26 September 2012 Ocean Acidification: Eating Away at Marine Ecosystems Posted by: Haley McKey | 1 comment | Share: by Haley McKey When you think of climate change, you think of more heat waves and droughts, extreme weather, and melting ice caps. But there’s another problem caused by carbon dioxide emissions, one which is less familiar to us, but no less catastrophic for our planet: ocean acidification. How it happens: Carbon dioxide (or CO2, its chemical formula) is released by the burning of fossil fuels and the clearing of forests and natural areas. Most CO2 goes into the earth’s atmosphere, but some is absorbed by our oceans; in fact, about a quarter of the carbon dioxide emitted every year. That comes to at least 5 million tons of CO2 absorbed every day. Algae and marine plants take up some of this CO2 for photosynthesis, just as land plants do. But a large amount of CO2 simply dissolves into surface seawater. This is what causes ocean acidification. When CO2 in the air is absorbed by the ocean, it bonds with water to form carbonic acid, the same stuff that gives an acidic bite to carbonated water and soda pop. Like all acids, it releases positively charged hydrogen atoms, leaving behind the bicarbonate ion. The problem is that many marine creatures make their shells from a substance with a slightly different chemical composition – calcium carbonate – and the bicarbonate formed by the extra acidity is useless at best, and downright dangerous at worst. Crustaceans like this sargassum crab need calcium carbonate to fortify their shells. Photo credit David S. Lee How it threatens wildlife: When the oceans have more bicarbonate and less carbonate, this interferes with the healthy growth of a variety of organisms, like mollusks (oysters and clams) and crustaceans (crabs, shrimp, lobsters and tiny krill, which are very important to the whole marine food web). Mollusks take in calcium carbonate, a molecule in ocean water, and excrete it over their bodies to form hard, protective shells. Crustaceans also use calcium carbonate to fortify their exoskeletons. But human activities have increased the acidity of the ocean by almost 30% making it more difficult it is for these creatures to create their natural armor. Even tiny zooplankton, the building blocks of marine food chains, need calcium carbonate and cannot grow properly in acidic seawater. Coral reefs may be in even more trouble. Corals secrete calcium carbonate skeletons over their bodies to protect them, just like mollusks and crustaceans do. Ocean acidification can cause corals to grow more slowly, and it is estimated that at current rates of increasing acidity, corals will no longer be able to lay down skeletons by 2150. Profound Effects: The animals directly harmed by acidification may be small, but the effects are far-flung. Baleen whales like the endangered Atlantic right whale depend on krill and plankton as a food source. We humans have built whole economies around shellfish, not to mention the hundreds of fish species we eat that depend on them for food, too. And as coral reefs die, the diverse and unique ecosystems they support can collapse. Ocean acidification pulls the rug out from under marine food chains and coastal economies. The only way to stop it is to make serious cuts to carbon emissions worldwide. If not, it won’t be long before species begin to disappear and many ocean systems collapse completely in their absence. One Response to “Ocean Acidification: Eating Away at Marine Ecosystems” Post Your Comment Click here to cancel reply. Name (required) Mail (required) (will not be published) You May also be interested in Two Too Many Development Projects in the Ivanpah Valley While these projects most definitely directly impact a species that has been identified as threatened and is dependent on the habitat where they would be built, Silver State South and Stateline’s approval is most troubling for a bigger reason. You see, this isn’t just an issue for the Ivanpah Valley. Developers and agencies need to be conscious of how and where they plan energy projects all across the country. They need to look at renewable energy planning with a landscape-wide lens, understanding that building in the right places and making an effort to minimize environmental impacts from the start are essential. California’s Rim Fire: Opportunities Rise from the Ashes After California’s devastating Rim Fire, will officials take the opportunity to give nature a chance to fully recover? What Montana Isn’t Saying: Why Wild Bison Aren’t Welcome in the State Montana is rounding up wild bison as they leave Yellowstone National Park and shipping them to slaughter. But why?