scholarly journals Plasticity, repeatability and phenotypic correlations of aerobic metabolic traits in a small estuarine fish

2020 ◽  
Vol 223 (14) ◽  
pp. jeb228098
Author(s):  
Jessica E. Reemeyer ◽  
Bernard B. Rees

ABSTRACTStandard metabolic rate (SMR), maximum metabolic rate (MMR), absolute aerobic scope (AAS) and critical oxygen tension (Pcrit) were determined for the Gulf killifish, Fundulus grandis, an ecologically dominant estuarine fish, acclimated to lowered salinity, elevated temperature and lowered oxygen concentration. Acclimation to low salinity resulted in a small, but significant, elevation of Pcrit (suggesting lower tolerance of hypoxia); acclimation to elevated temperature increased SMR, MMR, AAS and Pcrit; acclimation to low oxygen led to a small increase in SMR, but substantial decreases in MMR, AAS and Pcrit. Variation in these metabolic traits among individuals was consistent and repeatable when measured during multiple control exposures over 7 months. Trait repeatability was unaffected by acclimation condition, suggesting that repeatability of these traits is not context dependent. There were significant phenotypic correlations between specific metabolic traits: SMR was positively correlated with MMR and Pcrit; MMR was positively correlated with AAS; and AAS was negatively correlated with Pcrit. In general, within-individual variation contributed more than among-individual variation to these phenotypic correlations. The effects of acclimation on these traits demonstrate that aerobic metabolism is plastic and influenced by the conditions experienced by these fish in the dynamic habitats in which they occur; however, the repeatability of these traits and the correlations among them suggest that these traits change in ways that maintain the rank order of performance among individuals across a range of environmental variation.

2020 ◽  
Author(s):  
Jessica E. Reemeyer ◽  
Bernard B. Rees

ABSTRACTStandard metabolic rate (SMR), maximum metabolic rate (MMR), absolute aerobic scope (AAS), and critical oxygen tension (Pcrit) were determined for the Gulf killifish, Fundulus grandis, an ecologically dominant estuarine fish, acclimated to lowered salinity, elevated temperature, and lowered oxygen concentration. Acclimation to low salinity resulted in a small, but significant, elevation of Pcrit; acclimation to elevated temperature increased SMR, MMR, AAS, and Pcrit; acclimation to low oxygen led to a small increase in SMR, but substantial decreases in MMR, AAS, and Pcrit. Variation in these metabolic traits among individuals was consistent and repeatable when measured during multiple control exposures over seven months. Trait repeatability was unaffected by acclimation condition suggesting that repeatability of these traits is not context dependent. There were significant phenotypic correlations between specific metabolic traits: SMR was positively correlated with MMR and Pcrit; MMR was positively correlated with AAS; and AAS was negatively correlated with Pcrit. In general, within-individual variation contributed more than among-individual variation to these phenotypic correlations. The effects of acclimation on these traits demonstrate that aerobic metabolism is plastic and influenced by the conditions experienced by these fish in the dynamic habitats in which they occur; however, the repeatability of these traits and the correlations among them suggest that these traits change in ways that maintains the rank order of performance among individuals across a range of environmental variation.SUMMARY STATEMENTAerobic metabolism of an ecologically dominant estuarine fish is influenced by acclimation to environmental changes without altering trait repeatability. Furthermore, specific metabolic traits are phenotypically correlated.


2019 ◽  
Author(s):  
Michael Briga ◽  
Simon Verhulst

AbstractCrucial to our understanding of the ageing process is identifying how traits change with age, which variables alter their ageing process and whether these traits associate with lifespan.We here investigated metabolic ageing in zebra finches. We longitudinally monitored 407 individuals during six years and collected 3213 measurements of two independent mass-adjusted metabolic traits: basal metabolic rate (BMRm) at thermoneutral temperatures and standard metabolic rate (SMRm), which is the same as BMRm but at ambient temperatures below thermoneutrality.BMRmdecreased linearly with age, consistent with earlier reports. In contrast, SMRmincreased linearly with age. To the best of our knowledge, this is the first quantification of SMRm ageing, and thereby of the contrast between SMRm and BMRm ageing.Neither metabolic rate nor metabolic ageing rate were associated with individual lifespan. Moreover, experimental manipulations of environmental quality that decreased BMRm and SMRm and shortened lifespan with 6 months (12%) did not affect the ageing of either metabolic trait. Females lived 2 months (4%) shorter than males, but none of the metabolic traits showed sex-specific differences at any age.Our finding that ageing patterns of metabolic rate vary depending on the ambient temperature illustrates the importance of studying ageing in an ecologically realistic setting.Our results add to the mounting evidence that within an organism ageing is an asynchronous process.


2002 ◽  
Vol 205 (7) ◽  
pp. 1031-1036 ◽  
Author(s):  
Patrice Boily ◽  
Pierre Magnan

SUMMARY The objective of this study was to examine if individual variation in morphological characters is related to swimming costs in wild and domestic brook charr, and in wild yellow perch. Our results indicate that absolute swimming cost was higher in wild and domestic brook charr individuals having a stout body shape, and these individuals are therefore less efficient swimmers. These results are consistent with field observations that described relationships between individual variation in morphology and habitat use in salmonids. Further analyses indicated that standard metabolic rates were higher in individuals having a stout body shape, and that net swimming cost was not related to body shape. Accordingly, the higher swimming cost of stout individuals is probably an indirect consequence of an increase in standard metabolic rate. In wild yellow perch, absolute and net swimming costs were higher in individuals having a stout body shape and a low aspect caudal fin,and standard metabolic rate was not related to body shape. Therefore, in contrast to brook charr, individual variation in the swimming cost of yellow perch appears to be related to morphological characters that affect drag and thrust forces, which is consistent with previously published inter-specific observations.


2021 ◽  
Vol 288 (1959) ◽  
pp. 20211509
Author(s):  
Louise C. Archer ◽  
Stephen A. Hutton ◽  
Luke Harman ◽  
W. Russell Poole ◽  
Patrick Gargan ◽  
...  

Metabolism defines the energetic cost of life, yet we still know relatively little about why intraspecific variation in metabolic rate arises and persists. Spatio-temporal variation in selection potentially maintains differences, but relationships between metabolic traits (standard metabolic rate (SMR), maximum metabolic rate (MMR), and aerobic scope) and fitness across contexts are unresolved. We show that associations between SMR, MMR, and growth rate (a key fitness-related trait) vary depending on the thermal regime (a potential selective agent) in offspring of wild-sampled brown trout from two populations reared for approximately 15 months in either a cool or warm (+1.8°C) regime. SMR was positively related to growth in the cool, but negatively related in the warm regime. The opposite patterns were found for MMR and growth associations (positive in warm, negative in the cool regime). Mean SMR, but not MMR, was lower in warm regimes within both populations (i.e. basal metabolic costs were reduced at higher temperatures), consistent with an adaptive acclimation response that optimizes growth. Metabolic phenotypes thus exhibited a thermally sensitive metabolic ‘floor’ and a less flexible metabolic ‘ceiling’. Our findings suggest a role for growth-related fluctuating selection in shaping patterns of metabolic variation that is likely important in adapting to climate change.


2020 ◽  
Vol 8 (1) ◽  
Author(s):  
Louise C Archer ◽  
Stephen A Hutton ◽  
Luke Harman ◽  
W Russell Poole ◽  
Patrick Gargan ◽  
...  

Abstract Metabolic rates vary hugely within and between populations, yet we know relatively little about factors causing intraspecific variation. Since metabolic rate determines the energetic cost of life, uncovering these sources of variation is important to understand and forecast responses to environmental change. Moreover, few studies have examined factors causing intraspecific variation in metabolic flexibility. We explore how extrinsic environmental conditions and intrinsic factors contribute to variation in metabolic traits in brown trout, an iconic and polymorphic species that is threatened across much of its native range. We measured metabolic traits in offspring from two wild populations that naturally show life-history variation in migratory tactics (one anadromous, i.e. sea-migratory, one non-anadromous) that we reared under either optimal food or experimental conditions of long-term food restriction (lasting between 7 and 17 months). Both populations showed decreased standard metabolic rates (SMR—baseline energy requirements) under low food conditions. The anadromous population had higher maximum metabolic rate (MMR) than the non-anadromous population, and marginally higher SMR. The MMR difference was greater than SMR and consequently aerobic scope (AS) was higher in the anadromous population. MMR and AS were both higher in males than females. The anadromous population also had higher AS under low food compared to optimal food conditions, consistent with population-specific effects of food restriction on AS. Our results suggest different components of metabolic rate can vary in their response to environmental conditions, and according to intrinsic (population-background/sex) effects. Populations might further differ in their flexibility of metabolic traits, potentially due to intrinsic factors related to life history (e.g. migratory tactics). More comparisons of populations/individuals with divergent life histories will help to reveal this. Overall, our study suggests that incorporating an understanding of metabolic trait variation and flexibility and linking this to life history and demography will improve our ability to conserve populations experiencing global change.


2016 ◽  
Vol 50 (1) ◽  
pp. 138-144
Author(s):  
Patrick J Ruhl ◽  
Robert N Chapman ◽  
John B. Dunning

2017 ◽  
Vol 312 (3) ◽  
pp. R412-R425 ◽  
Author(s):  
Ian K. Townley ◽  
Sibel I. Karchner ◽  
Elena Skripnikova ◽  
Thomas E. Wiese ◽  
Mark E. Hahn ◽  
...  

The hypoxia-inducible factor (HIF) family of transcription factors plays central roles in the development, physiology, pathology, and environmental adaptation of animals. Because many aquatic habitats are characterized by episodes of low dissolved oxygen, fish represent ideal models to study the roles of HIF in the response to aquatic hypoxia. The estuarine fish Fundulus heteroclitus is found in habitats prone to hypoxia. It responds to low oxygen via behavioral, physiological, and molecular changes, and one member of the HIF family, HIF2α, has been previously described. Herein, cDNA sequencing, phylogenetic analyses, and genomic approaches were used to determine other members of the HIFα family from F. heteroclitus and their relationships to HIFα subunits from other vertebrates. In vitro and cellular approaches demonstrated that full-length forms of HIF1α, HIF2α, and HIF3α independently formed complexes with the β-subunit, aryl hydrocarbon receptor nuclear translocator, to bind to hypoxia response elements and activate reporter gene expression. Quantitative PCR showed that HIFα mRNA abundance varied among organs of normoxic fish in an isoform-specific fashion. Analysis of the F. heteroclitus genome revealed a locus encoding a second HIF2α—HIF2αb—a predicted protein lacking oxygen sensing and transactivation domains. Finally, sequence analyses demonstrated polymorphism in the coding sequence of each F. heteroclitus HIFα subunit, suggesting that genetic variation in these transcription factors may play a role in the variation in hypoxia responses among individuals or populations.


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