Underwater grass in the Chesapeake Bay continues to recover, report says
The gently waving underwater grasses of the Chesapeake Bay continue to recover after heavy rains destroyed almost half their volume in 2018 and 2019.
The Virginia Institute of Marine Science recently released the results of its 2022 submerged aquatic vegetation survey, finding a 12% increase in blooming acreage after last year’s study showed an increase of 7%. The bay lost 42% of recorded grasses in 2019.
Grass volume is a good indicator of the watershed’s overall health, according to a report from the Chesapeake Bay Program. Grasses are sensitive to climate conditions and pollution but are quick to respond to water quality improvements.
Less rain and cooler temperatures are boosting the growth of the grasses, which need water clear enough for sunlight to reach them. Storm runoff, especially from intense bouts of rain, can cloud the water.
Underwater grasses, such as widgeongrass and eelgrass, are vital to the bay’s ecosystem. They absorb pollutants, counteract wave energy and provide a habitat for marine life, including juvenile blue crabs.
Areas with saltier water showed greater recovery, while freshwater areas continued to lose volume, the survey showed. Researchers aren’t sure why, but believe it may have something to do with increased sediment in the evaluated freshwater areas.
Christopher Patrick, the director of the institute’s Submerged Aquatic Vegetation Monitoring and Restoration Program, attributes the recovery to the current cooler La Niña climate pattern. That pattern was in effect for about the last three years before recently transitioning to a neutral pattern, according to the National Weather Service.
The pattern is currently transitioning to an El Niño period, bringing weaker trade winds and warmer water in the Pacific around the Western U.S. That make the grasses’ recovery difficult, Patrick said in an institute report.
“The real test for those zones will be summer 2024 when hot summer temperatures, a known stressor of eelgrass, return with the predicted El Niño cycle,” he said.
The increase in intense storms because of climate change will continue to challenge recovery, said Brooke Landry, chair of the program’s Submerged Aquatic Vegetation Workgroup, in the report.
Residents’ use of rain barrels or rain gardens can slow the rate of stormwater runoff, the report stated. Localities can help by upgrading pollution-reducing technology and strategies, especially in wastewater plants.
Katrina Dix, 757-222-5155, katrina.dix@virginiamedia.com
