Jennifer Adler A river cooter swims out of the vegetation and into the spring run at Blue Spring.

HIGH SPRINGS, Fla. ― The sun is just rising above the cypress and pine forest as a dozen people step from sweatpants into wetsuits. Masks and fins emerge from trunks. The cicadas are already singing. A gray pickup with a University of Miami vanity plate pulls in, black Rubbermaid bins piled high in the bed. Jerry Johnston steps out. He is a turtle biologist and the leader of this group, made up of community members and his students at Santa Fe College in nearby Gainesville. The woods of north Florida are not the first place you’d expect to find people suiting up to do turtle research. We’re six hours north of Miami’s famous sandy beaches and sea turtles, but the Sante Fe River basin is within a globally significant turtle diversity hotspot, home to 14 native species of freshwater turtles. That’s almost as many as the entire Amazon River system, which is more than 2,000 times its size. Part of what makes this region a great home for turtles is its karst geology —limestone that was once the floor of a shallow sea underlies almost the entire state. Freshwater from this limestone aquifer flows to the surface at almost 50 freshwater springs along 23 miles of the lower Santa Fe River. These springs are direct links between the river and the underlying aquifer, which provides drinking water to more than 90% of Floridians. The springs have historically supported lush underwater meadows of native grasses on which many of the turtles subsist.

Jennifer Adler River cooters hover in the clear water at Ginnie Spring along the Santa Fe River. The grasses have disappeared at Ginnie, and now green algae carpet the edges of the spring.

But over-extraction of water to serve Florida’s growing population — Florida is now the third most populous state in the U.S. — as well as more extreme weather and pollution from farms and households are contributing to huge changes in the springs and the river ecosystem. Most of the freshwater springs are now carpeted with algae. The turtles’ once well-stocked underwater salad bar is disappearing, signaling trouble for the water that more than 17 million Floridians rely on every day. SUBSCRIBE AND FOLLOW Get the top stories emailed every day. Newsletters may offer personalized content or advertisements. Privacy Policy Newsletter Please enter a valid email address Thank you for signing up! You should receive an email to confirm your subscription shortly. There was a problem processing your signup; please try again later Twitter

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Flipboard Yet most are unaware of what’s happening to the water beneath their feet and the threatened ecosystems in their backyards. These freshwater springs are eyes into the aquifer and into the health of Florida’s drinking water, reflecting effects from changes in water quality and quantity. It can be hard to communicate these changes and connect people to the natural source of their water, but the turtles are a fun and engaging way to get people involved. That’s why part of Johnston’s work is to connect the community with the turtles in the Santa Fe River basin. His hope is that by exposing residents to the beauty and plight of their reptilian neighbors, he can motivate them to take action to protect the water the turtles live in — the very water on which the community itself relies.

Above: Gilchrist Blue Spring on Jan. 21, 2017, and then on Jan. 21, 2018. “If you Google the word ‘turtle,’ what do most people think of? Sea turtles, right? So, one of the goals is to just get people to become aware that there are more than just sea turtles in Florida,” Johnston says. The most prominent turtle species in the springs, the river cooter, is also the most sensitive to the changes taking place. Johnston calls them “the ambassadors of the ecosystem,” and it is these animals that he brings volunteers to study. Johnston and his team have found that as alga replaces grasses, river cooters are swimming farther to find food — more than 100 adult females have left the river to find food 12 to 30 miles away. He predicts that the population of turtles in the lower Santa Fe River will eventually decrease by 70% if aquifer levels continue to drop. While the springs have slowly been degrading since the 1990s, a drought in May 2012, followed by extensive flooding from Tropical Storm Debby in late June, caused some of the springs to temporarily stop flowing and algae replaced dying native grasses in the river.

Jennifer Adler Biology professor Jerry Johnston holds a Florida red-bellied cooter and a loggerhead musk turtle at Gilchrist Blue Springs State Park during a turtle research day. The snorkelers capture turtles by hand, place them in a canoe and paddle them to land for a health assessment and tagging.

“The river completely changed its character,” says Johnston, who started studying freshwater turtles in the springs in 2004 with the help of Travis Thomas, one of his zoology students at Santa Fe College. “I didn’t know anything about biology, and [Johnston] didn’t know anything about the river,” Thomas recalls. “I grew up on the river and knew my way around, so we were the perfect team.” In 2012, it became clear that their work could serve a bigger purpose. “Little did we know, we had been gathering baseline data that are now incredibly important,” says Johnston. “After the river changed, we realized we had an obligation to try to understand how the turtles are responding to this massive change in the ecosystem.” The reasons why algae are growing are complicated and involve changes in both water quality and quantity. “We’re still investigating the causes,” says Gregory Owen, who has worked in the springs for more than 10 years as a scientist at the Alachua County Environmental Protection Department. Nitrate in the groundwater feeding the springs has dramatically increased due to agriculture, livestock, septic tanks and household fertilizer use. In addition, spring flows — the amount of water flowing from the aquifer at the spring — have decreased because of long-term trends in rainfall and pumping water from the aquifer, while recreational use and floods have increased. And as more water is pumped from the aquifer, dissolved oxygen in the water has declined at many springs, which can affect the entire spring ecosystem, including grasses and algae. Try communicating this complexity and you lose people immediately. So Johnston turned to his hard-shelled ambassadors to tell the story for him. Once he and Thomas started showing people photos of the turtles and the work they were doing, more people wanted to come help. Today, the Santa Fe River Turtle Project has grown into a community-based project involving more than 200 people who study the turtles in northern Florida. Volunteers are recruited for research days out on the river and springs, where they can snorkel and hand-capture turtles or paddle a canoe following the snorkelers to collect the turtles they catch. They paddle the turtles to land, and volunteers help tag, weigh, measure and release the turtles.

Johnston wants to change the misconception that science is only for scientists. “We have to break down some of these perceptions when we think of barriers to science, so I want people to be involved in all of the steps. Then they understand the process.” He welcomes everyone — even if they are just out to enjoy the river, people like Scott Ferguson, a vacationer turned volunteer on the Ichetucknee River. “The turtles in canoes caught our attention, so I was talking to [Johnston] about why they were catching the turtles. I asked if I could help, and we had so much fun that we came back the next day,” Ferguson says. He and his girlfriend are already planning another trip to help. One of the core members of the Santa Fe River Turtle Project is Patricia Eaton, a former canine handler in the Air Force who lives locally. Sporting a long, brown braid and a neon green T-shirt with a cartoon turtle on the front, she comes to every turtle research day with armfuls of homemade sweets. Eaton met Johnston, whom students affectionately call “Dr. J,” during a study abroad trip to South Africa in 2016 and decided to try a day on the river with the team when they returned to Gainesville. “I have a really good time,” Eaton says. “Dr. J is so dedicated to it, and he gets so excited about finding new things. He’s very protective of not just the turtles but their environment, and it becomes infectious. You just want to be part of it.” Over the past three years, Eaton says she has learned a lot about the turtles and their link to the springs. “I never realized how dependent they are on the springs here specifically, how only a handful of locations in the world have this diversity of turtles.” It’s exactly that recognition and understanding that Johnston hopes to engender by bringing the community to the river and springs. Floridians spend their lives with the aquifer beneath their feet, but it too often remains out of sight, out of mind.

Jennifer Adler Patricia Eaton is one of the core members of the Santa Fe River Turtle Project.

While Johnston is introducing people to turtles, Owen is focusing on snails, which graze on the algae that are overwhelming the springs. Just like humans, snails depend on oxygen to live. As we pump more water from the aquifer, we are left with older, less-oxygen-rich water flowing from the springs. The underlying idea behind Owen’s work is that if we can restore higher levels of oxygen in the water, perhaps the snails will be able to survive to eat more algae ― and allow the grasses, and therefore turtles, to flourish. The project has been going on for only a little over a month, but very preliminary results — along with recent work from scientists at the University of Florida — suggest dissolved oxygen is important for healthy springs.

Jennifer Adler Alachua County scientist Gregory Owen closes the lid on his cages at Hornsby Spring. He planted native grasses in some of the plots and is testing the effect of increased dissolved oxygen on plant growth and alga cover.