The Green Analysis

One of the most publicized effects of anthropogenic climate change. Although it is talked about so much, what does ocean acidification mean? How does it work? And what are its implications for the world? This blog will explain all of this and more.

Introduction

Ocean acidification is the decrease in the pH of the ocean; its root cause is the excess amount of carbon dioxide within the atmosphere, which then causes excess carbon dioxide to be within the ocean. Once in the ocean, it reacts with water to form carbonic acid; this excess in carbonic acid lowers the pH of the ocean. Since many oceanic habitats are susceptible, even the slightest pH decrease can devastate ecosystems. This loss in biodiversity and organism populations, in turn, could heavily decrease the amount of all living resources humans extract, reducing the ocean’s economic yield. However, there are some solutions to ocean acidification, and more are being developed each day.

The Chemistry

The primary effect of ocean acidification is the change in the bicarbonate buffer system, which has profound consequences on shelled organisms. However, many other consequences of ocean acidification are unforeseen since detecting and correlating the consequences of changing pH in the ocean to other various trends is extremely difficult.
Focusing on the bicarbonate buffer system is a chemical reaction where both sides of the chemical reaction can be the products or reactants, depending on the surrounding environment. In this case, one side of the chemical reaction is carbonic acid, and the other is bicarbonate and a hydrogen ion. Carbonic acid is formed through the reaction of carbon dioxide and water. Carbonic acid is a weak acid, and bicarbonate is a weak base. If there is an excess of either side of the chemical equation in the water, this buffer system works, then the chemical reaction will occur with the excess chemical as the reactant. For example, in ocean acidification, an excess of carbon dioxide from the air gets dissolved into the water, resulting in an excess of carbonic acid, causing the ocean’s pH to decrease; the bicarbonate buffer system attempts to correct this by having carbonic acid as the reactant produce bicarbonate and hydrogen ions. This offsets the effects of the excess carbonic acid; however, due to the sheer amount of carbon dioxide being emitted into the atmosphere and then dissolved into the ocean, this buffer system cannot keep up, resulting in a drastic decrease in ocean pH.

Affect on Life

Ocean acidification affects shellfish most since a more acidic ocean leads to weaker shells with less calcium carbonate. This is because the carbon buffering system tries to rebalance the pH of the ocean, causing an excess of bicarbonate and free hydrogen ions to be present; the extra hydrogen ions bond with the carbonate present in the water to form bicarbonate. This is bad since organisms require carbonate to form their shells. Most organic shells are made of calcium carbonate, a compound formed by bonding a calcium ion with carbonate; this lack of carbonate results in much weaker shells, leading to reduced reproductive success and an increased likelihood of death.

In summary, increased atmospheric carbon dioxide increases ocean carbonic acid levels. Then, the bicarbonate buffer system produces more bicarbonate and hydrogen ions to counteract the excess carbonic acid. The excess free hydrogen causes carbonate to react with the hydrogen and turn into bicarbonate, removing the available carbonate in the water and reducing the strength and thickness of the shells.

Affect on Humans

Ocean acidification has many effects on human life as well. Firstly, many shellfish most affected by ocean acidification are also keystone species, essential to the prosperity of the ocean ecosystems they comprise. Not only will the population of shellfish be reduced, but this will compound throughout the entire ecosystem and cause the populations of all organisms in the ecosystem to be reduced since many areas of the world rely on resources from the ocean economically or for food. As such, any reduction in the volume of resources within these ocean resources that can be sustainably harvested will negatively impact these communities. Furthermore, some studies have shown that ocean acidification can cause the seafood we eat to be less nutritious, potentially leading to malnutrition.

Solutions

Many upcoming technologies and procedures are being developed to treat ocean acidification directly. However, these solutions are in their infancy; many researchers believe reducing carbon emissions is the best way to address ocean acidification currently. This would reduce the amount of carbonic acid produced in the ocean, allowing the bicarbonate buffer system to restore natural pH levels more effectively. Some potential solutions include geoengineering, increasing the area of blue carbon habitats, carbon capture, alkalinization, electrochemical reactors, and bioremediation. Each of these solutions has its strengths and weaknesses, and as time goes on, they will become more and more refined and practical.

Specifically, geoengineering is the large-scale manipulation of the environment for a desired outcome, in this case, saturating the water with iron to increase phytoplankton populations, which will extract carbonic acid from the water, and once the phytoplankton dies, transport the stored water to the bottom of the water column. Although this would be very effective theoretically, the drawbacks are many potential negative side effects when introducing large amounts of iron into the water. Another type of geoengineering is alkalization, where large quantities of bases such as sodium bicarbonate are released into the water; this increases the pH of the ocean to a more natural state and directly treats the problem of the ocean being too acidic. The extremeness of these solutions often causes them to be ruled out since the potential side effects are risky. Blue carbon habitats and bioremediation use ecosystems or organisms and their properties to solve environmental issues; these solutions have very few adverse effects and are very reliable; however, they can only be implemented in areas where that species is native to or can survive, which often limits the feasibility of these types of solutions. Carbon capture directly extracts carbon from the ocean, reducing the amount of carbonic acid in the water and thus making the ocean less acidic. Although this is very efficient, carbon capture requires a lot of energy to use and only becomes most effective where high concentrations of carbon are present. Electrochemical reactors use electricity and a series of membranes and cathodes to neutralize bases in the seawater directly. This solution has very few theoretical drawbacks. However, when applied in real life, this technology is not mature enough to be scaled to large enough scales where a noticeable effect can be made. However, as technology continues to improve, all the solutions mentioned will become increasingly viable in solving this monumental issue – ocean acidification.

Conclusion

Ocean acidification is a problem closely tied to the rest of climate change; as carbon dioxide continues to increase within our atmospheres, it also increases within our oceans, leading to an excess of carbonic acid, which acidifies the whole ocean. As the natural processes in place begin to struggle with the extreme amount of carbonic acid present in our oceans, the devastating effects of ocean acidification begin to be apparent. This causes vast ecological, economic, and humanitarian issues. However, as this problem grows, many potential solutions form. Over time, these solutions will mature and become effective at resolving climate change, and eventually, balance will be restored in our oceans.