OCEAN ACIDIFICATION & WHY IT MATTERS

CRYSTAL CLEAR

By Abrar Hasanat

It’s common knowledge that the increase in carbon dioxide is dangerous for Earth. All of us know the common effects of the gas - from global warming to various health-related issues - CO2 has played its part in many detrimental things. However, we often miss one of, if not the most dangerous impact of the increasing CO2 - and that is Ocean Acidification and its effect on marine ecosystems.

According to Brittanica, “Ocean Acidification is the worldwide reduction in the pH of seawater as a consequence of the absorption of large amounts of carbon dioxide (CO2) by the oceans.”₁

Now if we’re being honest, the oceans are in trouble. Every YEAR, 2.6 billion tons (you read that right!) of carbon dioxide gas is being released into the atmosphere by vehicles, factories, industries, and other sources.₂ The ocean absorbs about 40% of that carbon dioxide. As levels of atmospheric CO2 increase from human activity such as burning fossil fuels and changing land use (e.g., deforestation), the amount of carbon dioxide absorbed by the ocean also increases. When CO2 is absorbed by seawater, a series of chemical reactions occur resulting in the increased concentration of hydrogen ions.₃

As we know, the easiest and most widely used scale to determine whether something is acidic or basic is the pH scale - which is an inverse of the hydrogen ion concentration. So it basically means: more hydrogen ions = higher acidity and a lower pH. (Below 7 is acidic and above 7 is basic on a pH scale).₄

That’s bad news for the aquatic ecology. Many creatures who live in the oceans are quite sensitive to even the most subtle of changes in the acidity of the water. Increased acidity causes the shells and skeletons of several marine organisms to dissolve. It’s especially problematic for corals, oysters, and other creatures with delicate carbonate shells or skeletons, which are weakened by even very slight changes in the ocean’s acid balance.₅ Animals that produce shells have to spend extra energy either repairing their damaged shells or thickening them to survive. Using energy for this could impact the animals' abilities to grow and reproduce. Animals able to survive and reproduce in more acidic waters are likely to become smaller, potentially affecting the food chain that relies on them.₆

In the 200 years since the industrial revolution took place, the concentration of CO2 gas increased substantially in the oceans. As a result, the pH of the surface level ocean water has fallen by 0.1 pH units. Now it doesn’t sound like much - but it’s a logarithmic scale - so this translates to an approximate 30% increase of acidity in the water which is VERY dangerous for aquatic beings.₃

Two significant ecosystems, coral reefs and polar regions, are on the front lines of the acidification issue. Coral reefs critical to the protection of coastlines across tropical and subtropical parts of the world will fade as the rate of decay surpasses the rate at which corals can rebuild — with staggering consequences for related ecosystems like mangroves and seagrass. Meanwhile, in the north and south polar regions, marine plankton will be lost; some are already becoming thinner and with weaker shells. For example, pteropods are an important staple in the diet of salmon, mackerel, herring, cod, and baleen whales.₇

You can easily guess the impact of ocean acidification when you compare the following picture of the Great Barrier Reefs from a decade ago (left) to one taken in 2017 (right).

Ocean acidification isn’t only harmful to marine life, but also to human beings. Marine food production from oysters and mussels will reduce drastically. Coral reefs will be damaged, weakening the protection they provide our coastlines. The tourism industry will be affected by the destruction of marine life forms. A big number of tourists visits various places like the Great Barrier Reef or the Rainbow Reefs of Fiji just to see the beauty of the magnificent coral reefs. These surely have a big impact on local tourism, which will be greatly affected due to the destruction of such life forms.

Moreover, the oceans capacity of absorbing CO2 from the atmosphere decreases as ocean acidification increases. Thus the ocean will subsequently lose its capacity of absorbing CO2, which might result in a catastrophic situation because more acidic oceans will be less effective in moderating climate change - given the fact that they won’t be able to absorb the ever-growing amount of CO2.₈

Unfortunately, the future is not bright, it holds far more difficult challenges. Estimates of future carbon dioxide levels indicate that by the end of this century the surface waters of the ocean could have a pH of around 7.8, or more than 150 percent compared to today’s already corrosive state—and potentially even more, in some particularly sensitive parts of the planet, like the Arctic Ocean. The last time the ocean pH was this low was during the middle Miocene, 14-17 million years ago.₃,₅ Do you know what was happening back then? The entire planet was several degrees warmer and a major extinction event was occurring. 

Ocean acidification is a major, yet less discussed aspect of climate change. We should start taking significant steps and initiate larger campaigns in order to prevent a catastrophe that is just waiting to happen. We should always remember that anything we do to mitigate climate change today - will have a huge effect on the future of Earth and human beings.

Works Cited

1. “Ocean Acidification.” Encyclopædia Britannica. Encyclopædia Britannica, inc. Accessed August 1, 2021. https://www.britannica.com/science/ocean-acidification.

2. “2017 State of the CLIMATE: Ocean Uptake of HUMAN-PRODUCED CARBON: NOAA Climate.gov.” 2017 State of the climate: Ocean uptake of human-produced carbon | NOAA Climate.gov, August 1, 2018. https://www.climate.gov/news-features/featured-images/2017-state-climate-ocean-uptake-human-produced-carbon.

3. “Ocean Acidification.” Ocean acidification | National Oceanic and Atmospheric Administration. Accessed August 1, 2021. https://www.noaa.gov/education/resource-collections/ocean-coasts/ocean-acidification.

4. “What Is the Difference between ‘Magma’ and ‘Lava’?” USGS. United States Geological Survey. Accessed July 30, 2021. https://www.usgs.gov/faqs/what-difference-between-magma-and-lava?qt-news_science_products=0#qt-news_science_products.

5. Borunda, Alejandra. “Ocean Acidification Facts and Information.” Environment. National Geographic, May 4, 2021. https://www.nationalgeographic.com/environment/article/critical-issues-ocean-acidification.

6. “How Does Ocean Acidification Affect Marine Life?” Natural History Museum. The Trustees of The Natural History Museum, London. Accessed August 1, 2021. https://www.nhm.ac.uk/discover/quick-questions/how-does-ocean-acidification-affect-marine-life.html.

7. “OCEAN ACIDIFICATION.” Center for Biological Diversity. The Center for Biological Diversity. Accessed August 1, 2021. https://www.biologicaldiversity.org/campaigns/endangered_oceans/index.html.

8. “Ocean Acidification and Its Effects.” CoastAdapt. National Climate Change Adaption Research Facility & Australian Government: Department of the Environment and Energy, April 27, 2017. https://coastadapt.com.au/ocean-acidification-and-its-effects.