Ocean Acidification in the Caribbean

By Dawn-Marie Alexander

Ocean Acidification is sometimes referred to as Climate Change’s equally evil twin. Yet, it is not discussed equally as much. Twenty-two of the world’s leading marine scientists warn that we are not paying attention to the importance of ocean acidification. At first, many scientists thought that ocean acidification was a good thing, as they believed that it would leave less carbon dioxide in the atmosphere. But, they soon realized that this phenomenon, which was once naturally occurring, was accelerated by man during the industrial revolution. This phenomenon has impacted the pH and overall chemistry of oceans, causing immense damage that calls for immediate change.

Since the onset of the Industrial Revolution, humans burnt coals in notably large quantities, thus increasing the CO2 levels in the atmosphere. The levels of CO2 found in the ocean therefore increased anthropogenically, resulting in oceans becoming marginally more acidic over a substantial amount of time. Prior to this, CO2 in the atmosphere was calculated to be 280 parts per million (ppm) but as humans increased their use of fossil fuels, the CO2 concentration has increased to approximately 400ppm (and the growth rate has not stopped accelerating). When these high levels of CO2 combine with seawater, chemical reactions occur that results in the reduction of the sea water’s pH.

According to scientists, the ocean is currently absorbing around 1/4 of human CO2 emissions. According to the Woodshole Oceanographic Institution (WHOI), “had the ocean not absorbed these vast quantities of CO2, the atmospheric concentration would be even higher, and the environmental consequences of global warming would be more pronounced” (2018). Therefore, humans have actually benefited from the ocean’s capacity to hold on to a large amount of carbon dioxide. But despite all this, the ocean cannot continue to absorb CO2 at this rate without undergoing significant biological and chemical changes.

The atmospheric concentration of CO2 is now higher than it has been for the last 800,000 years! This has put a detrimental strain on marine organisms such as shellfish and corals in the region, as this rising seawater acidity impacts their ability to build shells and skeletons. Corals, in particular, grow their skeletons upwards towards sunlight and also thicken them for reinforcement. Research led by scientists at WHOI shows that ocean acidification hinders the thickening process which ultimately decreases the skeleton’s density and leave them susceptible to breaking.

Coral reefs are one of the most diverse ecosystems on Earth and holds considerable economic, ecological, and cultural value. Consider our Buccoo Coral Reef off the South-western coast of Tobago, it has long been known as a tourist attraction but as if recent years it too has been a victim to ocean acidification. As a result of the strain we’ve put on our reefs, their rate of bio-erosion and dissolution could increase, which would evidently be harmful to marine life and further increase the levels of CO2 in the atmosphere (and we know how that goes!).

Furthermore, the chemical of the ocean is greatly affected by ocean acidification. Seawater has an average pH of 8.2 because of the weathering of continental rocks. Since industrialization, this average has decreased to 8.1. Considering that the pH scale is logarithmic, this decrease represents a 26% increase in acidity (which is a rate 100 times faster than anything the ocean and its inhabitants have experiences in millions of years!).

Given that our ocean is the largest ecosystem on earth, it is imperative that we come together and take action for change:

1. Cut down energy: Fossil Fuels are burnt to produce energy; this, therefore, makes it a major contributor to ocean acidification. Using less energy would ultimately decrease the amount of fossil fuels burnt (plus, it’s economical)).

2. Reduce, re-use, recycle: This method that reduces pollution also applies to ocean acidification. Using less products will decrease the demand for new product materials, altogether decreasing carbon emissions in the atmosphere.

3. Ride a bike or take a walk: Try driving less, carpooling or using public transportation to decrease the levels of CO2 that emit from vehicles into the atmosphere.

Ocean acidification is another serious effect of excess CO2 in the atmosphere. Yet, it is constantly disregarded, leaving our oceans and their inhabitants constantly threatened by the uncomfortably low decrease in pH. Right here in the Caribbean, our coral reefs are in danger of losing their ability to produce their skeletons and ultimately diminishing. If we do not make an active effort to decrease CO2 emissions, these reefs would go extinct!

References

Humans can take action to slow the process of ocean acidification | Climate Interpreter. (2018, December 20). Climate Interpreter. https://climateinterpreter.org/content/humans-can-take-action-slow-process-ocean-acidification

Latin American and Caribbean countries threatened by rising ocean. (2018, August 21). IUCN. https://www.iucn.org/news/secretariat/201804/latin-american-and-caribbean-countries-threatened-rising-ocean-acidity-experts-warn

Ocean Acidification. (n.d.). Woods Hole Oceanographic Institution (WHOI). https://www.whoi.edu/know-your-ocean/ocean-topics/ocean-chemistry/ocean-acidification/

Scientists Pinpoint How Ocean Acidification Weakens Coral Skeletons. (2018, January 29). Woods Hole Oceanographic Institution (WHOI). https://www.whoi.edu/press-room/news-release/scientists-identify-how-ocean-acidification-weakens-coral-skeletons/