OXYGEN
CONSUMPTION
IN D1APTOMUS
Gabriel W. Comita
Department
of Zoology,
North
Dakota
State University,
Fargo
58102
ABSTRACT
The oxygen consumption
of fed and unfed Diaptomus
siciloides,
D. oregonensis,
D.
Zeptopus, and D. &wipes
was measured at five different
tcmpcraturcs
using a microWinkler technique.
Regression relationships
between log oxygen uptake and each of the
following
independent
variables, tcmperaturc,
log length, and log weight, as well as the
combinations
of temperature
and length and of temperature
and weight, were examined
for the four species mentioned
and Diaptomus
arcticus and Mixodiaptomzrs
Zaciniutus.
The simple regression of log oxygen consumption
on log dry weight at the five tcmpcratures and the multiple regression of log oxygen consumption
on temperature
and log dry
weight gave close approximations
to the cxperimcntal
means.
Kubik Eor her help during the experimental
phase of this study. I am especially gratcful to D. T. Eastlund for his extra care and
diligcncc during all phases of the study.
Parts of this work wcrc supported by the
North Dakota Institute for Regional Studies
and by National Science Foundation Grant
16415.
INTRODUCTION
Few oxygen consumption measurcmcnts
have been made with the freshwater
calanoids of the genus Diaptomus since the
work of Scherbakoff ( 1935). For those that
have been recorded, the nutritional
state
was usually mlknown, which probably contributed to the great amount of variability
reported.
In this study, respiration measurements
were made at four or five different temperatures, in the range between 5 and 25C,
for five species of female Diaptomus ranging in cephalothorax length from 0.80 to
3.11 mm. The species, all collected near
Fargo, North Dakota, were Diaptomus
siciloicles Lilljeborg
1889, D. oregonensis
Lilljeborg 1889, D. Zeptopus S. A. Forbes
1882, D. clavipes Schacht 1897, and D.
arcticus Marsh 1920. In addition, rcspiration measurements: for Mixodiaptomus
Zaciniatus Lilljeborg 1889 from Lago Maggiorc, Italy (Comita and Comita 1964),
were compared with those for the five local
organisms. For several species, some individuals were fed and some were not fed
before the experiments to demonstrate how
oxygen uptake was affected by feeding.
The effect of temperature on the rclationship between oxygen consumption
and
length or weight was also examined.
I am grateful to L. D. Zinsli and J, E.
Schindler for their assistance while they
were National Science Foundation undergraduate research participants and to P. J,
MATFXALS
AND
METHODS
Most of the animals were taken by towing
a No. 12 net from short; only D. siciloides
was taken in open water. The organisms
wcrc sorted into groups of up to five per
IO-ml beaker of water from the same source
that had been membrane filtered.
This
membrane-filtered
water was used for conditioning
and for the measurements of
respiration,
after aeration at the proper
temperature until oxygen saturation reached
near 90%.
Reforc each experiment, about 40 lo-ml
beakers were set up and females of one
species were segregated into each beaker,
Half the females received no food and the
others were given a suspension of Chlamydomonas eugametos sufficient to provide a
concentration
of 50,000 cells/ml.
Nonovigerous females were usually selected
for the experiments, but at times it was
necessary to include some bearing eggs.
Appropriate numbers of these animals were
then conditioned at a specified temperature
for from 15 to 70 hr ( Table 1). At the end
of this period the gut of the fed animals
51
52
GABRIEL
W.
COMITA
1. Oxygen consumption
data for fed and starved females and some males of five species of
Diaptomus
and one of Mixodiaptomus
and the results of Bartlett’s
test of homogeneity
of variances.
Observations
were not made at 5C for D. siciloides and M. laciniatus nor at 1OC for D. leptopus and
D. clavipcs. D. arcticus and M. laciniatus were not fed during the conditioning
period.
The variances
for D. leptopus are homogeneous at the 5% level
TABLE
Species
D. siciloides
D. oregonensis
Mean
length
cephalothorax
(mm)
?ep
Fed
Starved
c.v.*
(%)
(1)
(2)
(3)
(4)
(5)
(6)
(7)
(8)
D. leptopus
D. clavipes
D. arcticus
Conditioned
(hr)
Incubated
( hr)
10
15
20
23.5
7”
6
13
5
5
4
3
21
16
19
20
5.049
1.8-2.9
2.5-3.4
3.8-6.0
0.017
0.049
0.075
0.090
0.008
0.043
0.064
0.074
78.5
44.0
67.9
26.4
7
6
5
7
7
5”
4
3
15
19
16
20
18
17
4.9-6.0
5.7-6.7
2.5-3.6
3.0-4.2
5.2-6.2
2.7-3.7
0.023
0.026
0.042
0.041
0.064
0.098
0.023
0.023
0.054
0.028
0.042
0.084
39.5
38.8
50.8
39.6
26.3
31.7
10
15
20
12
10
12
6-7 $
4$
3-4 $
23
23
23
8.4-9.3
4.1-6.5
4.0-4.9
0.021
0.050
0.076
30.8
29.4
20.3
5
15
20
25
9
9
10
10
5
3
2
1
17
17
17
16
5.9-7.1
3.6-4.7
6.2-7.4
4.1-5.3
0.055
0.111
0.178
0.269
0.042
0.079
0.148
0.218
71.5
40.0
23.1
28.6
5
15
20
25
5
15
11
13
3
2
2
1
17
16
18
17
5.7-6.7
3.4-4.9
5.5-6.8
3.5-4.8
0.049
0.150
0.211
0.330
0.031
0.149
0.202
0.330
60.3
21.8
9.5
20.2
5
10
15
20
25
15
14
15
20
15
1
1
1
1
1
21
20
20
70
21
4.3-5.4
5.6-6.7
2.1-3.3
1.3-3.7
1.6-2.7
0.318
0.483
0.634
0.853
1.249
28.9
23.7
26.2
35.5
13.4
H,“,;T;yfvariances
X2
df
(9)
(10)
0.80
1.01
5
10
15
15
20
25
M. laciniatus
Females/
vial
Oxygen consumed
( pliter 0 -1 hr-1)
Determinations
1.02
10.428
1.42
5.87
17.74$
1.55
25.63$
3.11
* C.V. = coefficient of variation.
t Variances homogeneous between the 5 and 1% levels.
$ Variances homogeneous at less than the 1% level.
was green, and fecal pellets were present
in greater numbers than in the beakers
containing unfed animals.
After conditioning, the animals were incubated in vials containing approximately
2.2 ml oE filtered and aerated pond water.
For the two smaller copepods, D. siciloides
and D. oregonmsis, up to six females were
enclosed in each vial for the 5 and 1OC
measurements; for M. Zaciniatus, six and
seven malts were used at 1OC. The number
of females per vial was dccreascd according
to the size of the organism and as the experimental temperature was increased. For
the largest organism, D. nrcticus, only one
female was needed to obtain a mcasuremcnt at each of the five temperatures
( Table 1, col. 3).
At the end of the incubation period an
aliquot was withdrawn from each vial, and
the amount of oxygen was determined using
the micro-Winkler technique (Barnes 1959).
The difference in quantity of oxygen in
the experimental vials from that in control
OXYGEN
CONSUMPTION
IN
53
DZAPTOMUS
TAULE 2. Regression equations for log oxygen consumption
in $ters per female per hr on temperature
with ~~~ values computecl from them, and
for five species of Diaptomus,
and one of Mixodiaptomus,
results of tests for deviation from linearity.
I?” tests the hypothesis that the regression is linear. Because
I?’ was less than the tabular value for I! at the 5% leuel, the hypothesis of linearity for the log expressions is accepted in all cases, All correlation
coefficients are significant at the 1% level and all I? ratios
are highly significant
(OSOJO level) indicating ihat the regression coefficients
are different
from zero.
The ratios listed under F’ are used to test the null hypothesis that the equation is unreliable.
F’ is
obtained by dividing the regression sums of squares by the residual sums of squares after each is adThe hypothesis is rejected and the equation is reliable if the computed
justed for degrees of freedom.
F’ is greater than the tabular F (which is not listed in this table).
These F’ values are all highly significant indicating
reliable equations
Test for clcvintion from
linearity (logs)
D.
D.
M.
D,
D.
D.
n
T
32
40
34
38
40
79
0.70
0.76
0.88
0.83
0.89
0.84
Eqnntion
Species
siciloides
log 02 = 0.0574 ( To ) - 2.389
oregonensis
log 02 = 0.0342( T”)
log 02 = 0.0566( T”)
log 02 = 0.0398( T” )
log 02 = O.O431(T”)
log Oa = 0.0288( T” )
laciniatus
leptopus
clauipes
arcticus
- 1.914
-2.233
- 1.573
- 1.545
- 0.647
vials after the incubation period was the
oxygen consumption, expressed as Jiters
per female per hr. Length measurements
(ccphalothorax)
were made on the live females immediately
after the oxygen consumption readings, Weight was determined
after drying at 1OOC for about 30 min. The
data for Mixocliaptomus are from males but
appear to bc in the same order of magnitude
as that from the females of D. siciloides and
D. oregonensis.
Bartlett’s test of homogcncity of variances
was applied to the data from each species
( Table 1 ), but bccausc the appropriate
degrees of freedom in this analysis for all
species came to four or less, Box’s modification of this test was also done. The null
hypothesis tested by these treatments is
that there are no diffcrcnccs in variances
in the respiration measurements at each
temperature.
If the sample variances are
very much different from one another, the
chi-square and Box’s F-ratio are greater
than the tabular values. The results of
both tests show that the variances for only
one species, D. Zeptopus, arc homogeneous,
RESULTS
AND
DISCUSSION
F’
28.9
53.0
108.7
82.4
146.7
181
QKI
3.75
2.2
3.68
2.5
2.70
1.94
F”
1.52
0.62
3.83
0.06
1.80
0.69
Tabnlnr
( Fo.m =
(F0.20 =
(F’o.oo =
(Fo.,,, =
(Fo.lo =
(Fo.ro =
F
df
1.71)
1.64)
4.17)
1.70)
2.49)
1.59)
2,28
3, 30
1, 30
2, 30
2,30
3, 60
uptake were being obtained
with D.
siciloicles from a lake that contained a large
population of Daphnia middendorfiana.
At
the time of collection the Secchi disc reading was 4.9 m, which was at or near the
bottom of the lake. The usual reading
during 1965 was 0.3-0.9 m. Because considerably higher respiration rates had been
obtained earlier with the same species
from the same lake, it seemed possible that
the low rates were caused by insufficient
food. To test this hypothesis, one group of
the females was fed a suspension of C.
eugametos containing 50,000 cells/ml while
a replicate group was kept without food.
Nearly all the readings of oxygen uptake
obtained from the fed females were higher
than those obtained from the starved ones
(Table 1, col. 6 and 7).
Similarly designed expcrimcnts were also
carried out with D. oregonensis, D. leptopus,
and D. clavipes. Respiration rates for D.
Zeptopus were also significantly greater for
fed than for unfed animals, but in the case
of D. oregonensis and D. clavipes the presence or absence of food produced no consistcnt differences,
Effect of food
Effect of temperature
During the course of the measurements
it was noted that low readings of oxygen
Logarithms of the oxygen consumption
rates for the five species of Diaptomus and
54
GABRIEL
W.
COMITA
3. Log Oa as a function of length at five
temperatures.
Oxygen consumption
is in j.&ters
per female per hr and length in mm. All correlation coefficients
are significant
at the 1% level.
All F (= F’ in Table 2) ratios are significant
at
the 0.5% level
TAISLE
.
A
-
Temp
(Cl
Eqlration
n
5 log 02 = 0.528L - 2.153
;/;
10
15
20
25
~/.A-----+
.u
.,.,._................... I.&“---.---l-ec.--
I I
5”
I
I
I
I
I
I
S
-0
I
IO0
I
I
I
I
I
I
15”
I
I
I
I
20”
I
I
I
25”
log
log
log
log
02
02
0s
02
=
=
=
=
0.652L 0.521 L0.486L 0.476L-
2.355
1.820
1.594
1.373
30
27
37
43
32
T
0.92
0.95
0.93
0.91
0.79
F
157
228
235
192
346
TEMPERATURE
FIG. 1. The oxygen consmnption of five species
of Diaptomus
over the temperature
range from
5 to 25C. The curves are derived from the regression equations presented in Table 2. Closed circles
are the means from Table 1, col. G, for oxygen
consumption of Diaptomus arcticus, mean cephalothorax length, 3.11 mm (A);
open squares, D.
&wipes,
1.55 mm (C); small closed circles, D.
leptopus, 1.42 mm ( L); small open circles, D.
siciloicles, 0.80 mm (S ); and closed triangles, D.
oregonensis, 1.01 mm (0).
for 121.Zacirz.iatuswere plotted against tcmperature, and curves were fitted to the data
by the method oE least squares (Table 2).
For all curves, the regression coefficients
were significantly different from zero, and
there was no deviation from linearity for
the semilog plots. Q1o values derived from
the equations range from about two for D.
arcticus to 3.75 for D. siciloides.
Respiration data wcrc also plotted against
temperature without transformation to logs.
The curves for the five Diaptomus species
are shown in Fig. 1. The equations for
these curves were also tested Eor nonlinearity.
In the case of the three larger
species ( curves A, C, and L ), the temperature-oxygen relationship was not linear.
Relationship between respiration and size
The second regression relationship
examined was that of log O2 vs. length for
each of the five temperatures; these equations arc listed in Table 3. (The values
listed in Table 5, col. 3, arc obtained when
the equations are solved at different temperatures.) The F-ratios that were derived
from the equations are highly significant
and are approximately twice those obtained
for the data involving temperature.
The
calculated means from these equations are
closest to the experimental means for M.
laciniatus (see Table 5, col. 1).
The regression equations of log oxygen
consumption on log dry weight for each of
the five temperatures as well as for all tem-
TABLE 4. Regression equations for log oxygen consumption
and log weight in log form and in exponential form. Log Oa is expressed as pliters consumed per mg per hr; log weight as pg dry weight.
For
each species the mean weights were: D. siciloides, 3.2; D. oregonensis, 4.75; D. leptopus, 22.2; D.
clavipes, 28.7; D. arcticus, 300. In exponential
form, the R is oxygen consumption in ,uliters per female
per hr. All correlation
coefficients
are significant
at the 1% level. All l? (= F’ in Table 2) ratios are
significant
at the 0.5% level
Tknp
Equation
(C)
5
10
15
20
25
All
1: Standard
log
log
log
log
log
log
error
02 =
Oa =
02 =
O:! =
02 =
02 =
0.81310.8618
1.1714
1.3938
1.5775
1.1635
of cstimatc
-
n
0.3314
0.2792
0.3462
0.3743
0.3780
0.3418
of y (log
0,).
(log
(log
(log
(log
(log
(log
W)
W)
W)
W)
W)
W)
5
5
5
5
25
T
-0.97
-0.98
-0.98
-0.99
-0.99
-0.67
SE*
0.065
0.055
0.020
0.019
0.028
0.272
F
63
64
698
899
441
19
Exponential
R =
R =
R =
R =
R =
R =
form
6.50w”~ooD
7.27 W”.721
14.84 W”.O”l
24 76 W”.Ozo
3i.80 W”.“‘”
14.57W”J””
OXYGEN
TABLE 5.
peratures.
Te111p
(C)
CONSUMPTION
IN
Comparison of the results obtained from the five different
regression equations at five temP are the experimental
means for oxygen consumption
as given in Table 1, col. 6. Entries
in all columns are in pliters of oxygen per female per hr
P
Temp
Length
(1)
(2)
(3)
(2)
(2)
and (3) nnd (6)
(4)
(5)
0.019
0.015
0.040
0.062
10
15
20
25
0.011
0.021 0.022
0.050 0.041
0.076 0,079
0.152
0.024
0.020
0.051
0.080
0.130
5
10
15
20
25
0.049
0.150
0.211
0.330
0.045
0.045
0.097
0.144
0.232
10
15
20
23.5
25
-
0.027
0.038
0.053
0.073
-
Tcmp
Length
and (3)
nnd (6)
Log W
(6)
(1)
(2)
(3)
(4)
(5)
(6)
D. oregonensis
0.013
0.021
0.031
0.048
0.014
0.017
0.032
0.051
0.102 0.103 0.073 0.078
0.034
0.048
0.06G
0.092
0.128
0.023
0.026
0.042
0.064
0.018
0.027
0.040
0.059
0.062
0.087
0.120
0.165
0.235
0.024
0.020
0.051
0.079
0.033
0.047
0.064
0.090
0.018
0.027
0.041
0.062
0.018
0.022
0.041
0.066
0.098 0.087 0.128 0.122 0.094 0.099
D. leptopus
-
-
0.055
0.111
0.178
0.269
0.047
0.075
0.119
0.187
0.296
0.040
0.037
0.083
0.125
0.201
0.058
0.087
0.133
0.202
0.307
0.061
0.082
0.133
0.202
0.305
0.318
0.483
0.634
0.853
1.249
0.313
0.437
0.609
0.848
1.181
0.308
0.471
0.631
0.827
1.281
0.054
0.075
0.105
0.145
0.205
0.048
0.073
0.111
0.169
0.257
0.051
0.068
0.112
0.171
0.259
0.269
0.409
0.622
0.945
1.436
0.366
0.444
0.618
0.878
1.313
D. arcticus
D. clauipes
0.047
0.077
0.126
0.208
0.341
(2)
9
M. laciniatus
5
(2)
Log w
D. siciloides
0.008
0.017 0.015
0.049 0.030
0.075 0.057
0.090
(0.10) 0.111
5
55
DIAPTOMUS
pcratures combined arc prescntcd in Table
4 and shown graphically in Fig. 2. Solutions
based on these equations are listed in Table
5, col. 6. These solutions are the closest
overall approximations to the cxpcrimcntal
means obtained for the six spccics, although
the temperature equations (Table 2) seem
to bc equally acceptable.
The slope of the 1OC solid lint (Fig. 2)
deviates most, but not significantly
(F =
1.99, df 4, 15; Fo.05= 3.06) from that of the
lines at the other temperatures.
If these
equations arc in fact a family of curves as
they appear to be, this deviation may bc
enough to yield low rates of oxygen uptake
in the lower weight lcvcls shown in Fig. 2.
When these equations are transformed
from the log form to the exponential form,
the constants obtained range from 6.622
to 0.721. The exponential constant (0.658)
from the equation combining data from all
temperatures can bc compared with those
given by Conover (1960) : for herbivores,
0.559, and for carnivores, 0.649; although
Conovcr’s data were obtained over a much
0.339
0.480
0.640
0.909
1.264
narrower range of temperature.
I?or the
five species of Diaptomus, this constant is
closer to the theoretical value, expressed by
the relationship
R = hW0.67, relating respiration to surface area or % power of
weight. There is no evidence that any of
thcsc diaptomids are carnivorous. The data
presented by Raymont and Gauld ( 1951))
Gauld and Raymont ( 1953)) Conover (1956,
1959,196O) and Raymont ( 1959 ) for scvcral
marinc copepods can be compared with
these for Diaptomus.
Conovcr’s analysis led him to accept a
direct rcla tionship, involving no transformations, bctwecn oxygen consumption as pliter
per 1,000 copepods per hr and mg dry wt
per 1,000 copepods. The equivalent equation for these Diaptomus species based on
weight is 02 = 2.1466 (wt as mg) + 0.06744.
Since size measurements involve either
length or weight or both, examination was
made of the lengths and weights available
for five of the six species studied and
additional length-weight
data were used
that were taken from scvcral other local
56
GABRIEL
W.
COMITA
TARLE 6. Ponderal index values, k, derived from
length (mm) and weight (pg) data taken from
500 or more specimens of the seven species listed
Length (mm)
Species
D. siciloicles
D. oregonensis
D. sicilis
II). saskatchewanensis
leptopus
clavipes
arcticus
arcticus (1965)
D.
D.
D.
D.
FIG. 2. Rcgrcssion lines for oxygen consumption as a function of dry weight at five tempcratures. Lines arc dcrivcd
from the equations in
Table 4. Data points plotted arc the experimental
means shown in Table 1, col. 6, except for 5C at
3.2 ,ug and 1OC at 22.2 and 28.7 ,ug. The 5C
point is the cxpcrimental
mean ( closed circles ),
4.7 pg mg-’ hr-I, from unfed D. siciloides. It is
the mean respiratory
rate of nine replications
with
seven females in each vial. The 1OC points (closed
triangles)
plotted at 22.2 ,LL~ (D. Zeptopus) and
28.7 ,ug (D. &Apes)
as well as those for 3.2
,ug (D. siciloides)
at 15 and 20C were derived
from equations in Table 2. The 15C line (dashed)
represents two nearly identical lines, one for the
15C data and one for all temperatures
combined;
they are not separable in the figure.
populations,
including
some from these
same species taken in 1963, (Comita and
Schindler 1963). The expression, wt (pg) =
k ( length3), for the relationship between
length and weight as derived from the data
on hand was cxamincd (Table 6).
The only 7cvalue that departs markedly
from the others for the same sex is that for
D. nrcticus females ( 1965), which was
based on 79 length measurements but on
only 15 weight measurements. These femaics had a longer mean cephalothoracic
measurement (3.11 mm) than those taken
from the sami pond in an earlier year
( 1962). The reason for this difference is
not known. The other two 7cvalues for D.
arcticus prcsentcd in the table, one for
males ( 9.05) and one for females ( 5.84))
are from the 1962 populations
based on 500
- specimens, and they are probably more
representative because of the larger number
weighed. 7c values calculated for Limno-
d
0
0.75
0.74
0.80
0.76
1.45
1.39
2.34
0.95
0.78
0.95
0.87
1.70
1.68
2.80
3.11
k
d”
9.22
8.32
8.02
10.18
10.04
10.48
9.05
0
5.72
4.94
5.38
6.47
5.52
6.56
5.84
9.73
calanus johanseni (Comita 1956) are about
the same as those listed in Table 6.
Relationship between respiration and the
combination of temperature and size
When both length and temperature,
including
182 sets of data, are taken as
independent variables, a multiple regression
equation can be computed to show their
combined effect on log oxygen for all the
species. The equation, which also yields
close approximations to the measured respiration values, is: log O2 = 0.4732 ( L ) +
0.0286 (To) -2.085; (r = 0.80 for log 02
on length; r = 0.35 for log O2 on temperature ). The F-ratio is 116, and again is
highly significant. The standard error of Y
is reduced (from 0.315 to 0.246) by about
22% by the addition of temperature as the
second independent variable. The values
obtained from the solution of this equation
are shown in Table 5, col. 4.
Bimodality of length in Calanoid copepods
is a common phenomenon. In these diaptomids, a pronounced bimodality occurred
in both the D. siciloides and D. uregonensis
populations, and it is certain to be an important factor Mlucncing
the precision of
an cxprcssion involving
length mcasuremerits. For D. siciloides, the cephalothoracic
measurements ranged from 0.73 mm to
1.06 mm with the lower mode centering
around 0.78 mm and the upper mode centcring around 0.98 mm. For D. oregonensis,
a lower mode centers around 0.94 mm and
the upper mode around 1.06 mm (absolute
OXYGEN
CONSUMPTION
range, 0.80 to 1.17 mm). For D. leptopus,
there was a single mode at I.41 and for
D. clauipes and D. arcticus length measurcments were unimodal also.
Some of the specimens were weighed at
the time of these mcasurcments, and weight
recorded at other times from populations of
the same spccics from the same ponds were
used to supplement the data. The multiple
regression equations, combining temperature and all the weight data, were:
log O2 = 0.0364 (To) - 1.818 (W) + 0.3068;
r = 0.73 for log O2 on temperature;
-0.59 for log 02 on weight.
IN
57
DIAPTOMUS
If one adult female D.
middendorfiana.
siciloides having 0.028 calories respires at
its 20C starved rate, which is 0.064 ,Jiter of
Oz/hr (86% of its fed rate), it could theorctically consume itself in respiration in about
3.7 days (assuming no food intake), but
could survive for 8.1 days if its respiration
dropped to 40% of its fed rate. Thus, a
change in respiratory rate from 86 to 40%
of the fed rate increases the survival time
by a factor of about 2.2. This additional
time could help the animal survive a period
of intense competition with any herbivore.
r=
REFERENCES
H. 1959: Apparatus
and methods of
oceanography.
Intcrscience, New York. 341 p.
CCIMITA,
G. W.
1956. A study of a Calanoid
lake.
copepod
population
in an Arctic
Ecology, 37 : 576-591.
-,
1965. The
oxygen
consumption
of
Diaptomus
sicizooicles, Lilljeborg.
Limnol.
Oceanog.,
10 : 466-468.
AND J. J. COMITA.
1964. Oxygen upta<e in Mixodiaptomus
laciniatus Lill.
Mem.
1st. Ital. Idrobiol.,
17: 151-166.
-,
AND D. W. SCIIINIILE~.
1963. Calorific
values
of microcrustacea.
Science,
140 :
1394-1396.
CONOVER,
R. J. 19S6. Oceanography
of Long
Island
Sound 1952-1954.
VI.
Biology
of
Acartia clausi and A. tonsa. Bull. Bjnghnm
Oceanog. Collection,
56 : 156-233.
-.
1959. Regional and seasonal variation
in the respiratory
rate of marinc copepods.
Limnol. Oceanog., 4: 259-268.
-.
1960. The feeding behavior
and respiration of some marine planktonic
Crustacca.
Biol. Bull., 119: 399-415.
GAULD,
D. T., AND J. E. G. RAYMONT.
1953.
The respiration
of some planktonic
copepods.
II. The effect of temperature.
J. Marine Biol.
Assoc. U.K., 31: 447-460.
RAYMONT,
J. E. G. 1959: The respiration
of
some planktonic
copepods.
III, The oxygen
requirements
of some American
species.
Limnol. Oceanog., 4: 479-491.
-,
AND D. T. GAULD.
1951. The respiration of some planktonic copepods.
J. Marine
Biol. Assoc. U.K., 29: 681-693.
RICHMAN,
S. 1958. The transformation
of energy
by Daphnia
pulex.
Ecol. Monographs,
28:
BAJXNES,
log O2 = 0.0364 (To)-0.3418
+ 0.6182;
(log W)
r = 0.73 for log O2 on temperature; r =
-0.67 for log O2 on log weight. In both
equations, log 02 is measured in ,Jiter mg-l
hr-I, W in the first equation is in mg and
in the second in pg, and To is in C. These
equations are derived from 25 sets of observations. The F-ratio for the first cxpression is 61 (significant
at the 0.5% level)
and that for the second is 633-also highly
significant.
The standard error of the depcndent variable is reduced from 0.253 to
0.050, and the improvement F obtained by
the addition of log W as pugis 586. Evaluations of only the equation using the log
transformation of weight arc listed (Table
5, col. 5).
The log W equations ( Table 4) were
solved using the weight and respiration
data of other copepods compiled and reported by Richman ( 1958, his Table 7).
The oxygen consumption values thus obtained are about 1.2-1.4 times greater than
the observed values recorded. Although
the nutritional condition of those listed was
not known, it is probable that the reported
values are low because they are rates from
unfed animals.
It was mentioned earlier that rates for
D. siciloides were consistently lower when
living under sevcrc competition with D.
s,,E2z-yF:
A P 1g35 Ueber den Squerstof. .
.
L
fverbraudh
von einigen
Planktoncrustacccn.
Arb. Limnol. Sta. Kossino, 19: 67-89.