05/19/2020 | Environmental | 9 MINUTE READ

Understanding the Ocean Acidification Equation and Its Biological Impact


The impacts of climate change are already being felt all over the world. These impacts extend from poor air quality to damaged habitats throughout the environment. Among the largest reasons for climate change is ocean acidification, which is causing oceans around the world to become more acidic than they’ve ever been.

Even if you’ve heard of ocean acidification, you may not know that the process doesn’t actually start in the ocean. Acidification occurs when excess amounts of carbon dioxide enter the atmosphere. While carbon dioxide is essential for natural processes like photosynthesis, ocean acidification is brought about when carbon dioxide is being created more rapidly than it can effectively be absorbed. This process is creating problems with the ocean ecosystems and the marine life that lives within the oceans around the world.

While the process of ocean acidification can be difficult to understand, you can more readily know what it is by taking a look at the equation of CO2 + H2O -> (H+) + (HCO3-). When carbon dioxide reaches the ocean water, it forms what’s known as carbonic acid. The compound is then broken into hydrogen ions and bicarbonate, the former of which is what causes the oceans to become more acidic.

This article talks about ocean acidification and how it directly impacts the environment as well as the life inside the oceans.

Breaking Down the Ocean Acidification Equation

person holding piece of chalk for equations

To best understand what ocean acidification is, it’s important that you know about the equation behind this process. The equation itself is CO2 + H2O -> (H+) + (HCO3-). Ocean acidification is a process that results from too much carbon dioxide being absorbed into the water. Carbon dioxide is the CO2 in the equation. The water molecules that the carbon dioxide reacts with are the H2O in the equation.

When this reaction occurs, carbonic acid will develop, which has a formula of H2CO3. The carbonic acid compound further breaks down into bicarbonate and a hydrogen ion, the formulas of which are HCO3- and H+ respectively. The accummulation of hydrogen ions in the water results in the ocean water becoming more acidic. However, the bicarbonate molecule also causes a range of problems with marine life.

The Basic Chemistry of Ocean Acidification

fish under ocean dark water sea

Carbon dioxide is a chemical that’s naturally in the air and is needed for a variety of processes to take place. For instance, the photosynthesis process that plants require to grow and remain healthy is only accomplished by taking in a certain amount of carbon dioxide. However, the burning of fuels produces a substantial amount of carbon dioxide, which is then sent into the atmosphere. This carbon dioxide combines with the carbon dioxide that’s created when animals breathe.

Currently, there is more carbon dioxide within the atmosphere than ever before. The majority of the carbon dioxide remains in the atmosphere and slowly absorbs heat from the sun. The CO2 that’s currently in the atmosphere has created a blanket around the earth that is causing the temperature to increase. While most carbon dioxide remains in the atmosphere, around 30 percent of it falls down to ocean water, after which it dissolves into smaller CO2 molecules that eventually combine with others.

When the equation mentioned previously is brought about, the pH levels in the seawater begin to drop, which results in the water becoming more acidic. Some of the facts pertaining to ocean acidification that you should be aware of include:

  • Oceans are not naturally acidic and actually have a current pH reading of 8.06, which is slightly alkaline
  • The pH levels in ocean water are continuing to drop, which makes the water more acidic even though it still provides alkaline readings
  • Oceans are able to absorb carbon dioxide directly from the atmosphere
  • Carbon dioxide reduces the amount of carbonate ions in the water, which makes it difficult for shelled organisms like corals and mollusks to stay alive
  • Carbon dioxide decreases pH when it interacts with water and causes hydrogen ions to be created, which is a process that has resulted in a 30-35 percent increase in acidity since industrialization occurred
  • The changes are significant and are happening at a rapid pace

When combined with pollution, ocean acidification can be highly damaging, which is why wastewater treatment facilities are essential to ensure that some of the water within the water cycle has a minimal impact on the environment.

The Biological Impact of Ocean Acidification

dolphins in water ocean

The biological impacts of ocean acidification are substantial. While sea grasses and certain algae benefit from the higher amounts of CO2, almost every other facet of the ocean ecosystem is worsened by ocean acidification. For instance, pterapods are small sea creatures that are commonly referred to as sea butterfly. When pterapods are placed in water with carbonate and pH levels that match projections for the year 2100, the shell that surrounds the pterapod dissolves within just 45 days.

Corals are marine organisms that create their own skeletons and shells from calcium carbonate. When carbon dioxide increases the ocean water, calcium carbonate decreases, which has resulted in corals and similar organisms having difficulties creating their skeletons. While most of the negative effects of ocean acidification affect shelled organisms, all marine life is negatively affected by this process. All species require time to adjust to new pH levels in the water. However, carbon dioxide is reaching ocean water at a very fast rate, which doesn’t provide marine life with enough time to adapt to the changes in the water.

As for humans, ocean acidification affects the food that we eat by damaging the ability for shelled organisms to create their shells in the first place. The damage that acidification does to coral reefs is also problematic because of the role that these reefs play in medicine, tourism, food, and coastal protection. At the moment, ocean acidification is an emerging problem around the globe that will continue to have negative impacts on the ocean unless substantial measures are taken.

Why Ocean Acidity Matters?

adult hand in front of ocean background

The majority of chemical reactions can change significantly with even a small alteration of pH levels. For instance, normal pH levels for blood extend from 7.35-7.45. If these levels drop by just 0.2-0.3, it’s possible for someone to slip into a coma or suffer from a seizure. The same is true when ocean water starts to become more and more acidic. As mentioned previously, likely the most harmful issue of lower pH levels is that certain marine creatures are unable to build their skeletons.

Shelled organisms require carbonate ions to complete these processes but cannot extract these ions from the bicarbonate that’s produced by ocean acidification. You should care about ocean acidity because of how it negatively affects the entire ocean ecosystem. In order for this ecosystem to remain healthy on a long-term basis, ocean acidification needs to be reduced and pollution must be substantially decreased. Otherwise, marine life will continue to suffer, which will have an impact on everything.

The Future of Our Oceans

photo of fish in ocean sea

In order to maintain ocean acidification and eventually increase pH levels, it’s important to stabilize the amount of carbon dioxide that’s in the atmosphere. Once carbon dioxide reaches optimal levels, the pH in ocean water will return to its normal readings. In the past, the oceans were able to adapt to gradual changes in pH levels. However, the levels are currently dropping too rapidly, which is why additional measures must be taken to protect the future of the oceans.

The two primary steps that we can take include:

  • Cutting carbon emissions
  • Geoengineering

Back in 2013, carbon emissions reached 400 PPM in the atmosphere, which is much higher than the safe level of 350 PPM. If the oceans didn’t absorb a significant amount of carbon dioxide, it’s estimated that CO2 levels in the atmosphere would be as high as 475 PPM.

Likely the easiest way to reduce carbon emissions is by finding additional carbon sinks and burning a lower amount of fossil fuels. Carbon sinks can be obtained by regrowing marshes and mangroves. Even if these measures are taken immediately, carbon dioxide would take hundreds of thousands of years to fully stabilize.

As for geoengineering, this process involves actually developing technologies that can reduce carbon dioxide in the atmosphere. In order for geoengineering to be viable, planetary systems will need to be manipulated. For instance, one method of geoengineering involves reflecting sunlight back into space directly from the atmosphere. This would only reduce the amount of carbon dioxide to reach the atmosphere without reducing the amount that’s already in the atmosphere. Another form of geoengineering involves growing more organisms that require carbon dioxide to survive, which include phytoplankton. This particular method would be able to get rid of some of the excess carbon dioxide that’s currently in the atmosphere.

What Can You Do?

Ocean acidification affects marine life and human life alike. If you’re interested in doing your part to protect the environment and reduce the amount of carbon emissions that are sent into the atmosphere, there are numerous things that you can do every day to lessen the effects. For one, make sure that you reduce your energy use as much as possible by using public transportation, turning off lights when you’re not using them, and recycling. You could also support clean energy whenever possible, which could include installing solar panels onto your roof.

Your main goal should be to reduce your carbon footprint, which can be measured on this website. Think about taking what you’ve learned in this article and spreading it around to your friends and family. If they know about ocean acidification and the adverse effects it has on everyone, they may also be willing to do their part to reduce carbon emissions.

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Posted by Sensorex on May 19, 2020

Sensorex is a global leader in the design and manufacture of quality sensors for water quality and process applications. The company offers more than 2000 sensor packages for pH, ORP, conductivity, dissolved oxygen, free chlorine, chlorine dioxide, UV transmittance and other specialty measurements, as well as a full line of sensor accessories and transmitters. Its expert technical support engineers solve analytical sensor challenges with custom designs and off the shelf products.

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