Anthropization, Salinity and Oxidative Stress in Animals in the Coastal Zone

Abstract

In coastal and abiding zones, ground water continuously faces a very slight but alarmingly increasing trend in salinity due to several reasons such as the excess loss or use of it, with the constant dissolution of salts from the Earth’s surface and heat-trapping pollution from human activities, rising sea levels and finally, high flooding. Many recent studies have indicated that even a slight elevation in ground water salinity may affect freshwater inhabitants, highlighting the importance of research on the effects of low salinity stress on coastal zone freshwater inhabitants. Along with abiotic factors such as salinity, dissolved oxygen, pH, and alkalinity, anthropogenic factors also cause a lot of stress on the inhabitants in coastal zones. Climatic factors also play an important role in influencing the life of coastal water inhabitants. For example, statistics such as those obtained by correlation and discriminant function analysis indicate that sublethal salinity acts as a strong modulator in the physiology of inhabiting fish in fresh as well as coastal water. Parameters such as increase in body weight, feed intake and irregularities in morphometry increase under higher salinities, which are confirmed by a decline in the growth of fishes. Similarly, blood physiology aspects, such as a significant loss in hemoglobin content, the RBC count and eosinophils, are coupled with amelioration in neutrophil count at the higher salinities of 6 and 9 ppt in few freshwater organisms. Normal histoarchitecture is also lost in most fish under high salinity conditions and higher anthropogenic loads. The generation of tissue damage in terms of oxidative stress is prominent under high fluctuations in abiotic factors including higher salinity or under high anthropogenic loads. Hence, a loss in compromised normal physiology due to the toxic effects of low- or high-salinity saline water or in fresh inhabitants including hardy fishes under changing climatic conditions are evident. This raises concerns about maintaining water quality in coastal and allied zones globally in the coming decades.

Keywords

• coastal water
• environmental effect
• global climate change
• water salinity
• hardy fish
• multiple biological factors