Wednesday, March 9, 2016

Ocean Acidification: How the Ocean is Acidifying and Affecting the Organisms That Call it Home

By Zack Griggy, San Marin HS

             Pollution is a global problem. One way to find proof of this is to look to the seas. We all know that the oceans have suffered greatly from pollution, evidence of which can be seen almost anywhere, from areas suffering from oil spills to the huge cluster of garbage floating in the North Pacific Ocean. We also know that many aquatic species are dying and going extinct because of ocean pollution. However, oils spills and trash aren't the only causes. Another cause is ocean acidification, which is caused by air pollution.
             Ocean acidification begins with carbon dioxide. Carbon dioxide is an essential part of photosynthesis in plants. However, it is also a greenhouse gas, and carbon dioxide emissions have become a global problem. Carbon Dioxide is one of the main contributors to both global climate change and ocean acidification. Carbon dioxide is emitted in huge quantities around the world. Part of these emissions are absorbed by the oceans. This leads to chemical reactions within the oceans to form Carbonic Acid from carbonate and hydrogen ions, which are formed using CO2 absorbed by the oceans. Carbonic Acid is the main cause of ocean acidification. For the past 300 million years, the oceans have had a pH of 8.2, but recently since the industrial revolution, that pH has dropped to 8.1. Estimates say that the ocean acidity may drop by another 0.5 pH
            The effects of ocean acidification can be very harmful to marine ecosystems. Many marine organisms such as arthropods, coral, and plankton will be impacted by ocean acidification. These organisms use the process of calcification to create shells, exoskeletons, etc. Calcification relied on using two ions, carbonate and calcium ions. However, Carbonic Acid also uses carbonate ions, which makes it more difficult for the aforementioned organisms to make their exoskeletons or shells. In addition, when more carbon is absorbed by the oceans, hydrogen ions become more abundant, which makes it increasingly more difficult for the organisms to make their exoskeletons.

Sources:
1. https://www3.epa.gov/climatechange/science/indicators/oceans/acidity.html
2. http://www.iiasa.ac.at/web/home/about/news/150203-Ocean-Acid.html
3. http://www.co2science.org/subject/c/summaries/calcification.php
4. http://www.pmel.noaa.gov/co2/story/Ocean+Acidification
5. http://hilo.hawaii.edu/academics/hohonu/documents/Vol09x06OceanAcidification.pdf

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