ch
l a t e r in 1964.
A new method
(1964) was used f o r samples c o l l e c t e d
This method i s based on the o x i d a t i o n of ammonia to
n i t r i t e usi ng sodium h y p o c h l o r i t e in s t r o n g l y b a s i c s o l u t i o n , and the
subsequent determination of the n i t r i t e .
Phosphorus d e t e r m i n a t i o n s .
Phosphorus as d i s s o l v e d phosphate
was measured by the method de scr ib ed by Stephens
(1 96 3), in which
the molybdenum blue complex i s ex tra ct ed i n t o is o b u t a n o l .
I t was
ne ce ss ar y to use t h i s method because the brown o r g a n i c mat er ial
in
the water masked the blue c o l o r at tne wavelengths used f o r readin g,
but f o r t u n a t e l y was not e xt ra c t e d to any g r e a t ex te nt i n t o the
isobutanol,
i h i s methoc a iso has the advantage, at ;ow pnospnate
c o n c e n t r a t i o n s , o f con c e nt ra tin g the c o l o r p r i o r to r ea di n g, r e s u l t i n g
in a high s e n s i t i v i t y .
Total phosphorus was measured by con ce nt ra tin g the sample and
d i g e s t i n g vn th p e r c h l o r i c a c i d , followed by the use of the standard
phosphate procedure.
D i s s o l v e d phosphorus
( t o t a l ) was done in the
same way, but using micropore f i l t e r e d samples.
Techniques used f o r ot her an aly ses
Temperature was measured at h a lf - m e te r depth i n t e r v a l s using
a Whitney t h e r m is t o r thermometer.
L i g h t pe n e tr a ti o n de terminatio ns
a l s o employed a Whitney underwater instrument.
pH was measured in
the l a b o r a t o r y usi ng a Beckman expanded s c a l e pH meter.
Specific
c o n d u c t i v i t y was read at approximately 20°C usi ng a S e r f a s s conduct­
i v i t y bri d ge (Model RCM 15).
A l k a l i n i t y t i t r a t i o n s were c a r r i e d out u si n g .01 N HC1, and
a Beckman expanded s c a l e pH meter to determine the end -poin t.
From
t h i s in fo rm at io n and the pH, the t o t a l a v a i l a b l e carbon f o r the
uptake c a l c u l a t i o n s could be ca l cu la t e d .
Oxygen de termin atio ns used
the A l s t e r b e r g m o d i f i c a t i o n o f the Wi n k le r method, with samples f i x e d
in the f i e l d and t i t r a t e d in the lab o ra to ry .
Phytoplankton samples were preserved by adding Lugo V s
solution
d e sc r ib e d by Verduin (1960) to lake water in a p o ly et hy le ne b o t t l e .
PHYTOPLANKTON
Q u a l i t a t i v e in fo rm at ion about the dominant algae du rin g 1964
in Smith Lake i n d i c a t e s that there i s indeed a v a r i a t i o n in popula­
ti o n composition accompanying the v a r i a t i o n s in the n it r o g e n uptake
regime.
Counts were not made, and thus q u a n t i t a t i v e data are not
available.
In a d d i t i o n , any r e l a t i v e l y rare components of the algae
f l o r a would have been missed by the method used, which in vo lv e d
f i l t e r i n g a small a l i q u o t o f lake water, prese rv ed o r f r e s h l y
c o l l e c t e d , through e i t h e r a m i l l i p o r e f i l t e r (HA) or a Gelman GM-6
f i l t e r , pore s i z e .45 y.
The f i l t e r was examined m i c r o s c o p i c a l l y
a f t e r d r y in g and c l e a r i n g with cedar o i l .
During the w i n t e r months, on ly zooplankton were pr ese nt in
de te cta b le numbers.
These disappeared with the absence o f oxygen
in the water in s p r i n g .
In A p r i l
the algae which were sub se qu en tly
p r e s e n t throughout the f i r s t p r od uc t ive time appeared, and were most
numerous in the warmer water near the bottom.
These were dominated
n u m e r i c a l l y by Euglena s p . , C h l o r e l l a s p . , and small f l a g e l l a t e s .
A few Gymnodinium and Gloeocapsa sp. were found in a d d it io n .
This
p o pu la ti on p e r s i s t e d during the e n t i r e ic e - co ve r e d p e ri o d , and a l s o
s ub se q ue n tl y du rin g the f i r s t few days o f June, with Selenastrum
sp.
and a c o l o n i a l form t e n t a t i v e l y i d e n t i f i e d as Pyr ob otr ys sp.
appearing at t h i s time.
The f i r s t appearance o f la r g e numbers of
al gae in A p r i l corresponded in time with the presence o f tra ce s of
oxygen in the water, and the reappearance o f la r g e numbers of
immature zooplankton.
25
26
On June 6, Anabaena spp were found f o r the f i r s t time, and
w i t h i n a few days Anabaena fi l a m e n t s were abundant.
During t h i s
b u i l d i n g - u p phase, the fi l a m e n t s were long, with no d i f f e r e n t i a t e d
cells,
and a l l
the c e l l s had the appearance o f d i v i d i n g a c t i v e l y .
These alg ae were r e s t r i c t e d to the s u r f a c e meter.
the e a r l y s p r i n g po pu la tio n p e r s i s t e d in small
dominated by C h l o r e l 1 a and c o l o n i a l
forms.
At the bottom
numbers, again
The thermal and chemical
s t r a t i f i c a t i o n o f the water was thus a l s o r e f l e c t e d in a b i o l o g i c a l
stratification
at t h i s time.
On June 10, the Anabaena in the s u r f a c e
were very numerous and the po p u la ti o n was u n i a l g a l .
l i t t l e zooplankton present.
There were very
Within a few days, the Anabaena had formed
h e t e r o c y s t s and a k i n e t e s , and the bloom began to form scum on the
water s u r f a c e .
In the deeper water the s p r i n g p o p u la ti o n s p e r s i s t e d ,
with some al gae now attached to decomposing Anabaena fi la m e n t s.
Follo win g t h i s , the Anabaena appeared to d e t e r i o r a t e in c o n d i t i o n ,
and free a k ine te s were abundant in the water as well
as Anabaena
fi l a m e n t s which were surrounded by l a r ge numbers o f b a c t e r i a , c l e a r l y
v i s i b l e when f r e s h m at e r ia l was examined with p h a s e - c o n t r a s t microscopy.
Very few algae were found in the deeper water now.
The ak in et es were
l a r g e , often e q u i v a l e n t in length to s i x normal c e l l s
in the filament.
As the bloom d e c l i n e d , Euglena sp. , C h l o r e l l a sp. , and Selenastrum sp.
reappeared, although a few Anabaena fi la m e n t s were s t i l l
present.
During J u l y , Selenastrum s p . , Gloeocapsa s p . , and Euglena sp.
were the main c o n s t i t u e n t s o f a very small a lg a l
p o p ul a ti on .
Aphan-
izomenon sp. had now appeared at one meter depth, and G.ymnodinium sp.
was a l s o pr es en t at two meters.
Large zoopla nkt on, m os t ly copepods,
27
appeared as soon as the Anabaena bloom d e c l i n e d .
These p e r s i s t e d
d u r i n g the e n t i r e remainder o f the summer.
A u g us t r ep res en ted a p e r i o d i n which the p h y t o p l a n k t o n was
dominated by a dense p o p u l a t i o n o f Aphanizomenon sp.
S e l e n a s t r u m sp.
a lt h o u g h a few
and Chlor ophyceae were found, in a d d i t i o n to
o c c a s i o n a l Anabaena sp.
In September S e l e na st ru m was a l m os t u n i a l g a l
i n the w a te r , whereas i n October o n l y Gymnodinium sp. was found in
abundance.
A co nt i nu o us v a r i a t i o n
all
in dominant genera was e v i d e n t ; however,
components o f the p o p u l a t i o n f r e q u e n t l y seemed t o be p r e s e n t in
small
numbers even when they were not dominant.
RESULTS - PHYSICAL AND CHEMICAL BACKGROUND
S i n c e the b i o l o g i c a l
t h e ir physical
events i n a l ake cannot be d i v o r c e d from
and chemical environment, the d e s c r i p t i o n o f e n v i r o n ­
mental v a r i a t i o n s
l o g i c a l l y preceeds the d i s c u s s i o n o f ex peri ment al
results.
Thermal regime
The t a b u l a t e d temperature i n f o r m a t i o n i s g i v e n i n T a bl e s
1 and
2 in Appendix B.
In s p i t e o f the c o l d w i n t e r c l i m a t e i n i n t e r i o r A l a s k a , Smith
Lake does not f r e e z e to the bottom.
The water becomes g r a d u a l l y
c o n ce nt r a t e d as the i c e i n c r e a s e s i n t h i c k n e s s , e v e n t u a l l y r ea c h i n g
a t h i c k n e s s o f about one and a h a l f meters.
At t h i s
time o n l y about
two meters o f w at e r remain a t the r e g i o n o f maximum depth.
imum temperature reached a t the mud s u r f a c e i s
temperature g r a d i e n t i s found a t t h i s
3.0°C.
A r a t h e r s te e p
ti me, and the w at e r column i s
p r o b a b l y c h a r a c t e r i z e d by h i g h s t a b i l i t y r e s u l t i n g
w at e r movement.
The min­
i n ver y l i t t l e
Dur ing the e a r l y s p r i n g , c o n d i t i o n s a t the time o f
m e l t i n g are i m p or t a n t i n d e t er m i ni n g the temperature p r o f i l e e a r l y
i n summer.
I n 1963 the i c e mel ted from the edges p r od u c i n g an i s l a n d
o f i c e in the c e n t e r o f the l a k e w i t h wide l e a d s s u r r o u n d i n g i t .
T h i s open w at e r was warmed b e f or e a l l
s l i g h t wind was a l l
mix the e n t i r e l ake.
the i c e was gone, s o t h a t a
t h a t was needed to c o m p l et e l y m e l t the i c e and
I n 1964 the m e l t i n g took p l a c e i n a d i f f e r e n t
28
29
way, and a t h i c k l a y e r o f very t h i n v e r t i c a l
s p i c u l e s o f i c e covered
the e n t i r e l a k e wi th very l i t t l e m e l t i n g around the sho re r e g i o n s .
These v e r t i c a l
particles
columns o f i c e had channels between them, and a p p a r e n t l y
trapped i n these channels were r e s p o n s i b l e f o r heat a b s o r p t i o n
and the i n c r e a s e i n di ame ter o f the c hanne ls .
system c o l l a p s e d and mel t ed, but a l l
in the s u r f a c e r e g i o n .
E v e n t u a l l y the whole
the mel ted i c e i n i t i a l l y
remained
There was a p p a r e n t l y not complete m i x i n g even
as the w at e r warmed through an i s o th e r m a l
s t a t e , p r o b a b l y because o f
the d e n s i t y d i f f e r e n c e between the two l a y e r s r e s u l t i n g from the high
c o n c e n t r a t i o n o f d i s s o l v e d s u b s t a n c e s in the lower l a y e r .
A stable,
warm l a y e r o f w a t e r was thus formed, w i th a s h a r p t h e r m o c l i n e between
0.5 and 1 meters.
T h i s boundary g r a d u a l l y mixed down, but complete
m i x i n g o f the s u r f a c e 2 meters was not ach ieved u n t i l
o f June.
the l a s t day
Even then th ere was very l i t t l e m i x i n g t o a depth o f 2.5
meters.
The warming o f the s u r f a c e l a y e r s i s
very r a p i d i n S p r i n g , wi th
maximum summer temperature l e v e l s reached w i t h i n two weeks o f i c e free condition s.
D i s s o l v e d oxygen
The oxygen c o n c e n t r a t i o n s d u r i n g the 1963-1964 p e r i o d are shown
i n T a bl e s
1 and 2.
In a s h a l l o w l a k e o f t h i s
type l a r g e d e p a r tu re s
from e q u i l i b r i u m wi th the atmosphere are not t o be expected d u r i n g
the i c e - f r e e s eas on.
However, th ere i s some r e d u c t i o n in oxygen
c o nt e n t i n the deep wa t e r d u r i n g the summer, a l t h o u g h t h i s
does not p e r s i s t f o r l ong.
condition
The temperature p r o f i l e s showed t h a t
Table No. 1 .-
Depth
meters
0.0
0.5
1.0
1.5
2.0
m g / l it e r d i s s o l v e d oxygen, Smith Lake, 1963.
5/21/63
7.95
10.50
7.62
7.40
7.44
5.80
7.90
7.88
7.90
8.30
6.94
7.54
1.94
8.70
8.30
7.53
5.38
7.00
7.0
4. 8
4.0
8 /2 0/6 3
0.0
0 .5
1.0
1.5
2.0
6/11/63
7.57
7/23/63
0.0
0.5
1.0
1.5
2.0
2.5
6/05/63
6.82
6/19/63
0 .0
0.5
1.0
1.5
2.0
2.5
5/30/63
7.58
7.40
6.80
6.90
6.52
6/26/63
7/01/63
7/15/63
6.00
8.51
6.2
5.92
6.20
6. 24
8.00
8.80
6.30
5.6
4.53
2.23
7/30/63
7.00
6.75
6.80
6.80
6.75
8/27/63
7.75
6.33
7.68
7.70
7.00
8/0 7/6 3
6.90
6.90
7.05
7.10
6.85
9/25/63
8/1 2/6 3
7.10
7.45
7.45
6.80
6.60
12/09/63
7.20
Ice
7.80
6.0
8.35
2.2
Table No. 2 . -
Depth
meters
0.0
0.5
1.0
1.5
2.0
2.5
0.0
0.5
1.0
1.5
2.0
2,5
m g / lit e r d i s s o l v e d oxygen, Sm ith Lake, 1964.
1/03/64
Ice
Ice
4.0
I ce
Ice
.12
1.65
.15
3/24/64
4/08/64
2/2 6/6 4
3/18/64
Ice
Ice
I ce
I ce
0.008
.12
0. 58
0, 0
4/14/64
4/2 0/6 4
5/01/64
Ice
Ice
0. 0
I ce
Ice
0.5
Ice
Ice
0.0
Ice
I ce
0 .0
Ice
Ice
1.06
0. 0
0.0
0.0
0.0
Trace
2.32
0.00
5/12/64
6.27
0.50
5/18/64
8.57
1.74
5/23/64
5.25
0.6
-
-
6/02/64
0.0
0.5
1.0
1.5
2.0
2.5
2/19/64
Ice
Ice
.93
.55
5/05/64
0.0
0.5
1.0
1.5
2. 0
2.5
3.0
2/0 3/6 4
8.95
8.29
4.2
1.9
6/08/64
9.65
8.68
4.02
6/10/64
9.75
9.59
3.30
5/27/64
9.6
9. 8
9.3
5.1
0.7
6/1 2/6 4
6/1 6/6 4
11.6
12.6
9.4
7.7
1.9
.3
11.48
10.64
10.16
4.28
1.69
.19
Table No. 2 . -
Depth
meters
0.0
0.5
1.0
1.5
2.0
2.5
(co n tin u e d )
6/18/64
8.66
8.84
6.44
5.84
1.2
0.0
7/16/64
0 .0
0.5
1.0
1.5
2.0
0.0
0.5
1.0
1.5
2.0
7.64
-
7.18
-
6/23/64
6.68
6.50
6.41
6.48
6.24
.17
7/21/64
7.08
6.34
8/27/64
9/10/64
8.01
-
8.01
7/28/64
7.90
7.88
7.86
7.31
4.17
0.82
8/04/64
7/07/64
8.07
-
7.89
-
1.37
-
8/11/64
8.05
7.7
7.95
7.84
7.7
7.78
2.89
3.9
4.13
-
1.28
-
6.90
6.90
6.70
6.60
6.60
4.00
6/30/64
-
1.94
8.25
6/25/64
9.57
9/22/64
6.87
-
9.18
9.04
-
9.28
8.80
30
complete m i x i ng to the bottom i s
this
l ake .
not the r u l e d u r i n g the summer in
Dur ing the w i n t e r the oxygen c o n c e n t r a t i o n g r a d u a l l y
becomes lower in the w a t e r under the i c e , and f i n a l l y c o mp let el y
anoxic conditions obtain.
Dur ing t h i s o x y g e n - f r e e p e r i o d , which
l a s t e d through March and A p r i l
i n the w at e r, r e s u l t i n g
i n 1964, hydrogen s u l f i d e i s produced
i n a c h a r a c t e r i s t i c odor.
Oxygen reappear s
under the i c e e a r l y in May, c o i n c i d e n t a l l y w i t h the f i r s t appearance
o f l a r g e numbers o f a l g a e .
n i t r o g e n regime w i l l
The e f f e c t o f t h i s
a n o x i c p e r i o d on the
be d i s c u s s e d below.
S p e c ific conductivity
R e p r e s e n t a t i v e examples o f the depth d i s t r i b u t i o n o f c o n d u c t i v i t y
from the summer o f 1964 are shown i n T a bl e 3.
a t the two meter l e v e l
under the
i n June i s the r e s u l t o f the c o n ce n t r a t e d wa te r
i c e , whereas the
i n f l u e n t water.
The h i g h e r c o n d u c t i v i t y
dilute
la y e r above i s l a r g e l y
mel ted i c e and
On June 30th m i x i ng r e s u l t e d in a more even d i s t r i b u ­
t i o n w i t h depth.
pH
Smith Lake has a pH which f l u c t u a t e s around 7.0 wi th very smal l
deviations,
.6 pH u n i t s being an extreme.
tends to have a s l i g h t l y
The w at e r a t the bottom
l ower pH than t h a t a t the s u r f a c e , p r o b a b l y
as a r e s u l t o f CO2 r e l e a s e d by d e com po si t io n o r o r g a n i c m a t e r i a l .
D ur i n g the summer the pH i s
a l i t t l e h i g h e r than d u r i n g the w i n t e r -
the r e d u c t i o n i n w i n t e r a g a i n being p o s s i b l y due t o CO2 r e l e a s e d
under the i c e .
I n a d d i t i o n , d u r i n g the summer p h o t o s y n t h e t i c removal
T ab le No.
Depth
0.0
1.0
2.0
0.0
1.0
2 .0
3.-
S p e c i f i c c o n d u c t i v i t y - Micromhos.
6/16/64
6/18/64
6/22/64
75.8
77.2
103.0
83.9
85.1
113.4
76.4
80.3
110.5
7/18/64
7/21/64
7/28/64
95.0
91.9
108.5
89.2
96.6
95.0
92.1
87.7
91.0
6/30/64
88.6
89.2
97.2
7/07/64
92.4
93.2
105.2
o f CO2 i n the s u r f a c e w ate rs tends to r a i s e the pH.
The o n l y e x c e pt i on to the r e l a t i v e l y c o n s t a n t pH takes p l a c e
d u r i n g June a t the peak o f the p hy t o p l a n k t o n bloom.
At t h i s
the pH rose r a p i d l y to 9.5 i n 1963 and 9 . 8 i n 1964.
T hi s i n c r e a s e
is
time
very temporary, and w i t h i n a few days normal v a l u e s are found
again.
The t a b u l a t e d data f o r depth d i s t r i b u t i o n o f pH f o r the 19631964 p e r i o d are found in T ab le 3 and 4 in Appendix B.
Light
The p e n e t r a t i o n o f l i g h t i n t o Smith Lake wate r i s
the s t r o n g brown c o l o r .
reduced by
However d u r in g p e r i o d s o f low p r o d u c t i v i t y ,
the depth o f p e n e t r a t i o n o f 1% o f s u r f a c e l i g h t reaches a l m o s t t o the
bottom.
Dur ing the June f l o w e r i n g , the depth o f 1% p e n e t r a t i o n l i e s
somewhere between 0 and .5 meters.
The e f f e c t o f such a s h a l l o w
e u p h o t i c zone c o ul d be c o n s i d e r a b l e i n c o n t r o l l i n g the maximum
p r o d u c t i v i t y d u r i n g the bloom.
P a r t i c u l a t e nitrogen
P a r tic u la te nitrogen is
s i n c e the major i n t e r e s t l i e s
its
used here as an i n d i c a t o r o f b i o ma ss ,
i n the uptake o f n i t r o g e n , and thus
i n c o r p o r a t i o n i n t o the p a r t i c u l a t e o r g a n i c n i t r o g e n f r a c t i o n in
the water.
The i n c r e a s e i n p a r t i c u l a t e n i t r o g e n s h o u l d r e f l e c t the
net a s s i m i l a t i o n o f n i t r o g e n by the p hy t op l a n k t o n .
I n f o r m a t i o n on the depth d i s t r i b u t i o n o f p a r t i c u l a t e n i t r o g e n
i s g i v e n i n T a bl e s 5 and 6 i n Appendix B.
The s e a s o n a l
variations
Table No. 4 . -
Depth
meters
0.0
0.5
1.0
1.5
2.0
6/02/6
100
20.6
.5
.4
L i g h t pe n e tr a ti o n - percent reachin g each depth.
6/12/6
6/16/6
100
.5
.1
100
.6
.2
7/28/6
8/0 4/6
8/11/6
100
16.8
4.5
100
72.0
45.6
20.0
1.12
100
62.5
8.3
2.9
i n p a r t i c u l a t e n i t r o g e n in Smith Lake s u r f a c e w at e r are shown f o r
1963 i n F i g ur e 2 and f o r 1964 in F i g u r e 3.
The 1963 d i s t r i b u t i o n
shows a l a r g e maximum in June, and r e l a t i v e l y
remai nder o f the y e a r .
low l e v e l s d u r i n g the
There i s e vi de nce o f a s l i g h t r i s e i n f a l l .
The p a r t i c u l a t e n i t r o g e n da ta f o r 1964 are more complete, and show
a peak i n May i n a d d i t i o n to the June peak.
The depth a t which
t h i s e a r l y peak o ccurs i s one meter r a t h e r than s u r f a c e s i n c e the
lake s u r f a c e i s
i c e covered a t t h i s
time.
The June peak appears
to be s m a l l e r i n 1964 than in 1963, but t h i s
case.
The maximum a t t h i s
a t the s u r f a c e ,
is
not r e a l l y the
time was found a t one meter r a t h e r than
and t h e r e f o r e does not show up on t h i s p l o t o f
surface concentrations.
The p a r t i c u l a t e n i t r o g e n l e v e l
shows a
d e c l i n e a f t e r the June maximum, and then a temporary r i s e a f t e r
m i x i n g , s o t h a t the t o t a l
base wi dth o f the peaks f o r the two y e a r s
i s s i m i l a r even though the d e c l i n e in 1964 was more r a p i d .
Chlorophyll
a_
The data f o r c h l o r o p h y l l _a c o n c e n t r a t i o n s
g i v e n i n T a bl e s 7 and 8 i n Appendix B.
i n Smith Lake are
Surface concentration p lo ts
have been made on a s e a s o n a l b a s i s and are shown i n F i g u r e s 2 and 3.
The 1963 p l o t shows the peak o f 100 pg per l i t e r a t the s t a r t o f the
summer's work, the ab rup t drop i n c o n c e n t r a t i o n and then the low l e v e l
m a i n t a i n e d i n the l a ke d u r i n g the remainder o f the summer.
The 1964
d a t a , a g a i n f o l l o w c l o s e l y the b e h a v i o r o f the p a r t i c u l a t e n i t r o g e n ,
and show the r i s e i n May under the i c e , the d e c l i n e f o l l o w e d by the
June maximum, and then the s ha r p d e c l i n e f o l l o w i n g the bloom t e r m i n a -
F i g u r e 2. - The s e a s o n a l
d is tr ib u tio n of chlorophyll
a^ and
p a r t i c u l a t e n i t r o g e n c o n c e n t r a t i o n s in Smith Lake - 1963.
i?0
-1200
110
-1100
100
■ 1000
C h lo r o p h y ll a
t 90
■900
P a rtfc u Ja te * N
■i
-?00
5, 90
x:
%
f
70
?
60
•600
50
■50 0
40
40 0
30
- 300
20
200
u
*
10
________ I_____
MAY
JU N E
1
JU LY
F i g u r e 3. - The s e a s o n a l
d is tr ib u tio n o f chlorophyll
a and
p a r t i c u l a t e n i t r o g e n c o n c e n t r a t i o n s i n Smith Lake - 1964.
u9/liter
u 9/ 111 e r P a r t ic u la t e
CWorophyHj.
N
iim p n
pi i
33
tion.
Dur ing t h i s y e a r t h e r e i s
a t rend towards an i n c r e a s e a t
the end o f the summer which was not found in 1963.
N u t r ie n t chem istry
Ammonia.
Ammonia i s
the more i m p or t an t i n o r g a n i c n i t r o g e n
s o u r ce from the p o i n t o f view o f a v a i l a b i l i t y i n Smith Lake water.
It
i s p r e s e n t i n d e t e c t a b l e amounts a t a l m o s t a l l
ti mes.
During
the June bloom i n 1963 i t was a bs ent in the s u r f a c e w a te r , but
reappeared ver y q u i c k l y a f t e r the d e c l i n e .
In September the con­
c e n t r a t i o n was a g a i n t e m p o r a r i l y reduced.
During the f a l l
the w a t e r i s e v i d e n t ,
and w i n t e r , a s l o w i n c r e a s e i n ammonia in
r e p r e s e n t i n g a b a l a n c e between ammonia
r e l e a s e d from n i t r o g e n o u s
o r g a n i c m a t e r i a l and n i t r i f i c a t i o n .
After
the oxygen i n the wate r i s e xh aus te d, the r a t e o f i n c r e a s e i n c r e a s e s ,
p r o b a b l y both because n i t r i f i c a t i o n
is
i n h i b i t e d i n the absence o f
oxygen, a l l o w i n g the ammonia r e l e a s e d by d e c om p os it i on to accumulate,
and a l s o p o s s i b l y due t o ammonia r e l a s e d from the mud as a r e s u l t
o f the a n o x i c c o n d i t i o n s
( M o rt i me r ,
yg-atoms per l i t e r o f ammonia i s
bottom i n m i d - A p r i l .
by May 27th.
June 25th,
The l e v e l
The g r a d u a l
1941-1942).
p r e s e n t i n the wa te r nea r the
then drops to complete e x h a u s t i o n
i n c r e a s e f o l l o w s l e a d i n g t o a maximum on
f o l l o w e d a g a i n by a d e c l i n e to e x h a u s t i o n on A u g u s t 11,
f o l l o w e d a g a in by a s l i g h t i n c r e a s e .
A co n s ta n tly s i g n i f i c a n t rate
o f ammonia p r o d u c t i o n w i th a v a r i a b l e removal
seasonal
r a t e would e x p l a i n the
d i s t r i b u t i o n o f ammonia in Smith Lake.
analytical
A maximum o f 46.4
results
f o r ammonia in Smith Lake.
Table 5 shows the
Table No. 5 . -
Depth
meters
0.0
1.0
NH^-N p g - a t o m s / l i t e r , Smith Lake, 1963-1964.
6/12/63
0. 0
2.0
8/27/63
0.0
1.0
2.0
0.0
1.0
2.0
3. 58
4.03
4.69
2.0
0. 0
1.0
2. 78
1.49
7.74
.94
2.80
3.69
7/07/63
5.71
9.14
5.71
9 / 03/ 63
9/10/63
9 / 1 7/ 6 3
.46
6. 48
2.53
2.77
5.54
.51
8/20/63
3.57
1.43
5.71
9/25/63
2.84
1.91
6.00
10/25/63
10/23/63
11/07/63
12/04/63
4.59
6.61
4.76
6.30
5.34
3.17
8.28
6.80
23.5
2/03/64
5.29
6.34
11.23
2/19/64
2/2 6/6 4
3/18/64
7.64
10.24
19.9
13.37
11.37
5/0 5/6 4
5/13/64
3/24/64
4/08/64
4/14/64
29.74
12.13
32.67
32.14
46.40
5/1 8/6 4
5/23/64
5/27/64
2.0
0.0
1.0
2.0
6/26/63
10/09/63
1/03/64
0.0
1.0
6/19/63
3.13
2. 74
0.0
8.39
7.18
5/30/64
6/08/64
.36
.65
Table No. 5 . -
Depth
meters
0.0
( continued)
6/10/64
2.15
7/16/64
0.0
1.0
6/25/64
16.47
7/21/64
6/30/64
6.10
7/07/64
6.02
7/13/64
5.77
7/28/64
8/0 4/6 4
8/11/64
5.10
.58
.15
8/27/64
9/03/64
9/0 4 /6 4
9/10/64
.60
.60
0.00
2. 58
2.0
8/18/64
0. 0
1.0
1.49
2.71
9/22/64
10/06/64
2.0
0.0
1.0
2.0
.31
-
2.46
34
Nitrate.
T ab le 6.
The n i t r a t e c o n c e n t r a t i o n s i n Smith Lake are shown in
The f i r s t depth s e r i e s in June 26, 1963 shows a h i g h
c o n c e n t r a t i o n o f n i t r a t e , p r o b a b l y r e s u l t i n g from the n i t r i f i c a t i o n
o f ammonia r e l e a s e d from the Anabaena bloom.
n i t r a t e level g r a d u a lly r i s e s
this
Du r in g the w i n t e r the
to a maximum e a r l y i n February.
time the oxygen becomes ex haus te d, and the n i t r a t e l e v e l
rapidly.
At
drops
The most l i k e l y e x p l a n a t i o n f o r t h i s drop i s d e n i t r i f i c a t i o n ,
since n itra te ,
in the absence o f oxygen, can s er ve as a hydrogen a c c e p t o r
fo r certain bacteria.
On the b a s i s o f the l o s s o f n i t r a t e ,
an i dea o f the amount o f d e n i t r i f i c a t i o n
therefore,
o c c u r i n g can be o b t a i n e d .
F i g u r e 4 was o b t a i n e d i n the f o l l o w i n g manner.
The n i t r a t e
c o n c e n t r a t i o n s a t the one and two-meter l e v e l s were p l o t t e d f o r the
b e g i n n i n g o f oxygen d e p l e t i o n , one week l a t e r , one month l a t e r and one
a d d i t i o n a l month l a t e r .
The two depth p o i n t s f o r each date were then
connected by a s t r a i g h t l i n e ,
s i n c e th ere was no way to g e t a more
r e a l i s t i c e s t i m a t e o f the shape o f the depth d i s t r i b u t i o n curve.
Area
ODEP r e p r e s e n t s the n i t r a t e c o n c e n t r a t i o n a t the s t a r t o f the low
oxygen p e r i o d , OCFP r e p r e s e n t i n g the same one week l a t e r ,
is
and area CDEF
the d i f f e r e n c e between the two and can be taken as an a p p ro xi ma t io n
o f the amount o f n i t r a t e l o s t by d e n i t r i f i c a t i o n d u r i n g t h a t time.
This
as sumpti on i s r e a s o n a b l e , s i n c e the o n l y o t h e r a n o x i c d i s s i m i l a t o r y
p r o c e s s which i s
to n i t r i t e .
l i k e l y to remove n i t r a t e from the water i s
No s i g n i f i c a n t
reduction
i n c r e a s e i n n i t r i t e was found i n the
w at e r d u r i n g t h i s ti me, and t h e r e f o r e i t can be assumed t h a t the
r e d u c t i o n went to N2 o r N^O.
The area CDEF r e p r e s e n t s 53 yg- atoms
l o s t under a s u r f a c e ar ea o f 100 s q ua re c e n t i m e t e r s .
This i s eq uiva len t
Table No. 6 . -
Depth
meters
NO^-N ug -a to ms /1 ite r, Smith Lake, 1963-1964.
6/12/63
0.0
7.83
12.71
10.83
1.0
2.0
11/11/63
0.0
6/26/63
3.0
12/04/63
4.42
2/19/64
0. 0
1.0
2.0
10.0
6.8
4/14/64
0.0
1. 0
0.52
1.2
1.1
1.2
12/09/63
10/09/63
11/07/63
3.25
3.75
4.00
3.00
1/03/64
2/03/64
6.42
1.0
2.0
9/25/63
2/2 6/6 4
4. 68
1.65
4/20/64
0.26
7.7
5.7
3/18/64
1.28
0.51
4/28/64
0.66
8.97
5.30
3/24/64
13.01
8.99
4/08/64
0.32
0.19
5/0 5/6 4
3.02
5/12/64
0.26
2. 0
5/18/64
5/2 3/6 4
0.0
1.0
2.0
0. 24
0.32
6/12/64
0.0
1. 0
2.0
0. 23
0.05
0.30
0.11
0.33
6/16/64
0.16
0.22
0.59
5/27/64
0.00
0.00
0.51
6/18/64
0.08
0.09
0.40
6/02/64
0.26
0.33
6/23/64
0.27
0.33
0.45
6/10/64
0.13
0.04
0. 48
6/25/64
0.34
0.40
0.51
Table No. 6 . -
Depth
meters
0.0
1.0
2.0
1.7
( continued)
6/30/64
1.00
0.86
1.70
8/04/64
0.0
1.0
2.0
0.01
0. 67
0.82
9/10/64
0. 0
1.0
2.0
0. 09
0.20
0.23
7/07/64
0.49
0.67
1.78
8/11/64
0.08
0.01
0.58
9/22/64
0.31
0.00
7/13/64
0.33
0.53
1.65
8/18/64
0.09
0.08
0.22
10/06/64
0.06
0.11
0.08
7/21/64
0.65
0.83
0.96
8/27/64
0. 10
7/28/1
0.07
0.04
0.80
9/03/1
0.16
0.21
1.20
F i g u r e 4. - D i sa pp ea r an ce o f n i t r a t e in Smith Lake in the
s p r i n g o f 1964.
U e p in — m
ug-atoms
NG 3 - N / i i t e r
35
to 5. 3 ug-atoms per l i t e r .
The d i f f e r e n c e between a re as OCFP and OBGP r e p r e s e n t s the
amount o f n i t r a t e l o s t d u r i n g the next month.
1.9 yg-atoms per l i t e r .
The t o t a l
T hi s amounts to
l o s s o f n i t r a t e i s g i v e n by
area ADEH, which can be o b t a i n e d by o b t a i n i n g the area ABGH and
a ddi ng t h i s
represents
to the sum o f the p r e v i o u s r e s u l t s .
Area ABGH
.39 yg-atoms per l i t e r .
The t o t a l
amount o f n i t r a t e l o s t d u r i n g t h i s p e r i o d i s
yg- atoms p er l i t e r ,
a n o x i c week.
7.6
the bu lk o f t h i s being l o s t d u r i n g the f i r s t
T h i s e s t i m a t e i s p r o b a b l y c o n s e r v a t i v e s i n c e there
was some l o s s o f n i t r a t e p r i o r t o the date taken as s t a r t i n g p o i n t .
On an annual b a s i s , t h er e are o t h e r o c c a s i o n s d u r i n g the summer when
the oxygen t e n s i o n i s s u f f i c i e n t l y low t o a l l o w d e n i t r i f i c a t i o n .
As a r e s u l t o f t h i s n i t r a t e
loss,
there i s
very l i t t l e
nitrate
p r e s e n t at the time o f the f i r s t s i g n i f i c a n t p h y t o p l a n k t o n growth.
Both the u n d e r - i c e and the June bloom take p l a c e under low n i t r a t e
conditions,
and the f i r s t s i g n i f i c a n t
appearance o f n i t r a t e takes
p l a c e a f t e r the d e c l i n e o f the Anabaena bloom.
N itrite.
Nitrite
levels
i n the wa te r v a r i e d from u nd e t e c t a b l e
to about .4 yg-atoms per l i t e r .
S i n c e the w at e r c o l o r made a c c u r a t e
d e t e r m i n a t i o n a t these low c o n c e n t r a t i o n s d i f f i c u l t ,
not be d i s c u s s e d here.
n it r it e w ill
There was no s i g n i f i c a n t c o n c e n t r a t i o n o f
n i t r i t e a t any time.
Phosphorus
The phosphorus d a t a f o r Smith Lake can be found in Appendix B,
36
Tabl es 9 and 10.
The d i s s o l v e d phosphorus c o n te n t o f Smith Lake
w at e r shows c o n s i d e r a b l e v a r i a t i o n wi th the s e a s o n s .
The d i s s o l v e d
i n o r g a n i c f r a c t i o n shows the drop which i s expected d u r i n g p e r i o d s
o f h i g h p r o d u c t i v i t y , d ro ppi ng from 2.4 yg -at oms per l i t e r down to
.25 yg-atoms per l i t e r between mid-May and Mi d- June.
The s u r f a c e
c o n c e n t r a t i o n a l s o shows a drop s i m u l t a n e o u s l y , but owing to the
in itially
lower c o n c e n t r a t i o n a t t h i s depth the r e d u c t i o n i s
spectacular.
per l i t e r .
less
The minimum s u r f a c e c o n c e n t r a t i o n found was .2 yg-atoms
A t 1.5 meters no r e d u c t i o n i n c o n c e n t r a t i o n i s
ap par ent ,
whereas a t 2 meters the c o r r e l a t i o n wi th p r o d u c t i v i t y appears to be
negative.
Very high phosphate c o n c e n t r a t i o n s o f 6 yg- atoms per
l i t e r are found a t 2.5 meters under the i c e i n e a r l y S p r i n g , w i t h
a s l ow r e d u c t i o n e v i d e n t d u r i n g June.
A v a r i a b l e but c o n s i d e r a b l e amount o f d i s s o l v e d o r g a n i c phosphorus
i s p r e s e n t i n Smith Lake w at e r a t a l l
depths.
A r e d u c t i o n i n the
amount found a t one-meter depth i s e v i d e n t a t the end o f May, f o l l o w e d
by a s l i g h t peak c o r r e s p o n d i n g t o the time o f the peak o f the June
bloom.
EXPERIMENTAL RESULTS
P ri ma ry p r o d u c t i v i t y
In Smith Lake the h i g h e s t r a t e s o f carbon f i x a t i o n are found
in the e a r l y s p r i n g and summer.
is
The f i r s t maj or p r o d u c t i v i t y peak
found under the i c e in May and i s p r o b a b l y connected i n some
way w i t h the t e r m i n a t i o n o f the a n o x i c s t a t e o f the water.
During
the f i r s t y e a r ' s work t h i s peak was not o bs er v e d , because the s am pl i n g
was not s t a r t e d e a r l y enough.
At t h a t time o n l y one major peak i n
p r o d u c t i o n was f ound, due to a bloom o f Anabaena s p . which took
p l a c e d u r i n g both y e a r s soon a f t e r the i c e had melted.
F i g u r e 5 shows the l 4 C r e s u l t s f o r 1963, and r e p r e s e n t s the
i n t e g r a t e d r e s u l t s o f i n s i t u depth s e r i e s i n c u b a t i o n s , so t h a t each
v a l u e p l o t t e d r e p r e s e n t s the t o t a l
amount o f carbon f i x e d under a
s q u ar e meter o f w at e r s u r f a c e i n an hour.
The peak v a l u e o f 10 mg
o f carbon p er s quare meter per hour was a t t a i n e d a t the end o f the
f i r s t week i n June.
T h i s was f o l l o w e d by a s t e a d y d e c l i n e , w i t h low
r a t e s o f p h o t o s y n t h e s i s o c c u r r i n g d u r i n g the r e s t o f the summer, with
the e xc e p t i o n o f a mi nor peak i n Au gus t.
Figure 6 a l s o represents
uptake da ta from 1963, which are i n t h i s
cas e e x p re ss ed on a
u n i t volume b a s i s , from the r e s u l t s o f experi ments u s i n g s u r f a c e
water.
The p a t t e r n i s s i m i l a r to t h a t shown by the depth i n t e g r a t e d
c u r v e , w i th the p o s s i b l e e x c e p t i o n o f an a d d i t i o n a l
small
peak a t the
end o f May.
The r e s u l t s o f i n s i t u experiments d u r i n g 1964 are shown i n
37
Fi gu re 5. - Primary p r o d u c t i v i t y r e s u l t s f o r Smith Lake, 1963.
F i g u r e 6. - S u r f a c e p h o t o s y n t h e s i s measurements i n Smith Lake, 1963.
38
F i g u r e 7.
These v a l u e s were o bt a i n e d from s u r f a c e wa te r i n cub at ed
j u s t below the s u r f a c e .
1963, but i n t h i s
The p a t t e r n i s q u i t e s i m i l a r t o t h a t f o r
case a s u f f i c i e n t l y e a r l y s t a r t i n s p r i n g produced
a c l e a r p i c t u r e o f the e a r l y s p r i n g growth under the i c e cover.
Anabaena sp.
year,
The
bloom o ccurr ed a t the same time as i t had on the p r e v i o u s
the peak being reached on June 12 in both y e a r s .
The maximum
r a t e o f p h o t o s y n t h e s i s d u r i n g 1963 had been 175 yg o f carbon per
l i t e r per hour, whereas i n 1964 i t was o n l y 90 yg o f carbon per l i t e r
p e r hour.
The r a t e o f i n c r e a s e in the p h o t o s y n t h e t i c r a t e f o r the
two y e a r s was a p p r o x i m a t e l y s i m i l a r , b u t in the l a t t e r y e a r the d e c l i n e
was much more r a p i d .
The a c t u a l
h e i g h t o f the peak i s o f l i m i t e d
s i g n i f i c a n c e , s i n c e l i g h t c o n d i t i o n s on the p a r t i c u l a r day can be
o f g r e a t e r i mportance i n d e t er m i n i ng t h i s
between the two y e a r s .
indicate that conditions
than a c t u a l d i f f e r e n c e s
However, the s h a r p e r r a t e o f d e c l i n e does
i n 1964 were not as f a v o u r a b l e , and caused
the bloom t o te rmi n at e more p r e c i p i t o u s l y .
F i g u r e 8 a l s o shows d a t a f o r 1964, i n t h i s case the r e s u l t s o f
experi ments which were i n c u b at e d a t c o n s t a n t temperature ( 20°C),
and l i g h t .
The p a t t e r n s , as would be expect ed, are s i m i l a r t o the
i n s i t u p a t t e r n s , w i th the e x c e p t i o n o f s l i g h t l y
lower peak v a l u e s ,
s l i g h t l y h i g h e r midsummer v a l u e s , and the appearance o f an i n c r e a s e in
fall
which d i d no t show up i n the i n s i t u i n cu b a t e d samples .
l a t e summer i n c r e a s e seems t o i n d i c a t e t h a t the f a l l
is
Th is
bloom which
commonly found i n more s ou t h e r n l a t i t u d e s would a l s o o c cu r here,
were the l i g h t and temperature c o n d i t i o n s s u i t a b l e .
to gu es s which o f the two parameters i s
critical
I t is
in t h i s
not p o s s i b l e
case.
F i g u r e 7. - R e s u l t s o f i n s i t u
experi ments i n Smith Lake, 1964.
SEPTEMBE R
F i g u r e 8. - R e s u l t s o f
experi ments i n c u b a t e d under c o n s t a n t
l i g h t a t 20°C - Smith Lake s u r f a c e w at e r, 1964.
APRIL
MAY
uUNE
JULY
AUGUST
SEPTEMBER
OCTOBER
39
The t h i r d method o f i n c u b a t i o n ,
in which b o t t l e s were p l a c ed
i n a tank on the r o o f , d i d not produce r e s u l t s which were g r e a t l y
d i f f e r e n t than th os e o bt a i n e d by the o t h e r methods used.
There was
a tendency f o r the r a t e s to be somewhat lower than w i th o t h e r i n c ub a ­
t i o n methods, and l i g h t i n h i b i t i o n may have been a problem.
results,
little
t h e r e f o r e , are not i n c l u d e d .
There i s
a c t u a l l y remarkab ly
d i f f e r e n c e between the r e s u l t s o bt a i n e d by a l l
methods.
These
three incubator
On c l o u dy days the 20°C i n c u b a t i o n produced h i g h e r r a t e s ,
but under opt imal
c o n d i t i o n s on sunny days the in s i t u r e s u l t s were
highest.
Depth d i s t r i b u t i o n o f
uptake i n Smith Lake
F i g u r e 9 shows r e p r e s e n t a t i v e p l o t s o f the depth d i s t r i b u t i o n
o f photosynthesis
in the l ake .
Dur ing the p e r i o d o f h i g h p r o d u c t i v i t y ,
the r e d u c t i o n o f the p h o t o s y n t h e t i c r a t e wi th depth i s g r e a t , but even
a t o t h e r times the high e x t i n c t i o n p r o p e r t i e s o f the l a ke wate r p reven t
much p h o t o s y n t h e s i s below a depth o f one meter.
Winter p ro d u c t iv i t y
I t was not p r a c t i c a l
w i n t e r i n Smith Lake.
to attempt i n s i t u measurements i n the
However, p e r i o d i c a l l y , w at e r samples were
b r o u g h t i n t o the l a b o r a t o r y and i n cu b at e d w i t h
the p h o t o s y n t h e t i c a b i l i t y to f i x carbon was there.
were zero r e s u l t s o b t a i n e d ,
to see whether
At no time
the l o w e s t v a l u e measured in t h i s way
b ei ng .1 pg carbon per l i t e r per hour.
I n F eb ru ar y , wa te r c o l l e c t e d
F i g u r e 9. - The depth d i s t r i b u t i o n o f p h o t o s y n t h e s i s i n S m i t h ' L a k e
r e p r e s e n t a t i v e curves f o r 1963.
! P r | F f W W f P f V ¥ W l» r i^ 1 ^ F V T f P F P iW
M ay
Ju n e 2 0 . 1 9 6 3
3 0 ,1 9 6 3
y
X
X
J u ly
3 ,1 9 6 3 . . . .
w t
^
Aug. 1, 1963
A u g 27,1963
1
I
/
J
I
I
/
h /l
II
/
I
/
/
1
I
i
J
i
i
i
/
/
i
I
I
I
I
.
1
. 1 ......
1
1
i
140
0
^ 'te r /h o u r
1
I
j
I
J
1.
j
H
i.
I
1_ _ _
J...
/
j
1
I
i
I
I
i
i
40
i n the lake and br ou g ht i n t o the l a b o r a t o r y and i n cu b a t e d a t 4°C
w i th a g r o - l u x
lamp as the l i g h t sou rce showed a r a t e o f carbon
a s s i m i l a t i o n o f 1.4 yg carbon per l i t e r per hour.
The e f f i c i e n c y o f p h o t o s y n t h e s i s
Assuming t h a t a r e l a t i v e l y c o n s t a n t r e l a t i o n e x i s t s between
the amount o f c h l o r o p h y l l
in the wate r and the r a t e o f p h o t o s y n t h e s i s ,
and t h a t p h o t o s y n t h e s i s - l i g h t curves can be determined f o r p hy to pl an k to n
communities, c h l o r o p h y l l
c o n te n t can be used as a measure o f the
p h o t o s y n t h e s i s i n the water.
Ryt her and Yentsch
(1957) i n t r o d u c e d
t h i s method in o c e a n o g r a p h y , and from experi ment al
found in the l i t e r a t u r e ,
they adopted a v al ue o f 3.7 g carbom a s s i m i l a t e d
p er hour p er g o f c h l o r o p h y l l .
information i s
da ta and from data
S i n c e t h a t t ime, c o n s i d e r a b l y more
a v a i l a b l e c o nc er n in g s i m i l a r v a l u e s f o r both marine
and f r e s h w a t e r communities, and r e c e n t l y much o f t h i s
has been c o l l e c t e d
and t a b u l a t e d f o r both environments by I c h im u ra and Aruga (1964).
For l a k e s , they concluded t h a t v a l u e s from 2 - 6 , 1-2 and 0.1-1 g
o f carbon p er g o f c h l o r o p h y l l
per hour were the l i g h t - s a t u r a t e d
p h o t o s y n t h e t i c r a t e s f o r s u r f a c e p l an k t o n from e u t r o p h i c , m es o t r o p h i c
and o l i g o t r o p h i c l a k e s r e s p e c t i v e l y .
p h o t o s y n t h e s i s , however.
These v a l u e s are f o r g r o s s
Table 7 has been compiled from s i m i l a r
i n f o r m a t i o n f o r Smith Lake, but r e p r e s e n t s i n s i t u r e s u l t s f o r net
photosynthesis.
C o n s i d e r a b l e v a r i a t i o n i s found h er e, but a s u r ­
p r i s i n g l y h i g h r a t e o f carbon a s s i m i l a t i o n per u n i t c h l o r o p h y l l
found under the i c e in May.
a bl e a t t h i s
is
L i g h t c o n d i t i o n s c annot be very f a v o u r ­
ti me, but n u t r i e n t c o n c e n t r a t i o n s
are ver y h i g h.
Table No. 7 . -
Date
5/01/64
5/01/64
5/18/64
5/23/64
5/27/64
6/01/64
6/0 8/6 4
6/10/64
6/12/64
6/15/64
6/18/64
6/23/64
6/30/64
7/07/64
7/13/64
7/21/64
8/04/64
8/1 8/6 4
9/10/64
9/22/64
10/06/64
*
The r e l a t i o n s h i p between c h l o r o p h y l l
A
Chlorophyll
yg/liter
and p h o t o s y n t h e s is .
g
a
10
12
16.4
7.1
4.5
6.8
22.6
17.1
132.3
62.9
29.3
5.9
7.7
3.2
5.7
2.3
4.5
4.0
14.0
10.0
11.7
I n c u ba t e d a t 1 meter under i c e.
™ C uptake,
yg/1iter/hour
13.75*
33.5 *
6 .9 2 *
2 .24 *
2 .2 6 *
.84
34.10
29.65
89.74
35.68
14.91
5.29
3.34
5.76
5.49
4.54
9.06
5.38
4.34
2.39
7.32
B/ a
1.38
2.79
.42
.31
.51
.12
1.50
1.73
.68
.57
.51
.90
.43
1.80
.96
1.96
2.00
1.34
.31
.24
.63
41
Experi ment al
r e s u l t s - n i t r o g e n uptake
The n i t r o g e n uptake experi ments c a r r i e d out d u r i n g 1963 s erve
m a i n l y to e s t a b l i s h
the s e a s o n a l
patterns of nitrogen u t i l i z a t i o n
and e s p e c i a l l y to show the o ccurr ence o f a S p r i n g n i t r o g e n - f i x i n g
bloom o f Anabaena s p . ,
aquae.
p r i n c i p a l l y o f the s p e c i e s Anabaena f l o s -
The i n c u b a t i o n f a c i l i t i e s
d u r i n g t h a t y e a r were i n ade quat e,
and i n a d d i t i o n the n i t r a t e and ammonia uptake d a t a had to be r e ­
j e c t e d f o r the e a r l y p r o d u c t i v e p e r i o d s i n c e the amount o f n i t r o g e n - 15
added f o r the experi ment s a t t h a t time was too low and was a p p a r e n t l y
i n s t a n t l y used up, r e s u l t i n g in low ap parent uptake r a t e s .
The r e s u l t s
Tabl e 8.
o f the experi ments f o r the 1963 seas on are shown in
Very l i t t l e
n i t r a t e uptake i s e v i d e n t ; however, ammonia i s
used d u r i n g most o f the summer with s e v e r a l minor peaks in uptake
rate.
Nitrogen f i x a t i o n
The s e a s o n a l
is
o n l y i m p o r t a n t i n June.
d i s t r i b u t i o n of nitrogen f i x a t i o n
i s shown in F i g u r e
10, i n which the p a r t i c u l a t e n i t r o g e n l e v e l s in the s u r f a c e wate r are
a l s o shown.
fixation
The two peaks c o i n c i d e in time, and the drop i n both
and p a r t i c u l a t e n i t r o g e n l e v e l s f o l l o w i n g the peak i s s p e c t ­
acular.
Dur ing 1964, improved f a c i l i t i e s
f o r c o n tro lle d incubation
a ll o w e d the c o l l e c t i o n o f more c o n s i s t e n t ,
are shown in F i g u r e 11.
r e l i a b l e da ta.
These
The f i r s t major peak i n uptake c o i n c i d e s
wi th the p h o t o s y n t h e s i s peak under the i c e in May, and compri ses p r e ­
d o m i n an t l y ammonia uptake a t a maximum r a t e o f 13 yg per l i t e r per hour.
F i g u r e 10. - N i t r o g e n f i x a t i o n
r a t e s and the p a r t i c u l a t e
n i t r o g e n c o n c e n t r a t i o n i n Smith Lake s u r f a c e w a t e r ,
1963.
03Q
'1DO
AON
'1 d 3 S
isn 9nv
A inr
3Nnr
AVl^
T
/
001
'V/
ooe
OOtr
005
fc
*Q
N JJ D ir0 U J D d
1/
m m m
N
006
j:ate
008
PartiL
00Z
liter
009
N
Table No. 8 . -
The uptake o f n i t ro g e n compounds.
R e su lt s of
t r a c e r experiments, Smith Lake, 1963, s u r f a c e water.
ug N / l i t e r / h o u r
Date
5/30/63
6/12/63
6/19/63
6/26/63
7/02/63
7/16/63
7/23/63
7/30/63
8/07/63
8/1 2/6 3
8/20/63
8/27/63
9/03/63
9/10/63
9/17/63
9/30/63
10/25/63
11/13/63
NH^-N uptake
N0g-N uptake
N2 uptake
.13
.37
.86
.61
.59
.19
.79
.14
.18
.31
.37
.72
.36
.30
.29
.10
.00
.02
.26
.32
.01
.01
.01
.12
.02
.00
.09
.00
.00
.11
.02
.02
.05
.00
.00
.00
.00
.00
.00
.00
.00
.00
Table No. 9 . -
The uptake o f n it ro ge n compounds.
R e s u l t s of
t r a c e r experiments, Smith Lake, 1964.
N uptake - y g / 1 i t e r / h o u r
Date
2/26/64
3/18/64
3/31/64
4/13/64
4/28/64
5/01/64
5/05/64
5/12/64
5/18/64
5/23/64
5/27/64
6/01/64
6/0 4/6 4
6/06/64
6/08/64
6/10/64
6/12/64
6/15/64
6/18/64
6/23/64
6/30/64
7/07/64
7/13/64
7/21/64
7/28/64
8/08/64
8/11/64
8/18/64
8/27/64
9/0 3/6 4
9/10/64
9/2 2/6 4
10/06/64
NH3-N
.20
.07
.05
.56
1.00
1.40
2.24
13.03
6.01
.45
.95
1.22
.82
17.23
5.99
6.41
8.21
1.70
4.76
.94
5.36
.94
1.66
1.78
1.30
1.92
1.48
0.97
0.93
0. 78
1.52
0.88
0. 64
N03-N
. 0 1 (dk)
.00
.01
. 03( dk )
.06
.05
1.42
1.56
.01
.01
.36
4.88
4.12
.75
.37
.15
.15
.00
.13
.00
.00
.02
1.16
0.45
0.16
0.17
0.03
1.22
0.69
0.35
N2
.06
.02
1.76
2.45
2.88
2.28
.67
.19
.02
.30
.02
.01
.00
.01
.03
0.13
0.00
0.01
0.00
-
T o t al
N
.20
.08
.05
.57
1.03
1.46
2.29
14.45
7.57
.46
1.01
1.23
1.20
23.87
12.56
10.04
10.86
2.52
5.10
.96
5.79
.96
1.67
1.80
1.31
3.11
2.06
1.13
1.11
0.81
2.74
1.57
0.99
42
A l ower but s t i l l
time.
s i g n i f i c a n t n i t r a t e uptake was found a t the same
The n i t r o g e n regime in Smith Lake in S p r i n g appears to be
determined by the a v a i l a b i l i t y
Spring period.
little
The p o p u l a t i o n appears to b u i l d up at a time very
l i g h t c o ul d be r ea c hi n g the wat er , e s p e c i a l l y s i n c e most o f
the c h l o r o p h y l l
increase i s
i n c o n t a c t wi th the mud.
this
o f ammonia as a r e s u l t o f the a no xi c
in itial
in itially
I t i s p o s s i b l e t h a t the n u t r i t i o n d u ri n g
b u i l d - u p i n p o p u l a t i o n i s p r ed o mi n a nt l y h e t e r o t r o p h i c ,
since dissolve d organic material
at t h i s
a t the bottom i n wate r i mmediately
time.
is
c e r t a i n l y abundant in the water
The d e c l i n e i n p h y t o p l a n k t o n ,
and p a r t i c u l a t e n i t r o g e n i n f o r m a t i o n , as w ell
p h o t o s y n t h e s i s and n i t r o g e n a s s i m i l a t i o n
as seen i n the c h l o r o p h y l l
as the r e d u c t i o n in
r a t e s , co r re sp ond s i n time
to the e x h a u s t i o n o f the ammonia s u p p l y i n the water.
The second major p e r i o d o f n i t r o g e n uptake, then, takes p l a c e
s h o r t l y a f t e r the i c e i s mel ted,
representing a period o f rapid
i n c r e a s e in temperature and a v a i l a b l e l i g h t .
The f i r s t p o i n t t h a t becomes o bvi ou s i n c o nnec t ion w i t h the June
bloom in 1964 i s
t h a t even though a h ig h r a t e o f n i t r o g e n f i x a t i o n was
found, amounting to 3 pg per l i t e r per hour, t h i s s o u r ce appears
i n s i g n i f i c a n t when compared w i th the r a t e o f ammonia a s s i m i l a t i o n
found d u ri n g t h i s f l o w e r i n g .
The peak ammonia and n i t r a t e uptake r a t e s ,
r e s p e c t i v e l y 17.2 and 5 y g per l i t e r per hour, took p l a c e s e v e r a l
b e fo r e the peak in n i t r o g e n f i x a t i o n .
The n i t r o g e n f i x a t i o n peak
corres ponded i n time wi th the p h o t o s y n t h e s i s peak.
chlorophyll
days
The maximum
a c o n c e n t r a t i o n was found a few days l a t e r , f o l l o w e d by
F i g u r e 11. - The uptake o f i n o r g a n i c n i t r o g e n s o u r c e s in Smith
Lake i n 1964 - the r e s u l t s o f s t a b l e i s o t o p e t r a c e r experiments
on s u r f a c e w a te r , i n cu b a t e d a t 20°C and c o n s t a n t l i g h t .
43
the peak i n p a r t i c u l a t e n i t r o g e n .
concentration i s
de l a y i s
S i n c e the p a r t i c u l a t e n i t r o g e n
in a sense the i n t e g r a l
to be expected.
o f the uptake r a t e s ,
The ammonia a s s i m i l a t i o n
this
r a t e was reduced
t o 6 . 4 yg per l i t e r per hour by the time t h a t n i t r o g e n f i x a t i o n
i t s maximum r a t e ,
reached
and the n i t r a t e uptake r a t e had been reduced to .8
yg p er l i t e r per hour.
The r a t e s o f n i t r o g e n f i x a t i o n over a p e r i o d o f ten days du r in g
June account f o r the c o n t r i b u t i o n o f about 500 yg per l i t e r o f newly
f i x e d n i t r o g e n to the s u r f a c e w at e r o f Smith Lake.
These r a t e s are
among the h i g h e s t h i t h e r t o measured in any l a k e , and are o f a s i m i l a r
o r d e r o f magnitude as those measured d u r i n g a f a l l
i n S a n c t u a r y Lake ( Dugdale and Dug dale,
surprising
tion.
I t is
therefore
to f i n d at the same time a h i g h r a t e o f ammonia u t i l i z a ­
I t i s p o s s i b l e t h a t d u r in g n i t r o g e n f i x i n g a c t i v i t y ,
uptake w i l l
always appear to be high.
i n the wa te r i s
increase th is
ammonia
Where the ammonia c o n c e n t r a t i o n
low, any l a b e l e d ammonia added w i l l
significantly
c o n c e n t r a t i o n , and s i n c e the m e t a b o l i c r a t e o f the
nitrogen fix in g
this
1962).
bloom o f Anabaena
o r ga ni s ms i s p r o b a b l y high they may r a p i d l y absorb
added ammonia, even though they had not been u s i n g ammonia
previously.
actual
The uptake r a t e measured then would not r e p r e s e n t an
i n s i t u r a t e , but c o ul d r a t h e r be an experi ment al
due to the a d d i t i o n o f the t r a c e r .
artifact,
However, the i n c r e a s e i n d i s s o l v e d
ammonia i n the w a t e r as soon as the ammonia uptake r a t e dropped (see
Ta bl e 5) i n d i c a t e s t h a t ammonia had i ndeed been removed r a p i d l y p r e ­
viously.
S i n c e the ammonia c o n c e n t r a t i o n in the wate r was not h i g h
d u r i n g t h i s h i g h uptake p e r i o d ,
this
uptake was p r o b a b l y the r e s u l t
44
o f a h ig h r a t e o f r e c y c l i n g .
The amount o f p a r t i c u l a t e n i t r o g e n
p r e s e n t in the wa te r du r in g May and the amount newly f i x e d in June
are t o g e t h e r s u f f i c i e n t to account f o r the peak v al ue in p a r t i c u l a t e
n i t r o g e n p r e s e n t i n the wate r in June.
The t o t a l
in F i g u r e 12.
the t o t a l
uptake o f a l l
It
three forms o f n i t r o g e n f o r 1964 i s shown
i s ap pa re nt , by comparing t h i s with F i g u r e 10, t h a t
uptake very c l o s e l y co rr es p on d s to the uptake o f ammonia,
and t h a t c l e a r l y ammonia i s
the most i m p or t a n t s o u r ce o f n i t r o g e n to
the p h y t o p l a n k t o n in Smith Lake.
The uptake o f n i t r a t e i s
i mp or t an t in Smith Lake; however on two o c c a s i o n s
not Very
i n A u g u s t and
September, n i t r a t e was b ei ng used a t about the same r a t e as ammonia.
The e x c r e t i o n o f n e w l y - f i x e d
n i t r o g e n by p hy t opl an kt on
Reports on n i t r o g e n f i x a t i o n have i n c l u d e d e s t i m a t e s o f the amount
o f n i t r o g e n e x c r et ed i n t o the medium by b l u e - g r e e n a l g a e ( Fo g g, 1952).
I n Smith Lake, experiments were c a r r i e d out u s i n g the same samples as
th os e used f o r measuri ng n i t r o g e n f i x a t i o n , s o t h a t a r e l a t i o n s h i p be­
tween the amount o f n i t r o g e n f i x e d and the amount a pp e a r i n g in the
medium c o ul d be e s t a b l i s h e d .
particulate fraction,
by d i s t i l l a t i o n ,
F o l l o w i n g i n c u b a t i o n and removal o f the
the ammonia f r a c t i o n in the sample was c o l l e c t e d
and i t s
i s o t o p e r a t i o determined by l i q u i d c o n v e r s i o n
to n i t r o g e n gas u s i n g a l k a l i n e hypobromite as d e s c r i b e d i n N ees s, et a l .
(1962) .
The r emai ni ng w at e r was then c o nc e n t r a t e d by b o i l i n g ,
and then
d i g e s t e d by the m i c r o - K j e l d a h l method i n o r d e r to c o l l e c t the d i s s o l v e d
F i g u r e 12. - The t o t a l
uptake o f i n o r g a n i c n i t r o g e n i n Smith Lake,
1964.
H P P f i f m t u w u p ^ m i f f p v p i p f iipp
N 2 upt a k e ----------- --------------N O 2— N u p t a k e
mip11 miMipi
45
organic fraction.
digestion,
Th is was c o l l e c t e d as ammonia f o l l o w i n g the
c onvert ed t o n i t r o g e n gas as above and i t s
isotope r a t i o
measured.
Table 10 shows the r e s u l t s o f these d e t e r m i n a t i o n s .
I t must be
kept i n mind t h a t the l a k e water has an unknown amount o f d i s s o l v e d
o rgan ic material
o f unknown n i t r o g e n c o nt e n t , s o t h a t the d i s s o l v e d
o r g a n i c i s o t o p e r a t i o s c o ul d r e p r e s e n t a c o n s i d e r a b l e d i l u t i o n .
The ammonia c o n c e n t r a t i o n in the wa te r was i n c r e a s i n g d u r i n g the
c our se o f these e x p e ri m en t s, so t h a t to some e x t e n t the decreas e in
enrichment i n the ammonia f r a c t i o n i s
compensated, and the a c t u a l
e x c r e t i o n o f ammonia i s p r o b a b l y i n c r e a s i n g .
S i g n i f i c a n t l y high i s o t o p e r a t i o s
i n the d i s s o l v e d o r g a n i c f r a c t i o n
were found on June 12th, c o r r e s p o n d i n g t o the time o f a k i n e t e d i f f e r e n ­
t i a t i o n i n the Anabaena f i l a m e n t s .
On t h i s day, a l l
th ree i n c u b a t i o n
methods were used, and the h i g h e s t e x c r e t i o n o f both ammonia and
d i s s o l v e d o r g a n i c n i t r o g e n was found in the f l a s k which had been
i n c u b a t e d on the r o o f.
this
The r e d u c t i o n i n n i t r o g e n f i x a t i o n r a t e i n
f l a s k when compared w i t h the o t h e r two i n d i c a t e s s ub op ti mal
d i t i o n s wi th t h i s i n c u b a t i o n method, and p o s s i b l y t h i s
w i t h the h i g h e r e x c r e t i o n r a t e s .
is
con­
connected
However, one ex peri ment alone i s
i n s u f f i c i e n t to e s t a b l i s h any such c o nnec t io n.
There i s
also a
p o s s i b i l i t y t h a t the 2 4 - h r i n c u b a t i o n was s u f f i c i e n t l y l ong f o r some
breakdown i n c e l l s ,
and t h a t some m a t e r i a l
t o the medium i n t h i s way.
c o u l d have been r e l e a s e d
Table No. 10.-
Date
The e x c r e t i o n o f d i s s o l v e d n i t r o g e n d u r in g n i t r o g e n f i x a t i o n .
Incubation
method
(24 h o u r s )
Atom percer
percent
e x c e s s T5>
,3N
in p a r t i c u l a t e
f r a c t i on
Atom p e r c e n t
ex ce ss 15 m
i n ammonia
fraction
Atom p e r ce n t
ex ce ss in
d isso lve d organic
fraction
V I -08-64
In s i t u
3.2799
0.1180
0.0069
V I -10-64
In s i t u
3.1240
0.1266
0.0000
VI —12-64
Roof tank
2.1070
0.6048
0.1276
V I —12—64
In s i t u
4.2455
0.1601
0.0717
V I - 1 2 —64
20° room
4.5601
0.0930
0.1051
VI —18—64
20° room
0.5761
0.0338
0.0000
46
De t er mi n at i on o f the r a t e o f ammonia
s u p p l y i n Smith Lake water
I n many cas es the ammonia uptake r a t e was h i g h e r than the
amnonia c o n c e n t r a t i o n in the wa te r would i mpl y.
Rates o f ammonia
uptake, o f c o ur s e , p r o v i d e an i d e a o f the r a t e o f s u p p l y ; however,
a more d i r e c t method o f e v a l u a t i n g t h i s was a l s o employed.
The t e ch n iq ue used was d e s i gn e d t o measure the r a t e o f d i l u t i o n
o f l a b e l e d ammonia added to the l i q u i d f r a c t i o n .
11.9 yg-atoms per
l i t e r o f n i t r o g e n - 1 5 l a b e l e d ammonia was added t o l ake w a t e r , and
i mmed ia tel y an a l i q u o t was f i l t e r e d to remove the p a r t i c u l a t e m a t e r i a l .
The ammonia i n the f i l t r a t e was c o l l e c t e d by d i s t i l l a t i o n
i s o t o p e r a t i o determined.
f o r the experiment.
T h i s r e p r e s e n t e d the i n i t i a l
and i t s
isotope r a t io
The t e c hn i q u e s f o r c o n v e r t i n g the ammonia to
n i t r o g e n and o b t a i n i n g the i s o t o p e r a t i o were s i m i l a r to those used
i n h a n d l i n g the l i q u i d samples i n the e x c r e t i o n ex peri ment s d e s c r i b e d
above.
The sample was now i n c u b a t e d , and then the ammonia was c o l l e c t e d
as above and i t s
ratios
i s o t o p e r a t i o determined.
From t h es e two i s o t o p e
the r a t e o f d i l u t i o n was c a l c u l a t e d :
Fractional
rate =
A 1'-
ft.f.
t • Aa
where Aa = the average i s o t o p e r a t i o d u r i n g the ex peri ment , and t =
i n c u b a t i o n time.
47
Any r e d u c t i o n i n the i s o t o p e r a t i o o f the ammonia f r a c t i o n o ver t h i s
in itial
v a l u e has to r e s u l t from the a d d i t i o n o f u n l a b e l e d ammonia
from ano th er n i t r o g e n f r a c t i o n
in the s ys te m, and t h e r e f o r e r e p r e s e n t s
ammonia s u p p l y .
Results:
A-j
= 84.54%
A f = 14.18%
t =
Fractional
Au g us t 11, 1964
9.25 hr
r a t e o f s u p p l y = .1541.
P ercent age r a t e o f s u p p l y =
15.4 per hour.
A b s o l u t e r a t e o f ammonia s u p p l y 1.83 ug-atoms per l i t e r per hour.
The measured ammonia uptake
rate
at th is
time was 1.48
yg per
l i t e r per hour ( o r .11 yg- at oms p er l i t e r
p er hour) and th ere was
no d e t e c t a b l e ammonia i n the wate r a t t h i s
time.
DISCUSSION
The p r o d u c t i o n under the i c e
I t is
c l e a r from the i n o r g a n i c n i t r o g e n r e s u l t s
th at a large
amount o f ammonia appears in the wa te r under the i c e in s p r i n g ,
and
t h a t the f i r s t p o p u l a t i o n o f a l g a e depend l a r g e l y on t h i s s o u r c e f o r
t h e i r n i t r o g e n s u p pl y .
above.
The s o u r c e s o f t h i s ammonia have been d i s c u s s e d
The ammonia c o n c e n t r a t i o n i s
reduced by the a l g a e from 46.4
y g - a t o m s / l i t e r to u n d et e c ta b l e l e v e l s , which i n t h i s c a se r e p r e s e n t
c o n c e n t r a t i o n s somewhat lower than .2 yg - a t o m s / l i t e r .
t h is high a s s i m i l a t i o n ,
13 y g / l i t e r / h r
At the peak o f
( . 93 y g - a t o m s / h r ) o f ammonia
n i t r o g e n was b ei ng removed, and the amount a v a i l a b l e in the water was
7.18 y g - a t o m s / 1 i t e r .
T h i s amount would be ex haus te d in one day a t the
measured r a t e o f removal.
The p r o c e s s e s which r e l e a s e ammonia to the
w a t e r a p p a r e n t l y a ll o we d the p o p u l a t i o n to use a l a r g e r amount than
was p r e s e n t in the w at e r, a l t h o u g h both the r a t e o f removal
s t a n d i n g c o n c e n t r a t i o n i n the w at e r g r a d u a l l y d e c l i n e d u n t i l
and the
the
ammonia was c o m p l et e l y exhausted.
Dur ing the most a c t i v e p e r i o d o f ammonia uptake which covered a
p e r i o d o f 13 d a y s , an a ve rage o f 140 yg / l i t e r / d a y
(10 yg - a t o m s / l i t e r / d a y )
was a s s i m i l a t e d , whereas the d e c l i n e in the wa te r amounted to 6.41 y g - a t o m s /
l i t e r f o r the whole p e r i o d .
liter/day.
T h i s d e c l i n e a ve r ag e s o ut to .49 y g - a t o m s /
Th e re f or e 9 . 5 y g - a t o m s / 1 i t e r / d a y more ammonia was used than
was a p p a r e n t l y a v a i l a b l e .
P a r t o f t h i s d i s c r e p a n c y c o u l d r e p r e s e n t the
48
49
d i f f e r e n c e between g r o s s and net uptake o f n i t r o g e n , s i n c e the
t r a c e r method p r ob a b l y measures g r o s s uptake where s h o r t i n c u b a t i o n
times are used.
In a d d i t i o n , b a c t e r i a l
breakdown o f n i t r o g e n o u s
o r g a n i c m a t e r i a l was undoubtedly c o n t i n u i n g d u r i n g t h i s
a maj or p a r t o f the ammonia came from t h i s s o u r c e .
figures
i n d i c a t e t h a t ammonia s u p p l y i s
time.
Possibly
I n any e v e n t, these
i m p or t a n t d u r i n g such p e r i o d s
o f h i g h p r o d u c t i o n , and t h a t the d e c l i n e i n ammonia i n the w at e r i s
not a good measure o f the amount used, s i n c e 95 p e r ce n t o f the ammonia
used would have been m i s s e d by such methods.
Only 27.3 p er ce n t o f the
n i t r o g e n taken up showed up i n the p a r t i c u l a t e n i t r o g e n a t i t s maximum
concentration during th is period.
in y g - a to m s /1 ite r to ch lorop hyll
The r a t i o o f p a r t i c u l a t e n i t r o g e n
a^ in y g / l i t e r was 1.52, which i s
s i m i l a r t o the 1.65 r a t i o g i v e n by H a r r i s
(1959) f o r Long I s l a n d Sound
d u r i n g the b u i l d - u p o f a s p r i n g f l o w e r i n g .
The f i r s t
increases
when th ere was s t i l l
covered by s e v e r a l
in c h l o r o p h y l l ji appeared i n the deep water
more than one meter o f i c e on the l a k e s u r f a c e
i n ch es o f snow.
under low l i g h t c o n d i t i o n s .
i n the i n i t i a l
These o r ga ni s ms t h e r e f o r e grew
P o s s i b l y p a r t o f t h i s gr owth , a t l e a s t
p h a se s, was h e t e r o t r o p h i c .
true a r c t i c lake, Juoblatjokkojaure,
Rodhe (1963) d e s c r i b e s a
i n which th ere are l a r g e numbers
o f nannoplankton i n s p i t e o f extr emely low temperatures and o t h e r w i s e
seemingly in h o s p it a b le co ndition s.
as i n Smith Lake, C h l o r e l ! a i s
I t is
i n t e r e s t i n g to note t h a t here,
among the most numerous components,
a l t h o u g h i n Rodhe's cas e d i n o f l a g e l l a t e s
dominated i n b u l k .
Rodhe
f e e l s t h a t h e t e r o t r o p h i c p r o c e s s e s must be a l l o w i n g the gr owth , and
50
his p relim inary t e s t s with
this.
l a b e l e d g l u c o s e seemed to s u b s t a n t i a t e
The system, then, depends on energy s t o r e d d u r i n g the p r e v i o u s
summer through a u t o t r o p h i c p r o c e s s e s to i n i t i a t e the s p r i n g grwoth,
s o t h a t when l i g h t c o n d i t i o n s become s u i t a b l e the p o p u l a t i o n i s
p r e s e n t and can s w i t c h to a u t o t ro ph y.
In Smith Lake, by mi d-May,
s u f f i c i e n t l i g h t may p e n e t r a t e the i c e and snow to a l l o w t h i s .
the low sun a n g l e r e s u l t s
already
Earlier,
i n high a lb e d o , and f u r t h e r reduces the
p e n e t r a t i o n o f l i g h t i n t o the water.
Chi o r e ! l a i s
c ap ab le o f growth
h e t e r o t r o p h i c a l l y , m i x o t r o p h i c a l l y and a u t o t r o p h i c a l l y , and i t s
b e h a v i o u r under these d i f f e r e n t growth c o n d i t i o n s has been s t u d i e d by
E y s t e r , Brown and Tanner (1958) in terms o f m i n er a l
requirement s.
M i x o t r o p h y c o ul d a l l o w the e f f i c e n t use o f any l i g h t p e n e t r a t i n g the
ice.
I n any e v e nt , h e t e r o t r o p h y i s
a p o s s i b l e mechanism a l l o w i n g the
e a r l y development o f p hy t o p l a n k t o n under the i c e .
A s i m i l a r argument
was used by W r i g h t (1964).
The Anabaena s p . bloom
The bloom in June i s o f i n t e r e s t as the o n l y p e r i o d in which
n i t r o g e n f i x a t i o n s u p p l i e s a p o r t i o n o f the n i t r o g e n f o r the p h y t o pl a n kt o n.
All
the i n o r g a n i c n i t r o g e n in the w at e r i n combined form had been used
up p r i o r to t h i s bloom.
In each o f the y e a r s , t h i s bloom o cc ur r ed a t
the time o f maximum d a y - l e n g t h , when the wate r was r a p i d l y warming t o
i t s summer temperature.
I t i s not so e a s y i n t h i s
case to c a l c u l a t e the c o n t r i b u t i o n o f
n i t r o g e n from v a r i o u s s o u r c e s , s i n c e newly f i x e d n i t r o g e n may be i mmed ia tel y
51
r e l e a s e d to the water and then r e a s s i m i l a t e d .
There was no n i t r a t e
o r ammonia i n the w at e r a t the s t a r t o f the bloom, and t h e r e f o r e the
uptake o f n i t r o g e n in these forms must r e p r e s e n t the r e g e n e r a t i o n
o f n i t r o g e n from the p r e v i o u s growth p e r i o d o r the r e c y c l i n g o f newly
fix e d nitrogen.
The e x c r e t i o n i n f o r m a t i o n d i s c u s s e d above i n d i c a t e s
t h a t the l a t t e r may not be i m p o r t a n t ; however, the i n c u b a t i o n s f o r the
experi ments d e s c r i b e d i n Tabl e No. 10 were 24 h r , and i f
time i s much s h o r t e r ,
the t u r n o v e r
r e c y c l i n g would no t n e c e s s a r i l y be de te ct e d in
t h i s way.
The cause o f the t e r m i n a t i o n o f the bloom i s o f i n t e r e s t , s i n c e
p r e c i p i t o u s d e c l i n e seems to be a p r o p e r t y o f s p r i n g blooms r e g a r d l e s s
of latitude.
Lund (1950) was i n t e r e s t e d i n t h i s problem i n s e v e r a l
l a k e s o f the E n g l i s h Lake D i s t r i c t ,
bloom d e c l i n e t o s i l i c a
(1932).
s h o r t a g e c o n f i r m i n g the s u g g e s t i o n o f P e a r s a l l
The o rgani s ms i n t h i s
formosa Hass.
and he a t t r i b u t e d the s p r i n g
case were p r ed o mi n an t ly A s t e r i o n e l l a
I n Smith Lake the e a r l i e r bloom under the i c e d e c l i n e d
p r o b a b l y as a r e s u l t o f ammonia e x h a u s t i o n , and the r e g e n e r a t i o n r a t e
a t the low temperatures under the i c e may no t have been adequate to
s u p p o r t f u r t h e r growth.
The bloom i n June, however, was dominated by
Anabaena s p . , the dominant s p e c i e s b ei ng Anabaena f l o s - a q u a e .
Since
n i t r o g e n f i x a t i o n was being c a r r i e d o u t , presumably by t hes e a l g a e ,
n i t r o g e n e x h a u s t i o n cannot be a cause o f the bloom t e r m i n a t i o n i n
itself.
The most p l a u s i b l e e x p l a n a t i o n s t i l l
lies
in e x h a u s t i o n o f
some o t h e r n u t r i e n t .
I f nutrient lim itation
is
a f a c t o r t e r m i n a t i n g the s p r i n g bloom
52
i n Smith Lake, the most l i k e l y c r i t i c a l
p ho sph or us , i r o n o r molybdenum.
elements i n v o l v e d are
The f i r s t i s ,
o f c o u r s e , an
e s s e n t i a l n u t r i e n t which has been i m p l i c a t e d as a l i m i t i n g f a c t o r
i n many c as e s .
The amount r e q u i r e d f o r normal growth i s not g r e a t ,
however, and B e n o i t and C u r r y (1961) g i v e the c r i t i c a l
o f phosphorus f o r b l u e - g r e e n a l g a e as about 10 ppb.
concentration
Th is
is equivalent
to about 0.2 yg - a t o m s / l i t e r , which i s s i m i l a r t o the minimum c o n c e n t r a ­
t i o n found i n Smith Lake du r in g the bloom ( see Table 10, Appendix B).
C o ffin, et al.
(1949) have shown t h a t e s t i m a t i o n s o f s o l u b l e phosphate
are no t r e l i a b l e i n d i c e s o f f e r t i l i t y
i n some l a k e s , because th ere
tends t o be an e q u i l i b r i u m between s u p p l y and demand.
Hutc hi ns on and
Bowen (1950) have found t h a t the r a t e o f r e g e n e r a t i o n o f phosphorus
a f t e r uptake by p h y t o p l a n k t o n i s ver y r a p i d .
th is experimentally.
R i g l e r (1956) confi rmed
He used r a d i o a c t i v e p ho s ph or u s, and showed t h a t
phosphorus was being taken up by o r ga ni s ms even though the amount
d e t ec t ed a n a l y t i c a l l y remained c o n s t a n t , and from t h i s concluded
t h a t the phosphorus was b ei ng turned o v e r very r a p i d l y .
The c a l c u l a t e d
t u r n o v e r time f o r o rt h op ho s ph at e i n the t r o p h o g e n i c zone o f the lake
was o n l y 3.6 mi nutes.
L a t e r work by the same i n v e s t i g a t o r ( R i g l e r ,
1964) confi rmed t h i s r e s u l t ,
and in a d d i t i o n showed t h a t in a h i g h l y
p r o d u c t i v e l a k e , the t u r n o v e r time c o ul d be as s h o r t as 1 minute.
It
seems u n l i k e l y t h a t i n Smith Lake l a c k o f phosphorus cau ses the d e c l i n e
o f the bloom, s i n c e the phosphorus pool
in the l a k e i s
l a r g e , and even
i n 1963, when there was c o n t a c t between the mud s u r f a c e and the
t r o p h o g e n i c r e g i o n d u r i n g the bloom, the t e r m i n a t i o n o cc ur r ed i n a
53
s i m i l a r manner, a lt h o u g h l e s s a b r u p t l y .
The o t h e r two elements mentioned were s u g g e s t e d f o r the f o l l o w i n g
r ea so n s.
Iron i s
green a l g a e ,
r e q u i r e d in h ig h amounts by n i t r o g e n f i x i n g
blue-
and by the time the bloom d e c l i n e d , n i t r o g e n f i x a t i o n
was p r o v i d i n g 50 p er ce n t o f the n i t r o g e n f o r growth.
Maximum f i x a t i o n
o f n i t r o g e n takes p l a c e a t a c o n c e n t r a t i o n o f 10 m g / l i t e r o f f e r r i c
i r o n a c c o r d i n g to Carnahan and C a s t l e ( 1958) , and i s
both h i g h e r and lower c o n c e n t r a t i o n s
muscorum.
in h i b it e d at
in the b l u e - g r e e n a l g a Nos toe
S h a p i r o (1964) has shown t h a t y e l l o w o r g a n i c m a t e r i a l
of
the type found in Smith Lake water b i n d s i r o n i n c r e a s i n g l y f i r m l y
as the pH i n c r e a s e s ,
and i t
i s n o t a b l e t h a t the bloom d e c l i n e c o i n c i d e s
i n time w i t h an i n c r e a s e o f the pH o f the water.
The consequent
u n a v a i l a b i l i t y o f a metal would p r o v i d e a p o s s i b l e c o n n ec t io n.
b e h a v i o r o f molybdenum i n the presence o f o r g a n i c m a t e r i a l
known, b u t i t
is
The
i s not
r e q u i r e d in e c o l o g i c a l l y l a r g e amounts f o r n i t r o g e n
f i x a t i o n , and p r e l i m i n a r y enrichment experi ments wi th t h i s metal
r e s u l t e d i n 100 p e r ce n t i n c r e a s e in the ^ C
i n c u b a t i o n w i th a d d i t i o n a l molybdenum.
this
time had no g r e a t e f f e c t .
uptake a f t e r one day
The a d d i t i o n o f phosphate a t
The e f f e c t o f pH c o u l d a l s o be d i r e c t
i n r ed u c i n g the amount o f f r e e C02 i n the w a t e r , and t h e r e f o r e i n h i b i t i n g
photosynthesis.
Dur ing the peak o f the bloom, ^ C
uptake experi ments
were c a r r i e d out i n which ^ C was added to samples which were b u f f e r e d
a t pH 8.5 and 9.2 as w e ll
as c o n t r o l s a t l a k e wa te r pH o f about 7.4.
T h i s was d u r i n g the peak n i t r o g e n f i x a t i o n time.
A relationship
r e s u l t e d , i n which 14C uptake i n c r e a s e d w i th the i n c r e a s e i n pH in
54
a l i n e a r manner:
ug C/1 i t e r / h r
I t is
pH
7.4
12.38
pH
8.5
19.12
pH
9.2
23.46
f e l t that th is
indicates
was i ndeed p r e s e n t , r e s u l t i n g
June 10, 1964
t h a t very l i t t l e
o r g a n i c carbon
in a high proportional
uptake which
i n c r e a s e d w i t h pH as the a v a i l a b l e carbon d e c re as ed , p ro d uc i ng an
ap pa re nt i n c r e a s e i n p h o t o s y n t h e s i s w i th pH, which was in f a c t an
artifact.
The o r i g i n a l
v a l u e f o r a l k a l i n i t y was used in c a l c u l a t i n g the
a v a i l a b l e carbon, and s i n c e some o f the carbon was p r o b a b l y l o s t
t o the system by p r e c i p i t a t i o n o f c ar b o n a t e , t h i s o v e r e s t i m a t e o f
amount o f carbon c o ul d r e s u l t in a h ig h p r o p o r t i o n a l
a l s o ap pe ar i ng to be a h i g h a b s o l u t e uptake r a t e .
a c c u mu l a t i on r a t e
The amount o f f r e e
b i c a r b o n a t e may be the most r e a d i l y a v a i l a b l e s ou r ce .
However, i t
i s p o s s i b l e t h a t the p h o t o s y n t h e t i c r a t i o does indeed i n c r e a s e w i t h
pH i n t h i s range.
W r i g h t (1960) f e e l s
t h a t CO2 l i m i t a t i o n
is
bound
to be i n e f f e c t where n u t r i e n t l i m i t a t i o n i s not c o n t r o l l i n g the r a t e
of chlorophyll synthesis.
This
l i m i t a t i o n would be d e n s i t y dependent.
Ano th er p o s s i b i l i t y f o r the d e c l i n e o f the bloom i s
the a l g a e
thems el ves e x c r e t i n g a t o x i c s u b s t a n c e which accumulates as the
population increases
in both d e n s i t y and age.
Such a s u b s t a n c e ,
termed an e x o t o x i n , may i n i t i a l l y s e r v e t o p r ev e n t the growth o f o t he r
55
a l g a e , but e v e n t u a l l y i t
i s p o s s i b l e t h a t the s p e c i e s which produces
i t can no l o n g e r t o l e r a t e i t s
this
own g r o w t h - i n h i b i t i n g s u b s t a n c e s , and
c o ul d r e s u l t i n a sudder. crash i n p o p u l a t i o n .
Anabaena f l o s -
a q u a e , the dominant a l g a e i n the Smith Lake bloom has been s t u d i e d
by Gorham e t a l . ,
( 1964) , who f i n d t h a t i t e x c r e t e s s u b s t a n c e s t o x i c
to mammals and b i r d s .
I t i s no t known to what e x t e n t t hes e s ub s t a n c e s
are t o x i c t o z o op l a n k t o n , o t h e r a l g a e o r the Anabaena i t s e l f .
i t is strikin g
to note t h a t a t the peak o f the bloom Anabaena i s
almost u n i a l g a l ,
i s not unusual
However,
and th ere are very few z o op lan kt on .
However, i t
to f i n d fewer g r a z e r s a t the peak o f a bloom.
Ryt he r
(1954) has d i s c u s s e d such r e l a t i o n s h i p s .
A v i r u s which i s
a b l e to cause l y s i s
been r ep o r t e d by Saf ferman and M o r r i s
i n b l u e - g r e e n a l g a e has
( 19 6 3) , and t h i s
mechanism f o r bloom t e r m i n a t i o n in l a k e s .
is a possible
S i l v e y and Roach (1964)
s u g g e s t t h a t t h i s may be an e x p l a n a t i o n o f sudden d i s a p p e a r a n c e o f
blue-green a lg a l
cells
t h a t have a t t a i n e d h ig h d e n s i t i e s .
I n the Smith Lake bloom, the p r e c i s e t i m i n g f o r the two y e a r s
was s i m i l a r ,
and y e t the peak was much s h a r p e r i n 1964 than i n 1963.
Th is d i f f e r e n c e i n peak shape c o ul d have been due to the s t r a t i f i c a ­
t i o n o f the l a k e i n the former y e a r ,
to become c r i t i c a l more r a p i d l y .
in causing n u t rie n t depletion
In 1963, c o n t a c t w i t h the deeper
wa te r and the bottom mud a ll o w e d a l o n g e r p e r i o d o f h i g h p r o d u c t i o n .
A f t e r the bloom, however, the p r o d u c t i o n i n 1964 was h i g h e r , c o n f i r m i n g
the assumpti on t h a t m i x i ng f o l l o w i n g the bloom r e p l e n i s h e d a n u t r i e n t ,
which had remained i n the w a t e r because i t had not been a v a i l a b l e
d u r i n g the bloom.
56
The post-b loom p ro d u ctio n
Violent fluctuations
in a l g a e p o p u l a t i o n s are c h a r a c t e r i s t i c
o f c o n t r o l by n u t r i e n t d e p l e t i o n .
p r o d u c t iv i t y rates,
levels
tions.
In Smith Lake d u r in g J u l y ,
n i t r o g e n uptake r a t e s and n i t r o g e n n u t r i e n t
remain a l m os t c o n s t a n t , w i th o n l y s ma ll
and g r a d u a l
A d i f f e r e n t ki nd o f mechanism was then o p e r a t i n g .
remained the p r i n c i p a l s o u r ce o f n i t r o g e n d u r in g t h i s
uptake v a r i e d d i r e c t l y w i th p h o t o s y n t h e s i s ;
not c o n t r o l l i n g p r o d u c t i o n .
fluctua­
Ammonia
time, and i t s
t h u s , n i t r o g e n was p r ob a b l y
The amount o f ammonia p r e s e n t a t any
time was s u f f i c i e n t to a l l o w uptake a t the r a t e s measured f o r one o r
two days .
Very l i t t l e
Much o f the ammonia used, a g a i n , must have come from r e c y c l i n g .
n i t r a t e was p r e s e n t d u r in g t h i s
time.
On A u g u s t 11th, the ammonia c o n c e n t r a t i o n f e l l
lim it of detectability,
was measured.
below the lower
and y e t an uptake r a t e o f 1.48 yg / l i t e r / h r
However, the ammonia s u p p l y experi ment d e s c r i b e d above
f o r the same date s u g g e s t s a r a t e o f r e p l en i s hm en t in the w at e r which
i s even h i g h e r than would be assumed from the uptake measurements.
this
At
time o f y e a r the r oot ed v e g e t a t i o n around the s ho re i s w el l
developed, and th ere i s p r o b a b l y movement o f n u t r i e n t s from the open
w at e r t o these p l a n t s .
this
H o r i z o n t a l movement c o ul d be i m p o r t a n t a t
time.
D ur i n g the more o r l e s s s t e a d y - s t a t e p e r i o d i n the l a k e , zoop lan kton
c o ul d have p r o v i d e d both the c o n t r o l mechanism f o r a l g a l
population s i z e
and a l s o the mechanism f o r r e c y c l i n g ammonia d i r e c t l y and r a p i d l y .
57
T h i s type o f mechanism was d e s c r i b e d by H a r r i s
Sound.
(1959) in Long I s l a n d
Th is a u t ho r p o i n t s o ut t h a t the time r e q u i r e d f o r such r et urn
o f n u t r i e n t s by the animal p o p u l a t i o n i s n e g l i g i b l e when compared wi th
the time r e q u i r e d f o r b a c t e r i a l
p r o c e s s e s , and t h a t t h i s mechanism
r e t u r n s n u t r i e n t s to the p h y t o pl a n kt o n and thus b o l s t e r s
population r a p id ly ,
up the
p r o v i d i n g food f o r the expanding animal p o p u l a t i o n .
A r a p i d p o s i t i v e feedback thus o pe r at es between p h y to pl an k to n and
z o op lan kt on .
Zo opl ankton were abundant i n Smith Lake d u r i n g most o f
the summer f o l l o w i n g the s p r i n g f l o w e r i n g ,
building
up to about 30
i n d i v i d u a l s p er l i t e r a t the s u r f a c e i n e a r l y September.
I n A u g u s t , the i n c r e a s e in both ammonia and n i t r a t e uptake r e s u l t e d
i n d e p l e t i o n o f the ammonia.
Following th i s
a lower s t e a d y ammonia
uptake w i t h c o n s t a n t l y d e t e c t a b l e but low n i t r a t e uptake r a t e s co nt i nu e d
f o r the remainder o f the month.
N i t r a t e was used a l m o s t as r a p i d l y
as ammonia i n September, a t a time when the dominant a l g a was Sel enas tr um
sp.
In October, ammonia and n i t r a t e were used, in the r a t i o 2 : 1 ,
population at t h i s
the
time c o n s i s t i n g al mos t e x c l u s i v e l y o f Gymnodinium s p .
C o n tr o l by g r a z i n g was the e x p l a n a t i o n i nvoked by Anders on, Comi ta,
and Engstrom-Heg (1955) f o r such i n v e r s e r e l a t i o n s h i p s between z oopl ankton
and p h y t o pl a n kt o n i n two Washington l a k e s .
N i t r a t e as a n i t r o g e n - s o u r c e in Smith Lake
The l a c k o f i mportance o f n i t r a t e as a n i t r o g e n s ou rc e i n Smith
Lake may be due i n p a r t t o i t s
unavailability.
e vi de nce t h a t s i g n i f i c a n t r a t e s o f n i t r i f i c a t i o n
However, th e re i s
do take p l a c e i n the
58
s u r f a c e wa te r o f the l a k e d u r i n g the summer months.
In 1963,
n i t r i f i c a t i o n was a n t i c i p a t e d f o l l o w i n g the r e l e a s e o f n i t r o g e n
from the June bloom, and wi th the c o op e r a t i o n o f Dr.
S t a n l e y Watson
enrichment c u l t u r e s d e s i g n e d to i s o l a t e n i t r i f y i n g o r g an i sms were
s e t up.
These produced c u l t u r e s wi th very s t r o n g n i t r i f y i n g
w i t h i n a few da ys , i n d i c a t i n g
t h a t the o rgani s ms i n i t i a l l y were
p r o b a b l y p r e s e n t i n l a r g e numbers in the water.
levels
i n the wa te r a t t h i s
n i t r i f i c a t i o n g o i n g on.
ab ility
The high n i t r a t e
time s u g g e s t t h a t there was i ndeed a c t i v e
In 1964, the s ma l l n i t r a t e i n c r e a s e f o l l o w i n g
the bloom c o i n c i d e d w i th the f i r s t m i x i ng o f the l a k e , and s o i t i s
not e a s y to e s t a b l i s h i t s
very l i t t l e
origin.
However, p r e v i o u s l y there had been
n i t r a t e a t any depth, and a s t e a d y s l ow i n c r e a s e from
June 18 t o June 30 took p l a c e , so t h a t p r o b a b l y some n i t r i f i c a t i o n was
b ei ng c a r r i e d out.
Steemann N i e l s e n (1959) has p o i n t e d out t h a t in s h a l l o w waters
i n c o n t a c t w i th the bottom, temperature i s an i m p o r t a n t f a c t o r
g o v e r n i n g p r o d u c t i v i t y , because the b a c t e r i a l enz yma ti c p r o c e s s e s
r e s p o n s i b l e f o r n u t r i e n t r e g e n e r a t i o n are temperature dependent.
Since n i t r i f i c a t i o n
i s an i m p or t a n t p r o c e s s d u r i n g much o f the w i n t e r
under the i c e i n Smith Lake, i t s h o u l d be even more so a t the h i g h e r
summer temperatures .
N e v e r t h e l e s s , most o f the time the ammonia i s
a p p a r e n t l y used r a p i d l y and the r a t e would s u f f i c e t o p reven t s i g n i f i ­
c a n t a cc umul at i on.
In 1963, the n i t r a t e acc umu la t io n f o l l o w i n g the
June bloom c o ul d be e x p l a i n e d by the complete d e p r e s s i o n o f uptake,
s i n c e the d e c l i n e i n p h o t o s y n t h e s i s and a l g a e p o p u l a t i o n was so extreme
59
i n t h a t y e a r.
The b e h a v i o r o f n i t r a t e p r o v i d e s c o n f i r m i n g evi de nce f o r the
i de a t h a t d e p l e t i o n o f ano th er n u t r i e n t i s
the June bloom.
the t e r m i n a t i n g cause f o r
The e x h a u s t i o n o f molybdenum, f o r i n s t a n c e , would
p r ev e n t the u t i l i z a t i o n o f n i t r a t e .
o b viou sly replenished e s s e n t ia l
In 1964, m i x i ng from the bottom
nutrients,
and a ll o we d the n i t r a t e to
be used, whereas i n 1963 the e n t i r e wa te r column was a p p a r e n t l y d e pl et ed.
I n t e r r e l a t i o n s h i p s w i th m i c r o o r g a n i s m s
U n f o r t u n a t e l y very l i t t l e
is
known about the r e l a t i o n s h i p
between a l g a l
p r o d u c t iv i t y cycles
water.
r e a s o n a b l e t o assume t h a t n i t r i f y i n g o r g a n i s m s , f o r
I t is
and o t h e r m i c r o o r g a n i s m s i n the
i n s t a n c e , i n c r e a s e i n numbers f o l l o w i n g a p e r i o d o f o r g a n i c p r o d u c t i o n .
Less obvi ou s r e l a t i o n s h i p s must s u r e l y a l s o o ccur.
S i I v e y and Roach
(1964) d e s c r i b e m i c r o b i o t i c c y c l e s i n s u r f a c e w a t e r s , and p o i n t out
t h a t th ere are c y c l i c a l
changes i n both b a c t e r i a and actimomycete
p o p u l a t i o n s accompanying those i n the a l g a e .
blooms,
With b l u e - g r e e n a l g a e
they f i n d an accompanying i n c r e a s e in g r a m - n e g a t i v e b a c t e r i a ,
whereas f o l l o w i n g the b l u e - g r e e n a l g a l
d e c l i n e , act i n omy c et e s a t t a c k
the remains o f the a l g a e , and reduce the b a c t e r i a l
by a n t i b i o t i c p r o d u c t i o n .
p o p u l a t i o n , presumably
F o l l o w i n g t h i s , g r a m - p o s i t i v e b a c t e r i a take
ov er , and then t he c y c l e may be repeated w i t h a n o th e r a l g a l
bloom.
Th i s type o f i n t e r r e l a t i o n s h i p c ould e x p l a i n the p r o d u c t i v i t y p a t t e r n s
i n many l a k e s .
The nat ure o f the r e l a t i o n s h i p between the g r a m - n e g a t i v e
60
b a c t e r i a and the b l u e - g r e e n a l g a e ,
i s not known but i t i s w e l l
known
t h a t many b l u e - g r e e n a l g a e are not easy to grow i n the absence o f
b a c t e r i a.
A comparison o f Smith Lake and
S an c t u a r y Lake, P e n n s y l v a n i a
I n S a n c t u a r y Lake, P e n n s y l v a n i a , p r e l i m i n a r y work had been done
i n d e t e c t i n g n i t r o g e n uptake u s i n g s i m i l a r methods to th os e used
here ( D u g d al e and Dug dale, 1965).
S a n c t u a r y Lake has some f e a t u r e s
i n common w i th Smith Lake, e s p e c i a l l y depth and the marshy n a t ur e
o f the s u r r o u n d i n g d r a i n a g e b a s i n .
is
In S a n c t u a r y Lake, however, there
c o n ti n uo u s f l o w through the l a k e , and much o f the c y c l i c a l
o f the uptake p a t t e r n s can be c o r r e l a t e d w i t h v a r i a t i o n s
and phosphorus income from i t s major i n l e t .
behavior
in nitrogen
I t was not n e c e s s a r y there
t o assume any h i g h r e g e n e r a t i o n r a t e o f n u t r i e n t s t o account f o r the
uptake regime.
In Smith Lake, we are c o n s i d e r i n g an i s o l a t e d i n t e r n a l
c y c l e , which i n s t e a d o f income a p p a r e n t l y undergoes l o s s o f n u t r i e n t s
from the open wa t e r t o the r oot ed v e g e t a t i o n .
I n both l a k e s i t
is
ap parent t h a t h i g h ammonia and n i t r a t e uptake r a t e s accompany n i t r o g e n
fixation,
and f o r the s p r i n g blooms i n both l a k e s ,
the p r o p o r t i o n o f
the n i t r o g e n c o n t r i b u t e d by the three s o u r c e s i s ver y s i m i l a r .
Lake has a f a l l
Sanctuary
bloom which i s h e a v i l y dependent on n i t r o g e n f i x a t i o n ,
whereas no such n i t r o g e n f i x i n g
fall
bloom i s found i n Smith Lake.
I n the S a n c t u a r y Lake d a t a , the expected i n v e r s e r e l a t i o n s h i p
61
between u t i l i z a t i o n and d i s s o l v e d f i x e d n i t r o g e n l e v e l s shows up
clearly.
Both la ke s d r a i n marshy a r e a s ,
and i t has been p o i n t e d out
t h a t the humic m a t e r i a l s which are br o ug ht i n t o a l a k e by d r a i n a g e
from such l a nd c o ul d be very i m p o r t a n t e c o l o g i c a l l y ,
are known t o s t i m u l a t e p r o d u c t i o n i n c u l t u r e .
s i n c e they
Phinney and Peek
(1961) have a t t r i b u t e d the u n e x pl ai n e d h i g h p r o d u c t i v i t y o f Klamath
Lake t o t h es e m a t e r i a l s ,
th is material
is
and they s u g g e s t t h a t the maj or r o l e o f
chelation.
In a t te m p t i n g to i s o l a t e the Anabaena
f l o s - aquae from the Smith Lake bloom, i t became ap pa re nt t h a t i t would
grow much more r e a d i l y in c u l t u r e media in the presence o f a few drops
o f c o nc e n t r a t e d Smith Lake water.
A r e l a t i o n s h i p may e x i s t between
s i g n i f i c a n t n i t r o g e n f i x a t i o n and such m a t e r i a l s i n a l ake.
CONCLUSIONS
1.
Ammonia i s
the most i m p or t an t s ou rc e o f n i t r o g e n to the
p h y t o p l a n k t o n in Smith Lake.
I t i s produced in l a r g e amounts by
b a c t e r i a l breakdown o f n i t r o g e n o u s o r g a n i c m a t e r i a l
under the i c e
d u r i n g the w i n t e r , and then f u r t h e r accumulates as a r e s u l t o f the
suppression
spring.
of n itrific a tio n
d u r in g a n o x i c c o n d i t i o n s i n e a r l y
T h i s ammonia s er v e s as the p r i n c i p a l
the p r o d u c t i o n under the i c e in e a r l y s p r i n g ,
n i t r o g e n s o u r ce f o r
and a l l
becomes i n ­
co r p o r a t e d i n t o o r g a n i c m a t e r i a l p r i o r to the m e l t i n g o f the i c e .
A maximum ammonia uptake r a t e o f 13 y g / l i t e r / h r was measured d u r in g
t h i s growth p e r i o d .
A t the same time a p h o t o s y n t h e t i c r a t e o f
33 yg C / l i t e r / h r was measured i n s i t u in the l a k e .
This represents
a C:N r a t i o o f 2 .5 :1 .
2.
N i t r a t e i s not an i m p or t an t n i t r o g e n s o u r c e i n Smith Lake,
a l t h o u g h i t accumulates s l o w l y as a r e s u l t o f n i t r i f i c a t i o n d u r in g
the w i n t e r .
By e a r l y s p r i n g a l a r g e amount o f n i t r a t e i s p r e s e n t
i n the w a t e r , but i s
l o s t when the oxygen becomes d e pl et e d.
most p r ob a b l e f a t e o f t h i s n i t r a t e i s
i f this
is
The
l o s s by d e n i t r i f i c a t i o n , and
the c as e , about 8 y g - a t o m s / 1 i t e r o f n i t r o g e n may be l o s t
to the l a k e d u r i n g t h i s
a n o x i c time.
A l t ho u gh n i t r i f i c a t i o n
probably
c o n t i n u e s d u r i n g the summer, there i s never any acc umu la t io n o f n i t r a t e .
The n i t r i f i c a t i o n
r a t e s are a p p a r e n t l y s u f f i c i e n t l y s l o w s o t h a t even
a very low uptak e, o r perhaps b a c t e r i a l
62
r e d u c t i o n , p r ev en t s any
63
d i s c e r n i b l e acc umul at i on.
Occasional
accompany ammonia u t i l i z a t i o n ,
pulses o f n i t r a t e u t i l i z a t i o n
but n i t r a t e i s never the s o l e o r
even the more i m p o r t a n t s o u r ce o f n i t r o g e n .
3.
The n i t r o g e n - f i x i n g bloom o f Anabaena s p . ,
Anabaena f l o s - a q u a e ,
o ccur s i n June w i t h temporal
dominated by
reproducibility.
As t h i s bloom b u i l d s up, ammonia p r o v i d e s the pr i ma ry n i t r o g e n s o u r c e ,
although n i t r a t e i s
used a t the same time.
r a t e reaches i t s maximum, n i t r o g e n f i x a t i o n
i mportance.
clear.
As the p h o t o s y n t h e t i c
increases in r e l a t i v e
The s ou rc e o f the ammonia f o r t h i s
There i s
r a p i d uptake i s not
abrupt t e r m i n a t i o n o f the bloom, which, a lt h o u g h
accompanied by a unique r i s e
by n u t r i e n t d e p l e t i o n .
i n pH, i s more l i k e l y t o be determined
T h i s bloom accounts f o r the a d d i t i o n o f about
500 y g / l i t e r o f newly f i x e d n i t r o g e n to the l a k e s u r f a c e water.
a l g a e form a k i n e t e s ,
The
and l a r g e l y become dormant f o r the remai nder o f
the y e a r , a lt h o u g h an o c c a s i o n a l
s e q u e n t l y i n the water.
individual
f i l a m e n t i s found s ub ­
The r a t i o between carbon and a t o t a l
nitrogen
uptake d u r in g the peak o f t h i s bloom was 3:1.
4.
The remainder o f the gr owi ng season i s c h a r a c t e r i z e d by a
more s t e a d y but modest r a t e o f p h o t o s y n t h e s i s and n i t r o g e n u t i l i z a t i o n
rates,
and an i s o l a t e d experi ment t o determine ammonia p r o d u c t i o n r a t e s
i n d i c a t e s t h a t r a p i d r e c y c l i n g o f ammonia ta kes p l a c e , and t h a t t h i s
probably involves a d i r e c t phytoplankton-zooplankton r e l a t i o n s h i p in
a d d i t i o n to b a c t e r i a l
processes.
64
5.
High p r o d u c t i v i t y r a t e s are i n v a r i a b l y accompanied by
h i g h ammonia uptake r a t e s ,
and f o r t h i s
lake s i m i l a r seasonal
p a t t e r n s are o b t a i n e d when pri mary p r o d u c t i v i t y , ammonia uptake
or to ta l
6.
n i t r o g e n uptake i s
co ns id e re d .
The n i t r o g e n u t i l i z a t i o n
regimes i n l a k e s would appear
to be s i m i l a r over a wide g e o g r a p h i c a l d i s t r i b u t i o n .
The s i m i l a r i t y
o f uptake p a t t e r n s d u r i n g the s p r i n g bloom i n s u b a r c t i c Smith Lake,
A l a s k a and temperate S a n c t u a r y Lake, P e n n s y l v a n i a are s t r i k i n g .
I t i s p o s s i b l e t h a t n u t r i e n t c y c l e s t u d i e s in one r e g i o n can thus
produce g e n e r a l i z a t i o n s which may be a p p l i c a b l e t o s i m i l a r l a k e s
i n o t h e r p a r t s o f the w or l d.
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Ed. Comm. Sugawara F e s t i v a l Volume, Maruzen Co. L td. l okyo,
65-81.
R i c h a r d s , F. A . , w i t h T. G. Thompson.
1952.
The e s t i m a t i o n and
c h a r a c t e r i z a t i o n o f p l a n k t o n p o p u l a t i o n s by pigment a n a l y s e s .
II.
S p e c t r o p h o t o m e t r i c method f o r the e s t i m a t i o n o f p l an k t o n
p igment s.
J. Mar. R e s . , 11:156-172.
R i g l e r , F. H.
1956.
A t r a c e r s t u d y o f the phosphorus c y c l e in
l ak e water.
E c o l o g y , 3 7 (3 ) :5 5 0- 56 2 .
R i g l e r , F. H.
1964.
The phosphorus f r a c t i o n s and t u r n o v e r time
o f i n o r g a n i c phosphorus i n d i f f e r e n t types o f l a k e s .
Limnol.
and O c e an o gr . , 9 ( 4 ) : 5 1 1-518.
R i l e y , G. A.
1963.
Ed. M a r i n e B i o l o g y .
I.
F ir s t International
I n t e r d i s c i p l i n a r y Conference on M a ri n e B i o l o g y , A. I . B. S.
286. pp.
R i l e y , J. P.
1953.
The s p e c t r o p h o t o m e t r i c d e t e r m i n a t i o n o f
ammonia in n a t u r a l wa te r s w i t h p a r t i c u l a r r e f e r e n c e t o sea
water.
A n a l y t . Chim. A c t a . , 9:575-589.
70
R i t t e n b e r g , D. A. S . , Keston, A. S . , Roseburg, and B. Schoenheimer.
1939.
S t u d i e s in p r o t e i n met aboli sm.
II.
The d e t e r m i n a t i o n
o f n i t r o g e n i s o t o p e s in o r g a n i c compounds.
J. B i o l . Chem.,
127:291-299.
Rodhe, W.
1955.
Can p l a n k t o n p r o d u c t i o n proceed d u r i n g the
w i n t e r darknes s in s u b a r c t i c l a k e s ?
Verh. I n t e r n . Ver.
Limnol. ( S t u t t g a r t ) .
12:117-122.
Rodhe, Wilhelm.
1963.
I n M ari ne B i o l o g y I .
F ir s t International
I n t e r d i s c i p l i n a r y Conference on Mari ne B i o l o g y . Gordon
A. R i l e y , Ed. A. I . B. S.
286. p.
R o h l i c h , G. A. and W. L. Lea.
1949.
The o r i g i n o f p l a n t n u t r i e n t s
i n Lake Mendota.
Report to Univ. o f W i s c o n s i n Lake I n v e s t i g a t i o n s
Committee ( mi meo gr . ) 7:844 pp.
R yt h e r, J. H.
1954.
I n h i b i t o r y e f f e c t s o f p h y to pl an k to n upon the
f e e d i n g o f Daphnia magna w i t h r ef e r e n c e t o g r owt h, r e p r o d u c t i o n
and s u r v i v a l .
E c o l o g y , 3 5 (4 ) : 5 2 2 - 5 3 3 .
R y t h e r , J. H. and R. R. L. G u i l l a r d .
1959.
Enri chment experi ment s
as a means o f s t u d y i n g n u t r i e n t s l i m i t i n g to p hy t o p l a n k t o n
p r o d u c t i o n , Deep-Sea Research 6:65- 69.
Ry t he r , J. H . , and C. S. Yentsch.
1957.
The e s t i m a t i o n o f
p h y to pl an k to n p r o d u c t i o n in the ocean from c h l o r o p h y l l
and l i g h t da ta.
Limnol. and O ce an o gr . , 2: 281-286.
S a f f e r ma n , R. S. and M. E. M o r r i s .
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1963.
Algal
virus:
Isolation.
Sawyer, C. N . , J. B. Lackey, and R. T. Lenz.
1945.
An i n v e s t i g a t i o n
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Rept.
Gov. Comm., M adi son, W i s c o n s i n .
92 pp.
S h a p i r o , Joseph.
1964.
E f f e c t o f y e l l o w o r g a n i c a c i d s on i r o n
and o t h e r m e t a l s i n water.
J. Amer. Water Works A s s o c . ,
56(8) :1 062 -1 082 .
S i l v e y , J. K. G. and A. W. Roach.
1964.
S t u d i e s on m i c r o b i o t i c
c y c l e s i n s u r f a c e water.
J. Amer. Water Works A s s o c . ,
5 6 ( 1 ) :60-72.
71
Steemann N i e l s e n , E.
1952.
The use o f r a d i o a c t i v e carbon ( C ^ )
f o r measuri ng o r g a n i c p r o d u c t i o n i n the s ea.
J. Cons.
I n t e r n a t . E x p l o r . Mev\ 18:117-140.
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1959.
Pri mary p r o d u c t i o n i n t r o p i c a l marine
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J. Mar. B i o l . As s oc . I n d i a , 1 ( 1 ) : 7 - 1 2 .
S t e p he ns , K.
1963.
D e t e rm i na t io n o f low phosphate c o n c e n t r a t i o n s
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Bull.
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1925.
L i m n o l o g i s c h e P h y t o p l a n k t o n s t u d i e n Die B e s i e d e l u n g
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S u p p l . , 5:1- 527.
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1942.
Some chemical, p h y s i c a l and o p t i c a l c h a r a c t e r i s t i c s o f
C r a t e r Lake.
E c o l o g y , 23:97-103.
V e r d ui n , Jacob.
1960.
P h y t op l an k to n communities o f western Lake
E r i e and the C02 and 02 changes a s s o c i a t e d w i th them.
Limnol.
and O ceano gr . , 5 ( 4 ) : 3 7 2 - 3 8 0 .
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1959.
N i t r o g e n met abol is m in p l a n t s .
P e ter s on B i o l o g i c a l Monographs.
A l l a n H. Brown, Ed.
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W o l f e , M.
1954.
The e f f e c t o f molybdenum upon the n i t r o g e n
met ab ol i sm o f Anabaena c y l i n d r i c a . I .
A s t u d y o f the
molybdenum requ ire ment s f o r n i t r o g e n f i x a t i o n and f o r n i t r a t e
and ammonia a s s i m i l a t i o n .
Ann. B o t . , London, 18:299-308.
W r i g h t , John C.
1960.
The l i m n o l o g y o f Canyon F er r y R e s e r v o i r .
III.
Some o b s e r v a t i o n s on the d e n s i t y dependence o f p ho to ­
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W r i g h t , R i c h a r d T.
1964.
Dynamics o f a p h y t o p l a n k t o n community
i n an i c e - c o v e r e d l a ke .
Limnol. and O c e a n o g r . , 9 ( 2 ) : 1 6 3 - 1 7 8 .
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1960.
P h y s i o l . , 11:25-36.
Nitrogen f i x a t i o n .
Ann.
Rev.
Plant
APPENDIX A
in Vi:ifn! ?!,:!,■*
H ep rin ti'd
from
L im n o i.o cv
\va-ir.:
am j
O ck a m k .h a p iiy
V o l. T , X o . 2 , A p r i l , 1 9 6 2
1 6 3 -1 6 9
pp.
NITROGEN METABOLISM IN LAKES
MEASUREMENT OF NITROGEN FIXATION W ITH N 15 ’
I.
John C. Neess,2 Richard C. Dugdale,3 Vera A. Dugdale ,3 and John J. Goering2
ABSTRACT
A m eth o d fo r m easurin g the rates o f n itro ge n fix a tio n in sam ples o f lake w ater using
N in as a tracer is d e sc rib e d , and a d e ta ile d d e scrip tio n o f glassw are re q u ir e d is p r o v id e d .
T h e n itrogen p resent in the w a ter is r e m o v e d b y flu sh in g w ith H e -O m ixture an d th en
rep la ced b y the la b e le d n itrogen . A fter in cu b a tion and treatm ent, th e is o to p e ratio in the
o rg a n ic m aterial is d e te rm in e d on a m ass sp ectrom eter. A nalyses o f lake w ater an d ( N H 4)
SO* as iso to p e ratio blanks are d e s c rib e d and a resum e o f statistical data from these
analyses is p resented.
ular organ ism s resp o n sib le for th e activity
IN T R O D U C T IO N
an d their in d iv id u a l p h y siolo gies.
In several p a p ers, o n e or th e oth er o f us
has recen tly
rep o rte d
on
the
results
of
METHOD
direct m easu rem en ts o f rates o f n itro gen fixation
in
sam p les
of
natural
fresh
F r e e n itro gen
or
m arine w a ter ( D u g d a le , e t al. 1 9 5 9 ; D u g ­
m o v e d b y aeration w ith m in im u m d istu rb ­
dale a n d N eess 19 6 0 ; D u g d a le , M e n z e l and
R yth er 19 6 1 ; N eess, e t al. in p r e s s ).
d isso lv ed in an en clo sed
v o lu m e o f n atural w ater is c o m p le te ly re­
ance
E a ch
of
the
o xygen .
of these la ck ed a c o m p le te description o f
con centration
of
d isso lv ed
N itrog en gas m ore or less h ea vily
en rich ed w ith N 15 is then a d d e d , an d the
the m e th o d u sed . T h e p u rp o se o f this c o m ­
m u n ication is to su p p ly su ch a description
sa m p le is in c u b a te d fo r a tim e u n d er a p a r­
alon g w ith certain com m en ts th at w ill m ak e
ticular set o f cond itions.
it p o ssib le
total K je ld a h l n itrogen is r e c o v ered
to
interpret
th e
results
m ore
term in ed .
H e a v y n itrogen ( N 15) has b e e n u sed su c­
o f th e isotop es in it d e te rm in ed w ith a m ass
olism o f organ ism s an d in the stu d y o f b io ­
sp ectrom eter.
logical nitrogen fixation (R itte n b e r g , e t al.
sa m p le o f w ater are k n o w n , th en it is p o s­
sib le to c o m p u te the a m o u n t o f fre e n itro­
Such m o d ific a ­
g en c o n v erte d to K je ld a h l n itrogen in the
tions as w e h a v e in tro d u ced are in k eep in g
our o b jec tiv e o f
treating
natu ral w ater,
w ith
o f N 13 in
the total a m o u n t o f “fix e d ” n itrogen in the
O u r m e th o d is id en tical in prin cip le
to th ose p rev iou sly u sed , and m ech an ica lly
u n m o d ifie d
I f the proportion
the origin ally in tro d u c ed n itrogen gas an d
1 9 3 9 ; Burris an d M ille r 19 4 1 ; Burris, et al.
sim ilar in m a n y respects.
T h erea fter the a m m o n ia is oxi­
d ize d to free n itrogen and the proportion s
cessfu lly in the stu d y o f th e n itrogen m e ta b ­
w ith
from
th e sa m p le as a m m o n ia and its q u a n tity d e ­
critically.
1 9 4 2 ).
A fte r in cu b a tio n
course o f th e in cub ation.
essentially
its b iota
C o lle c tio n o f th e sa m p le an d tr ea tm en t
intact an d fu n ction a l, sim p ly as a reagent
b e f o r e in cub a tion
for fixin g n itrogen , an d o f stu d yin g its p r o p ­
erties as such, la rg ely ign orin g the p a rtic­
In M a d iso n , our sam p les h av e b e e n c o l­
le c te d in the ordin ary w a y , u su ally w ith a
1 T his w o rk w as su p p o rte d b y the N ation al In ­
stitutes o f H ea lth ; in th e early stages som e fu n d s
w ere p r o v id e d b y the F a c u lty R esearch F u n d o f
the U niversity o f K en tu ck y. W e are in d e b te d to
R. H . Burris o f the U niversity o f W is co n sin an d
to R . A bram s o f the M o n te fio r e H osp ita l Institute
o f R esearch , P ittsbu rgh , fo r the use o f the mass
sp ectrom eters in their lab ora tories.
2 U n iversity o f W is co n sin .
3 U n iversity o f P ittsbu rgh .
K em m erer
b ottle.
It
w o u ld
p r o b a b ly
be
d esirable to use a plastic or n o n -to x ic sa m ­
pler, b u t w e h a v e n ot alw ays
so m etim es
u sin g
one
m ade
d o n e this,
o f brass.
At
P ittsb u rgh glass or plastic sam plers h av e
b een u sed exclusively.
Sam ples are taken
as
to
q u ic k ly
W h e th e r
as p o ssib le
the
or n o t the sam p les
163
73
laboratory.
are exposed
164
j.
c.
M ii-:ss,
ii.
< . i ) i '< ; i ) A i . i - . ,
v .
\.
i n o n u .i.,
a
m
)
j
.
j
. (.oi-,ia\<
i.—
F i g . 1.
A p p a r a t u s f o r r e p l a c i n g t h e d i s s o lv e d n itroe'en
to w e a k nr strong illum ination
oubation
m ay
b efore
a ffe c t the results later
in
ob­
in w a t e r s a m p le s v i l l i
.\g; n i.
d a
a cco m p lish ed b\
V ".
the inlet,
con necting
the
fhi.s is
llasks to
tained: d e p e n d in g upon the particular cir
the m anifold s show n in Figure I. T h e inlet
cu m stan ees
m a n ifo ld
of
an
ex p erim en t,
control
ol
is a sim ple
large-d iam eter
one-
illu m in ation o f the sa m p le m a y b e desir­
able.
P relim in ary treatm en t o f the sam p les is
carried ou t in the apparatus show n in F ig ­
ure f .
way,
Sam ples o f w ater, u n treated in any
are en clo sed
in
each
of
the
flasks.
T h ese m ay b e o f any practical volum e'; w e
have
g en erally
u sed
thos«.
som etim es 25 0 or 5 0 0 m l.
necks
fitted
joints
to
with
receive
!iu k liu K
stan dard-taper
the
o n e -p ie c e
units, sh ow n in p lace in F igu re
detail in F ig u re 2.
1 I..
T h e flasks have
ground
aeration
I and
in
E ach o f the latter has
a gas-in let exten din g to the b o tto m ot the
flask and en d in g in a sintered glass sparger,
and a g as-ou tlet en terin g at the very top of
the flask w hen it is closed.
are fitted with . s t o p c o c k s .
Inlet and outlet
W h e n the M a s k s
are filled with w ater, with aeration units in
place b u t with stopcocks on inlet and outlet
open, pressure is m ain tain ed at 0 .S atm at
the outlet with an a ir-p u m p , and a m ixture
u
-t— U ittu s e r sin tere d glass.
containing 0.8 vol o f h eliu m and 0-2 vol ol
A
M l
AS!
Ill-M IN
I
(II
H \ V T I ( 1\
\ I I I« k : | '\
b elow .
y
W IT H
\
A sa m p le is taken from the m an ifold
for m ass spectrom etric analysis, and som e
gas is a d m itted into the flasks by o p en in g
each
outlet
sealed
stopcock
flasks
sligh th
b riefly.
en close
m ore than
total
J atm
The finally
pressures
of
and contain
at­
m o s p h e r e s vv i t h a b o u t 0 .2 ( 1 a t m p a r t i a l [ i r e s
sun' o f nitrogen , a bo u t 0.6 4 app o f helium
and about 0 .1 6 app of o xygen . W e have ob -
1
U tlin U
the
:;
1JJ.11
Isom et
, .: l
±1
1 i■l l -S
\ ’ ’ - Lf i w m
C lJJ.
( ’orporation
U
Palisades
Park
New Jersev.
\\ hen sealed, the flasks are discon n ected
from the m a n ifo ld an d shaken b y h an d or
with
a w rist-action
m ech an ical
shaker
to
eq u ilib rate liq u id and gas phases.
Flasks are in cu b a ted under various c o n ­
ditions and for various periods.
possible1, w e h av e
piece affair to w h ich
the tlask inlets and
cylinder con tain in g the H e -O
m ixture are
eonneeted with rul)l)cr tubing.
iiia iiim iu
i.'i
m a ul.;
constructed
up
uj
of capillary
th e outlet
j.iiu i\ iu u < .u
tu b in g ;
a im .' )
the units
con n ect to each other and to the gas-rescrvoir raid sa m p le -b u lb at one end with balland-socket grou n d joints.
T h e units arc' il­
lustrated in F igu re 3.
with
CO_.
and carries nitrogen , along
and
atm osp h eric
constituents
('(her than o\v gen. out of the I lasks
W ith
eq u ip m en t d e sign ed as ours, with 1- 1. sa m ­
ples
<;l
water
stream et
gas.
and
a reasonably
\ igurous
15 mill is stilfieient to re­
m o v e anv nitrogen
d e te rm in a b le b v mass
spectrornetric analysis from the o u tlet gas.
'The behavior of m a cro sco p ic /.oopianktcrs
such as c o p ep o d s
an d D a p lm ia is app a r­
ently u n a ffe c te d b y this treatm ent.
A fte r aeration, inlet and outlet stopcocks
total pressure in the flasks o f 0.8 atm and
an atm osp h ere con tain in g only heiiu m ancl
The
outlet m a n ifo ld
is then ex­
h austed to a h igh v acu u m and disconn ected
from the vacu u m p u m p .
riched in h eavy nitrogen
at distances from the surface correspon din g
to the depths at w hich the w ater was c o l­
lected. or oth erw ise, in the laboratory under
artificial illu m in ation or in the dark.
After in cu b a tio n , the flasks are o p en ed ,
the contents a cid ified w ith a sm all qu an tity
o f I F S Q 4 and b o ile d
dow n
to
a v olu m e
m l m icro -K jeld a h l digestion flask.
S u b se­
q u en t d ig estion o f the sa m p le is carried out
lor IS hr at the b oilin g point of a m ixture ol
2 ml o f H , S O t ,
1.2 to
abou t 5 0 m g H g S O ,
1.4
g K ,S O ,
and
D igestion under such
severe, con d ition s is n ecessary to obtain cor­
rect results in su b seq u en t stages o f the p ro ­
ced u re (s e e R itten b erg , et ol. 1 9 3 9 ) . N itrortvvn ic rnnnrororl from flm rliffpcf ■")s NTT 1
a c o m p le te ly standard m icro -K jeld a h l d is­
tillation into 2 %
H3BO3 acid , fo llo w e d by
titration w ith 0.0 1 n H C 1 in the presence of
are closed in that order, leav in g a residual
oxygen.
lake from w h ich the sam p les originated and
sm all en o u gh to b e a cc o m m o d a te d in a 3 0 -
T h e H e -O m ixture leaves the spargers in
small b u b b le s
W henever
su sp en d ed th em in the
N itrog en gas e n ­
(u p to 9 9 .7 atom
a m eth y l red -m e th y le n e b lu e indicator. T h e
result o f the titration is the total K je ld a h l
nitrogen o f the sam p le of lake w ater
After
titration, the sample' is re-distilled into HC1
to rid it o f th e indicator.
tillation n eed
T h e secon d d is­
not recover the nitrogen
of
the sa m p le q u an tita tiv ely , and m a y b e e lim ­
per cent N 1 ’ ) is in tro d u ced into the e v a c u ­
inated
ated m an ifold at a pressure slightly a bove
clone w ith a p H -m e te r instead o f the in d i­
1
cator.
atm
lo n n u la
from
lor
the
the
reservoir
c on fin in g
(F ig .
iluid
1 ).
is
A
given
en tirely
if the original titration
is
Free n itro gen is o b tain ed fro m the resu lt­
73
lfifi
c
J.
\F F S S
C
H
n f C O M
F.
V
IH 'C D U
F.
\N I)
J.
(.
e ;e)F.ru\c,
ing N H ,C 1 In treating it w ith alkaline hy-
h y p o b ro m ite preparation as a result
p o h ro m ite u n der va cu u m .
T h is j.s a c c o m ­
ol sp on tan eou s O-j produ ction , which
plish ed in a special p ie ce o f apparatus so
b ecom e s a sign ifican t com p on en t of
arranged that the h y p o b r o m ite solu tion and
sm all gas sa m p les.
the sa m p le distillate are
m ix e d b y tilting
p o b ro m ite prep aration o f Rittenberg,
part o f the apparatus after it has b een ev a c ­
e t al. ( 1 9 3 9 ) this d iffic u lty has been
uated.
la rg ely o vercom e.
O u r apparatus is ex actly like that
d e scrib ed
by
form u las
for
g iv en b e lo w .
R itten b erg ,
et
h y p o b r o m ite
B y usin g the hy­
(1 9 3 9 );
al.
solutions
T h e n itrogen gas released is
then m o v e d w ith a T o e p le r p u m p
C a lcu lations
are
into a
T h e a m o u n t o f nitrogen fix ed is calcu­
lated b y the expression
g a s-sa m p le b u lb arran ged to con n ect at the
sa m p le-in let o f the m ass sp ectrom eter, or
it is sea led into a 3 -c m p ie ce o f glass tu bin g
a ccord in g
to
the
m eth o d
of
W e in h o u s e
w h ere Nr = n itrogen fixed ( m g ) .
is n eces­
A j = a tom p er cen t excess N lr’ in en­
sary.
F o r assay o f isotop e con ten t w e h av e
rich e d No su p p lied at the b e ­
u sed
C o n so lid a te d
(1 9 4 6 ).
No
further pu rification
M odel
2 1 -2 0 1
ginn ing o f the experim ent.
Iso to p e
N , = total red u c e d nitrogen
R atio M a ss Sp ectrom eters.
at the
en d o f the experim en t as deter­
R e a g e n ts
m in e d
A ll reagen ts to b e m a d e up w ith fresh
C o n fin in g
m icro-K jeld ah l
flu id s.
15%
Na^SO.j +
5%
T h e term a to m per cen t excess refers to the
I L S 0 4 . T o 15 g \ a . S O j ( reagent g r a d e '
itom per cen t \ T15 in a sa m p le a b o ve some
a d d 8 0 m l I F O and 3 ml rea gen t grade
arbitrary standard, for instance, the norm al
if s o
2.
the
A / = a to m per cent excess N ’ 5 in N ( .
g lass-distilled w ater.
1.
by
p ro ce d u re ( m g ).
atom per cen t \’ l:' fou n d in b iolo gica l m a­
4.
K je k la h l d ig estion m ixture.
terials or in the atm osp h ere.
1 .2 -1 .4 g K 2S 0 4 (r e a g e n t g r a d e ) and 50
usually tak en to b e 0 .3 58.
H g S 0 4 (r e a g e n t g r a d e )
mg
F F S O 4.
The
and 2 ml
salts m a y b e m ix e d
and
p la c e d in the m icro -K je ld a lil flasks b e ­
T h is value is
T h e results are also so m etim es expressed
as “ per cent n itrogen fix ed .” T h is refers to
the a m o u n t ca lcu la ted b y :
fore the sa m p le is ad d ed .
3.
In d icator for K je k la h l distillation ( used
if p H
m eter is not in u se )
0 .2 4 8
g
m eth yl
111*.
m eth y len e
red
b lu e
dissolved
in
and
0 .3 7 5
300
ml
O A p l L .'v M W ll.',
7.
,->ii i i p l i f i L
d
.L '.’. d
95%
a fairly sm all v alu e during the course of
the experim ent.
4 0 % N a O H — a d d 10 0 g N a O H crystals
S e le ctio n o f Standards
to 2 2 5 m l o f freshly distilled w ater, cool
6.
a it
hold as lo n g as the ch an ge in .V, is held to
an d store in a r u b b er-sto p p ered bottle.
5
L II
g
ethvl alcohol.
4.
A,
m eth yl-red
m eth vleu e b lu e.
Boric acid 2 % .
0.01
The
im p o rtan ce o f gettin g
an
estimate' o f A y is obviou s from
n H C 1— this sh ou ld b e accurately
discu ssion ;
the
selection
of
the
accurate
the above
standard
stan dardized .
a b o v e w h ich
Alkaline' h yp ob rom ite.
com es a critical m atter since' isote)pe>-ratio
a. S ml b rom in e and 3 5 ml of 1 I M N a O H
m ass spectrom eters arc ne)t ordinarily cali­
brated
rend •ihsnlnte isotop e ratios
70 T~rt1 Hi\tiHed witer
b. \Vc
h av e
experienced
prep arin g lo w
ni.t^s
d iffic u lt)
nitrogen
'.peetl'OMieti \
usm u
in
sam p les tor
the
il>o\<
the excess is calcu lated
Several standards are in co m m o n u se:
be­
1)
laboratory air, 2 ) tank N - , 3 ) N L> obtained
I >\ e o n \ e r s i o n
ol
s o m e ' el nMSt i t . i l
e'om pound
M t A M
T m s i. k
u l m l .n
i
o f
n i t r o g e n
167
n
S p e c ih o m e t e k
L a k e w a t e r b la n k s
L a k e M e m lo t a
13
0.3000
1"
O 360S
L a k e w a t e r b la n k s
L a k e W in g r a
15
13
0 .3 6 0 4
0 .3 0 8 0
l) . 0 t ) 0 0 ] 2 U o , '}
0 .0 000 4-187 2
0 .0 000 1
0 .0 0 3 4 7
0.0 0 6 7 0
0 .0 0 3 7 0
0 .0 0 6 3 3
0 .0 0 0 8 4
0 .0 0 1 8 6
0.00010
0 .0 0 0 1 6
l'i i i s m
i U tI i
0 .0 0 0 0 4 0 0 8 2
S i ’ i u . i u d m i -.i k i i
I ,;ik c w a tc -r
n
8
19
and
M ass
I >07
(MlO.-SOi
I'ank \
experim ent.
M a ss
L a k e w a te r
a u t o c la v e d b la n k s
X 1' a d d e d
< \ U . i" S O ,
s ta n d a rd s
of am m o n ia ,
w i t h
Statistical resu m e nf data o b ta in e d from standards and blanks
I.
W is c o n s i n
Sr
S.
f i x a t i o n
0 .3 5 0 8
0 .3 5 2 8
0 .3 531
0 .0 0 0 0 0 1 165
0 .0 0 0 0 0 0 7 2 2
0 .0 0 0 0 0 0 2 7 1
0 .0 0 1 0 8
0 .0 0 0 8 5
0 .0 0 0 5 2
0 .0 0 0 2 4
0 .0 0 0 3 0
0 .0 0 0 1 6
4)
a control
from
the
B ecau se the en rich m en ts o b ­
w ater sam p les su b jected to the sa m e treat­
m ent.
The
tained in the early experim en ts w ere sm all,
least
sign ifican t d iffe re n ce ,
at the
and w ere expected to rem ain at relatively
»o'/o c o n fid en c e ievei, is U.UU27 a tom
lo w
on
cent, or pra ctically 0 .0 0 3 a to m per cen t for
the re­
the P ittsburgh m ass spectrom eter, an d sim ­
con verted
ilarly 0 .0 0 3 8 atom per cen t for the W i s c o n ­
levels,
m easu rem en ts
w ere
m ade
the m ass spectrom eter c o m p a rin g
sults
o b ta in ed
fro m
( N H 4) 2S 0 4 an d
tank
b o ile d
blanks fro m tw o lakes.
taken fro m
pum ped
N 2,
dow n
la ke-w ater
A sin gle b u lb o f N L>
a tank o f c o m p re ssed , w ater-
nitrogen
w as
u sed
as
prim ary
standard u sing the fo llo w in g p ro ced u re:
i 1 ) Su ccessive determ in ation s w ere m ad e
on
som e lo w value.
T h e sa m p le to be read
(la k e -w a te r
blrmk or r-nn verted
was
a d m itted and the ratio d eterm in ed .
(3 )
A n o th e r tank N 2 sa m p le w as read.
(4 )
R e p e a t o f steps ( 2 ) and ( 3 ) .
A sim ilar series was run on w ater from
Lake
the
P ittsburgh
M e n d o ta
and
Lake
W in g r a ,
w h ich
Since the am plifiers
m ach in e
have
recen tly
b een reb u ilt b y th e m an u factu rer, resulting
in greatly im p ro v ed p e rform an ce , it m a y b e
a ssu m ed that th ese figures arc m ore or less
optim al.
C o n tro ls
tank IV. until the isotop e ratio
n o lo n ger d e clin ed , b u t varied about
(2 )
sin m ass spectrom eter.
in
pei
T h e data fr o m th e standards in dicate that
routine controls are n ot essential and that
a m m o n iu m su lfate is an a d eq u a te standard
iui lliu isuLopu-ialiw J elciliiiiiatiu ii.
N c\cl
theless, p e rio d ic a lly a u to clav ed lake w ater
is in c lu d e d in the
experim en ts
an d m ore
fre q u e n tly sa m p les o f lake w ater are b o ile d
d o w n for isotop e-ratio analysis.
also in clu d e d a n u m b e r o f a u to cla v ed lake-
D ISCU SSIO N
w ater sam p les to w h ich N 15 w as a d d e d in
the usual w a y .
T h e results o f an analysis
It is entirely
u nlikely that the positive
Tank
results w e h a v e o b tain ed u sin g these m e th ­
n itrogen is q u ite o b v io u sly a less suitable
ods represen t a m thing b u t active b io lo g ica l
standard
fixation o f nitrogen w h ich occurs during the
of these data are g iven in T a b le 1.
than
P resu m ably
is
c on v erte d
im purities
are
( N H .j ^ S O .,.
added
during
incubation.
W e h av e o b ta in ed no e v id en c e
conversion, b rin g in g the resu ltin g ratio of
that the
distribution
the latter u p to that o b se rv ed fro m the lake
in u n a u to c la v ed la k e -w a ter blanks differs
73
o f nitrogen
isotopes
I(»S
|.
I . XI-.l-.^S.
I;.
( . m
(, 1J vl I , V .
\.
IM e .IJV i.l.,
A M J
j.
|.
(.(Jl-.lilM .
siu,i1111<_au11\ trom the distribu tion in a sa m ­
that a m
ple ol
ple of lake w ater will bring about changes
|-’ isll(T
primarv
A lth o u g h
V
IV t \ H i ' l-_'SO, u s e d
standard
lul
"ordinal v
as
’
nitrogen.
the m atter o f isotope c fle c ts
in
b iological transform ations o f nitrogen is not
m its bchavieii. il wouiel be use'tiil to know
how
take
m ost
currently
a v a ilab le
data
su gg est that there is no isotop e e ffe c t
b io lo g ic a l nitrogen fixation
( H o e rin g
king its n orm al n itro gen -fix ing ability
persists under these1 conditions.
y et c o m p letely settled, it seem s sa fe enough
to
p ro lon g ed c on fin em en t of a sam­
A lo n g w ith n itro gen , C O .. is exhausted
to
Irom the flasks d u rin g aeration, with a re­
in
sulting
and
F o rd 1 9 6 0 ) , and also that the nitrogen of
d isp la c e m e n t o f the
carbon ate
eq u ilib riu m .
carb on ate-b i­
We
h ave
never
m a d e m ea su rem en ts o f the ch an ges in pH
b io lo g ic a l m aterials docs n ot in gen eral d if­
du rin g aeration, nor estim ated the losses of
fer
C O -.
strikingly
com p osition
ones.
or
consisten tly
fr o m
th at
of
in
isotopic
n o n -b io lo g ic a l
W e c o n clu d e that w e h av e m a d e 110
overestim ates
o f rate o f n itrogen
in c o n tact with
ism s not thus b een red u ce d . A u sefu l m odi­
ot carbon a v a ila b le to p h o to syn th etic organ­
lake w ater
experience
fixation are lower
in the sam e sam p les o f w ater h a d the amount
n itrogen gas en rich ed in N K’ has n ever in
our
nitrogen
than th ose that w o u ld h av e b een realized
fixation
du e to isotop e e ffe c i.
A u to c la v e d
It is entirely p o ssible that our meas­
u red rates of
in corporated
N 15 into
fication
o f the m e th o d
w o u ld
be
the in­
its
clusion o f C O - at so m eth in g like the normal
K je ld a h l nitrogen , su gg estin g th at n o n on -
atm osp h eric partial pressure in the aerating
active processes, such as a to m ic exch ange,
gas m ixture, alth ou gh this co u ld neit be ex-
hnvc led to nnr v^siilt^'
j 1 i
I f remain'- p.
1
1 ^.UlKL.iiU■ illiU ilii Ol Cell'UK.
1
th ou gh unlikely, that the a u to clav in g itself
b on a te and b ica rb o n ate steady in all sam­
has interfered w ith som e n on -active process
ple's o f lake1 w ater.
le ad in g to n et uptake o f N lr’.
ft is also no d o u b t possible that the eleva­
D u rin g incubation the partial pressure oi
nitrogen at eq u ilib riu m with the sample
is
tion
oi
pH
eonseejueiit
upon
aeration
of
som e sam ples w ou ld lead to injury to some
about 0.2 atm . abou t on e-fou rth it.s norm al
<4
value. In v ie w o f the fin d in g s o f Burris am !
stated
W ils o n ( 1 9 4 6 ) th at the h a lf m a x im u m rate'
plankters is not c h a n g ed du rin g aeration,
o f nitrogen fixation
b y N o s fo r
iniisconini
the
and
organism s
above,
prese'iit.
the
in deed
activity
usually
occurs at a partial pressure o f 0.02 atm . w e
throu gh
h ave con sid ered that red u cin g the pressure
d icatin g no v iolent
the
N orm ally,
o f v isib le
rem ains
as
zoo-
unchanged
e'ntire' incubation
p eriod,
d a m a g e to the
in­
biota.
has led to no m ore than m inor u n d erestim a ­
W e have- o ccasion ally observed d a m a g e to
tion o f the rates that w o u ld h av e occurred
the
in the llasks had norm al concentrations of
green
nee
each
n iliogeii
oeen
d eterm in ation
ava ilab le;
Hie cost
has
appreciably
been
ol
the
such
color turned
that the
healthy
y ello w , and suspect a
c o n o la tio n with un du ly pro lon g ed aeration.
The
q uestion
ot
pH
change1 m entioned
above1 mav be1 im portant here1.
red u ced thereby.
O rd in a rily
p h vtop lan k ton
tim e
of
in cu b ation
o f our earlv results
( D u g d a le . rf al.
In asm u ch as n itrogen c o m b in ed as nitrite
lias
b een no greater than 2 4 hr, o iten less. Some1
1959''
<:r
nitrate
is
lost
from
an
u n m od ified
Kjeldahl de'term ination. it is p o ssible that
su gg est that the rate oi fixation inside one
we
of the flasks tends to rise with increasing
the
have made' sm all
tim e o f in cubation and that th erefore the
som e sample's o w in g to the' m ovem en t of
total
(jiiantities
e'rrors in estim ating
of
nitrogen
fixed
in
latter should b e kept as short as possible.
lie W 1\ Ii\v d 11i! I 0 'j,( ii into Ill'll lie or uitiatc
W e have ne'ver tumid e*v idence tor a change'
during
in rate* w ithin 24 hr.
periods ol in cubation, this seem s verv
Kurther inv ostigation s
in cubation.
view
have1 occurred.
ol
the
short
un­
oi the e llc c ls ol p ro lon g ed incubation are1 m
likely
progress, but it is possible now to sav little
cannot be1 expe'cled to occur during incuba­
m ore than the a b o v e .
tion in the pv, srtii-i'
It is to b e expected
to
In
D enitrilieation
o| abundauf
" i 'l l
M l. \ M lii M l \ I O l
bn!
is
11 i r t h e r m o r e
unlikely
fo
have
lar^c' (.'11c‘c•t u p o n m e a s u r e d r a t e ol
b e c a u s e ol
\ I'l IU K . l - . N
anv
fixation
t h e l a r g e ex ces s o f f r e e n i t r o g e n
i n t h e f l a s k s (.5—1 0 m g o l f r e e n i t r o g e n c o m ­
p a r e d t o s o m e t h i n g ni t h e o r d e r of
tolal c om bi ne d ni tr o g e n . o n h
f r i c t m n nl
oi
iiitriU
which
wi
In d e r
cumstances, t h is
he
is o r d i n a r i l y
n it ia tc ui tin
cubation).
! m g of
a very small
in t he I n r m
1m•^ i i i u 111l; oi
exatlh
(lie
conclusion
in
right
might
cir­
have
to
r (l\ ise<t.
FIX A T IO N
— ■—
.
}i> pi - i s
H
P.
AM)
Ii
K
\\ .
W
1 I lU .N i
I
!*" i
i i .s o n
algae.
< 11
WD
\
i <i
ati nn .
--
------ .
(,,
|I
19-12.
llt«
\ \ iii i
s t r i (! \
Science. 9 3 :
and
P.
\ V.
h
(if
H
\\ v,.. -v
Stu d ie s
.
19 4 1 .
1 1111111 g i < ! 1
ol
bio­
\ p p l i c a ti o n
n i t ! i p ’ i ■11
! i\
114-115.
W ' i i .s o
n
.
19 Ki.
C h a ra c te r-
ist ies ol the n i t r o g e n 4 ix i n g en /\ m c sy st e m in
Ao.sYoe in u s<'Oi a i n .
B o ta n. ('.a/.. 1 0 8 : 2 5 4 -
Hh ii.\i:i», \’i i;\ ] ) i » a > A i . i . Joi i \ \ i
\\t>
k i -’s s .
1 9 fi n
R ec e nt o b ­
f ix a t i o n
S e m i n a r on
in
blu e -g re en
Algae a n i l M e t r o ­
p o l i t a n W a s t e s . I . S. i ' u b l i e H e a l t h S e n ice,
R o b e r t A . T a f t K n g i n e e r i n g (Center, C in c in nati. O h i o .
---------- D a v i d \\'_ M i n x e i .. a n d J o h n H . R y t h i .h .
19(> I .
X i l i o g e n I ix a t l o h ill tin
i *« « p S, .t \U ■■ . 7 : J.9S . H ‘
H o i him ,,
Thom as
C .,
and
H.
1.
Sa iga -M i Sea.
Fonn.
I9 6 0 .
I lie isotope e ffec t in t he f ix a ti o n o f n i t r o g e n
by A z o t o b a c t c i .
•>- o --•) t
|o}i n
C
J.
Am.
R ic h - m i d
Chem.
('
Soe.,
'
■!
w ii
\
n i tr o g e n
b ’i
V n ;\
O rc iiv i r.
\.
io||\
in
lakes
( io l- H IM
S n V n r f '
82:
John
D r < at \i i
f.
iih , 1- n i i nit ill
cycle,
firs t
K.
D . . A. S.
K k sio n .
S( ik a - m 11 ixi i- n.
Ic in
m e ta b o l is m .
n i tr o g e n
isoto pe s
in
B i o l . ( ’h e m 1 2 7 :
W i - iNiincsi-..
S.
1940.
on
in
I 1- ) ' 1-!
1 3 0 r
\ i t t'( > ' M' I i
S 5 9
SftO.
1^ ,
<(\-i
“ Prep aration
I l ie,'!''
D
.in k .
\nn
( h i p ress)
The
o rg a n ic
Stu d ie s
in
73
pr o-
determ ination
of
c o m p o u n d s.
J.
291-299,
The
p re p a ra t i o n
and M e a s u r e m e n t
\V \\ i k o n f K d
\rbor.
the
Radio-
\\ R o s f : h u i u ; , a n d
19-49.
11.
jatcs
Sy m p o siu m
•■cologN, B o u l d e r . C o lo ra d o .
jin iim u u c .
ol
19fil.
of
bon d io xi d e sam ple s f o r is oto pe analyses.
202.
lio n
Tra ns.
( in m iN i,
logical n i t ro g e n f ix a t i o n w i t h isot opi c u i t r o k
Pnw
S . - i l S. i S („ . \ ;, i . 7 : 2 “ S 2f O
----------.
C. \
I >
111• -v.
.
vxi) J o n \
169
s e rv a t i o n s on n i t r o g e n
\ i iss
ill
W l I'M \
of
1
car­
In :
I so t o p i c
\V K d
APPENDIX B
APPENDIX
SMITH
B TABLE
LAKE
1
1963
TEMPERATURE
(DEGREES CENTIGRADE)
DEPTH
( M)
0.0
0.5
1.0
1.5
2.0
2.5
MAY 21
06.5
06.5
06.2
05.4
04.9
04.0
MAY 30
13.4
12.8
12.6
1 1.4
09.3
07.3
MAY 31
13.4
13.4
13.4
13.4
12.1
08.4
J UN
12
12
12
12
12
12
0.0
0.5
1.0
1.5
2.0
JUN 07
16.0
15.9
13.2
12.7
11.9
J UN 11
19.0
18.4
15.6
14.1
12.8
J U N 12
18.7
18.5
16.9
14.4
13.0
J UN
19
17
16
14
13
19
4
4
0.0
0.5
1.0
1.5
2.0
J U N 26
16.1
15.3
15.1
15.0
14.2
J U L 01
18.0
18.0
18.0
18.0
11.1
J U L 07
22.9
22.3
19.0
17.7
17.0
JUL
20
19
19
19
18
15
7
7
4
J U L 23
19.3
19.3
18.5
16.7
16.4
J U L 30
16.8
16.7
16.7
16.7
16.3
AUG 07
15.8
15.6
15.3
15.1
15.0
AUG
15
14
14
13
12
20
0.0
0.5
1.0
1.5
2.0
4
0.0
0.5
1.0
1.5
2.0
AUG 27
14.6
14.5
14.4
14.0
13.9
S E P 17
08.0
•
•
•
•
S E P 25
06.7
•
06.3
#
06.2
SEP
08
0
74
05
8
8
8
8
8
6
0
7
8
0
5
1
5
2
8
30
\\
75
APPENDIX
B
TABLE
1 CONTINUED
depth
( M)
0.0
OCT 0 9
07.0
0.5
1.0
1.5
2.0
DEC
04
0.0
0.5
1.0
1.5
2.0
•
02.5
03.6
04. 1
OCT 25
00.0
02.2
02.9
03.6
04.0
NOV
06
02.3
03.1
03.7
04.0
NOV
13
02.8
•
03.9
APPENDIX
SMITH
B TABLE
LAKE
2
1964
TEMPERATURE
(DEGREES CENTIGRADE)
DEPTH
( M)
0.0
0.5
1.0
1.5
2.0
2.5
MUD
JAN
02. 1
03.2
03.9
04.0
MAR
0.0
0.5
1.0
1.5
2.0
2.5
MUD
08
01.5
02.4
03.4
03.9
MAY
0.0
0.5
1.0
1.5
2.0
2.5
3.0
MUD
18
01.6
02.6
03.1
03.4
APR
0.0
0.5
1.0
1.5
2.0
2.5
MUD
03
12
•
•
03.8
03. 1
03.0
03.3
03.7
04.0
FEB
03
01.9
03.7
04.1
04.5
MAR
24
01.6
02.6
03.1
03.7
APR
14
01.6
02.4
03.4
03.9
MAY
18
•
•
03.2
03.3
03.2
03.3
•
03.9
76
FEB
19
01.6
02.6
03.4
03.9
MAR
31
01.4
02.4
03.0
03.8
MAY
01
01.7
02.1
03.2
04.0
MAY
27
•
04.2
04.8
04.2
04.0
03.5
03.4
03.6
FEB
26
02.3
02.9
03.4
03.6
APR
03
01.5
02.2
03.3
03.7
MAY
05
01.8
02.2
02.9
04.0
MAY 3 0
13.5
08.2
05.6
05.2
04.3
03.6
•
03.5
77
APPENDIX
DEPTH
( M)
0.0
0.5
1.0
1.5
2.0
2.5
3.0
MUD
MAY 31
13.9
12.0
08.0
06.4
05.4
•
B
TABLE
2 CONTINUED
03.9
J UN 01
17.8
16.8
15.6
07.6
05.3
04.6
04.0
04.0
J UN 02
17.3
16.6
10.1
07.2
05.8
05. 1
04.6
04.4
J UN
18
16
14
10
06
05
05
05
0.0
0.5
1.0
1.5
2.0
2.5
3.0
MUD
J UN 0 6
19.0
18.8
18.8
10.2
08.3
05.9
05.7
•
J UN 08
20.6
18.8
17.2
09.7
07.8
05.9
05.5
05.4
J U N 10
18.2
18.2
18.2
17.9
08.6
06.6
05.5
•
J UN
20
17
16
12
08
06
05
05
0.0
0.5
1.0
1.5
2.0
2.5
3.0
MUD
J U N 16
20.4
20.2
18.6
13.3
10.2
07.2
06. 1
05.9
J UN 18
22.2
21.5
18.7
15.8
10.7
07.5
J U N 23
18.8
18.9
18.8
18.8
09.6
•
J UN
17
17
16
15
15
09
0.0
0.5
1.0
1.5
2.0
2.5
MUD
J U N 30
18.4
18.4
18.4
16.2
13.6
10.5
09.8
J U L 02
17.5
17.5
17.5
16.9
14.0
11.1
08.6
J U L 07
20.9
19.0
18.7
16.8
14.8
11.4
10.3
JUL
19
19
18
16
15
11
10
0.0
0.5
1.0
1.5
2.0
2.5
MUD
J U L 16
24. 7
21.7
20' . 3
17.0
14.9
11.8
•
J U L 21
18.8
18.6
17.3
16.6
15.8
12.3
10.2
J U L 28
19.8
19.7
19.1
17.9
15.9
12.7
•
AUG
19
18
18
17
16
12
11
•
06.3
•
06
04
3
3
0
6
5
5
1
0
12
5
9
5
3
8
1
7
6
25
2
2
7
6
0
5
8
13
7
2
0
4
1
5
3
04
0
9
2
8
5
3
8
78
APPENDIX
B
TABLE
2
CONTINUED
depth
( M)
0.0
0.5
1.0
1.5
2.0
2.5
MUD
AUG 11
19.3
19.3
18.8
17.6
16.8
14.8
11.8
AUG 18
18.1
18.0
17.8
17.2
16.6
13.5
•
AUG 27
14.2
14.3
14.3
14.3
14.3
14.3
14.1
0.0
0.5
1.0
1.5
2.0
2.5
MUD
S E P 10
12.0
11.0
10.7
10.5
10.3
10.3
10.3
S E P 22
08.5
07.7
07.5
07.5
OCT 06
04.4
04.4
04.3
04.3
07.5
07.7
04.3
04.6
S E P 03
12.2
12.2
12.2
12.2
12.2
12.2
12.2
APPENDIX
SMITH
B
LAKE
TABLE
3
1963
PH
DEPTH
(M>
0.0
0.5
1.0
1.5
2.0
J U N 05
7.0
•
7.3
•
7.2
J UN 19
9.5
9.3
7.7
7.1
•
JUN 26
7.2
•
7.0
7.1
7.1
J U L 01
7.1
•
7.0
7.1
8.0
0.0
0.5
1.0
1.5
2.0
J U L 15
7.3
7.2
7.3
7.1
•
J U L 23
7.2
7.3
7.1
7.1
•
J U L 30
7.2
7.2
7.2
7.2
7.3
AUG 0 7
7.3
7.3
7.3
7.2
7.2
0.0
0.5
1.0
1.5
2.0
AUG 20
7.2
7.2
7.2
7.1
7.1
AUG 27
7.1
7.1
7.1
7.1
7.2
S E P 17
7.4
•
•
•
*
O C T 25
7.2
•
7.2
•
7.1
NOV 13
7.1
DEC 09
•
•
6.9
•
6.9
0.0
0.5
1.0
1.5
2.0
7.0
•
6.9
79
APPENDIX
SMITH
B TABLE
LAKE
4
1964
PH
DTPTH
( M)
0.0
1.0
1.5
2.0
2.5
J A N 03
•
6.9
•
6.9
•
F E B 03
•
6.8
6.8
•
6.8
F E B 19
•
6.9
•
•
6.9
MAR 18
•
6.9
•
•
6.9
0.0
1.0
2.0
2.5
MAR 24
•
7.0
•
•
A P R 08
•
6.8
•
•
A P R 13
•
6.8
•
•
A p r 20
•
6.8
•
6.8
0.0
1.0
2.0
2.5
A P R 28
•
6.9
•
•
MAY 05
•
6.9
•
6.8
MAY 12
•
6.9
•
•
MAY 18
.
7.0
.
6.8
0.0
1.0
1.5
2.0
2.5
3.0
MAY 23
•
6.4
•
6.7
•
•
MAY 27
•
7.2
•
•
•
6.9
J U N 02
7.1
7.1
7.0
6.9
7.0
•
J UM 0 8
7.2
7.1
.
6.7
6.7
.
0.0
1.0
2.0
JUN, 10
7.8
7.4
7.0
J UN 12
8.8
7.9
7.0
J U N 15
9.8
9.9
7.0
J U N 18
7.9
7.6
6.9
0.0
1.0
2.0
J U N 23
7.3
7.3
6.9
J UN 30
7.6
7.5
7.0
J U L 07
7.6
7.5
6.9
J U L 13
7.4
7.3
7.0
0.0
1.0
2.0
JUL' 21
7.4
7.4
7.2
J U L 28
7.7
7.5
7.1
AUG 0 4
7.7
7.4
7*4
A UG 11
7.2
7.4
7.6
80
81
APPENDIX
B
TABLE
DEPTH
( M)
0.0
1.0
2.0
AUG 18
7.4
7.4
7.2
AUG
0.0
1.0
2.0
S E P 22
7.4
7.4
7.5
OCT 0 6
7.4
7.4
7.4
27
f,U
7.5
7.4
4
CONTINUED
S E P 03
7.4
7.4
7.3
S E P 10
7.5
7.4
7.4
APPENDIX
SMITH
B
LAKE
PARTICULATE
(MICROGRAMS
TABLE
5
1963
NITROGEN
/ LITER)
DEPTH
( M)
0.0
1.0
2.0
MAY 21
131.1
.
.
MAY 3 0
188.6
.
.
JUN 05
199.0
194.7
129.2
J UN 12
885.6
752.8
158.1
0.0
1.0
2.0
AUG 27
063.2
043.6
082.2
S E P 03
047.6
039.2
.
S E P 10
029.7
033.4
043.9
S E P 25
023.5
0.0
1.0
2.0
OCT 0 9
026.9
.
.
OCT 25
041.9
015.3
065.6
NOV 0 6
028.3
NOV 11
037.9
0.0
DEC 04
104.1
1.0
2.0
.
075.8
82
.
035.2
•
APPENDIX
SMITH
B
TABLE
LAKE
6
1964
PARTICULATE NITROGEN
(MICROGRAMS / L IT E R )
DEPTH
( M)
0.0
1.0
2.6
JAN
0058.6
0039.1
MAR
0.0
1.0
2.0
03
18
0092.9
0168.0
APR
20
0.0
1.0
2.0
0104.8
0098.3
MAY
18
0.0
1.0
2.0
3.0
0.0
1.0
2.0
0.0
1.0
2.0
0218.0
0190.0
F E B 03
I C E COVER
0027. 1
0047.0
FEB
19
FEB
26
0055.4
0061.8
0076.8
0055.4
MAR 24
I C E COVER
0108.0
.
APR
APR
0140.0
0072.4
0076.4
0083. 1
A P R 28
I C E COVER
0130.7
0130.7
MAY
MAY
MAY 23
I C E COVER
0146.2
0556.0
08
05
14
12
0222.6
0256.9
MAY
JUN 02
0125.3
0155.3
0136.1
27
0211.7
0092.9
0190.1
J U N 06
0263.6
1758.2
0762.5
J UN 08
0358.8
0370.4
0316.8
J U N 10
0405.4
0389.8
0198.4
J U N 12
0640.1
0305.7
0104.1
J U N 16
0753.1
0602.5
0126.2
J UN 18
0387.6
0221.5
0087.1
JUN
J U N 25
0071.3
0094.1
0079.7
83
23
.
0101.5
0129.6
APPENDIX
DEPTH
( M)
B
TABLE
6
CONTINUED
J U N 30
0324.0
0047.6
J U L 07
0119.6
0137.3
0022.7
J U L 13
0084.2
0066.4
0037.7
J U L 21
0050. 1
0046.4
0044.3
J U L 28
0074.4
.
.
AUG 0 4
0067.6
0076.4
0051.3
AUG 11
0086.3
0075.4
0051.3
AUG 18
0052.5
0052.5
0060.1
S E P 03
0061.1
0159.3
0069.8
S E P 10
0093.8
0101.4
0050.2
S E P 22
0059.0
2.0
AUG 27
0058.9
0645.6
0069.8
0.0
1.0
2.0
OCT 06
0063.3
0103.7
0084.0
0.0
1.0
2.0
0.0
1.0
2.0
0.0
1.0
•
0028.4
APPENDIX
SMITH
B TABLE
LAKE
7
1963
CHLOROPHYLL A
(MICROGRAMS / L I T E R )
DEPTH
( M)
0.0
1.0
2.0
J U N 12
099.3
060.2
•
JUN 19
100.1
058.4
016.7
J U L 18
007.2
•
•
J U L 23
004.3
•
•
0.0
1.0
2.0
J U L 30
003.6
•
•
AUG 07
003.9
002.5
011.9
A UG 12
002.8
003.6
002.5
AUG 27
004.2
007.7
005.4
0.0
1.0
2.0
S E P 03
002.5
002.4
007.4
S E P 10
002.5
•
002 .6
S E P 17
002.2
•
•
S E P 25
004.0
003.2
006.3
0.0
1.0
2.0
OCT 09
001.2
•
•
OCT 25
001.5
001.7
•
NOV 11
001.2
•
•
DEC 04
002.7
001.3
•
FEB
26
•
001.3
001.3
•
MAR
MAR
APR
APR
APR
0.0
1.0
2.0
2.5
0.0
1.0
14
003.4
18
•
005.1
004.5
•
20
•
007.7
85
24
•
007.9
•
07
•
•
010.4
APPENDIX
SMITH
B TABLE
LAKE
8
1964
CHLOROPHYLL A
(MICROGRAMS / L IT E R )
Ufcr I H
( M)
0.0
1.0
2.0
APR
28
•
011.8
•
MAY
01
•
010.0
•
MAY
05
•
012.0
•
MAY
12
•
017.0
•
MAY
18
•
016.4
034.9
048.4
MAY
25
•
007.2
020.3
065.9
MAY
0.0
1.0
2.0
2.5
27
•
004.5
016.5
027.9
J UN 02
003.3
006.8
012.4
016.7
0.0
1.0
2.0
J U N 08
022.6
010.7
010.1
JUN 09
046.3
028.6
015.2
J U N 10
017.1
034.7
006.8
J U N 12
132.3
019.4
•
0.0
1.0
2.0
J U N 15
062.9
051.8
009.2
J UN 16
036.9
032.0
005.5
J UN 18
029.3
007.4
006.4
J UN 23
005.8
007.1
012.2
0.0
1.0
2.0
J U N 25
005.3
005.5
002.9
J UN 30
007.7
008.2
003.2
J U L 07
003.2
004.6
002.2
J U L 13
005.7
002.8
003.1
0.0
1.0
2.0
J U L 21
002.3
001.9
001.5
J U L 28
003.4
003.4
002.8
AUG 0 4
004.5
002.7
004.0
AUG 11
004.7
003.8
0* 0 2. 5
0.0
1.0
2.0
AUG 18
004.0
003.3
002.2
S E P 10
014.0
013.6
005.0
S E P 22
010.3
005.0
003.6
OCT 0 6
011.7
011.0
007.0
86
APPENDIX
B TABLE
SMITH
9
LAKE
DISSOLVED INORGANIC
( M I C R O G R A M ATOMS
PHOSPHORUS
/ LITER)
1963
DEPTH
( M)
0.0
1.0
2.0
4.57
1.78
OCT 03
•
0.63
1.09
O C T 06
1.37
•
•
OCT 09
0 . 24
0.75
•
0.0
0.5
1.0
OCT 10
0.31
0.56
0.57
OCT 17
0.35
•
•
O C T 23
0.41
•
•
O C T 25
•
0.52
0.79
0.0
1.0
2.0
NOV 11
1.42
0.74
•
D E C 04
1.17
F E B 19
•
3.15
•
3.58
F E B 26
•
•
•
4.58
SEP
25
•
1.50
1964
0.0
1.0
1.5
2.5
0.0
1.0
2.0
2.5
J A N 03
•
1.86
•
3.52
MAR 18
•
4.22
•
5.60
FEB
03
•
2.58
2 .64
2.74
MAR
•
•
•
4.01
24
APR 07
•
•
4.54
•
APR 1
•
3.33
•
6.03
88
APPENDIX
B
TABLE
9 CONTINUED
DEPTH
(M)
0.0
1.0
2.5
A P R 21
•
3.30
5.24
A P R 28
•
3 .46
•
MAY 05
•
3.53
4.07
MAY 12
•
4 .83
5.68
0.0
0.5
1.0
1.5
2.0
2.5
3.0
MAY 18
•
•
3.36
•
•
4.24
•
MAY 23
•
•
4 .40
•
2.98
#
5.24
MAY 27
•
•
3.43
•
0.93
•
6.34
MAY 30
2 . 18
2.10
1.71
1 .78
3.54
3.97
•
0.0
1.0
1.5
2.0
2.5
J U N 01
1.91
2.86
2.31
•
3.30
J UN 02
2.16
•
2.76
2.94
3.89
J U N 08
1.63
1.52
•
2.48
•
J U N 09
1 .84
1.32
•
3.53
•
0.0
1.0
2.0
J U N 10
2.04
2.02
2.84
J UN 12
0.30
1 .04
3.01
J UN 15
0.21
0.64
2.77
J U N 16
0.58
0.25
2.15
0.0
1.0
2.0
2.5
J U N 23
0.72
0.95
2.59
•
J U N 25
0.44
0.45
0.37
2.12
J U N 30
0.25
0.31
1.20
•
J U L 01
•
0.20
2.55
•
0.0
1.0
2.0
J U L 27
•
0.18
•
AUG 0 4
0.37
0.63
1.52
APPENDIX
SMITH
B TABLE
10
LAKE
D IS S O L V E D ORGANIC
( M I C R O G R A M ATOMS
PHOSPHORUS
/ LITER)
1964
DEPTH
( M)
0*0
1.0
1.5
FEB 03
.
1.87
1.76
F E B 19
•
1.69
2.0
.
.
2.5
2.22
2.32
F E B 26
•
.
1.74
APR
07
.
.
2.00
.
APR
14
.
1.15
0.0
1.0
MAY
.
.
MAY
12
.
1.44
2.0
.
.
.
2.5
2.59
.
0.87
3.0
.
0.0
0.5
1.0
1.5
2.0
2.5
3.0
0.0
1.0
2.0
05
MAY
27
.
.
2.09
.
.
.
2.81
JUN
09
2.08
0.40
8.18
APR
21
.
2.05
MAY
18
.
1.84
.
JUN
10
.
0.96
0.91
89
APR
28
1.06
JUN
MAY
23
•
2.04
2.39
•
2 . 14
01
.
3.24
1.51
2.12
6.01
.
2.43
2.79
•
MAY
30
0.7
2
1.41
1.63
1.32
18
1.90
0.0
1.0
2.0
2.5
1.71
MAR
2.70
.
JUN
12
0.76
1.45
, 1.44 .
J U N 02
1.76
1.79
2.24
3.32
JUN
15
0.66
0.47
1.15
APPENDIX
DEPTH
( M)
0.0
1.0
2.0
2.5
J U N 16
2.44
3.50
.
.
1.0
J U L 07
0.45
B
TABLE
J U N 23
0.66
0.69
0.63
.
10
CONTINUED
JUN 25
0.82
0.91
0.48
0.64
J U N 30
0.62
0.56
0.49
APPENDIX
SMITH
(MG
B
L4KE
TABLE
11
1963
ALKALINITY
/ LITER CAC03)
DEPTH
( M)
0.0
1.0
2.0
J U N 05
26.5
26.5
26.5
J UN 19
22.0
29.7
28.3
J U L 15
31.1
29.8
30.7
J U L 23
30.9
30.6
30.5
0.0
1.0
2.0
J U L 30
31.4
31.6
34.0
A UG 07
33.5
33.4
22.0
AUG 2 0
34.5
34.8
41.2
AUG 27
38.8
36.4
36.0
S E P 25
44 . 0
44 * 0
44.0
OCT 25
48.0
45.0
44.0
NOV 13
40.0
50.0
49.0
DEC
0.0
1.0
2.0
91
09
•
54.0
57.0
APPENDIX
SMITH
(MG
DEPTH
( M)
0.0
1.0
2.0
JAN
03
12
1964
ALKALINITY
/ LITER CAC03)
FEB
03
FEB
24
•
66.0
•
28
•
54.0
•
70.0
72.0
APR
08
•
60.0
t
MAY
19
•
•
65.5
65.0
APR
0.0
1.0
2.0
LAKE
•
MAR
0.0
1.0
2.0
B TABLE
05
•
54.0
45.0
74.0
74.0
APR
13
•
59.0
•
MAY
12
MAR
18
•
38.9
64.0
APR
20
•
58.0
61.0
MAY
18
34.5
•
•
26.8
61.5
•
MAY
23
•
14.0
52.0
MAY
0.0
1.0
2.0
27
•
13.5
•
J U N 02
18.0
23.0
40.0
JUN 08
27.0
27.5
43.1
0.0
1.0
2.0
J U N 10
25.0
23.0
42.0
J UN 12
35.0
26.0
43.0
J UN 18
27.0
27.7
34.3
J UN 23
30.0
29.0
40.0
0.0
1.0
2.0
J U N 30
28.5
29.0
31.0
J U L 07
30.0
•
34.5
J U L 13
28.0
28.1
28.0
J U L 02
30.0
31.0
29.0
0.0
1.0
2.0
J U L 28
30.0
28.5
32.8
A UG 0 4
37.1
32.9
35.0
A UG 11
25.0
28.5
27.0
A UG 18
31.0
31.0
31.0
92
93
APPENDIX
DEPTH
( M)
0.0
1.0
2.0
AUG 27
29.4
30.8
30.3
0.0
1.0
2.0
OCT 06
36.0
37.7
32.9
B
TABLE
S E P 03
33.0
33.0
32.0
12
CONTINUED
S E P 10
28.2
26.2
26.5
S E P 22
32. f
31 . b
32.3