Influence of Anthropogenic Activities on Redox Regulation and Oxidative Stress Responses in Different Phyla of Animals in Coastal Water via Changes in Salinity

Salinity is a decisive abiotic factor that modulates the physiology of aquatic organisms. Salinity itself is modulated by various factors—most notably by anthropogenic factors. In coastal regions, increasing salinity is observed mostly due to the elevated rate of evaporation under high temperatures, especially under global warming. In addition, many other anthropogenic factors, climatic factors, chemicals, etc., also contribute to the changes in salinity in coastal water. Some of these include rainfall, regional warming, precipitation, moisture, thermohaline circulation, gaseous pollutants, dissolved chemicals, wind flow, and biocrusts. Salinity has been found to regulate the osmotic balance and, thus, can directly or indirectly influence the biomarkers of oxidative stress (OS) in aquatic organisms. Imbalances in OS potentially affect the growth, production, and reproduction of organisms; therefore, they are being studied in organisms of economic or aquacultural importance. Salinity-modulated OS and redox regulation as a function of phylum are covered in this review. The literature from 1960 to 2021 indicates that the altered OS physiology under changing salinity or in combination with other (anthropogenic) factors is species-specific, even within a particular phylum. Thus, knowing the response mechanisms of such organisms to salinity may be useful for the management of specific aquatic animals or their habitats.