The Shellfish Know Climate Change is Real

by s.e. smith March 1, 20137:00 pm

  
You might think that laypeople are hard to convince when it comes to talking about climate change and related phenomena, like ocean acidification, but in fact, they’re often more in-tune with these issues than the researchers who talk about the issue at big conferences. That’s because they can see the real-world effects in action. Take people who work with shellfish, for example, including those who dig wild clams, harvest shellfish from wild beds and manage oyster farms and similar facilities. In recent years, they’ve been noticing a number of problems with their precious shelled cash cows, and all of those problems trace back to one thing: ocean acidification.

What exactly is ocean acidification? As carbon dioxide, much of it from human sources, builds up in the atmosphere, it eventually dissolves into waterways. Once it reaches the water, a chemical reaction takes place, causing the water to become more acidic. Some researchers refer to this phenomenon as “the other CO2 problem,” contrasting it with global warming, caused by the carbon dioxide that remains in the atmosphere.

In the wild, organisms known as calcifiers, which use calcium carbonate in their shells and skeletons (think shellfish and corals) rely on a very specific and stable ocean pH of around 8.2. When the pH drops, they have trouble forming shell matter, and can develop problems like weak or crushed shells. Larvae may never fully develop, and others can be vulnerable to infection and disease. In some cases, marine organisms are actually dissolving in corrosive water. Coral dieoffs have been observed in several regions of the world, as have problems with shellfish, a potentially serious commercial as well as environmental issue.

Shellfish, after all, play a vital role in the ocean environment. Many filter and clean water, making it safer for other organisms by sequestering toxins. They can filter nitrogen out of the water, addressing nitrogen pollution caused by humans, and of course they’re a tasty food source for numerous other ocean organisms. Researchers view them as a keystone species. If their numbers dwindle, that’s an indicator that something is very wrong, and that things could go much worse.

For people who rely on shellfish for an income, the need for a fix for these issues is critical. Today, they’re using techniques like controlling water flows, monitoring conditions carefully and adding components to the water on shellfish farms to help their charges grow and develop to full size. But pros recognize the problem is much larger than this, and if we don’t find a fix soon, their way of life is likely to disappear.

Already, the ocean’s pH has dropped to around 8.1 on average, which is a significant change. By 2100, it could be as low as 7.8 worldwide, and life as we know it in the world’s oceans could be changed forever. That’s terrible news, because the oceans are incredibly complex and diverse, and we rely on them to sustain life on Earth far more than we may realize. Many industry professionals, consequently, have joined with scientists to raise awareness about acidification and related issues, and to search for a way to combat the problem before it’s too late.