Underwater grass abundance in the Chesapeake Bay surged to a record for the second straight year, continuing a four-year trend of improving numbers, according to a new survey released Thursday.
Researchers at the Virginia Institute of Marine Science say seagrass beds in the bay expanded overall by 8 percent from 2015 to 2016 to about 97,433 acres. That’s 7,433 more acres than the 2017 restoration goals set under the Chesapeake Bay Program to restore the estuary and the highest number VIMS has ever recorded.
In fact, actual abundance numbers are likely even higher, researchers say, because there were portions of the Potomac River they weren’t able to survey this time because of weather and security restrictions. If you factor in old 2015 figures for those unsurveyed areas, they said, it would likely bring abundance up to 99,409 acres, or 54 percent of the goal.
Robert “J.J.” Orth calls the achievement “fantastic.” Orth heads up the seagrass monitoring and restoration program at VIMS.
“We are at numbers that we have not seen in — ever,” Orth said. “I think it’s pretty impressive, and I think it speaks a lot to the fact that we think that the efforts to clean up the bay, the TMDLs, probably are working.”
TMDLs are the total maximum daily loads imposed by the U.S. Environmental Protection Agency on Virginia and other bay states in 2010 after they had failed for decades to come up with ways to curb watershed pollutants.
Each jurisdiction devised its own blueprint for meeting antipollution goals, such as curbing discharges from wastewater treatment plants, stormwater and agricultural runoff. Recent studies indicate those measures are working, and the bay health is improving.
CBP Director Nick DiPasquale said state and community pollution control measures have reached a “tipping point” in bay health.
“What we are doing is working,” DiPasquale said in a statement. “We just need to do more of it.”
Driving the meteoric rise in overall abundance, Orth said, is a near-tripling in widgeongrass abundance in the moderately salty waters of the middle and lower bay, which includes Hampton Roads, where widgeon grass and eelgrass are the predominant species.
Researchers divide the bay into four distinct salinity zones for the survey — tidal fresh, slightly salty, moderately salty and full salinity — the better to connect changes in grass communities and growing conditions.
Not every zone showed improvement in 2016, though. The large increase in the moderately salty zone was offset by slight decreases in the slightly salty and full-salinity zones. Meanwhile, the tidal fresh zone increased slightly.
It’s also not clear if the record overall trend will continue. Widgeon grass is considered a “boom or bust” species that can experience dramatic die-offs for reasons scientists still can’t explain.
“We keep waiting for the crash,” Orth has said. “But it hasn’t happened.”
It could be that…