This study examines the metabolic responses of two populations of desert pupfish (Cyprinodon n. amargosae) from geographically isolated habitats with different thermal regimes (the Amargosa River and Tecopa Bore) when acclimated to high and low temperatures in the laboratory. The results show that the two populations differ in their lactate dehydrogenase (LDH) activity responses to temperature, with the Tecopa Bore population showing decreased LDH activity at cold temperatures compared to the Amargosa River population. However, both populations showed equivalent LDH activity at high temperatures. Citrate synthase (CS) activity, a measure of aerobic metabolism, did not differ between temperatures in either population.
Chemical equilibrium is about reversible reaction, how equilibrium set up n physical and chemical processes,equilibrium constant, its application and Le Chatlier's principle and factors altering the composition of equilibrium
Chemical equilibrium is about reversible reaction, how equilibrium set up n physical and chemical processes,equilibrium constant, its application and Le Chatlier's principle and factors altering the composition of equilibrium
Behavioral responses to annual temperature variationalter th.docxtaitcandie
Behavioral responses to annual temperature variation
alter the dominant energy pathway, growth, and
condition of a cold-water predator
Matthew M. Guzzoa,1, Paul J. Blanchfielda,b, and Michael D. Renniea,c,d
aDepartment of Biological Sciences, University of Manitoba, Winnipeg, MB R3T 2N2, Canada; bFreshwater Institute, Fisheries and Oceans Canada, Winnipeg,
MB R3T 2N6, Canada; cDepartment of Biology, Lakehead University, Thunder Bay, ON P7B 5E1, Canada; and dIISD Experimental Lakes Area Inc., Winnipeg,
MB R3B 0T4, Canada
Edited by Mary E. Power, University of California, Berkeley, CA, and approved July 11, 2017 (received for review February 17, 2017)
There is a pressing need to understand how ecosystems will
respond to climate change. To date, no long-term empirical studies
have confirmed that fish populations exhibit adaptive foraging
behavior in response to temperature variation and the potential
implications this has on fitness. Here, we use an unparalleled 11-y
acoustic telemetry, stable isotope, and mark–recapture dataset to
test if a population of lake trout (Salvelinus namaycush), a cold-
water stenotherm, adjusted its use of habitat and energy sources
in response to annual variations in lake temperatures during the
open-water season and how these changes translated to the
growth and condition of individual fish. We found that climate
influenced access to littoral regions in spring (data from teleme-
try), which in turn influenced energy acquisition (data from iso-
topes), and growth (mark–recapture data). In more stressful years,
those with shorter springs and longer summers, lake trout had
reduced access to littoral habitat and assimilated less littoral en-
ergy, resulting in reduced growth and condition. Annual variation
in prey abundance influenced lake trout foraging tactics (i.e., the
balance of the number and duration of forays) but not the overall
time spent in littoral regions. Lake trout greatly reduced their
use of littoral habitat and occupied deep pelagic waters during
the summer. Together, our results provide clear evidence that
climate-mediated behavior can influence the dominant energy
pathways of top predators, with implications ranging from indi-
vidual fitness to food web stability.
food web | climate change | habitat coupling | lake trout |
north-temperate lake
There is growing urgency to understand how ecosystems areresponding to climate change (1, 2). Recent work, using
latitudinal gradients as proxies to warming, has argued that the
behavioral responses of mobile top predators to changing tem-
peratures can drive fundamental shifts in aquatic food webs by
altering the coupling of major energy pathways (3, 4). Although
this work is intriguing, no one has yet examined long-term em-
pirical data that have explicitly tested if populations of top
predators can shift their foraging behavior in response to annual
changes in temperature or has evaluated what implications this
might have for individual fitness. Tempor.
Nutrient enrichment modifies temperature-biodiversity relationships in large-...sediman
Climate effects and human impacts, that is, nutrient enrichment, simultaneously drive spatial biodiversity patterns. However, there is little consensus about their independent effects on biodiversity. Here we manipulate nutrient enrichment in aquatic microcosms in subtropical and subarctic regions (China and Norway, respectively) to show clear segregation of bacterial species along temperature gradients, and decreasing alpha and gamma diversity toward higher nutrients. The temperature dependence of species richness is greatest at extreme nutrient levels, whereas the nutrient dependence of species richness is strongest at intermediate temperatures. For species turnover rates, temperature effects are strongest at intermediate and two extreme ends of nutrient gradients in subtropical and subarctic regions, respectively. Species turnover rates caused by nutrients do not increase toward higher temperatures. These findings illustrate direct effects of temperature and nutrients on biodiversity, and indirect effects via primary productivity, thus providing insights into how nutrient enrichment could alter biodiversity under future climate scenarios.
Experiments with duckweed–moth systems suggest thatglobal wa.docxelbanglis
Experiments with duckweed–moth systems suggest that
global warming may reduce rather than promote
herbivory
TJISSE VAN DER HEIDE, RUDI M. M. ROIJACKERS, EDWIN T. H. M. PEETERS AND
EGBERT H. VAN NES
Department of Environmental Sciences, Aquatic Ecology and Water Quality Management group, Wageningen University,
Wageningen, The Netherlands
SUMMARY
1. Wilf & Labandeira (1999) suggested that increased temperatures because of global
warming will cause an increase in herbivory by insects. This conclusion was based on the
supposed effect of temperature on herbivores but did not consider an effect of temperature
on plant growth.
2. We studied the effect of temperature on grazing pressure by the small China-mark moth
(Cataclysta lemnata L.) on Lemna minor L. in laboratory experiments.
3. Between temperatures of 15 and 24 �C we found a sigmoidal increase in C. lemnata
grazing rates, and an approximately linear increase in L. minor growth rates. Therefore, an
increase in temperature did not always result in higher grazing pressure by this insect as
the regrowth of Lemna changes also.
4. At temperatures below 18.7 �C, Lemna benefited more than Cataclysta from an increase in
temperature, causing a decrease in grazing pressure.
5. In the context of global warming, we conclude that rising temperatures will not
necessarily increase grazing pressure by herbivorous insects.
Keywords: Cataclysta, grazing, herbivory, Lemna, temperature
Introduction
Duckweeds (Lemnaceae) are often abundant in dit-
ches and ponds (Landolt, 1986). Especially when
nitrogen and phosphorus concentrations in the water
column are high, the surface area can become covered
with dense floating mats of duckweed (Lüönd, 1980,
1983; Portielje & Roijackers, 1995). These mats have
large impacts on freshwater ecosystems, restricting
oxygen supply (Pokorny & Rejmánková, 1983), light
availability of algae and submerged macrophytes
(Wolek, 1974) and temperature fluxes (Dale &
Gillespie, 1976; Landolt, 1986; Goldsborough, 1993).
These changed conditions often have a negative effect
on the biodiversity of the ecosystem (Janse & van
Puijenbroek, 1998). Other free-floating plants such as
red water fern (Azolla filiculoides), water hyacinth
(Eichhornia crassipes) and water lettuce (Pistia stratiotes)
often cause serious problems in tropical and sub-
tropical regions (Mehra et al., 1999; Hill, 2003).
Various species of herbivorous insects consume
free-floating macrophytes. Several species of weevils
(Coleoptera: Curculionidae) are able to consume large
amounts of red water fern, water hyacinth and water
lettuce (Cilliers, 1991; Hill & Cilliers, 1999; Aguilar
et al., 2003), while the larvae of the semi-aquatic Small
China-mark moth (Cataclysta lemnata) are capable of
removing large parts of floating cover of Lemnaceae
covers (Wesenberg-Lund, 1943). Duckweed is not
only used as food source, but also as building material
Correspondence: Rudi M. M. Roijacker ...
ABSTRACT- Biological rhythms are the equal combination of ecological & physiological events producing the internal sense of time in living
being. The internal metabolic rate is influenced by the degree of voluntary activity that is affected by environmental conditions & is associated with
changing season time of day or month and body size Bliss and Montel (1968) found that, in general, the smaller individuals within a species or a
small sized the species have higher metabolic rate per unit rate and time then larger animals. Dehnel and wines (1960) observed the distinct diurnal
rhythm of oxygen consumption the rhythm is characterized that maximum utilization is at 8.00 to 9.00 a.m. by a second smaller peak is at 10.00 to
11.00 p.m. at midnight. Several workers carried out such type of studies [Diwan and Nagbhushnam (1972)]. The crab, B. jaquemontii were collected
and kept for laboratory acclimatization. The pH & temperature were 7.2 & 150C respectively. All the crabs were in the size range was 3.0 cm. to 7.0
cm. The experiments were performed of 30 animals and the oxygen consumption of each individual was measured by Wrinkler’s Method (1960).
Key words- Oxygen consumption, Aquatic respiration, Respiration, Oxygen
Zooplanktonic Diversity and Trophic Status of Pashupatinath Pond in Relation ...IOSR Journals
Present investigation were carried out to physico chemical characterstics and trophic status of
Pashupatinath pond Mandsour (M.P.).water sample were collected seasonal basis for a period of December
2008 to September 2010 using plastic container .standard procedure were followed during collection
,preservation and analysis of water sample for various physicochemical and biological parameter .
The water quality is remained moderately alkaline PH (8.11) while electrical conductivity (0.2176 ms/cm), TDS
(187ppm) chloride (22.123ppm), Hardness(139.166ppm) and alkalinity (75.33ppm) show low mean value
.Average dissolve oxygen levels were at (7.771 ppm) ,while average nitrate and phosphate The water remained
modertly alkaline PH (7.95) while electrical conductance (0.2165ms/cm),TDS (153.66ppm)chloride (22.83ppm)
hardness (138.66ppm )and alkalinity (62.166 ppm) showed low mean values .Average dissolved oxygen level
were at (7.58 ppm ) while average nitrate and phosphate level were (0.2126ppm) and (0.5868 ppm) respectely
.On the basis of water quality parameter .Mirzapur dam was found to be oligotrophic. A low density of
Zooplankton were also observed during the study period
This opinion article aims to highlight the use of the Word Association technique (WA) as a food safety tool, as evidenced in the article by J.M. Latorres and coauthors.
The influence of climate change on water quality, soil moisture and fires in ...Nicolas Racedo
Three research papers on the influence of climate change on water quality, soil moisture and fires in the CEI "San Ignacio" - Fundacion Cruzada Patagonica (an agro-technical high school).
Papers were presented at the GLE 2008, organized by the Globe program (www.globe.gov) in Cape Town, South Africa.
Behavioral responses to annual temperature variationalter th.docxtaitcandie
Behavioral responses to annual temperature variation
alter the dominant energy pathway, growth, and
condition of a cold-water predator
Matthew M. Guzzoa,1, Paul J. Blanchfielda,b, and Michael D. Renniea,c,d
aDepartment of Biological Sciences, University of Manitoba, Winnipeg, MB R3T 2N2, Canada; bFreshwater Institute, Fisheries and Oceans Canada, Winnipeg,
MB R3T 2N6, Canada; cDepartment of Biology, Lakehead University, Thunder Bay, ON P7B 5E1, Canada; and dIISD Experimental Lakes Area Inc., Winnipeg,
MB R3B 0T4, Canada
Edited by Mary E. Power, University of California, Berkeley, CA, and approved July 11, 2017 (received for review February 17, 2017)
There is a pressing need to understand how ecosystems will
respond to climate change. To date, no long-term empirical studies
have confirmed that fish populations exhibit adaptive foraging
behavior in response to temperature variation and the potential
implications this has on fitness. Here, we use an unparalleled 11-y
acoustic telemetry, stable isotope, and mark–recapture dataset to
test if a population of lake trout (Salvelinus namaycush), a cold-
water stenotherm, adjusted its use of habitat and energy sources
in response to annual variations in lake temperatures during the
open-water season and how these changes translated to the
growth and condition of individual fish. We found that climate
influenced access to littoral regions in spring (data from teleme-
try), which in turn influenced energy acquisition (data from iso-
topes), and growth (mark–recapture data). In more stressful years,
those with shorter springs and longer summers, lake trout had
reduced access to littoral habitat and assimilated less littoral en-
ergy, resulting in reduced growth and condition. Annual variation
in prey abundance influenced lake trout foraging tactics (i.e., the
balance of the number and duration of forays) but not the overall
time spent in littoral regions. Lake trout greatly reduced their
use of littoral habitat and occupied deep pelagic waters during
the summer. Together, our results provide clear evidence that
climate-mediated behavior can influence the dominant energy
pathways of top predators, with implications ranging from indi-
vidual fitness to food web stability.
food web | climate change | habitat coupling | lake trout |
north-temperate lake
There is growing urgency to understand how ecosystems areresponding to climate change (1, 2). Recent work, using
latitudinal gradients as proxies to warming, has argued that the
behavioral responses of mobile top predators to changing tem-
peratures can drive fundamental shifts in aquatic food webs by
altering the coupling of major energy pathways (3, 4). Although
this work is intriguing, no one has yet examined long-term em-
pirical data that have explicitly tested if populations of top
predators can shift their foraging behavior in response to annual
changes in temperature or has evaluated what implications this
might have for individual fitness. Tempor.
Nutrient enrichment modifies temperature-biodiversity relationships in large-...sediman
Climate effects and human impacts, that is, nutrient enrichment, simultaneously drive spatial biodiversity patterns. However, there is little consensus about their independent effects on biodiversity. Here we manipulate nutrient enrichment in aquatic microcosms in subtropical and subarctic regions (China and Norway, respectively) to show clear segregation of bacterial species along temperature gradients, and decreasing alpha and gamma diversity toward higher nutrients. The temperature dependence of species richness is greatest at extreme nutrient levels, whereas the nutrient dependence of species richness is strongest at intermediate temperatures. For species turnover rates, temperature effects are strongest at intermediate and two extreme ends of nutrient gradients in subtropical and subarctic regions, respectively. Species turnover rates caused by nutrients do not increase toward higher temperatures. These findings illustrate direct effects of temperature and nutrients on biodiversity, and indirect effects via primary productivity, thus providing insights into how nutrient enrichment could alter biodiversity under future climate scenarios.
Experiments with duckweed–moth systems suggest thatglobal wa.docxelbanglis
Experiments with duckweed–moth systems suggest that
global warming may reduce rather than promote
herbivory
TJISSE VAN DER HEIDE, RUDI M. M. ROIJACKERS, EDWIN T. H. M. PEETERS AND
EGBERT H. VAN NES
Department of Environmental Sciences, Aquatic Ecology and Water Quality Management group, Wageningen University,
Wageningen, The Netherlands
SUMMARY
1. Wilf & Labandeira (1999) suggested that increased temperatures because of global
warming will cause an increase in herbivory by insects. This conclusion was based on the
supposed effect of temperature on herbivores but did not consider an effect of temperature
on plant growth.
2. We studied the effect of temperature on grazing pressure by the small China-mark moth
(Cataclysta lemnata L.) on Lemna minor L. in laboratory experiments.
3. Between temperatures of 15 and 24 �C we found a sigmoidal increase in C. lemnata
grazing rates, and an approximately linear increase in L. minor growth rates. Therefore, an
increase in temperature did not always result in higher grazing pressure by this insect as
the regrowth of Lemna changes also.
4. At temperatures below 18.7 �C, Lemna benefited more than Cataclysta from an increase in
temperature, causing a decrease in grazing pressure.
5. In the context of global warming, we conclude that rising temperatures will not
necessarily increase grazing pressure by herbivorous insects.
Keywords: Cataclysta, grazing, herbivory, Lemna, temperature
Introduction
Duckweeds (Lemnaceae) are often abundant in dit-
ches and ponds (Landolt, 1986). Especially when
nitrogen and phosphorus concentrations in the water
column are high, the surface area can become covered
with dense floating mats of duckweed (Lüönd, 1980,
1983; Portielje & Roijackers, 1995). These mats have
large impacts on freshwater ecosystems, restricting
oxygen supply (Pokorny & Rejmánková, 1983), light
availability of algae and submerged macrophytes
(Wolek, 1974) and temperature fluxes (Dale &
Gillespie, 1976; Landolt, 1986; Goldsborough, 1993).
These changed conditions often have a negative effect
on the biodiversity of the ecosystem (Janse & van
Puijenbroek, 1998). Other free-floating plants such as
red water fern (Azolla filiculoides), water hyacinth
(Eichhornia crassipes) and water lettuce (Pistia stratiotes)
often cause serious problems in tropical and sub-
tropical regions (Mehra et al., 1999; Hill, 2003).
Various species of herbivorous insects consume
free-floating macrophytes. Several species of weevils
(Coleoptera: Curculionidae) are able to consume large
amounts of red water fern, water hyacinth and water
lettuce (Cilliers, 1991; Hill & Cilliers, 1999; Aguilar
et al., 2003), while the larvae of the semi-aquatic Small
China-mark moth (Cataclysta lemnata) are capable of
removing large parts of floating cover of Lemnaceae
covers (Wesenberg-Lund, 1943). Duckweed is not
only used as food source, but also as building material
Correspondence: Rudi M. M. Roijacker ...
ABSTRACT- Biological rhythms are the equal combination of ecological & physiological events producing the internal sense of time in living
being. The internal metabolic rate is influenced by the degree of voluntary activity that is affected by environmental conditions & is associated with
changing season time of day or month and body size Bliss and Montel (1968) found that, in general, the smaller individuals within a species or a
small sized the species have higher metabolic rate per unit rate and time then larger animals. Dehnel and wines (1960) observed the distinct diurnal
rhythm of oxygen consumption the rhythm is characterized that maximum utilization is at 8.00 to 9.00 a.m. by a second smaller peak is at 10.00 to
11.00 p.m. at midnight. Several workers carried out such type of studies [Diwan and Nagbhushnam (1972)]. The crab, B. jaquemontii were collected
and kept for laboratory acclimatization. The pH & temperature were 7.2 & 150C respectively. All the crabs were in the size range was 3.0 cm. to 7.0
cm. The experiments were performed of 30 animals and the oxygen consumption of each individual was measured by Wrinkler’s Method (1960).
Key words- Oxygen consumption, Aquatic respiration, Respiration, Oxygen
Zooplanktonic Diversity and Trophic Status of Pashupatinath Pond in Relation ...IOSR Journals
Present investigation were carried out to physico chemical characterstics and trophic status of
Pashupatinath pond Mandsour (M.P.).water sample were collected seasonal basis for a period of December
2008 to September 2010 using plastic container .standard procedure were followed during collection
,preservation and analysis of water sample for various physicochemical and biological parameter .
The water quality is remained moderately alkaline PH (8.11) while electrical conductivity (0.2176 ms/cm), TDS
(187ppm) chloride (22.123ppm), Hardness(139.166ppm) and alkalinity (75.33ppm) show low mean value
.Average dissolve oxygen levels were at (7.771 ppm) ,while average nitrate and phosphate The water remained
modertly alkaline PH (7.95) while electrical conductance (0.2165ms/cm),TDS (153.66ppm)chloride (22.83ppm)
hardness (138.66ppm )and alkalinity (62.166 ppm) showed low mean values .Average dissolved oxygen level
were at (7.58 ppm ) while average nitrate and phosphate level were (0.2126ppm) and (0.5868 ppm) respectely
.On the basis of water quality parameter .Mirzapur dam was found to be oligotrophic. A low density of
Zooplankton were also observed during the study period
This opinion article aims to highlight the use of the Word Association technique (WA) as a food safety tool, as evidenced in the article by J.M. Latorres and coauthors.
The influence of climate change on water quality, soil moisture and fires in ...Nicolas Racedo
Three research papers on the influence of climate change on water quality, soil moisture and fires in the CEI "San Ignacio" - Fundacion Cruzada Patagonica (an agro-technical high school).
Papers were presented at the GLE 2008, organized by the Globe program (www.globe.gov) in Cape Town, South Africa.
Variability in Dissolved Arsenic in Shallow Aquifers Linked to Local Hydrology
Effects of temperature on metabolism in two populations of the desert pupfish Cyprinodon nevadensis
1. Extreme environmental temperatures pose significant metabolic challenges for ectothermic
organisms such as teleost fishes.
Pupfishes (genus Cyprinodon, Figure 1) in the Death Valley region of California and Nevada,
USA, occupy remote aquatic habitats that vary widely in temperature conditions making them an
ideal study organism to investigate metabolic acclimation and evolution in the face of varying
thermal environments.
In this study, we evaluate the aerobic and anaerobic metabolic responses of C. n. amargosae
pupfish from two geographically isolated habitats – the Amargosa River and Tecopa Bore – when
fish from these habitats are acclimated under laboratory conditions to high and low temperatures
(35°C and 23°C respectively).
•Both the Amargosa River and Tecopa Bore habitats support populations of C. n. amargosae
pupfish, but the habitats are the strikingly different in thermal regime (Table 1).
What is more, the Tecopa Bore habitat experienced an approximately 15°C increase in mean
temperature between 2008 and 2013 to the values shown in Table 1 due to a human-mediated
change in water flow.
Here, we quantified activity of Citrate Synthase (CS) and Lactate Dehydrogenase (LDH) as
measures of metabolic status. CS is a robust indicator of an animal's capacity for aerobic
metabolism (where CS activity is measured in μmol/ming) due to that fact that it is a
mitochondrial enzyme involved in the Krebs cycle. LDH is the final enzyme in the fermentation
pathway; thus LDH activity (μmol/ming) reflects an animal's capacity for anaerobic respiration.
Our results indicate that the two populations of pupfish differ in their acclimatory change in LDH
activity in response to varying temperatures:
1) Pupfish from the Tecopa Bore population showed decreased LDH activity in cold
temperatures, while pupfish from the Amargosa River population showed increased LDH
activity in cold temperatures.
2) Surprisingly, the Tecopa Bore and Amargosa River populations showed equivalent LDH
activity in high temperatures.
Our results showed no significant difference between low and high temperature acclimation in either
population’s CS activity.
There was, however, a significant linear regression observed in both populations when comparing body
size with CS activity. This body mass relationship is to be expected due to metabolic scaling (Clarke &
Johnston, 1999).
While predications were not entirely correct, the overall hypothesis was supported by the varying
anaerobic metabolic rate observed in both the Tecopa Bore and Amargosa River populations between
high and low temperatures. No significant conclusions can be drawn regarding changes in aerobic
metabolic rate due to variable temperature from the current data set.
Effects of temperature on metabolism in two populations of the desert pupfish
Cyprinodon nevadensis
Emily J. Resner, Alex A. Westman, Sean C. Lema, Kristin M. Hardy
Biological Sciences, California Polytechnic State University, San Luis Obispo, CA 93407
Introduction
Acknowledgments
Population Temp. mean Temp. range
Amargosa River 19.4°C 16.1 to 22.5°C
Tecopa Bore 36.7°C 33.8 to 41.5°C
Table 1. Recorded temperature data from 48 hrs of observations during May 2014.
Conclusions
Results
Figure 1. Pupfish, Cyprinodon nevadensis amargosae, from the Death Valley region.
Table 2. Enzyme activity measurements (U/g tissue wet weight) in pupfish from the Amargosa River
and Tecopa Bore. There was no significant effect of population, temperature or their interaction on CS
activity (ANCOVA, p>0.05) Means with different letters within each enzyme are significantly different
from one another (ANCOVA; Tukey’s HSD; α=0.05)
References
We would like to acknowledge the Cal Poly Biological Sciences Department for funding assistance via
College Based Fee funds. Additional support was provided in the form of a New Investigator Award
from the CSU Program for Education and Research in Biotechnology (CSUPERB) to S.C.L. Pupfish
were collected with permission from the California Department of Wildlife (Permit # SC-4793).
Clarke, A and N.M. Johnston. 1999. Scaling of Metabolic Rate with Body Mass and Temperature in Teleost Fish. J Anim
Ecology 68.5:893-905.
Future Work
•Data collection will continue until all samples have been processed.
•In the face of evidence that wild fish from these populations vary in thyroid hormone physiology, we
will also examine the role of temperature in modulating the potential regulation of metabolism by
thyroid hormones by treating fish from both populations under high and low temperatures to
triiodothyronine (T3) for 16 hours.
•We hypothesize that T3 exposure may influence the way that temperature affects metabolism in each
of these populations, and will test for such an influence as we complete data collection.
Figure 4. Effect of temperature (high=23oC; low=35oC) on lactate dehydrogenase (LDH) activity
(U/g of tissue wet wt) in C. nevadensis amargosae pupfish from the Amargosa River and Tecopa
Bore habitats. The effect of temperature on LDH activity differed between the two populations
(population*temperature interaction; ANCOVA with body mass as a covariate; F1,43=5.8656,
p=0.0197). Analysis performed on log transformed data; n = 12-18 per treatment group. Columns
with different letters are significantly different from one another (Tukey’s HSD, α=0.05) Error bars
represent S.E.M.
AB
AB
A
B
•For LDH analysis, a 1:10 diluted sample supernatant was combined with Tris-HCl buffer (pH 7.6)
with NADH. The reaction was started with the addition of pyruvate. Analysis was run at 340 nm for 5
min in an Implen NanoPhotometer P-Class P300. Enzyme activity (μmol/min*g) was calculated using
the slope of the absorbance change following addition of pyruvate. All samples were run in duplicate.
•For CS analysis, sample supernatant was combined with Tris-HCl buffer (pH 8.1) with DTNB and
Acetyl CoA. The reaction was started with the addition of oxaloacetate. Analysis was run at 412 nm for
5 min in a NanoPhotometer P300. Enzyme activity (μmol/min*g) calculated using the slope of the
absorbance change immediately following addition of oxaloacetate. All samples were run in singles.
•Statistical comparisons between temperatures and populations were conducted using two-way
ANCOVA models using ‘population’, ‘temperature’, and their interaction as factors and body mass
(g) as a covariate (JMP v. 11 software).
Methods
Figure 2. Amargosa River on left, Tecopa Bore on right.
Figure 5. Effect of body mass on citrate synthase (CS) activity (U/g tissue wet wt) in C. nevadensis
amargosae fish from Amargosa River (n = 27) and Tecopa Bore (n = 21) habitats. Linear regression
analysis revealed a significant scaling effect of body mass on CS activity in both Amargosa (y=-
0.47x+4.32, r2=0.128, F1,25=3.68, p<0.001) and Tecopa Bore (y=-0.886x+5.05; r2=0.37, F1,19=11.265,
p=0.0033) populations. There is a decrease in CS activity with an increase in body mass, which is expected
based on metabolic scaling relationships (Clark & Johnson, 1999).
Hypothesis:
Acclimation to various temperatures will effect metabolic enzyme activity
similarly in pupfish from the Tecopa Bore and Amargosa River
populations.
Prediction 1:
Both populations of pupfish should have higher CS and LDH activity levels
at the higher temperature.
Prediction 2:
The cooler adapted Amargosa River pupfish population will have higher
CS and LDH activity at either temperature relative to the warm adapted
Tecopa Bore pupfish.
Habitat Temperature n CS activity (U/g) LDH activity (U/g)
Amargosa River High 18 3.3±0.26a 200.17±12.9a,b
Low 11 3.43±0.23a 261.43±37.4b
Tecopa Bore High 11 3.93±0.29a 211.40±13.35a,b
Low 12 3.25±0.35a 148.52±16.38a
Objectives
•Adult pupfish were collected from the Amargosa River
and Tecopa Bore using minnow traps. Fish from each
population were maintained in captivity under either low
(23°C) or high (35°C) temperature conditions for 4
months. Select fish from each temperature treatment were
given exogenous thyroid hormone (triiodothyronine, T3)
for 16 hrs. Liver tissue was collected from each fish for
CS and LDH activity measures.
population (AR or TB)
control T3-treated
low temp (23°C) high temp (35°C)
control T3-treated
Figure 3. Illustration of the three factor (population
origin, temperature regime, T3 hormone treatment)
design of the experiment.