By Katherine Rapin for Yale Environment 360.
Broadcast version by Danielle Smith for Keystone State News Connection reporting for the Solutions Journalism Network-Public News Service Collaboration

On a recent summer morning near Camden, New Jersey, two divers from the U.S. Environmental Protection Agency hovered over a patch of sediment 10 feet below the surface of the Delaware River. With less than two feet of visibility in the churning estuary, they were transplanting a species crucial to the ecosystem: Vallisneria americana, or wild celery grass. One diver held a GoPro camera and a flashlight, capturing a shaky clip of the thin, ribbon-like blades bending with the current.

Watching the divers’ bubbles surface from the EPA’s boat was Anthony Lara, experiential programs supervisor at the Center for Aquatic Sciences at Adventure Aquarium in Camden, who had nurtured these plants for months in tanks, from winter buds to mature grasses some 24 inches long.

“It’s a little nerve-wracking,” he said of releasing the grasses into the wild, where they could get nudged out by a competing plant or eaten by a duck. “But that’s life.”

This was the first planting of a new restoration project led by Upstream Alliance, a nonprofit focused on public access, clean water, and coastal resilience in the Delaware, Hudson, and Chesapeake watersheds. In collaboration with the Center for Aquatic Sciences, and with support from the EPA’s Mid-Atlantic team and the National Fish and Wildlife Foundation, the alliance is working to repopulate areas of the estuary with wild celery grass, a plant vital to freshwater ecosystems. It’s among the new, natural restoration projects focused on bolstering plants and wildlife to improve water quality in the Delaware River, which provides drinking water for some 15 million people.

Such initiatives are taking place across the United States, where, 50 years after passage of the Clean Water Act, urban waterways are continuing their comeback, showing increasing signs of life. And yet ecosystems still struggle, and waters are often inaccessible to the communities that live around them. Increasingly, scientists, nonprofits, academic institutions, and state agencies are focusing on organisms like bivalves (such as oysters and mussels) and aquatic plants to help nature restore fragile ecosystems, improve water quality, and increase resilience.

Bivalves and aquatic vegetation improve water clarity by grounding suspended particles, allowing more light to penetrate deeper. They also have exceptional capacity to cycle nutrients — both by absorbing them as food and by making them more available to other organisms. Thriving underwater plant meadows act as carbon sinks and provide food and habitat for scores of small fish, crabs, and other bottom-dwellers. Healthy bivalve beds create structure that acts as a foundation for benthic habitat and holds sediment in place.

“Why not take the functional advantage of plants and animals that are naturally resilient and rebuild them?” says Danielle Kreeger, science director at the Partnership for the Delaware Estuary, which is spearheading a freshwater mussel hatchery in southwest Philadelphia. “Then you get erosion control, water quality benefits, fish and wildlife habitat, as well as better access for people.”

One hundred miles north of Philadelphia, the Billion Oyster Project has been restoring the bivalves in New York Harbor since 2010, engaging more than 10,000 volunteers and 6,000 students in the project. Oyster nurseries are being installed in Belfast Lough in Northern Ireland, where until recently they were believed to have been extinct for a century. And a hatchery 30 miles west of Chicago has dispersed 25,000 mussels into area waterways, boosting the populations of common freshwater mussel species.

Underwater vegetation restoration projects have been underway in the Chesapeake Bay and Tampa Bay for years, and more recently in California where seagrass species are in sharp decline. (Morro Bay, for example, has lost more than 90 percent of its eelgrass beds in the last 15 years.) The California Ocean Protection Council’s 2020 Strategic Plan to Protect California’s Coast and Ocean aims to preserve the mere 15,000 acres of known seagrass beds and cultivate 1,000 more acres by 2025.

Scientists stress that these projects must be implemented alongside strategies to continue curbing contaminants, mainly excess nutrients from sewage and fertilizers, flowing into our waterways — still the most critical step in improving water quality. After several decades of aquatic vegetation plantings in the Chesapeake Bay, for example, scientists say that the modest increase of plants is largely due to nature restoring itself following a reduction in nutrient pollution.

And any human intervention in a complex ecosystem raises a host of compelling concerns, such as how to ensure sufficient genetic diversity and monitor competition for food and resources. Scientists say that, in many cases, they’re learning as they go.

Still, in areas where the natural environment is improving, bringing back bivalves and aquatic plants can create a lasting foundation for entire ecosystems. And restoration initiatives are an active form of stewardship that connects people to their waterways, helping them understand the ecosystems we depend on for our survival.

Until five years ago, the extent of wild celery grass beds in the Delaware estuary was a bit of a mystery. Many scientists didn’t think the water quality was suitable, and since the estuary contains a lot of sediment and roils with the tides, the plants weren’t visible in aerial imagery.

But in 2017, EPA researchers started surveying by boat to detect submerged vegetation and were surprised to find the plant thriving in parts of a 27-mile stretch of the Delaware River from Palmyra, New Jersey, past Camden and Philadelphia, to Chester, Pennsylvania. That’s the only section of the river designated by the Delaware River Basin Commission as unsafe for “primary contact recreation” — activities like jet skiing, kayaking, and swimming.

The discovery of healthy grass beds was exciting, says the EPA Mid-Atlantic region’s senior watershed coordinator Kelly Somers, because the plant is an indicator of water quality. The EPA’s research, accessible via online maps, has been especially helpful for the Upstream Alliance’s restoration work, says founder and president Don Baugh, because most of the research on wild celery grass is from other places — primarily the Chesapeake Bay. The restoration of wild celery and other aquatic plant species has been underway there for more than 30 years.

Among the Chesapeake’s experts is Mike Naylor, aquatic biologist for the Maryland Department of Natural Resources, who, back in the 1990s, was pulling National Archives images of the Chesapeake Bay to find out what bay grass beds looked like in the 1930s and ‘50s. When combined with similar research by the Virginia Institute of Marine Science, he found that at least 200,000 acres of underwater vegetation flourished in the bay in those decades, dropping to about 38,000 by 1984.

When I talked to Naylor in mid-July, he had just been out with volunteers from the ShoreRivers group harvesting redhead grass (Potamogeton perfoliatus) — enough to fill the back bed of a pickup truck, which will yield a couple gallons of seeds for replanting, he says.

In recent years, scientists on the Chesapeake Bay have switched from transplanting adult plants to direct seeding, which is far less resource-intensive and laborious. “You can spread tens of acres of seeds in one day with just three people,” Naylor says.

More efficient techniques combined with site selection informed by accumulated data on plants’ requirements could significantly boost the success of restoration efforts. Still, scientists agree that the modest increases in seagrass growth over the last 30 years are mainly due to natural repopulation following improvements in water quality.

“In the Chesapeake Bay, the thing that has led to wide-scale [aquatic vegetation] recoveries is nutrient load reductions,” says Cassie Gurbisz, assistant professor in the environmental studies program at St. Mary’s College in Maryland.

Excess nutrients — mainly nitrogen and phosphorus from sewage and agricultural runoff — are among the biggest detriments to water quality. And it’s a problem that bivalves can help address. The Billion Oyster Project, which has restored oysters at 15 reef sites, is working to determine how oysters affect — and are affected by — water quality. The project’s goal is to restore 1 billion oysters to New York Harbor by 2035.

A 2017 pilot project in the Bronx River Estuary studied the cleaning capabilities of the marine ribbed mussel. Researchers estimated that 337,000 adult ribbed mussels floating in the estuary could sequester 138 pounds of nitrogen in their tissues and shells in six months. As it eats, a single mussel can filter up to 20 gallons per day, remove excess nitrogen both by assimilating it into their shells and tissues and burying it in the sediment as waste. Because they’re especially sensitive to poor water quality, freshwater mussel species are among the most endangered groups of animals.

“In some watersheds, the reasons why they went away are still there, and so they’re not really yet restorable,” says Kreeger of the Partnership for the Delaware Estuary, which has been researching freshwater mussels in the region for 15 years. The reasons include habitat destruction caused by dredging or filling, sedimentation or siltation from runoff, and climate change factors like warming water and increased stormwater runoff.

“In many areas, water quality has come back enough and habitat is stable enough that you can rebuild,” says Kreeger. The partnership’s proposed hatchery and education center would have the capacity to propagate 500,000 native mussels each year.

Kreeger says the hatchery team is working on biosecurity and genetics preservation plans to address the concern that releasing large numbers of hatchery-raised mussels could dilute genetic diversity and introduce diseases in the wild.

“Propagation or restoration projects should maintain the current genetic makeup and diversity and should not disrupt the natural and evolutionary processes,” says Kentaro Inoue, research biologist at the Daniel P. Haerther Center for Conservation and Research at Shedd Aquarium in Chicago. He’s working with the Urban Stream Research Center’s hatchery — which has released about 25,000 mussels into Chicago-area waterways — to analyze DNA samples from restoration sites.

The key issue is that many propagated animals have exactly the same maternal genetics. (The first 24,000 juveniles released by the hatchery were the progeny of just four mother mussels.) The center is working to mitigate some of these concerns by tagging their mussels so as not to propagate animals with the same genetics in a subsequent season. Even still, “We need to conduct more post-release monitoring after releasing hatchery-reared juveniles into the wild,” says Inoue.

Despite these concerns, scientists say bringing back bivalve and aquatic vegetation communities is an important tool to continue improving water quality. Says Kreeger, “We’re restoring nature’s ability to keep itself clean.”


Katherine Rapin wrote this article for Yale Environment 360.


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Nevada scored high for its well-funded conservation programs and for the state's commitment to public land protections.

A new report by The Center for Western Priorities evaluated eight Western states within three categories - land protection and access, responsible energy development, and land use and planning for growth.

The Center's Policy Director Rachael Hamby said Nevada has done a good job of becoming an "assertive leader" as it relates to public land protection and conservation - especially with 67% of the state being made up of public lands, according to the Bureau of Land Management.

She added that Nevada was also the first state Legislature to endorse the global 30X30 Initiative, which is a plan to conserve 30% of nature by 2030 - to avoid what Hamby called a "biodiversity crisis."

"They've made progress towards that goal too, opening a couple new state parks," said Hamby, "and again this is a state doesn't always have as much of a surface area to work with - and this shows that is OK. You can be a conservation leader with your state-level policies in place for the lands that you do manage on behalf of Nevadans."

Hamby said the Silver State has also taken action to protect wildlife, including what she calls a "strong habitat framework" that is a direct result of an executive order signed in 2021 by former Gov. Steve Sisolak.

Nevada also passed a bill in 2021 that requires developers to consult with the Department of Wildlife on their subdivision plans and assess how projects will impact wildlife connectivity.

Nevada didn't have a legislative session in 2024, but it will have one in 2025.

Hamby said despite Nevada being in a good spot, there are still areas for improvement, such as responsible energy development.

Despite Nevada not being a major oil-producing or natural-gas producing state, it currently has no statewide setback requirements for oil and gas wells or any laws or rules on the books to reduce methane emissions.

Hamby said each state can celebrate its wins, but must also get to work where they're lagging.

"So hopefully the scorecard can help with identifying some area for growth in each state," said Hamby, "as policymakers are looking for ideas of what they might be able to do to advance conservation goals."

Hamby added that the positive economic implications of a transition to a clean energy economy will become even more evident in years to come.

Since the passage of The Clean Energy Plan in 2022, Nevada has seen more than 20,000 new jobs across the state.

When the Champlain Towers South collapsed in Surfside in 2021 taking 98 lives, it sent shock waves across South Florida. The tragedy has left lingering questions about the safety of coastal high-rises and whether the ground beneath them is as solid as once thought.

A new study by scientists from the University of Miami uncovered a troubling pattern: 35 buildings along the coastline from Miami Beach to Sunny Isles Beach are sinking, some at rates of up to eight centimeters in the past seven years.

Farzaneh Aziz Zanjani, a postdoctoral researcher at Washington University in St. Louis and the study's lead author, called the findings significant.

"We saw a correlation between the start of the subsidence and the nearby construction activities and we also found some correlation between the geology," Aziz Zanjani explained. "As we move from Sunny Isles to Miami Beach, the amount of subsidence is less."

Using satellite-based technology, the team tracked subtle ground movements which are otherwise invisible. Sunny Isles Beach, known for its luxury high-rises, showed the most dramatic rates of subsidence. The researchers believe the southern Florida geology with softer sandy layers within the limestone may be a factor.

For longtime residents, the study is unsettling. The idea some buildings may be sinking in a region already grappling with rising seas and stronger storms adds concerns about the future. Aziz Zanjani cautioned against jumping to conclusions.

"It doesn't necessarily mean that these buildings are unsafe," Aziz Zanjani pointed out. "This is beyond the scope of the study we had. It just shows that there is something happening under these buildings and it's related to geology and a lot more factors that we don't understand, and we need to do more research."

The research was motivated by the Surfside collapse but scientists found no evidence subsidence contributed to the tragedy. Still, Aziz Zanjani emphasized the study highlights the need for transparency and better monitoring of structural stability across the region. Aziz Zanjani's paper is open-access to the public.


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The Iowa Department of Natural Resources is training operators of Concentrated Animal Feeding Operations on the safest ways to apply manure to their fields and what to do if a spill happens. It is part of the state's effort to help reduce accidents and protect the environment.

Iowa produces about 50 million tons of manure every year or enough to fertilize roughly 17% of the state's cropland.

Jeff Prier, senior environmental specialist for the Iowa DNR, said the state is teaching commercial and smaller operators how to apply it safely by following a required manure management plan.

"When they go out to do their application, they need to comply with any separation distances to residence, church, business, school, public use area, water sources," Prier outlined. "Dependent on their application method."

Manure from Concentrated Animal Feeding Operations is known to pollute air and groundwater when it is not properly applied. Commercial operators said they are looking for more environmentally friendly ways to operate while trying to meet consumer demand for high quality meat. The deadline to apply for the DNR training is next week.

The DNR charges commercial operators $225 for a manure application permit and $175 for smaller operators. Prier noted it is a small price to avoid fines of between $3,000 and $5,000 for applying fertilizer without state certification.

"When they hear the numbers, they tend to open their eyes pretty big and think that's a pretty big number," Prier observed. "But the best reason is being in compliance with the rules and regulations and knowing what to do if there is a spill."

Prier, who has been overseeing training for 26 years, added given the amount of manure spread on Iowa farms every year, the number of spills is relatively small.


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