Stress caused by ocean acidification endangers marine organisms

Even a little too much carbon dioxide in the Earth’s atmosphere may become a big problem for our oceans as well as the waters around Tampa Bay.

Carbon dioxide does not simply build up in the air. It also enters the seas, where it changes into chemicals such as carbonic acid, bicarbonate and one called carbonate, which is responsible for shell growth in oysters as well as the limestone structures of Florida’s coral reefs.

As more carbon dioxide diffuses into the marine ecosystem, the chemical balance is changing. More carbonic acid is forming, which reduces carbonate. The stress caused by this ocean acidification endangers marine organisms and habitats as shells and reefs begin to dissolve in this new seawater chemistry.

Seawater’s acidity/alkalinity — its pH— is measured on a logarithmic scale. This means that a change in pH from 9 to 8 is 10 times more acidic, and a change from 9 to 7 is 100 times more acidic. Even a pH change from 8.2 to 8.1 is a massive shift.

As Florida is surrounded by seawater and economically supported by the billions of dollars earned each year with marine-based industries developed around tourism, boating and fishing, the unabated increases in carbon dioxide could quickly begin to affect the state economy.

This is not the first time that the Earth has experienced ocean acidification due to a high concentration of atmospheric carbon dioxide. A similar event happened 55 million years ago at the Paleocene-Eocene boundary. (A bit of context: The earliest primates emerged at this time, the horse’s ancestor was about the size of a dog, and dinosaurs had been extinct for about 10 million years).

Over a period of 8,000 years, an increase in atmospheric carbon dioxide and methane led to mass extinctions of benthic (seafloor-dwelling) marine organisms, ranging from 30 to 55 percent of all such species. Several factors are considered to have caused the increase in atmospheric carbon dioxide and methane: volcanic activity, changes in ocean circulation and the release of frozen methane deposits.

This time, high concentrations of atmospheric carbon dioxide are expected to be reached in fewer than 300 years — not 8,000.

In a relatively short time we could see devastation to our ocean’s ecosystems. Studies have already shown that our present acidifying ocean has begun to stress marine life today.

People may be the problem, but they can also be the solution. In 1997, the Kyoto Protocol was adopted internationally to stabilize and control, in part, carbon dioxide emissions. The United States never ratified the treaty.

While the United States itself is not a party to the treaty, many cities are, on their own, promising to meets its standards. Seattle Mayor Greg Nickels founded the United States Conference of Mayors’ Climate Protection Agreement (USCMCP), and more than 1,000 American cities have all vowed to reduce industry carbon dioxide emissions with standards and time frames conforming to the Kyoto Protocol. This includes Miami, Tallahassee, Tampa and West Palm Beach.

There is also hope in private industries. For example, a high-tech company called Solix Biofuels has partnered with New Belgium Brewing Co. in Fort Collins, Colo., to turn waste — the carbon dioxide produced in brewing beer — into energy by “feeding” it to a type of algae that naturally contains high lipid levels, which then allow biofuel to be created from the algae’s lipids (oils). The requirements to grow the algae consist of an exposure to the sun, water and carbon dioxide. Carbon dioxide is naturally emitted in the brewing process, and from it, energy is produced as the algae grow, which is then used to make more beer.

Algae biofuel has the potential to be many times more efficient than other biofuels. According to the U.S. Energy Department, if algae biofuels replaced other alternative fuel crops, they would yield up to 30 times more energy. This would equate to an area in the United States as big as Maryland, or 15,000 square miles needed to supply energy to the United States.

Innovative ideas such as these can grow new businesses and keep carbon dioxide from acidifying and endangering the world’s oceans and the marine life they harbor.

Paul Suprenand is a Ph.D. student at the University of South Florida. He is researching marine organisms in the Eastern Tropical Pacific, the Gulf of Mexico and Antarctica that may show early indications of ocean acidification stress. Joanie Kleypas, who will lecture at USF on Thursday, was his supervisor for an internship with the National Center for Atmospheric Research, in Boulder, Colo., and introduced him to the concerns and topics in research pertaining to ocean acidification.

Listen to lectures:

Ice sheets and sea level; ocean acidification

On Wednesday and Thursday, the University of South Florida College of Marine Science is hosting an eminent scholars lecture series on the twin topics of ice sheets and sea level rise and ocean acidification. The lectures will be held at the Karen A. Steidinger Auditorium at the Florida Fish and Wildlife Research Institute, 100 Eighth Ave. SE, St. Petersburg. Call (727) 553-1130 or go to for more information. All lectures are free and open to the public.

Paul Suprenand,, 2 March 2010. Article.

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