Physiological Adaptations of Marine Organisms to Environmental Stressors

Marine organisms face an array of environmental stressors including rising temperatures, ocean acidification, deoxygenation and fluctuating salinity. To survive, many employ biochemical and physiological strategies that maintain homeostasis under challenge. Heat shock proteins and molecular chaperones stabilise proteins during thermal stress, while antioxidant enzymes counteract reactive oxygen species generated by metabolic imbalance. Acid–base regulation is achieved through specialised ion transporters in gills or epithelial surfaces, ensuring pH stability and ammonia excretion. Some species deploy metabolic depression, reducing energy demand during hypoxia or food scarcity, whereas others sustain aerobic performance by adjusting ventilation and cardiac output. Membrane lipid remodelling preserves cellular function at varying temperatures, and shifts in energy allocation prioritise survival over growth or reproduction. Collectively, these adaptations underpin resilience across taxa—from molluscs and crustaceans to fish and cnidarians—highlighting convergent strategies that confer tolerance to global change and sustain ecosystem function.

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Physiological Adaptations of Marine Organisms to Environmental Stressors publication trend

The graph below shows the total number of articles in physiological adaptations of marine organisms to environmental stressors across all publications each year (not limited to Nature Index journals).

Technical terms

Acid–base regulation: The physiological processes that maintain stable internal pH through ion transport and buffering systems.

Aerobic scope: The difference between an organism’s maximal and basal oxygen consumption, indicative of available energy for activity.

Critical oxygen tension (Pcrit): The ambient oxygen level below which an organism can no longer sustain its standard metabolic rate.

Molecular chaperones: Proteins that assist the folding, repair or degradation of other proteins under stress conditions.

Redox regulation: Control of oxidation–reduction balance through enzymes that mitigate damaging free radicals.

Metabolic depression: A reversible reduction in metabolic rate to conserve energy during adverse conditions.

References

1. Projected ocean temperatures impair key proteins used in vision of octopus hatchlings. Global Change Biology (2024).
2. Bathyal octopus, Muusoctopus leioderma, living in a world of acid: First recordings of routine metabolic rate and critical oxygen partial pressures of a deep water species under elevated pCO2. Frontiers in Physiology (2022).
3. Aerobic performance of two tropical cephalopod species unaltered by prolonged exposure to projected future carbon dioxide levels. Conservation Physiology (2019).