Lowest Chesapeake Bay ‘Dead Zone’ levels in nearly 20 years

The Chesapeake Bay is a much healthier place for fish this year. The 2015 dead zone level is the fifth lowest since officials started keeping records in 1985.

Dead zones are created when too many nutrients (such as fertilizer and waste) wash into regional streams and rivers. They suck the oxygen out of the water when they flow into the Bay and fish can’t live in those sections.

Chesapeake Bay dead zone (oxygen) report
Dead Zones are orange and red. The lower graph shows depth of the dead zones. The deepest parts of the Bay typically have low oxygen levels. Due to high winds in June, some areas of the Bay weren’t tested. That explains the grey areas. (Graph courtesy Maryland Department of Natural Resources)

Scientists believe the better results this year are mainly due to lower than normal water flows down the Susquehanna River this past Spring. That resulted in about 10% less nutrients mixing into the Chesapeake Bay. Also helping — our colder than average winter kept more oxygen in the water and the windy June stirred up waves which pulled oxygen deeper into the water.

(Graph courtesy Maryland Department of Natural Resources)
Longer bars show more Dead Zones found in the Chesapeake Bay. 2015 levels are best in 17 years, the 5th best since measuring started in 1985. (Graph courtesy Maryland Department of Natural Resources)


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