Can Oysters Boost the Recovery of the Chesapeake Bay?

The Chesapeake Bay Dead Zone

Once again, the Chesapeake Bay, the United States’ largest estuary, is battling a dead zone. Generally happening each July, this year’s dead zone is the second largest measured since 1985.

Dead zones, a common phenomenon during summer months, happens as water temperatures rise and oxygen levels in the water drop. Warmer water, which holds less oxygen than cooler water, is only part of the equation that creates hypoxia.

The Chesapeake Bay, spanning 64,000 square miles and covering six states, is subject to an array of human activities that cause an excess of nutrients (nitrogen and phosphorus) to be present in the water. Excess nutrients create the perfect growing environment for harmful algal blooms which block sunlight from reaching aquatic plants that create oxygen beneath the surface.

Excess nutrients and recent consecutive days of triple digit weather that warmed the bay’s waters to 90 degrees have created a dead zone worthy of concern as fish and other aquatic life cannot survive without oxygen.

On the Road to Recovery

The Chesapeake Bay is historically known for its yearly dead zones, but years of work have been put into cleaning up the bay and increasing water quality. Before this year’s dead zone, the bay’s water quality was the highest since monitoring began 30 years ago. As a result of restoration efforts, this year’s crab population doubled and aquatic grasses (a good indicator of pollution or good water health) increased to over 100,000 acres.

In 2010 the U.S Environmental Protection Agency instituted a total maximum daily load pollution limit in the bay which put a cap on the amount of nitrogen, phosphorus, and sediment pollution the water could handle before it became unfit to support aquatic life.

This limit has required many to take action to reduce the amount of pollution entering the water which has increased the water quality over time. Although this year’s water quality results were something to celebrate, at least early on, there is still work to be done and some think oysters might help get the job done.

Can Oysters Help Clean the Chesapeake Bay?

Oysters and shellfish act as natural water purifiers and have been explored by many as a cost-effective way to clean waterways. A recent study by The Nature Conservancy and the Virginia Institute of Marine Science found that for every 100,000 oysters grown and harvested annually, six pounds of pollution from nitrogen and phosphorus would be eliminated from Chesapeake Bay waters.

Although this is not a whole package solution to the water quality issues of the bay, an increase in oyster aquaculture may help boost the recovery of the bay alongside the other restoration efforts already in place.

Oxygen Management, One Buoy at a Time

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