Wild celery grass restoration underway in the Delaware Estuary
The plant is both an indicator of water quality and an improver of it
| June 20, 2022
In a small classroom at the Center for Aquatic Sciences at Adventure Aquarium in Camden, N.J., the early stages of a massive science project are underway. In eight clear plastic totes equipped with bubblers and lights, rows of wild celery grass, Vallisneria americana, wave bright and green.
This plant is among the most important species of submerged aquatic vegetation in freshwater and estuarine ecosystems. It provides habitat for fish and organisms that live on the river bottom and food for waterfowl (the canvasback duck species, Aythya valisineria, was named after the plant); clarifies water by filtering sediment; increases dissolved oxygen and stores carbon.
It’s both an indicator of water quality and an improver of it.
And somewhat surprisingly, it’s thriving in some parts of the 27-mile stretch of the Delaware River from the Tacony-Palmyra Bridge in Palmyra, N.J., and the Commodore Barry Bridge in Chester, Pa. That stretch is designated unsafe for primary contact for activities such as jet skiing, kayaking and swimming, which are referred to as “primary contact recreation.”
The US EPA Mid-Atlantic Region found the celery grass in 2017 during a survey of the estuary by boat using an echo sounder to detect vegetation. For the past five summers, researchers have continued their surveys, building baseline data and making it available to the public via online maps.
“When we saw it, we were stunned at the abundance of the grasses,” said Don Baugh, founder and president of Upstream Alliance, a local nonprofit focused on public access, clean water and coastal resilience. In collaboration with the Center for Aquatic Sciences and with support from the EPA’s Mid-Atlantic team, the alliance is leading efforts to repopulate more areas of the Delaware estuary with this crucial plant.
For decades, people have been working to restore grasses in estuaries like the Chesapeake Bay where Baugh helped launch restoration efforts known as Bay Grasses in Classes in his former role directing education programs for the Chesapeake Bay Foundation.
But in the Delaware River watershed, there have only been a few unsuccessful attempts so far. “It’s really the blank canvas of the Delaware River that’s fascinating,” Baugh said.
The plants currently in tanks at the aquarium are destined for three locations on the back channel — one near where the grass is currently thriving as a sort of control, and two in barren locations — and another one near the new Cramer Hill Waterfront Park. They’ll be planted by members of the EPA’s dive team later this month.
The initial phase of the project is funded by part of a $15,000 grant from the National Fish and Wildlife Foundation for the alliance’s work on the Camden River Water Trail, a project by Camden County to create a 13-mile trail with water access points to encourage recreation around the back channel that runs between Camden and Petty Island and Cooper River parks.
The long-term goal is to repopulate wild celery grass in the back channel and to encourage more restoration projects by other organizations, ultimately repopulating wild celery grass in all areas of the Delaware estuary that will support it.
For the next couple of years, though, the focus is on gathering information; namely, how to best propagate the plants as well as where and how to plant them.
“We’re kind of making it up,” Baugh said. “You use the best science and the best historical information, learning from the people who’ve tried it in different places, and you make your best guesses — but that’s kind of what science is.”
Experimenting with harvesting and growing
The wild celery plants at the aquarium were grown from turions, or winter buds, that the team collected from a patch of celery grass thriving in the U.S. Army Corps of Engineer’s slip at Fort Mifflin. The area was slated to be dredged, and, because submerged aquatic vegetation, including wild celery grass, is protected as essential fish habitat in the Magnuson-Stevens Fishery Conservation and Management Act, the Corps of Engineers was required to mitigate harm of this bed of grass. Allowing the team to harvest the plant’s winter buds served as its mitigation effort.
The first day of fieldwork was Jan. 20. “It was freezing cold,” said Anthony Lara, experiential programs supervisor at the Center for Aquatic Sciences and the main caretaker of the wild celery plants.
Lara and Upstream Alliance and EPA team members used rakes wrapped in chicken wire to pull clumps of sediment into buckets. They were searching for buds about the size of a slender earthworm and the color of a river-logged twig — not easy to find, Lara said. They gathered 13 that day, and 24 a few weeks later.
On the third try in March, though, the team made a discovery.
“We were raking the mud and we saw some of them just come up,” said Lara. “So, we came up with the idea: ‘Why don’t we try to just shimmy them out and see if they float?’”
They were able to capture them at the surface, collecting 90 in just a few hours.
Eve Quinones, Upstream Alliance’s Camden liaison, had researched the supplies they’d need to grow the plants through the spring: 12-gallon clear plastic totes, bubblers, lighting that mimicked both sun and moonlight and sediment. She, Lara and the rest of the team assembled the tanks and settled the turions into the sediment.
“The first one that germinated, I was like, ‘You have a name,’” Lara said. “I called him Big Homie because he was the only one out of all the homies that decided to grow.” Another plant that grew especially fast and tall was dubbed Fabio. (When curious kids come into the classroom and ask what’s in the tanks, Lara starts his explanation by introducing Big Homie and Fabio.)
He’s been spending several hours a week with the plants, feeding them micronutrients and monitoring the tanks for algae, which he painstakingly removes from each individual leaf with tweezers when there’s overgrowth. He kept count and was surprised when the number in one tote increased; the plant had started sending out rhizomes — horizontal stems that produce more roots and shoots.
Of the 126 harvested, the team has nearly 150 plants thriving, including the rhizomes. “It’s coming out to be a really good turnout,” Lara said.
Quinones spoke of the many benefits of the grass.
“It provides such a nice habitat for a lot of fish, especially shad and herring, which are two species we’re really trying to get back into the Delaware,” Quinones said. “And it also helps with shoreline establishment.”
Wild celery increases coastal resilience by reducing erosion and absorbing wave energy — more thriving grasses would help mitigate the impact of increasingly severe storms on the Camden shoreline.
Engaging environmental stewards
After the planting this month, the team will monitor the grasses and record observations about their progress. Of course, there are many variables that will influence whether or not these transplants take in their new homes. Restoration work is incredibly difficult, Baugh said, but the project isn’t just about growing grasses.
Engaging people — tying Camden residents back to the waterways that are part of the ecosystem of the city — is also a main objective. That’s already starting in a small way, with Lara and Quinones, who are learning as they help lead this work. Eventually, the team hopes to bring in more people by partnering with schools and Camden residents to grow plants in small tanks across the city.
“A component of it is to engage people in the conservation of water, and also the respect and stewardship of it,” Baugh said. “Having a project like wild celery, it’s a great way of getting people out to show them, to give them access — and then you get to see that, ‘Hey, there things we can do for the water quality here.’”