scholarly journals Thermal performance curves for aerobic scope in a tropical fish (Lates calcarifer): flexible in amplitude but not breadth

2021 ◽  
Author(s):  
Hanna Scheuffele ◽  
Francesc Rubio-Gracia ◽  
Timothy D. Clark
Keyword(s):  
Thermal Performance ◽  
Growth Rates ◽  
Daily Temperature ◽  
Tropical Fish ◽  
Metabolic Phenotype ◽  
Performance Curve ◽  
Aerobic Scope ◽  
Lates Calcarifer ◽  
Thermal Performance Curve ◽  
Performance Curves

Aerobic metabolic scope is a popular metric to estimate the capacity for temperature-dependent performance in aquatic animals. Despite this popularity, little is known of the role of temperature acclimation and variability in shaping the breadth and amplitude of the thermal performance curve for aerobic scope. If daily thermal experience can modify the characteristics of the thermal performance curve, interpretations of aerobic scope data from the literature may be misguided. Here, tropical barramundi (Lates calcarifer) were acclimated for ∼4 months to cold (23℃), optimal (29℃) or warm (35℃) conditions, or to a daily temperature cycle between 23 and 35℃ (with a mean of 29℃). Measurements of aerobic scope were conducted every 3-4 weeks at three temperatures (23℃, 29℃ and 35℃), and growth rates were monitored. Acclimation to constant temperatures caused some changes in aerobic scope at the three measurement temperatures via adjustments in standard and maximal metabolic rates, and growth rates were lower in the 23℃-acclimated group compared with all other groups. The metabolic parameters and growth rates of the thermally variable group remained similar to those of the 29℃-acclimated group. Thus, acclimation to a variable temperature regime did not broaden the thermal performance curve for aerobic scope. We propose that aerobic scope thermal performance curves are more plastic in amplitude rather than breadth, and that the metabolic phenotype of at least some fish may be more dependent on the mean daily temperature rather than on the daily temperature range.

scholarly journals Phytoplankton thermal responses adapt in the absence of hard thermodynamic constraints

2018 ◽  
Author(s):  
Dimitrios - Georgios Kontopoulos ◽  
Erik van Sebille ◽  
Michael Lange ◽  
Gabriel Yvon-Durocher ◽  
Timothy G. Barraclough ◽  
...  
Keyword(s):  
Thermal Performance ◽  
Thermal Sensitivity ◽  
Meta Analysis ◽  
Habitat Type ◽  
Performance Curve ◽  
Thermal Environments ◽  
Thermal Performance Curve ◽  
Performance Curves ◽  
Minor Influence ◽  
A Minor

AbstractTo better predict how populations and communities respond to climatic temperature variation, it is necessary to understand how the shape of the response of fitness-related traits to temperature evolves (the thermal performance curve). Currently, there is disagreement about the extent to which the evolution of thermal performance curves is constrained. One school of thought has argued for the prevalence of thermodynamic constraints through enzyme kinetics, whereas another argues that adaptation can—at least partly—overcome such constraints. To shed further light on this debate, we perform a phylogenetic meta-analysis of the thermal performance curves of growth rate of phytoplankton—a globally important functional group—, controlling for environmental effects (habitat type and thermal regime). We find that thermodynamic constraints have a minor influence on the shape of the curve. In particular, we detect a very weak increase of maximum performance with the temperature at which the curve peaks, suggesting a weak “hotter-is-better” constraint. Also, instead of a constant thermal sensitivity of growth across species, as might be expected from strong constraints, we find that all aspects of the thermal performance curve evolve along the phylogeny. Our results suggest that phytoplankton thermal performance curves adapt to thermal environments largely in the absence of hard thermodynamic constraints.

A thermal profile of metabolic performance in the rare Australian chelid, Pseudemydura umbrina

2014 ◽  
Vol 62 (6) ◽  
pp. 448 ◽  
Author(s):  
Sophie G. Arnall ◽  
Gerald Kuchling ◽  
Nicola J. Mitchell
Keyword(s):  
Thermal Performance ◽  
Activity Patterns ◽  
Standard Metabolic Rate ◽  
Co2 Production ◽  
Performance Curve ◽  
Thermal Performance Curve ◽  
Performance Curves ◽  
Consumption Rates ◽  
Flow Through ◽  
Metabolic Performance

Thermal performance curves are useful for predicting how organisms might respond to environmental change, and are becoming increasingly applicable for ectothermic animals threatened by climate change. Here we present a thermal performance curve for the critically endangered western swamp turtle (Pseudemydura umbrina) based upon measurements of O2 consumption and CO2 production obtained by flow-through respirometry at temperatures between 15 and 30°C. Standard metabolic rate was significantly higher at 30°C (0.030 mL g–1 h–1 O2, 0.021 mL g–1 h–1 CO2) than at 20°C (0.007 mL g–1 h–1 O2, 0.006 mL g–1 h–1 CO2) and the 20−30°C Q10 for O2 and CO2 were 4.60 and 3.55 respectively. Oxygen consumption rates at 15°C and 25°C were 0.002 (±0.000) and 0.018 (±0.000) mL g–1 h–1, with a corresponding Q10 of 9.21. Beyond ~30°C there was a decline in physiological performance, which was supported by activity patterns reported for P. umbrina in the literature.

scholarly journals Genetically distinct behavioral modules underlie natural variation in thermal performance curves

2019 ◽  
Author(s):  
Gregory W. Stegeman ◽  
Scott E. Baird ◽  
William S. Ryu ◽  
Asher D. Cutter
Keyword(s):  
Thermal Performance ◽  
Quantitative Trait ◽  
Recombinant Inbred Lines ◽  
Thermal Reaction ◽  
Reaction Norms ◽  
Heritable Variation ◽  
Locomotory Behavior ◽  
Thermal Performance Curve ◽  
Performance Curves ◽  
Trait Locus

AbstractThermal reaction norms pervade organismal traits as stereotyped responses to temperature, a fundamental environmental input into sensory and physiological systems. Locomotory behavior represents an especially plastic read-out of animal response, with its dynamic dependence on environmental stimuli presenting a challenge for analysis and for understanding the genomic architecture of heritable variation. Here we characterize behavioral reaction norms as thermal performance curves for the nematode Caenorhabditis briggsae, using a collection of 23 wild isolate genotypes and 153 recombinant inbred lines to quantify the extent of genetic and plastic variation in locomotory behavior to temperature changes. By reducing the dimensionality of the multivariate phenotypic response with a function-valued trait framework, we identified genetically distinct behavioral modules that contribute to the heritable variation in the emergent overall behavioral thermal performance curve. Quantitative trait locus mapping isolated regions on Chromosome II associated with locomotory activity at benign temperatures and Chromosome V loci related to distinct aspects of sensitivity to high temperatures, with each quantitative trait locus explaining up to 28% of trait variation. These findings highlight how behavioral responses to environmental inputs as thermal reaction norms can evolve through independent changes to genetically distinct modular components of such complex phenotypes.Article SummaryPlastic responses to environmental inputs, reaction norm phenotypes that can be summarized with parameters of fits to a mathematical function, are pervasive across diverse organismal traits and crucial to organismal fitness. We quantified the nematode Caenorhabditis briggsae’s behavioral thermal performance curves as function-valued traits for 23 wild isolate genotypes and 153 recombinant inbred lines. We identified quantitative trait loci on multiple chromosomes that define genetically distinct behavioral modules contributing to the emergent overall behavioral thermal performance curve. These findings highlight how dynamic behavioral responses to environmental inputs can evolve through independent changes to genetically distinct modular components of such complex phenotypes.

scholarly journals Antagonistic effects of intraspecific cooperation and interspecific competition on thermal performance

eLife ◽  
2020 ◽  
Vol 9 ◽  
Author(s):  
Hsiang-Yu Tsai ◽  
Dustin R Rubenstein ◽  
Bo-Fei Chen ◽  
Mark Liu ◽  
Shih-Fan Chan ◽  
...  
Keyword(s):  
Thermal Performance ◽  
Abiotic Factors ◽  
Biotic Interactions ◽  
Niche Width ◽  
Burying Beetle ◽  
Thermal Niche ◽  
Thermal Performance Curve ◽  
Performance Curves ◽  
Species Specific ◽  
The Relationship

Understanding how climate-mediated biotic interactions shape thermal niche width is critical in an era of global change. Yet, most previous work on thermal niches has ignored detailed mechanistic information about the relationship between temperature and organismal performance, which can be described by a thermal performance curve. Here, we develop a model that predicts the width of thermal performance curves will be narrower in the presence of interspecific competitors, causing a species’ optimal breeding temperature to diverge from that of its competitor. We test this prediction in the Asian burying beetle Nicrophorus nepalensis, confirming that the divergence in actual and optimal breeding temperatures is the result of competition with their primary competitor, blowflies. However, we further show that intraspecific cooperation enables beetles to outcompete blowflies by recovering their optimal breeding temperature. Ultimately, linking abiotic factors and biotic interactions on niche width will be critical for understanding species-specific responses to climate change.

scholarly journals Adaptive evolution shapes the present-day distribution of the thermal sensitivity of population growth rate

2019 ◽  
Author(s):  
Dimitrios - Georgios Kontopoulos ◽  
Thomas P. Smith ◽  
Timothy G. Barraclough ◽  
Samraat Pawar
Keyword(s):  
Climate Change ◽  
Growth Rate ◽  
Adaptive Evolution ◽  
Thermal Performance ◽  
Population Growth Rate ◽  
Thermal Sensitivity ◽  
Rapid Evolution ◽  
Performance Curve ◽  
Thermal Performance Curve ◽  
The Relationship

AbstractDeveloping a thorough understanding of how ectotherm physiology adapts to different thermal environments is of crucial importance, especially in the face of global climate change. A key aspect of an organism’s thermal performance curve—the relationship between fitness-related trait performance and temperature—is its thermal sensitivity, i.e., the rate at which trait values increase with temperature within its typically-experienced thermal range. For a given trait, the distribution of thermal sensitivities across species, often quantified as “activation energy” values, is typically right-skewed. Currently, the mechanisms that generate this distribution are unclear, with considerable debate about the role of thermodynamic constraints vs adaptive evolution. Here, using a phylogenetic comparative approach, we study the evolution of the thermal sensitivity of population growth rate across phytoplankton (Cyanobacteria and eukaryotic microalgae) and prokaryotes (bacteria and archaea), two microbial groups that play a major role in the global carbon cycle. We find that thermal sensitivity across these groups is moderately phylogenetically heritable, and that its distribution is shaped by repeated evolutionary convergence throughout its parameter space. More precisely, we detect bursts of adaptive evolution in thermal sensitivity, increasing the amount of overlap among its distributions in different clades. We obtain qualitatively similar results from evolutionary analyses of the thermal sensitivities of two physiological rates underlying growth rate: net photosynthesis and respiration of plants. Furthermore, we find that these episodes of evolutionary convergence are consistent with two opposing forces: decrease in thermal sensitivity due to environmental fluctuations and increase due to adaptation to stable environments. Overall, our results indicate that adaptation can lead to large and relatively rapid shifts in thermal sensitivity, especially in microbes where rapid evolution can occur at short time scales. Thus, more attention needs to be paid to elucidating the implications of rapid evolution in organismal thermal sensitivity for ecosystem functioning.Author summaryChanges in environmental temperature influence the performance of biological traits (e.g., respiration rate) in ectotherms, with the relationship between trait performance and temperature (the “thermal performance curve”) being single-peaked. Understanding how thermal performance curves adapt to different environments is important for predicting how organisms will be impacted by climate change. One key aspect of the shape of these curves is the thermal sensitivity near temperatures typically experienced by the species. Whether and how thermal sensitivity responds to different environments is a topic of active debate. To shed light on this, here we perform an evolutionary analysis of the thermal sensitivity of three key traits of prokaryotes, phytoplankton, and plants. We show that thermal sensitivity does not evolve in a gradual manner, but can differ considerably even between closely related species. This suggests that thermal sensitivity undergoes rapid adaptive evolution, which is further supported by our finding that thermal sensitivity varies weakly with latitude. We conclude that variation in thermal sensitivity arises partly from adaptation to environmental factors and that this may need to be accounted for in ecophysiological models.

scholarly journals Thermal Performance Curves of Multiple Isolates of Batrachochytrium dendrobatidis, a Lethal Pathogen of Amphibians

2021 ◽  
Vol 8 ◽  
Author(s):  
Ciara N. Sheets ◽  
Deena R. Schmidt ◽  
Paul J. Hurtado ◽  
Allison Q. Byrne ◽  
Erica Bree Rosenblum ◽  
...  
Keyword(s):  
Thermal Performance ◽  
Growth Rates ◽  
Batrachochytrium Dendrobatidis ◽  
Abiotic Factors ◽  
Phenotypic Traits ◽  
Genetic Lineage ◽  
Multiple Traits ◽  
Performance Curves ◽  
Key Factor ◽  
Environmental Temperatures

Emerging infectious disease is a key factor in the loss of amphibian diversity. In particular, the disease chytridiomycosis has caused severe declines around the world. The lethal fungal pathogen that causes chytridiomycosis, Batrachochytrium dendrobatidis (Bd), has affected amphibians in many different environments. One primary question for researchers grappling with disease-induced losses of amphibian biodiversity is what abiotic factors drive Bd pathogenicity in different environments. To study environmental influences on Bd pathogenicity, we quantified responses of Bd phenotypic traits (e.g., viability, zoospore densities, growth rates, and carrying capacities) over a range of environmental temperatures to generate thermal performance curves. We selected multiple Bd isolates that belong to a single genetic lineage but that were collected across a latitudinal gradient. For the population viability, we found that the isolates had similar thermal optima at 21°C, but there was considerable variation among the isolates in maximum viability at that temperature. Additionally, we found the densities of infectious zoospores varied among isolates across all temperatures. Our results suggest that temperatures across geographic point of origin (latitude) may explain some of the variation in Bd viability through vertical shifts in maximal performance. However, the same pattern was not evident for other reproductive parameters (zoospore densities, growth rates, fecundity), underscoring the importance of measuring multiple traits to understand variation in pathogen responses to environmental conditions. We suggest that variation among Bd genetic variants due to environmental factors may be an important determinant of disease dynamics for amphibians across a range of diverse environments.

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