by TIM WHEELER, Bay Journal News Service
Restoring the Chesapeake Bay’s depleted underwater meadows is a painstaking process, requiring lots of elbow grease, savvy and patience.
Paradoxically, it begins by pulling up a little of what’s left of the critical aquatic habitat.
Standing knee-deep in the Wye River on Maryland’s Eastern Shore, Elle Bassett and a handful of helpers raked clumps of wispy green grass from the water one warm June day. They piled the vegetation, known as horned pondweed, in orange plastic baskets for transport by boat to shore.
“This one is easier than others to harvest,” noted Bassett, the Miles-Wye Riverkeeper. Some species of Bay grass are more firmly rooted in the bottom, she explained, and have to be collected one handful at a time.
For the last four years, Bassett and other staff and volunteers with the nonprofit group ShoreRivers have been working with experts from the Maryland Department of Natural Resources and Anne Arundel Community College learning how to restore Bay grasses.
“We’re doing what I would call a ‘technology transfer’” said Mike Naylor, a DNR biologist specializing in the Bay grass restoration effort who was on hand to help.
Now, with a $75,000 grant from the Chesapeake Bay Trust, ShoreRivers has ramped up its efforts, with a focus on mid and upper Eastern Shore waters. Their aim: to double the state’s overall restoration capacity.
A lot is at stake. Bay grasses, also known as submerged aquatic vegetation, or SAV, are a vital component of the Chesapeake ecosystem. They provide food and shelter for waterfowl, turtles, fish, blue crabs and other creatures.
They also consume some of the excess nutrients that foul the water, clearing it up and infusing it with fish- and shellfish-sustaining oxygen. For those reasons, the grass beds are closely monitored as an indicator of the Bay’s health.
Like the rest of the Bay, the grasses need all the help they can get.
Historical photos show that they once covered at least 185,000 acres of the bottom of the Chesapeake and its tributaries, and probably much more.
But by 1984, with the Bay suffocating from nutrient and sediment pollution, the coverage had dwindled to just 38,227 acres.
Bay grasses are so important to the estuary’s health that federal, state and local agencies and nonprofit groups have been trying for decades to restore them, with mixed results.
A few years ago, it looked like the Bay’s grasses were rebounding quite well on their own. By 2018, aerial surveys spotted underwater vegetation growing across more than 100,000 acres of Bay and river bottom, well on their way to achieving the restoration effort’s goal of having 130,000 acres by 2025.
Water quality has proven to be a major factor, both in the past decline of the Bay’s aquatic plants and in the recovery seen so far. Like upland vegetation, underwater grasses need sunlight to grow. But sediment or nutrient-fed algae blooms cloud the water, which stunts or even kills the plants.
“It really only required a modest improvement in water quality for SAV to improve,” noted Brooke Landry, a DNR biologist and chair of the federal-state Chesapeake Bay Program’s SAV workgroup.
But 2018 and 2019 brought heavy and persistent rains, which clouded the water and altered its salinity – another critical factor for sustaining certain species of underwater vegetation. The Bay’s grasses shrank by 40 percent in 2019 and by another 7 percent in 2020, the surveys found.
Now, manual grass-restoration efforts, which seemed almost superfluous just a few years ago, have taken on renewed importance.
“I think every little bit does help,” Landry said.
In Maryland, biologists at Anne Arundel Community College figured out how to raise Bay grasses from seeds collected from the wild. They set up an aquatic plant nursery there capable of producing batches of underwater vegetation.
“Instead of doing huge projects, we’ve been concentrating on small-scale restoration efforts of an acre or less,” Landry said. They’ve also chosen to skip the logistical challenges of raising aquatic plants in nurseries or classrooms and instead sow the seeds directly on the bottom.
The aim, she said, is to plant about 20 acres a year, roughly evenly divided between Maryland and Virginia.
“We started working with waterfront homeowners,” she explained, “planting little, tiny half-acre projects, just placing seeds offshore.” Those have worked, she said, in places like the upper Chester River.
“The hard part is collecting and processing seeds,” Landry added.
Complicating restoration efforts: Each river has a different type or mix of underwater vegetation – horned pondweed, widgeon grass, redhead and wild celery – each with its own characteristics and optimal growing conditions.
The grasses harvested by ShoreRivers staff and volunteers are being taken to Chestertown, where the group has forged a partnership with Washington College to process and store the seeds for replanting the next spring. They’ve built a “turbulator,” a sort of Rube Goldberg contraption on the grounds of the college’s new Semans-Griswold Environmental Hall. It is based on a prototype built by Anne Arundel Community College.
In the turbulator’s big, water-filled fiberglass tank, ShoreRivers staff and volunteers dump in batches of Bay grass to give them hot tub-like baths. Shopvacs churn the water, beginning the process of separating the tiny grass seeds from their stalks. The seeds and some plant matter sink to the bottom, where they’re drawn out by draining the tank.
Staff and volunteers must meticulously cull the seeds from plant debris by hand. They first sift them through a series of wooden trays lined with successively finer screens, much as miners pan for gold. Finally, they pore over them, trying to spy and winnow out seeds that don’t look like they’re ripe enough to germinate successfully later.
“Every seed counts,” said Amy Narimatsu, the group’s volunteer coordinator.