Ocean Acidification and Its Impact on Marine Biodiversity: Ecological Consequences and Future Perspectives

AUTHOR

Vivek Kumar Saini*

ABSTRACT  

Ocean acidification has emerged as one of the most serious environmental issues affecting marine ecosystems in the twenty-first century. Human activities such as fossil fuel combustion, deforestation, and industrialization results into rapid increase in the level of atmospheric carbon dioxide (CO₂) has altered the chemistry of oceans to a significant level. Carbon dioxide released from source reaches to one of the sink i.e. oceans which absorb nearly one third of the anthropogenic CO₂ released into the atmosphere.  When carbon dioxide mixes with seawater, forms carbonic acid which subsequently dissociated into bicarbonate and hydrogen ions. The hydrogen ions released in sea water increase the pH level of sea water and alters the carbonate balance essential for marine life. Since the beginning of the Industrial Revolution, the average pH of surface ocean waters has decreased from approximately 8.2 to about 8.1. Although this change appears small, it represents nearly a 30% increase in ocean acidity and indicates a significant shift in ocean chemistry. This chemical alteration reduces the availability of carbonate ions which is required by marine organism for the formation of calcium carbonate shells and skeletons. Acidification of oceans mainly affects the calcifying organism like corals, mollusks and other certain plankton species.  Under acidic conditions, low calcification rates, reduced growth, weakened shells and physiological stress has been observed. In addition to ecological impacts, ocean acidification also threatens fisheries, aquaculture industries, and coastal economies that depend on marine biodiversity. Therefore, understanding the causes, mechanisms, and ecological consequences of ocean acidification is essential for developing effective conservation strategies and sustainable marine management policies in the context of global climate change.

Keywords: Ocean acidification, Marine biodiversity, Climate change, Coral reefs, Calcification, Marine ecosystems