It's no secret that the health of the Chesapeake Bay has been in peril for decades, but ocean acidification poses what may be the greatest threat to the oyster population of the bay. Sadly, for most people this will go unnoticed. It's not like the obvious environmental threat of trees being cut or land being bulldozed. Damage occurring to oysters and other aquatic species can't be seen from a casual observation of the surface, but the threat is real. With water covering so much of the earth's surface it's easy enough for people to think that our waters can handle whatever we pour into them, but nothing could be further from the truth.

There have been a lot of efforts to protect and restore the Chesapeake Bay. Those efforts are noble. But they're not enough. It's beyond time to get serious about doing something. The time for studying is over. It's time for action.

The world's oceans are becoming more acidic, and that threatens the health of the bay. That's not just an environmental issue but an economic one as well. Healthy oysters provide food and jobs, and they help to filter out other nutrients and pollutants in the water.

Around 30 percent of the carbon dioxide in the earth's atmosphere is absorbed by the oceans, where it turns into carbonic acid, raising the acidity levels of the waters. Also contributing to acidification are the effects of agricultural runoff and sewage. Because of all of this, oceans are almost 30 percent more acidic than they were in the pre-industrial age from 250 years ago. There's no indication that this trend is slowing down. Without specific action, it won't.

What's the big deal about ocean acidification? Acidification of the bay makes it difficult for oysters to build their shells through the process of calcification. Young shellfish need calcium carbonate to form their shells. When acidic water reduces the amount of that needed element, shellfish are stressed as they try to form their shells. Oysters do act as natural filters for the waters of the bay, but they're in a fight to keep up with the pace of acidification. Increasingly that's becoming a losing battle. The stress of trying to form shells in acidic water is often fatal to shellfish. On the other hand, it helps the natural predators of oysters, such as blue crabs, to build their shells more quickly, upsetting the ecological balance.

From the time English settlers first arrived in Virginia, oyster shells have been stripped away from the bay and have not been replenished at a rate consistent with their removal. The oyster population that remains is but a small percentage of what once flourished in the waters of the bay. In fact, what remains is about 1 percent of the historical oyster stocks. This delicate situation is fragile at best.

It's going to take a great deal of effort and money to successfully reintroduce oyster shells to the bay. Oyster farmers are working to restore the population, but there are simply not enough oyster farmers to regulate the acidity in the bay given its enormous size. There is an immediate need for limits to be placed on greenhouse gas emissions, a consideration of carbon taxes and more conservation practices. This will take both federal and state action.

The time for the debate about taking care of the bay is over. Environmental science is clear about what needs to be done. But these actions require a human commitment. They require a commitment of the citizens as well as business and government.

The Chesapeake Bay is a beautiful and marvelous resource. It is both strong and resilient. But it can no longer be taken for granted. Steps need to be taken now, not later. Time is running out.

Michael Hild is the owner of Anderson's Neck Oyster Company, which is located on the Chesapeake Bay in Virginia. His email is michaelhild@andersonsneck.com.



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