Saving Shellfish: Geoengineering to Change Ocean Acidification

By Rachel L. Shoebridge



This paper explores ocean acidification and the effect it has on shellfish. Due to anthropogenic carbon emissions, the ocean is warming quickly. The rapid change is causing ocean acidification. Ocean acidification creates difficulty for shellfish to build shells and skeletons. The drastic changes already made to the sea call for more help than humans cutting back emissions. This paper explores different forms of geoengineering to get ocean pH to slow or stop changing. One exceptional form of geoengineering is needed to save shellfish from future extinction.

Keywords: Geoengineering, shellfish, ocean acidification, anthropogenic, carbon dioxide


Saving Shellfish: Geoengineering to Mitigate Ocean Acidification

There are many different issues related to climate change in today’s world. One of those issues that has a highly negative impact on oceans is acidification. Ocean acidification is happening faster than ever due to fossil fuels trapping carbon dioxide in the atmosphere. At first, the ocean taking carbon dioxide out of the atmosphere was good; now, too much is causing the sea to acidify. These changes negatively affect almost all marine life, one being shellfish. Shellfish use calcium carbonate to build their shells and skeletons, but due to ocean acidification, this necessary life skill is becoming more and more difficult. Although one reasonable option may be for humans to stop using fossil fuels, there is no way of knowing if it is too late to change the rapidly acidifying ocean. Due to the rising amount of acidification in oceans from climate change, geoengineers must take action to save shellfish from extinction.

Ocean acidification directly relates to climate change as it is consequential of a large amount of carbon dioxide in the atmosphere. According to Jennifer Bennett (2018), a team member of the National Oceanic and Atmospheric Administration (NOAA), around a quarter of carbon dioxide from the use of fossil fuels ends up in the ocean rather than in the air (para. 1). Scientists thought the ocean was doing the earth a favor by soaking up excess CO2 but now realize it is causing drastic changes in the sea. Although the sea is enormous, this extra carbon dioxide will make drastic changes in ocean acidity over time. The ocean is changing too quickly for shellfish to adapt, as they are having a hard time building and keeping their shells due to acidification.

Saving shellfish may seem like a small matter in the ocean acidification crisis, but the impacts of losing them will have drastic effects. Many other sea creatures use shellfish as a food source. If ocean acidification takes out shellfish, it removes a significant food source for other predators. If that is not bad enough, the loss of shellfish due to ocean acidification will take away an excellent food source for humans as well. The shellfish industry is a vast food source worldwide, but ocean acidification is becoming a massive threat to the industry. Eve Zuckoff (2021), a climate change journalist for Cape, Coast, and Islands (CAI), warns that by 2100 the shellfish industry is estimated to lose $400 million annually (para. 12). This information explains the importance of saving the shellfish for the whole world, as the clock is ticking before catastrophe strikes.

Ocean acidification has a life-threatening impact on shellfish. All life forms are sensitive to any slight change in pH, so when ocean pH changes, it harms shellfish. These changes create complications in reproduction, growth, and chemical communication. One of the biggest challenges shellfish are facing against ocean acidification is building their shells. Bennett (2018) explains that hydrogen ions bond with carbonate to create an essential component of calcium carbonate shells, adding that shellfish create calcium carbonate by combining carbonate from the ocean with a calcium ion while releasing water and CO2. In addition, hydrogen ions are more attracted to carbonate than calcium, creating a bicarbonate ion. This forms difficulty for shellfish as they cannot get carbonate from a bicarbonate ion, meaning they cannot grow a new shell (para. 12-14). As carbonate becomes harder for shellfish to find, it becomes harder and harder to build homes. Even when shellfish can make their shells in acidic water, more energy is used, which takes away from the energy needed for other life activities. Ocean acidification can also cause the dissolving of current shells. As a result of these changes threatening the lives of shellfish, geoengineering is their only hope of survival.

Geoengineering involves the manipulation of the biosphere and planetary systems, which could help remove carbon dioxide from the air or acidity from the sea without eliminating carbon emissions. Scientists work to find different ways to use geoengineering to mitigate disasters of a quickly acidifying ocean and climate change. One proposed geoengineering method is adding fertilizers such as iron to the sea to cause a phytoplankton bloom. Bennett (2018) explains: “This phytoplankton would then absorb carbon dioxide from the atmosphere, and then, after death, sink and trap it in the deep sea” (para. 55). Although this method shows signs of success, there are unknown risks and factors such as whether it will affect other marine life that uses phytoplankton as a food source. A phytoplankton bloom is just one of many proposed forms of geoengineering that could help in saving shellfish.

Another proposed way of geoengineering is carbon dioxide removal (CDR) from the ocean. Phillip Williamson and Carol Turley (2012), geoengineers, stated that CDR-based engineering aims to keep down global warming by offsetting carbon dioxide emissions, which leads toward stabilizing carbon dioxide in the atmosphere, then adding the likelihood of reaching the international target of CO2 is little to none in just reducing emissions. CDR-based geoengineering could be the answer to finding ocean stabilization once again. However, a downfall of this type of geoengineering is that few techniques of CDR would be able to prevent approximately half of current greenhouse gasses sufficiently (pp. 4329-4332). This means only some improvement can be made with this technique, concluding that any progress is better than none in the ocean acidification crisis.

One more way of geoengineering to mitigate ocean acidification is by alkalinity injection. The study is conducted because the Great Barrier Reef is beginning to acidify due to the anthropogenic use of fossil fuels, leading to climate change. Mongin et al. (2021), a group of environmental scientists, conducted a study called Reversing Ocean Acidification Along the Great Barrier Reef Using Alkalinity Injection. This study aims to see if artificial ocean alkalinization (AOA) can mitigate or reverse ocean acidification. This study showed that reversing decades of ocean acidification could be achievable (para. 1). The downside is that the process is very costly, and there could be unknown risks associated with that amount of alkalinity added to the ocean. Although there is some unknown risk associated with this type of geoengineering, more studying could prove its potential in saving the shellfish.

Ocean acidification directly relates to climate change because of too much carbon dioxide. Both issues are anthropogenic due to fossil fuels like coal, oil, and gas. One might wonder, why not cut, or stop the use of fossil fuels to end ocean acidification? There is no way to get the entire world on board to stop using fossil fuels right now, which would need to happen to have any hope of restoring the ocean. Of course, every human should strive to cut back on carbon emissions, but without drastic change from everyone worldwide, there is no way to stabilize carbon dioxide in the ocean by just “cutting back.” In addition, even if the world could make a difference in carbon emissions, there would not be an immediate change in ocean acidification. Even if humans were able to stop using fossil fuels successfully, “the climate will continue to change, the atmosphere will continue to warm, and the ocean will continue to acidify” (J. Bennett, 2018, para. 52).  Carbon dioxide lasts even longer in the ocean than it does in the air, causing a dire need for immediate action from the whole world.

In a rapidly changing ocean environment, action must be taken to save the shellfish. Through geoengineering, carbon dioxide can be removed from the ocean to make a stable environment for shellfish and all other marine life, for that matter. As each individual should do their best to release fewer carbon emissions, it is not likely that the use of fossil fuels will come to a complete stop. Instead, using new technology and science, the world should come together to find a form of geoengineering that will drastically change ocean acidity for the better.



Bennett, J. (2018, April). Ocean Acidification | Smithsonian Ocean. Ocean Acidification.

Mongin, M., Baird, M. E., Lenton, A., Neill, C., & Akl, J. (2021). Reversing ocean acidification along the Great Barrier Reef using alkalinity injection. Environmental Research Letters, 16(6), 064068.

Williamson, P., & Turley, C. (2012). Ocean acidification in a geoengineering context. Philosophical Transactions. Series A, Mathematical, Physical, and Engineering Sciences, 370(1974), 4317–4342.

Zuckoff, E. (2021, February 10). Ocean Acidification Could Wipe Out Shellfish Industry: Report. CAI.

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