363
NOTES AND COMMENT
no added glucose, and a series of standards
having increasing amounts of glucose added
to the experimental sample of water. Glucose standards were prepared by serial dilutions from a 0.200 M stock solution. The
difference between the sample with no
added glucose and the blank was proportional to the glucose present in the water.
The concentration
could be determined
from the standard curve which was a
straight line over a wide range of concentrations. With the use of constriction micropipettes for small volumes and with careful
attention to pipetting, multiple analyses of
a sample usually agreed within a few fluorimeter units. Because of this reproducibility we have confidence in determinations
where the blank value was as much as 80%
of the experimental value. This sets the
lower limit of sensitivity at about 1 x 10-S
M glucose in freshwater and 3 X 1O-s M in
seawater (which must be diluted three
times before analysis ) .
We have been able to measure the
amount of glucose in local fresh and brack-
ish ponds and in inshore seawater with this
technique. The values are usually in the
range of 2 to 6 X 1O-8 M. A more extensive
series of measurements in the open ocean
is described elsewhere (Vaccaro et al. 1968).
SONJA E. HICKS~
FRANCIS G. CAREY
Woods Hole Oceanographic Institution,
Woods Hole, Massachusetts
02543.
REFERENCES
GUILBAULT, G. G., AND D. N. KRAMER. 1964.
New direct fluorometric
method for measuring dehydrogenase
activity.
Anal.
Chem.,
36: 2497-2498.
LOWRY,
0. H., J. V. PASSONEAN, AND M. K. ROCK.
1961. The stability
of pyridine
nucleotides.
J. Biol. Chem., 10: 2756-2759.
VACCARO, R. F., S. E. HICKS, H. W. JANNASCH,
AND F. G. CAREY. 1968. The occurrence
an d role of glucose in seawater.
Limnol.
Oceanog., 13 : 356-360.
2 Present address:
Massachusetts
Technology,
Department
of Nutrition,
Massachusetts.
Institute
of
Cambridge,
TEMPERATURE ,~ND CURRENT OBSERVATIONS IN CRATER LAKE, OREGON*
Crater Lake occupies a caldera formed
when the ancient Mt. Mazama collapsed
within itself. The near circular lake (shoreline development of 1.33) is 589 m deep
and 55 km2 in area. The lake surface is
presently 1,882 m above mean sea level;
however, the level of the lake has fluctuated as much as 4.5 m in the last 20 years
(Byrne 1965). The extreme clarity of the
water adds to the unique physical characteristics of Crater Lake.
There has been some debate in the past
as to the degree of thermal stratification
that takes place during summer. Hasler
(1938) reported definite temperature stratification during July and August. Fairbanks
(cited in Nelson 1961) also collected data
indicating thermal stratification.
Temperature profiles taken by Kemmerer, Bovard,
l Oregon Agricultural
nical Paper No. 2354.
Experiment
Station
Tech-
and Boorman (1924) led them to believe
that Crater Lake might not stratify thermally.
Another unusual thermal feature of the
lake is that it seldom freezes over. Ice was
observed to cover the lake from midFebruary through April in 1949 (Ruhle
1949), for two days in 1924, and possibly
during the winters of 1887 and 1898
(Waesche 1934).
There is a paucity of data on the currents
of the lake. The only previously known
attempt to study surface currents was by
Kartchner and Doerr (1939) who followed
movements of a vertical floating log.
In an effort to describe further the physical features of Crater Lake, temperature
and current measurements were made in
summer 1966. Vertical and horizontal temperature profiles were taken and drift devices were released to follow the surface
currents .
36-I
0
IO
20
ii?
F
g 30
zE 40
FIG. 2.
Surface isotherms of Crater Lake based
on five transects (- - - -) made from 31 July to
10 August 1966.
fJ
0
50
60
70
111111111
I5
0
TEMPERATURE
OC
FIG 1. Temperature
profile of Crater Lake on
25 August 1966 at the time of the highest heat
content of summer.
course at 90 to 135 cmjsec. Temperature
readings were taken at l-min intervals during five different crossings.
Floats used to determine currents were
constructed from 4-liter polyethylene bags
filled with approximately 3.5 liters of water
and tied shut leaving a small air pocket
extending not more than 5 cm above the
water surface. Three to four bags were released early in the morning on calm days
and followed by boat throughout the day.
Their positions were determined periodically (1 to 2 hr) by triangulation
from
compass readings on at least two prominent points on the caldera wall.
RESULTS
METHODS
AND
MATERIALS
An electrical resistance thermistor was
used to measure temperature from the surface to 150 m at 10 sampling stations on
43 occasions from 28 May to 5 September
1966. The data collected on 25 August were
used for calculating the summer heat income using the method given by Hutchinson (1957). Differences in the temperature
over the lake surface were measured with
a thermistor probe that was placed over
the side of a boat moving on a straight
Although the thermal stratification of the
lake varies slightly from station to station,
the thermal profile shown in Fig. 1 is considered to be representative of maximum
thermal development in the lake during
summer 1966. Temperature data from Fig.
1 were used to calculate a summer heat
income of 30,010 Cal/cm”. The maximum
surface temperature recorded was 18.8C
on 13 August at a point 100 m northeast of
Pumice Point and only 10 m from shore.
An isotherm plot indicating
temperature
differences across the surface of the lake is
NOTES
AND
shown in Fig. 2. These data are based on
five transects run in late July and early
August. The thin band of cold water off
the east shore of thk lake and the lower
temperatures observed in an area southwest of Pumice Point are of interest. The
surface water in these areas is the same
temperature as the water at the 13- to 14-m
depth (Fig. 1) .
The general surface currents are shown
in Fig. 3. There appears to be a counterclockwise (cyclonic)
movement along the
shoreline. The maximum observed current
speed of 10.3 cm/set was recorded on 22
July. The minimum water movement occurred in Cleetwood Cove, the northernmost portion of the lake. Currents from
midlake appeared to terminate in Cleetwood Cove, which supports a common belief that anything lost on the lake will
eventually float into Cleetwood Cove.
The most interesting current pattern is
the anticyclonic movement that occurred in
the northwestern portion of the lake (Fig.
3). A temperature transect (bottom of Fig.
3) shows a definite drop in temperature
through this gyre. The period of rotation
for this anticyclonic movement closely approaches the theoretical period of an inertia
current. The period (Tp) of such a movement set up by an external force was calculated from the equation TP= T/(w sin 4)
(Hutchinson 1957) where a is the angular
velocity of rotation of the earth (0.729 x
1O-4radians see-l) and 4 is the latitude, in
this case (42”56’N).
The theoretical time
for completion of the circle was calculated
to be 17.6 hr. The measured time, based
on the drift bags completing 90% of gyre,
was 17.7 hr.
DISCUSSION
The discrepancies in the literature over
the degree of thermal stratification may be
due to thermal profiles being taken at different locations where upwelling may be influencing temperature-depth
relationships.
Changes in climatic conditions from year
to year may also account for the recorded
differences.
The comparatively
high heat budget,
365
COMMENT
MERRIAM
POINT
WINEGLASS
FIG. 3. Surface current directions measured on
Crater Lake in summer 1966. A horizontal temperature
profile
and the current
direction
are
shown for a transect from Merriam Point to Wineglass.
30,010 Cal/cm”, is at least partially responsible for the fact that Crater Lake rarely
freezes over. Strong wind action during
winter also plays a part in preventing
freeze-over for a lake at such a high altitude.
Variations in the surface temperature
could be due to differential heating of the
water near pollen patches, upwelling,
or
springs. The low temperature along the
northeast shore is possibly due to upwelling created by a strong wind-driven flow.
A second explanation for this cold band of
water might be springs, which are numerous in the caldera wall on the east shore,
and which may also be present below the
water line in this region.
The cyclonic circulation is most likely
generated by the wind-south-prevailing
during summer. Once inside, however, the
caldera winds whip around the wall and
consequently at any given point on the lake
the wind can be blowing any direction.
The wind is also of primary importance in
366
NOTES AND COMMENT
setting up the inertial
Point.
gyre east of Merriam
H. v. KIBBY
J. R. DONALDSON
C. E. BOND
Department of Fisheries and Wildlife,
Oregon State University,
Corvallis
97331.
REFERENCES
BYRNE, J.V.
1965. Morphometry
of Crater Lake,
Oregon.
Limnol. Oceanog., 10: 462-465.
HASLER, A. D. 1938. Fish, biology,
and limnology of Crater Lake.
J. Wildlife
Management, 2: 94-103.
JOURNAL
COVERAGE
IN THE
Because of greatly increasing interest in
water resources, numerous and varied institutes are being set up to deal with freshwater problems, including those of basic as
well as applied limnology. Through the advice of their scientific colleagues, librarians
serving such institutes are becoming aware
that the literature of limnology is extremely
diverse, and scattered over a wide range
of periodicals.
This paper briefly examines the periodical coverage of limnology
through a study of most-cited journals in
two volumes of the Proceedings of the International Associution of Pure and Applied
Limnology
(Verhandlungen
der Internationalen Vereinigung fiir Theoretische und
Angewandte Limnologie). One volume (No.
15, 1964) contains the papers presented in
1962 at the 15th International Limnological
Congress in Madison, Wisconsin, U.S.A.;
the other volume (No. 16, 1966) contains
the majority of papers presented in 1965 at
the 16th International Congress in Warsaw,
Poland (Part 3 had still to appear when this
report was prepared). Through this choice
of sources both European and North American limnologists are well represented, and
the biases of language and nationality are
minimized. That they are not entirely overcome is shown by the high ranking (18th
l Contribution
Research Center,
No. 65 from the Limnological
University
of Minnesota.
HUTCHINSON, G. E. 1957. A treatise on limnology, v. 1. Wiley, New York. 1015 p,
KARTCHNER, W., AND J. E. DOERR. 1939. Wind
currents on Crater Lake as revealed by the
old man of the lake.
Crater Lake Nature
Notes, 11: 31-35.
KEMMERER, G., J. F. BOVARD, AND W. R. BOORMAN.
1924.
Northwestern
lakes of the
United States: biological and chemical studies
with reference to possibilities
in production
of fish.
U.S. Bureau Fisheries,
Bull., 39:
51-140.
RUHLE, G. C.
1949. An historical
passage.
Crater Lake Nature Notes, 15: 14-15.
WAESCHE, H. H. 1934. The lake (physical characteristics ) .
U.S. Natl.
Park Serv. Files,
Crater Lake, Oregon.
7 p.
FIELD
OF LIMNOLOGY'
and 19th) of two Polish journals ( Ekologia
Polska and Polskie Archiwum
Hydrobiologie) in the list of most-cited periodicals.
The two volumes included 309 articles
(266 with references), totaling 2274 pages
and yielding 2,568 citations to 703 identifiable periodicals. These were identified by
criteria approximately
the same as those
used by Brown (1956).
The periodicals cited were listed in rank
order from most- to least-cited, and a cumulative curve was plotted to show the increase in percentage of total citations covered as successive journals were added to
the list ( Fig. 1). This curve demonstrates
very clearly that to obtain reasonable coverage of the field one must have access to
a great many journals. Although 10 journals
accounted for 25% of citations, 52 were required for 50% coverage, and 200 for 75%
coverage. (It must also be borne in mind
that these per cent coverages are if anything somewhat high, because a number of
obscure citations could not be identified as
to their source journal.)
The results for limnology were similar to
those shown for ecology by Anderson (1966).
However, citation-coverage per journal was
slightly lower in the current instance, perhaps because of the more international
nature of the source periodicals chosen for
limnology. Only English-language journals
(Ecology and the Journal of Animal Ecol-