A decline in seawater pH that occurs because of high levels of respiration by marine life—typically bacteria involved in decomposition of algae. Respiration releases carbon dioxide into the water, which leads to formation of carbonic acid. Coastal acidification (CA) is often fueled by nutrients carried into the ocean by rivers, stimulating outbreaks of phytoplankton that subsequently decompose on or near the seabed. This phenomenon happens in coastal waters because that is where high nutrient levels and algal blooms occur. Coastal acidification is differentiated from ocean acidification (OA), which is a global-scale phenomenon of carbon dioxide from the atmosphere dissolving into the ocean. However, both CA and OA involve increases in carbon dioxide in the water.
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