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70% of the surface of the Earth is covered with water and 80% of life on earth lies under the water. Many of us forget how immense the Ocean is. Its capacity is hidden from us still remaining in mystery. With containing the vast biodiversity, one of its role is to chemically balance the pH of the entire earth. The enormous body of water acts as a buffer. A buffer can resist sudden changes of pH whether the atmosphere is too basic or too acidic.
Day to day, Earth is maintaining a constant equilibrium with Carbon Dioxide (CO2). Depending on the amount of the CO2 the Ocean either absorbs or releases CO2. While CO2 still remains as a key substance which flourishes all the greens on earth (photosynthesis), the earth came to a point where the level of CO2 is threatening the beautiful life under the water.
So how actually does CO2 acidify the Ocean? The Atmospheric CO2 dissolves into the water. When it meets the water it becomes a Carbonic acid (H2CO3). Since the carbonic acid is a weak acid with 6.4 pKa(whereas one of the strongest acid; Hydrochloric acid’s pKa is just about -10), it constantly tries to be in an equilibrium from H2CO3 to Biocarbonate ions (HCO3–) and Hydronium ions (H3O+). However, increased concentration of Hydronium ions lowers the pH. The ocean naturally has a base, a carbonate ion (CO32-),that can bind with the hydronium ions to restore the normal pH. When natural concentration of CO32- in the sea gets depleted, organisms like shellfish and corals that build their structure with Calcium ion (Ca+) and Carbonate ion (CO32-) gives up their minerals to balance the acidity. Then they become “bleached out” due to the escape of CO32- in the organism’s structure.
Losing the corals means destroying billions of fish’s habitat and their source of food. The more acidic the ocean becomes the more organisms will melt into the sea to stop the acidification. Why should they be the ones melting away because of our convenience and ignorance? When we become more aware of our better daily choices to the environment and more uncomfortable about our selfish habits, the chance of saving the biodiversity increases. Reducing unnecessary consumption of red meat, voting for political parties actively involved in sustainability, choosing green energy, and simply just using and spending less will remarkably decrease the CO2 emission.
Dahye Kim
https://bravenewclimate.com/2008/08/29/top-10-ways-to-reduce-your-co2-emissions-footprint/