Bio-buffering to combat ocean acidification?

Atmospheric carbon dioxide (CO2) concentration is rising faster than ever before, due to continuous surge in burning fossil fuel. According to the ‘State of the Climate in 2017’ report from the National Oceanic and Atmospheric Administration (NOAA) and the American Meteorological Society, the global growth rate of atmospheric CO2 concentration was approximately 0.6 ± 0.1 ppm/year in the 1960s [3]. However, in the last decade, the growth rate has jumped to 2.3 ppm/year. The estimated atmospheric CO2 concentration is expected to reach 800–1000 ppm by the end of this century [6]. Oceans absorb nearly 30% of the global CO2 emissions [8], resulting in decrease in ocean pH, known as ocean acidification (OA). While atmospheric CO2 is the major contributor to OA globally, other anthropogenic activities influence OA on a local level. These include acid rain from vehicle emissions and industry in urban areas, inflow of organic carbon to the oceans in the form of sewage, and nutrient loading into the oceans from agricultural runoff; all of which contribute to OA [7].

Ocean acidification not only lowers the pH of ocean water, but also decreases dissolved carbonate ion (CO32−) concentration and alters the saturation states of calcium carbonate minerals. Calcifying organisms, such as corals, mollusks, and shellfishes, which use CO32− ions along with calcium ions to produce their calcium carbonate skeletons and shells, are negatively impacted by decreased CO32− levels. In addition, OA causes changes in habitat quality and nutrient cycling, which have numerous effects on food web interactions. Overall, complex changes occur in populations, communities, and the entire ecosystem; the scope of which is yet to be fully understood.

Datta R. & Sarkar D., in press. Bio-buffering to combat ocean acidification? Current Pollution Reports. Article (subscription required).

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