Posted on KCET: January 9, 2013 — By Cathy Hue
Our ocean is absorbing carbon dioxide at a rapid rate, and the window of opportunity to do something about it is getting smaller and smaller. Madeleine Brand follows how our changing ocean is affecting not only the marine organisms that live in it, but also the west coast shellfish industry and, ultimately, the seafood we eat. (Watch that segment here.)
At L&E Oyster Bar in Silver Lake, we spoke with chef Spencer about the luxurious, sensual, and appetizing appeal of the oyster. But local restaurants are becoming increasingly affected by the lack of local Pacific oyster supplies — the reason: ocean acidification. In a story we’ve been working on for “SoCal Connected,” we look at this process of atmospheric CO2 absorption, which results in lowered pH levels. We also examine the ramifications for farmers, researchers, and consumers of the popular mollusk.
In the last 200 years, the change in the pH level of our open ocean has dropped from 8.2 to 8.1, increasing the sea’s acidity. The .1 drop seems minimal, but the rate at which human activity and greenhouse gas production has caused this change is equivalent to millions of years of natural activity (i.e., volcanoes, breaking down of organic material). The carbon dioxide is absorbed by the ocean, and its chemistry is changing because of it.
This change becomes apparent when you look at flora and fauna that secrete skeletons with calcium carbonate — shellfish and coral among them. Scientists have seen a decrease in the population and size of these animals and in the amount of calcium carbonate in the water. Ocean acidification has had the biggest effect on Pacific oysters, the cultivation of which contributes $84 million to $111 million to the coastal economy. This would put more than 3,000 jobs in the region at risk, according to a 2011 study by the National Oceanic and Atmospheric Administration.
Like the shellfish themselves, the entire oyster industry is having to adapt. Carlsbad Aquafarm is diversifying their portfolio, adding abalone and mussels to their farm and depending less on oyster seed. Interestingly, higher C02‘s have even opened up a whole new business for them — seaweed. Also, though west coast oysters are not adapting too well to ocean acidification, sea urchins are. And given the trend of eating sea urchin roe in recent years, the spiny specialty may have no choice but to swim beyond the sushi bars and onto mainstream seafood lovers’ plates.