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Warming-induced "plastic floors" improve hypoxia vulnerability, not aerobic scope, in red drum (Sciaenops ocellatus)

  • 0Department of Marine Science, University of Texas at Austin, Port Aransas, TX 78373, United States; Department of Biological Sciences, Idaho State University, Pocatello, ID 83209, United States.
The Science of the Total Environment +

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February 20, 2024

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February 20, 2024

View abstract on PubMed

Summary

This summary is machine-generated.

Ocean warming challenges marine fish. Red drum acclimated to warmer waters reduced metabolic rates, improving oxygen use and expanding habitat potential despite initial challenges.

Area Of Science

  • Marine biology
  • Physiological ecology
  • Climate change adaptation

Background

  • Ocean warming poses a significant threat to marine ectotherms, impacting their metabolic functions and survival.
  • The "plastic floors, concrete ceilings" hypothesis suggests metabolic acclimation to warming involves reduced standard metabolic rate (SMR) and stable maximum metabolic rate (MMR), enhancing aerobic scope (AS).

Purpose Of The Study

  • To evaluate the "plastic floors, concrete ceilings" hypothesis in red drum (Sciaenops ocellatus) under simulated ocean warming.
  • To investigate the influence of warming on hypoxia vulnerability (critical oxygen threshold; P<sub>crit</sub>) and mitochondrial performance in red drum.

Main Methods

  • Red drum were acclimated to 20°C or 28°C for 12 weeks.
  • Respirometry was conducted bi-weekly to measure metabolic rates (SMR, MMR) and P<sub>crit</sub>.
  • Mitochondrial respirometry was performed on liver and heart tissues at the study's conclusion.

Main Results

  • Warm-acclimated fish initially exhibited higher SMR, MMR, and P<sub>crit</sub>, but SMR significantly decreased by 36.2% over 12 weeks.
  • Contrary to the hypothesis, AS did not improve due to a concurrent decline in MMR.
  • P<sub>crit</sub> decreased in warm-acclimated fish, equalizing between treatments by 12 weeks; liver mitochondrial function improved, suggesting plasticity.

Conclusions

  • Warming-induced metabolic suppression in red drum offsets increased oxygen demand, mitigating hypoxia vulnerability.
  • Mitochondrial plasticity in the liver may contribute to reduced SMR under thermal stress.
  • These adaptations expand the potential habitable range for red drum in a warming ocean.

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