Oh My Oyster!

How pollution is affecting the oyster population

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The problem at hand....

Oysters are commonly known as one of nature's finest filters, but lately they've been biting off more than they can chew. With all the pollution being dumped into the waters, oysters are unable to do their job effectively. According to Ben Raines, " some of the nation’s estuaries are so overwhelmed with excess fertilizer that it would take more oysters than the bays can hold in order to purify the water." Adult oysters can filter 50 gallons of water a day. They oysters main job is to filter nitrogen that is contributed to the waterways by sewage treatment plants and farm fertilizers. In the water, Nitrogen fuels the growth of phytoplankton.
"The problem with nitrogen, he said, is that it fuels the growth of algae, which then dies and falls to the bottom, where it decays. The decay process consumes oxygen, leaving the water with too little oxygen to support fish and other marine life," Ben Raines says.
Bill Walton, a marine biologist who has also contributed to Raines' article states, ""Putting shellfish out in the system is a lot like putting sheep in an overgrown pasture. The sheep are going to graze down the excess plants. Removing nitrogen sounds like you are filtering a pollutant. You’re not. Essentially, the oysters are grazing down excess plants."

Why is this happening?

Oysters, like all other life, have minimum requirements to live; however, these requirements aren't being met. In bodies of water that are the most polluted, there is just not enough space to support the amount of oysters trying to exist in it. The carrying capacity is way over the limit. "oysters and other shellfish can be part of a strategy for managing nitrogen pollution, but cannot solve pollution problems alone," Raines says.
"In places like the Chesapeake, they are struggling to get a natural population back, to restore a historical population," says Dauphin Island Sea Lab scientist Ruth Carmichael, another coauthor of the study.
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