BALTIMORE – An annual aerial survey of Chesapeake Bay grasses has found they continued to decline last year, and researchers are again blaming a pair of 2011 storms.
Hurricane Irene and Tropical Storm Lee dumped mud and debris into the bay, and surveyors said Thursday that is the mostly likely cause for the 24 percent drop.
“Literally millions and millions of tons of mud came in [to the bay] with Tropical Storm Lee, particularly. And that clouded the water. These plants need sufficient light to grow,” says from Lee Karrh, biologist with the Maryland Department of Natural Resources and chair of the the Chesapeake Bay Program’s work group on grasses.
A more than 20 percent decline the previous year was blamed on the same storms and summer heat.
“In the lower part of the bay, we had a die off of Eel Grass due to heat stress in 2010, and we’re not seeing that recover,” Karrh says.
Underwater grass acreage has now dropped to levels last reported in 1986. The die-off was least severe in the southern bay, where new beds were found in the James River. Grass beds declined by nearly a third in the upper bay.
The grasses provide food and habitat for many species while absorbing pollutants and helping clear water.
“Bay grasses are an indicator of water quality … They are dependent on having clear water with very little algae, very little sediment, to grow,” Karrh says.