Oxidative Stress Responses in Aquatic Ecosystems

Aquatic organisms constantly face the challenge of reactive oxygen species (ROS) generation when environmental conditions shift beyond their physiological optimum. Sources of ROS in water bodies include ultraviolet radiation, temperature extremes, hypoxia–reoxygenation cycles and anthropogenic pollutants such as pesticides, heavy metals and organic contaminants. In response, living cells deploy a network of enzymatic and non-enzymatic antioxidant defences to maintain redox homeostasis. Key enzymatic systems—superoxide dismutase, catalase and glutathione-dependent pathways—scavenge superoxide anion and hydrogen peroxide, while low-molecular-weight antioxidants intercept lipid peroxidation chain reactions. When the balance tilts towards pro-oxidant conditions, oxidative damage to lipids, proteins and nucleic acids can impair tissue integrity, immune function and reproductive success, with cascading impacts on population dynamics and ecosystem services. Monitoring oxidative stress biomarkers in sentinel species has thus become an important tool for assessing water quality and the biological effects of emerging contaminants. Moreover, insights into molecular stress pathways are informing conservation strategies, aquaculture practices and pollutant regulation on a global scale.

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Oxidative Stress Responses in Aquatic Ecosystems publication trend

The graph below shows the total number of articles in oxidative stress responses in aquatic ecosystems across all publications each year (not limited to Nature Index journals).

Technical terms

Reactive oxygen species (ROS): Chemically reactive molecules, including superoxide anion and hydrogen peroxide, produced as by-products of aerobic metabolism or environmental stressors.

Lipid peroxidation: Oxidative degradation of polyunsaturated lipids leading to membrane damage and formation of malondialdehyde as a measurable by-product.

Superoxide dismutase (SOD): An enzyme that catalyses the conversion of superoxide anion into oxygen and hydrogen peroxide, constituting a first line of defence against ROS.

Catalase (CAT): An enzyme that decomposes hydrogen peroxide into water and oxygen, preventing its accumulation and subsequent oxidative harm.

Biomarker: A measurable biological response—such as enzyme activity or oxidative damage product—that reflects exposure to or effect of environmental stressors.

References

1. Toxicity of the Herbicide Atrazine: Effects on Lipid Peroxidation and Activities of Antioxidant Enzymes in the Freshwater Fish Channa Punctatus (Bloch). International Journal of Environmental Research and Public Health (2010).
2. Deltamethrin-induced oxidative stress and biochemical changes in tissues and blood of catfish (Clarias gariepinus): antioxidant defense and role of alpha-tocopherol. BMC Veterinary Research (2012).
3. Therapeutic Effect of Intestinal Autochthonous Lactobacillus reuteri P16 Against Waterborne Lead Toxicity in Cyprinus carpio. Frontiers in Immunology (2018).