Effects of temperature on metabolic scaling in silver carp

AbstractPredicting population persistence and dynamics in the context of global change is a major challenge for ecology. A widely held prediction is that population abundance at carrying capacity decreases with warming, assuming no change in resource supply, due to increased individual resource demands associated with higher metabolic rates. However, this prediction, which is based on metabolic scaling theory (MST), has not been tested empirically. Here we experimentally tested whether effects of temperature on short-term metabolic performance (rates of photosynthesis and respiration) translate directly to effects of temperature on population rates in a phytoplankton species. We found that effects of temperature on organismal metabolic rates matched theoretical predictions, and that the temperature dependence of individual metabolic performance translated to population abundance. Population abundance at carrying capacity, K, decreased with temperature less than expected based on the temperature dependence of photosynthesis. Concurrent with declines in abundance, we observed a linear decline in cell size of approximately 2.3% °C−1, which is consistent with broadly observed patterns in unicellular organisms, known as the temperature-size rule. When theoretical predictions include higher densities allowed by shifts toward smaller individual size, observed declines in K were quantitatively consistent with theoretical predictions. Our results indicate that outcomes of population dynamics across a range of temperatures reflect organismal responses to temperature via metabolic scaling, providing a general basis for forecasting population responses to global change.

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Temperature and predator cues interactively affect ontogenetic metabolic scaling of aquatic amphipods

Biology Letters ◽

10.1098/rsbl.2020.0267 ◽

2020 ◽

Vol 16 (7) ◽

pp. 20200267

Author(s):

V. Gjoni ◽

A. Basset ◽

D. S. Glazier

Keyword(s):

Ecological Factors ◽

Interactive Effects ◽

Common Belief ◽

Metabolic Scaling ◽

Predator Cues ◽

Mass Scaling ◽

Freshwater Spring ◽

Body Design ◽

Effects Of Temperature ◽

Mechanistic Basis

A common belief is that body mass scaling of metabolic rate results chiefly from intrinsic body-design constraints. However, several studies have shown that multiple ecological factors affect metabolic scaling. The mechanistic basis of these effects is largely unknown. Here, we explore whether abiotic and biotic environmental factors have interactive effects on metabolic scaling. To address this question, we studied the simultaneous effects of temperature and predator cues on the ontogenetic metabolic scaling of amphipod crustaceans inhabiting two different aquatic ecosystems, a freshwater spring and a saltwater lagoon. We assessed effects of phenotypic plasticity on metabolic scaling by exposing amphipods in the laboratory to water with and without fish cues at multiple temperatures. Temperature interacts significantly with predator cues to affect metabolic scaling. Our results suggest that metabolic scaling is highly malleable in response to short-term acclimation. The interactive effects of temperature and predators show the importance of studying effects of global warming in realistic ecological contexts.

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Peer Review #2 of "Effects of temperature on metabolic scaling in black carp (v0.2)"

10.7287/peerj.9242v0.2/reviews/2 ◽

2020 ◽

Author(s):

H Scheuffele

Keyword(s):

Peer Review ◽

Metabolic Scaling ◽

Black Carp ◽

Effects Of Temperature

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Oxygen limitation may affect the temperature and size dependence of metabolism in aquatic ectotherms

Proceedings of the National Academy of Sciences ◽

10.1073/pnas.2003292117 ◽

2020 ◽

Vol 117 (50) ◽

pp. 31963-31968

Author(s):

Juan G. Rubalcaba ◽

Wilco C. E. P. Verberk ◽

A. Jan Hendriks ◽

Bart Saris ◽

H. Arthur Woods

Keyword(s):

Body Size ◽

Aquatic Organisms ◽

Oxygen Limitation ◽

Oxygen Availability ◽

Ecological Niches ◽

Metabolic Rates ◽

Aerobic Scope ◽

Metabolic Theory ◽

Metabolic Scaling ◽

Effects Of Temperature

Both oxygen and temperature are fundamental factors determining metabolic performance, fitness, ecological niches, and responses of many aquatic organisms to climate change. Despite the importance of physical and physiological constraints on oxygen supply affecting aerobic metabolism of aquatic ectotherms, ecological theories such as the metabolic theory of ecology have focused on the effects of temperature rather than oxygen. This gap currently impedes mechanistic models from accurately predicting metabolic rates (i.e., oxygen consumption rates) of aquatic organisms and restricts predictions to resting metabolism, which is less affected by oxygen limitation. Here, we expand on models of metabolic scaling by accounting for the role of oxygen availability and temperature on both resting and active metabolic rates. Our model predicts that oxygen limitation is more likely to constrain metabolism in larger, warmer, and active fish. Consequently, active metabolic rates are less responsive to temperature than are resting metabolic rates, and metabolism scales to body size with a smaller exponent whenever temperatures or activity levels are higher. Results from a metaanalysis of fish metabolic rates are consistent with our model predictions. The observed interactive effects of temperature, oxygen availability, and body size predict that global warming will limit the aerobic scope of aquatic ectotherms and may place a greater metabolic burden on larger individuals, impairing their physiological performance in the future. Our model reconciles the metabolic theory with empirical observations of oxygen limitation and provides a formal, quantitative framework for predicting both resting and active metabolic rate and hence aerobic scope of aquatic ectotherms.

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Effects of temperature on metabolic scaling in black carp

PeerJ ◽

10.7717/peerj.9242 ◽

2020 ◽

Vol 8 ◽

pp. e9242

Author(s):

Qian Li ◽

Xiaoling Zhu ◽

Wei Xiong ◽

Yanqiu Zhu ◽

Jianghui Zhang ◽

...

Keyword(s):

Surface Area ◽

Body Mass ◽

Volume Ratio ◽

Effect Of Temperature ◽

Scaling Exponent ◽

Surface Boundary ◽

Metabolic Scaling ◽

Black Carp ◽

Higher Temperature ◽

Effects Of Temperature

The surface area (SA) of organs and cells may vary with temperature, which changes the SA exchange limitation on metabolic flows as well as the influence of temperature on metabolic scaling. The effect of SA change can intensify (when the effect is the same as that of temperature) or compensate for (when the effect is the opposite of that of temperature) the negative effects of temperature on metabolic scaling, which can result in multiple patterns of metabolic scaling with temperature among species. The present study aimed to examine whether metabolic scaling in black carp changes with temperature and to identify the link between metabolic scaling and SA at the organ and cellular levels at different temperatures. The resting metabolic rate (RMR), gill surface area (GSA) and red blood cell (RBC) size of black carp with different body masses were measured at 10 °C and 25 °C, and the scaling exponents of these parameters were compared. The results showed that both body mass and temperature independently affected the RMR, GSA and RBC size of black carp. A consistent scaling exponent of RMR (0.764, 95% CI [0.718–0.809]) was obtained for both temperatures. The RMR at 25 °C was 2.7 times higher than that at 10 °C. At both temperatures, the GSA scaled consistently with body mass by an exponent of 0.802 (95% CI [0.759–0.846]), while RBC size scaled consistently with body mass by an exponent of 0.042 (95% CI [0.010–0.075]). The constant GSA scaling can explain the constant metabolic scaling as temperature increases, as metabolism may be constrained by fluxes across surfaces. The GSA at 10 °C was 1.2 times higher than that at 25 °C, which suggests that the constraints of GSA on the metabolism of black carp is induced by the higher temperature. The RBC size at 10 °C was 1.1 times higher than that at 25 °C. The smaller RBC size (a larger surface-to-volume ratio) at higher temperature suggests an enhanced oxygen supply and a reduced surface boundary limit on bR, which offset the negative effect of temperature on bR.

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