EFFECT
OF TEMPERATURE
ON METABOLISM
PERIPHYTON
COMMUNITIES
DEVELOPED
IN LABORATORY
STREAMS’
OF
Hawy K. Phinney and C. David McIntire
Department
of Botany,
Oregon State University,
Corvallis
ABSTRACT
The effect of short-term
variations
in tcmpcraturc
on metabolism
of periphyton
communities developed
in laboratory
streams was investigated
with a !%litcr
rcspirometcr
chamber. The range of tempcraturcs
used was from 6 to 21C, similar to the range normally
recorded in the laboratory streams during the year.
In an experiment the tcmpcrature
was increased from 6.5 to 16.6C during a 5-hr period,
and the rate of community respiration incrcascd from 41 to 132 mg O2 m-” hr-I. When the
temperature was decreased from 17.5 to 9.4C during a 5-hr period, the rate of community
respiration
decreased correspondingly
from 105 to 63 mg O2 mm2 hr-‘. An increase in temperaturc from 11.9 to 2O.OC was accompanied by an increase in gross oxygen evolution from
335 to 447 mg O2 rnw2 hr-’ when the intensity of illumination
was approximately
22,000 lux.
The rate of oxygen production was not affected significantly
at illumination
intensities below
11,100 lux.
-
premise that, in the absence of other comThat temperature variations affect the plicating factors, an increase in temperarates of metabolism of organisms is a gen- ture results in an increased rate of respiracrally accepted fact. Miller ( 1938, p. 955 tion. The task of measuring this effect is
and 594) stated “It is apparently well es- difficult, because results are quite variable
tablished that the rate of respiration in- and may depend on circumstances only
tenuously connected to the primary rclacreases with the tempcraturc, until the lattionship between temperature and respirater begins to injure tissues,” and “When
neither light nor the concentration of car- tion. For example, the aggregation of individuals into an experimental group, or
bon dioxide is a limiting factor, the rate
of photosynthesis is increased by an in- the separation of an individual from an aggregation,
often creates behavioral
recrease in temperature, just as are many
sponscs
that
tend
to
modify
the
cffcct
of
chemical reactions. However, when the
temperature.
Study
of
this
aggregation
cflight intensity is low, tempcraturc has little
feet occupied a number of ecologists in the
effect-a
characteristic
of photochcmical
1930’s ( Allee 1931). Reyers ( 1962) sugreactions.” Rabinowitch
( 1956) summagests
that a kind of aggregation effect may
rized results of temperature experiments
influence
the response of organisms in an
with many plant species, including a number of species of algae. These studies were integrated community to variations in tempcraturc.
“Balanced”
aquaria were exconcerned with individual
plants or plant
posed
to
tempcraturc
variations
of approxiparts of macroscopic species or with unimately
7C
above
and
below
normal
mainalgal or pure cultures of microscopic spcwithout
significant
ties, and the same fundamental responses tenance temperature
changes in community metabolism.
The
were evident in practically all casts.
results
were
interpreted
as
indicating
Animal physiologists have accepted the
thermal independence of microccosystcm
metabolism,
This conclusion appears to
‘~Technical Paper No. 1876, Oregon Agricultural
Expcrimcnt
Station. A contribution
from the Pacific
support the often exprcsscd fears that deCooperative Water Pollution and Fisher&
Rcscarch
terminations of the physiological rcsponscs
Laboratories.
This investigation
was supported in
of individual
organisms or of mlispecific
part by National
Scicncc Foundation
Grant Gcultures in vilro do not always accurately
10732.
341
INTRODUCTION
342
‘r AISLE
HARRY
1.
periphyton
clecreasecl
Light
intensity
(111x)
21,SOO
16,700
11,400
7,400
4,300
2,150
1,180
620
K. PHTNNEY
AND
Rates of net oxygen evolution
by a
community
subjected to progressively
light intensities
at two temperature
ranges
7 Fcb 1964
Mean
temp
8 Fch 1964
Net 02
MCllll
evolved
( “C ) ( mg m-2 hr-1)
7.9
8.6
9.1
9.3
9.5
9.7
9.8
9.9
226
200
180
201
121
133
42
44
temp
( “Cl)
18.5
18.5
18.4
18.2
18.3
18.3
18.1
18.3
Net 02
evolved
(mg rw2 hr-1)
361
331
439
182
208
2
-62
represent the responses of more complex
community aggregations.
To test the effects of temperature variation in lotic ecosystems, experiments were
designed to use sections of a long-standing
periphyton
community dcvelopcd in laboratory streams at the Pacific Cooperative
Water Pollution
and Fisheries Research
Laboratories. A portion of the gravel and
rubble to which the community adhered
was held on porcelain-coated steel trays. To
provide easy control of temperature and
light and to permit cast and accuracy of
measuring metabolic rates, these trays of
bottom material were transferred to the
photosynthesis-respiration
(P-R) chamber.
[The description
of this apparatus and
its use has been presented by McIntire ct
al. ( 1964). Illumination
for study of photosynthetic rates was provided by a 1500w incandescent bulb that allowed variation
of illumination
intensities from approximately 500 to 22,000 lux.
WC wish to express our appreciation to
Dr. Peter Doudoroff for his advice and suggcstions and to Mr. George Chadwick for
technical assistance in maintaining the experimental equipment.
The experimental
streams were constructed in cooperation
with the Robert A. Taft Sanitary Enginccring Center, U.S. Public IIealth Service.
PROCEDURES
AND
RESULTS
The first cxpcriment measured the effect
of two ranges of temperatures on rates of
C. DAVID
McINTIRE
photosynthesis at diffcrcnt light intensities.
Trays containing 0.2 m2 of the community
wcrc removed from the stream and placed
in the P-R chamber on the evening of 6
February 1964. On the following morning
the light was adjusted to give 21,500 lux.
The tcmpcrature in the chimbcr was maintained at 8.9 -L 1C. The rate of net oxygen
production for the first 30 min was 226
mg m 2 hr-I. The light was then readjusted
to provide 16,700 lux and the run continued
for a second 30 min. Subsequently, the illumination intensity was reduced following
each 30-min period for 3 hr. ( Table 1).
A thermostatically
controlled heater was
placed in the constant-head jar and the
exchange water heated so that the contents
of the P-R chamber were subjected to tcmperaturcs ranging between 18.1 and 18.5C.
On 8 February a parallel series of measurcments was made at this higher range of
temperatures. The rate of net oxygen production was consistently
higher at the
higher range of temperatures when the illumination
intensities exceeded 7,400 lux
(Table 1). Respiration was also affected
as indicated by ‘the negative value for net
oxygen cvolvcd (obtained at 620 lux) .
We then modified the procedure by rcversing the order of prcscntation of light
intensities so that the community would be
illuminated by periodically increased intensities. The effect of variation in temperature upon the rate of community respiration was also determined by placing trays
containing a community in the P-R chamber on the evening of 25 February and
covering the chamber with a black plastic
sheet. The temperature of the chamber
was maintained at the natural tempcraturc
of the water supply ( ca. 6.2-6.3C) overnight. On the following morning, measurements of the concentration
of dissolved
oxygen were made at hourly intervals. During the first 2 hr the temperature of the
water in the chamber increased from 6.2
to 7.lC, and the mean rate of consumption
of oxygen was 44.9 mg m-2 hr-‘. The heater
in the constant-head jar was then turned
on and the water jacket drained. The temperature of the contents of the chamber in-
TEMPERATURE
EFFECTS
2.2
0
TEMPERATURE
INCREASING
A TEMPERATURE
DECREASING
6
2. I
1.6-O
1.5
6
I
8
I
IO
TEhl&r”Fi~
FIG,
mined
I
I
16
I
I
I8
I
20
“c
1. Rates of community
respiration
at various mean temperatures.
dcter-
creased gradually as the water was cxchanged. In 4.5 hr the temperature increased from 7.1 to 17.7C and the rate of
consumption of oxygen increased from 49.4
to 132 mg m-2 hr-l.
The heated water was allowed to flow
through the chamber overnight, maintaining the community at temperatures ranging between 17.1 and 17.7C. The following day at 9:30 AM, the tempcraturc in the
chamber was 17.lC. Consumption of oxygen was again measured at hourly intervals. At a mean temperature of 17.5C,
oxygen consumption was 104 mg m-2 hr-‘.
At 11:30 AM the heater was turned off and
unheated water allowed to exchange in the
P-R chamber. In the next 4 hr, the temperaturc decreased from 17.7 to 9.3C, and
the rate of oxygen consumption dccrcascd
to 63 mg m-2 hr-‘.
The combined data from this two-day
study arc presented in Fig. 1 On the basis
of these data, the Qlo for this range of
tempcraturcs would be approximately 2.
On the evening of 16 March, trays of the
periphyton community were placed in the
P-R chamber and maintained overnight at
the natural temperature of the stream water
( approximately &SC). At 8:25 AM on the
following day the incandescent lamp was
adjusted to provide 840 lux. The water
ON
343
PERIPHYTON
temperature during the cxpcrimcnt ranged
between 8.7 and 12.lC. The rate of oxygen production was determined for each
half-hour period and at the end of each
period the light was readjusted to give
increasing illumination
to a maximum of
22,300 lux during. the last 308min. Following thcsc determinations, the light was discontinued and the chamber covered with a
black plastic sheet. The mean rate of community respiration was determined during
the following 2 hr. From these data, gross
oxygen production was estimated for each
light intensity by adding the net rates of
oxygen production to the mean rate of
respiration ( Fig. 2).
The immersion heater in the constanthead jar was turned on and heated water
was exchanged in the P-R chamber overnight. At 8:3O AM the following day, the
temperature in the chamber was 18.2C.
The same procedure was then followed as
on the previous day. The light was adjusted each 30 min to the same values as
before. The temperature during the following 4 hr varied from 18.2 to 21.1C. Following the determination
of net oxygen
evolution, the mean dark respiration was
dctcrmincd
as before and gross oxygen
evolution at each light intensity calculated
(Fig. 2).
When the light intensity was approximatcly 22,000 lux, an increase in temperature from 11.9 to 2O.OC was accompanied
by a concurrent increase in gross oxygen
evolution from 335 to 447 mg m-2 hr-l. The
rate of gross oxygen evolution was not af-
.
0
W30
INTENSITY
10.000
OF
ILLUMINATION
11.000
IN
*0,000
I
1%ca
LUX
FLG. 2.
The relationship
of oxygen evolution
light intensity at two ranges of tcmpcrature.
to,
344
HARRY
fected significantly
below 11,100 lux.
K. PHINNEY
at the light
AND
intensities
DISCUSSION
The rates of oxygen evolution were enhanced at higher light intensities whether
the light was presented in a pattern of increasing or decreasing intensities.
However, the rates presented an irregular relationship to light intensity when the intensity was periodically dccrcased. We believe that this irregularity resulted from the
rapid evolution of oxygen at the higher
light intensities and its accumulation
as
bubbles trapped in the layers of filaments
constituting
the periphyton
community.
The solution of the gas in these bubbles
was delayed and affected measurements
made at lower light intensities during subsequent sampling periods.
Our results emphasize the rate-limiting
effect of light intensity and, by inference,
the effect of free and adequate exchange of
gases and other mctabolites upon the relationship between community metabolism
and such physical factors as light and temperature. Communities in the aquaria studied by Beyers ( 1962), and in other standing-water ecosystems, are periodically sub-
C. DAVID
McINTIRE
jected to variations in the concentration of
metabolic gases and nutrients that tend to
influence metabolic rates and modify effects of light and temperature. In shallow
lotic systems, where the medium surrounding the community is rapidly mixed and
exchanged, the effect of temperature variance upon metabolic rates is comparable to
that commonly reported by physiologists
for unispecific plant or animal populations.
At least for temperatures ranging not too
widely from the maintenance temperature
of the community, a Qlo of approximately
2 may be generally applicable to rates of
community respiration in lotic systems.
REFERENCES
W. C. 1931. Animal
aggregations.
A
study in general sociology.
Univ. of Chicago
Press, Chicago. 431 p.
BEYERS, R. J. 1962.
Relationships
between temperature and the metabolism of experimental
ecosystems.
Science, 136 : 980-982.
MCINTIRE,
C. D., R. L. GARRISON, H. K. PHINNEY,
1964. Primary producAND G. E. WARnEN.
tion in laboratory streams.
Limnol. Oceanog.,
9: 92-102.
MILLET,
IX. C.
1938. Plant physiology,
2nd ed.
McGraw-Hill,
New York. 1201 p.
RABINOWITCH,
E. I. 1956. Photosynthesis
and
related processes, v. II, Part 2, p. 12112088. Interscicncc,
New York.
ALLEE,