Thermal sensitivity of field metabolic rates of marine fishes across global latitude gradients

Dr Clive Trueman, Gabriele Stowasser, Lloyd Peck, Ryan Saunders
Rationale: 

Predicting how animals will respond to climatic change depends on a clear understanding of the mechanisms that link performance in the wild to temperature. Metabolism is a unifying currency in ecology and estimates of the energy demands of individuals are central to understanding how an animal interacts with its environment.

This project will help to fill to a fundamental knowledge gap in physiological ecology: the realized metabolic cost of operating in complex natural settings, and the relationship between field metabolic rates (FMR) and external temperature.

Bioenergetic theory predicts that animals living in environments with narrow seasonal temperature ranges will be more sensitive to warming (or cooling) than those from temperate environments. At the same time, the thermal sensitivity of field metabolic rate is likely to be exaggerated at life stages where energetic demands are maximized and the possibility of behavioral responses to warming are limited. Combined, these hypotheses predict that the thermal sensitivity of field metabolic rate will be maximized in polar and tropical regions and during larval and spawning life stages. However, to date no direct tests of the effect of temperature on field metabolism of fishes across climatic zones and over life stages has been conducted.

Methodology: 

This project will draw on a novel chemical proxy for FMR developed in Southampton. The stable isotope composition of carbon in fish otoliths can be used to infer metabolic rate, which, combined with estimates of temperature derived from otolith oxygen isotopes and growth rates derived from otolith incremental growth give a unique view of the bioenergetic response of wild-ranging fishes to changes in environmental temperatures.

This project will apply the otolith isotope FMR proxy to determine and compare the thermal sensitivity of field metabolic rate in demersal fishes from polar (Arctic and Antarctic), temperate (European shelf) and tropical (Caribbean or Indian Ocean) settings. You will test hypotheses predicting relationships between the thermal sensitivity of FMR and variation in environmental temperature, and explore whether thermal sensitivity of FMR is uniformly expressed across fish life stages.

Ultimately your insights will help to develop our understanding of the relationships between environmental temperature and energy budgets. Your results will have immediate relevance for predicting species performance, persistence and geographic redistribution in the face of ongoing climate change.   Tropical and temperate fishes in particular support major commercial and artisinal fisheries and your model species will include taxa underpinning regionally significant fisheries.

 

Location: 
University of Southampton
Training: 

The INSPIRE DTP programme provides comprehensive personal and professional development training alongside extensive opportunities for students to expand their multi-disciplinary outlook through interactions with a wide network of academic, research and industrial/policy partners. The student will be registered and hosted at the University of Southampton and will also spend time in BAS laboratories at Cambridge. Fieldwork is a possibility but the main aims of the project could be realised using existing otolith collections.

Specific training will include:

  • All aspects of otolith sclerochonology: extraction and preparation, age and growth analyses, and geochemical analyses.
  • Stable isotope ecology, both practical and conceptual
  • Ecophysiology and climate change ecology of aquatic organisms
  • Polar and tropical biology
  • Data analysis and visualization (mainly R)
  • Team working

We operate an inclusive lab policy, recognizing the diversity crisis in academic science, and work to identify our privileges and to reduce existing barriers associated with ethnicity, gender, sexuality and disability.

 

Eligibility & Funding Details: 

Please check https://inspire-dtp.ac.uk/how-apply for details.  

 

Background Reading: 

Chung et al (2019) Field metabolic rates of teleost fishes are recorded in otolith carbonate Communications Biology 2 doi: 10.1038/s42003-018-0266-5 https://doi.org/10.1038/s42003-018-0266-5

Chung et al (2021) First measurements of field metabolic rate in wild juvenile fishes show strong thermal sensitivity but variations between sympatric ecotypes. Oikos 130 https://doi.org/10.1111/oik.07647

Dahlke et al (2020) Thermal bottlenecks in the life cycle define climate vulnerability of fish Science 369, 65-70 https://www.sciencemag.org/lookup/doi/10.1126/science.aaz3658