Reducing the flow of fertilizers, animal waste, and other pollutants into the Chesapeake Bay is shrinking oxygen-depleted “dead zones” in America’s largest estuary, a new study finds. The bay’s health deteriorated during much of the 20th century, contributing to a drop in fish and shellfish populations.
When the algae die, their remains sink to the bottom, where they are consumed by bacteria. As they dine on algae, the bacteria utilize dissolved oxygen in the water. This leads to a condition called hypoxia, or depletion of oxygen. As this process continues through the spring and summer, the lack of oxygen turns vast stretches of the Chesapeake into dead zones. Hypoxia sometimes results in fish kills.
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