This story was produced in collaboration with PBS News Hour.

Debbie Fountain and her husband are oyster farmers in Biloxi, Mississippi. They are part of a new wave of shellfish farmers looking to feed the growing demand for seafood while also helping to preserve nature.

“I feel a stewardship, you know. We’re doing something that’s renewable,” Fountain said. “You grow an oyster. They filter the water. You can feed people. It’s a huge, beautiful source of protein. What’s not to love about it?”

But the couple is struggling against the volatile new reality of the Mississippi River. Last year, heavy precipitation linked to climate change swelled the river to record levels. The Army Corps of Engineers had to open the gates to the Bonnet Carré Spillway, a massive safety valve just upriver from New Orleans, for an unprecedented 123 days.

The spillway temporarily added a branch to the river, allowing excess water to flow six miles to Lake Pontchartrain, an estuary that connects to the Gulf of Mexico. As a result, fresh water from the Mississippi River diluted the saltier coastal water — with disastrous effect.

Volunteers found the remains of more than 150 dolphins and 23 turtles. Scientists blamed the loss of marine life on the influx of fresh water.

“Two parts per thousand salinity. You can stick your finger in it, and it tastes like fresh water. These animals are simply not made for that kind of fresh water,” Fountain said, adding that the flood water reached their oyster bed nearly 100 miles east of the river. “For us it was 100 percent mortality. We lost about probably 14,000 oysters in that event.”

She added, “We’re gonna have to do what farmers all over America do. Try and insure if we can. And a lot of prayer. Because we have no control over some of those things.”

Debbie and Andy Fountain of Fountain’s Deer Island Oysters. Source: Nexus Media/PBS News Hour

Author and chef Melissa Martin sees the same changes showing up in her kitchen. The Mosquito Supper Club in New Orleans. It’s an intimate dining venue that features food that Martin grew up eating in Louisiana’s bayou country.

“I opened this restaurant so we could start a conversation about south Louisiana and talk about sustainability and food and life and the environment. What we do here is try to give people a meal that they would have at my grandmother’s house or my mom’s house,” Martin said.

“I get worried, when I peer into the future, about running a restaurant. I won’t be running a restaurant based on seafood from other places. I will always be running a restaurant based on what I could get here,” she said. “And that may mean that one day that I’m not a seafood restaurant. And that’s a really sad thought, but that’s kind of the reality of where we are.”

For Martin, the problem isn’t just fresh water contaminating saltwater. Often, it’s the other way around. Oil and gas companies in south Louisiana have erected a maze of canals to navigate the region. These canals allow seawater to spill into marshlands, threatening species of oysters and other creatures that can’t tolerate a lot of salt.

Chef and author Melissa Martin. Source: Nexus Media/PBS News Hour

Terrebonne Parish, where Martin grew up, used to be one of the richest sources of oysters in the state. “But once the saltwater intrusion started happening because of the oil fields, we lost pretty much all of our oyster beds. The amount of shrimp that we have has changed because we just don’t have estuaries for them to live in. You know they’re just being eaten away by saltwater,” she said.

Aerial photographer Ben Depp, a transplant to southern Louisiana, has documented these threats.

“Everywhere you look, you see the thousands of miles of canals cut through the wetlands, which caused saltwater intrusion, which killed the vegetation and caused the ground to erode,” he said. “You can see the marsh just fragmenting apart.”

He added that the oil sector isn’t the only industry responsible for the canals. Many were made to transport trees during a surge in coastal logging at the turn of the 20th century, when Louisiana was the nation’s largest producer of timber. Depp said when that the wilderness was cut down and sold, much more was lost than anyone realized.

“This place used to be a thriving ecosystem, mostly forested with cypress and tupelo — just this expansive, wet, hardwood forest full of alligators and fish,” he said. “Some areas here are still incredible, but it’s kind of just the edges of what this place used to be.”

It will be difficult to repair the damage that humans have inflicted. The bald cypress, for instance, can grow to be 1,700 years old. Scientists say it would take about that amount of time to reverse the human impact on the Mississippi Delta.

In the meantime, Debbie Fountain offered her own plan, saying, “We all have to be better stewards of what we use and how we behave and what we do. All of us have to become better stewards.”

Josh Landis writes for Nexus Media, a nonprofit climate change news service.