Ocean Alkalinity Enhancement:

The negative effects of anthropogenic climate change takes its toll on our oceans as unprecedented levels of carbon dioxide are being dissolved into seawater. One result of increased carbon dioxide in the ocean is acidification.

Ocean acidification makes maintaining and producing calcium carbonate structures for calcifying organisms incredibly difficult. Minerals needed by calcifying organisms to build their shells and skeletons are dissolved by acidic waters.The ocean's overall pH decreases as excess carbon dioxide from the atmosphere is dissolved. The average pH of seawater is 8.1.Before the Industrial Revolution,it was 8.2.While a 0.1change may not seem significant,pH is logarithmic. That seemingly small 0.1 change describes a nearly 30 percent increase in acidity.

This change is worrying as it threatens the livelihood of corals,the backbone of reef systems.A quarter of the ocean?s fish populations depend on healthy reefs.

In an effort to mitigate the harm that ocean acidification creates,scientists at the NGO Ocean Visions are researching ocean alkalinity enhancement. Ocean alkalinity enhancement (OAE),also called enhanced weathering,aims to modify seawater chemistry by dispersing finely ground alkaline minerals such as lime or olivine into seawater or coastal lands.As these silicates and carbonate minerals dissolve,alkalinity increases,allowing more carbon to be dissolved into seawater while decreasing ocean acidification.OAE materials could be derived from industrial processes, mined,pulverized,and then spread on beaches or added directly into seawater through pipelines or ships.While OAE has the potential to reduce ocean acidification and promote growth for calcifying organisms,there are several negative factors to consider.

In order to obtain the materials needed for OAE, mass infrastructure,including mining sites,is needed.The hazards of terrestrial mining include exposure to pollution, harm to local biodiversity,poor air and water quality,and potential harm to miners.The mined minerals themselves may contain impurities such as metallic elements or other unwanted minerals.The result of such substances being released into the environment is detrimental.CO2 emissions from mining,transportation, and dispersion of OAE materials contribute to emissions and pose a counterintuitive question.

Ocean alkalinity enhancement may prove useful in the mitigation of ocean acidification.However, the ocean is,simply put,huge. At the moment,OAE is proposed for vulnerable areas subject to biodiversity loss and coral bleaching,such as parts of the Great Barrier Reef.OAE is a relatively new concept and requires further research. Currently,OAE is not a viable option to reduce ocean acidification.However,with further research and an emphasis on sustainability, ocean alkalinity enhancement may become a tool to mitigate ocean acidification.