Freshwater turtles are a quiet, reserved species that tend to keep to themselves. But the role they play in local ecology cannot be overstated. As omnivores, turtles helps with insect, snail and vegetation management and also provide seed dispersal and nutrient cycling. Freshwater turtles are also indicator species, meaning their presence, or lack-thereof, is an immediate sign of river health and water quality.
Which is why local environmentalists and investigators from The Florida Fish and Wildlife Conservation Commission are both troubled and perplexed by the recent deaths of more than one hundred freshwater turtles scattered throughout the St. Johns River watershed, including in parts of the river that run through Putnam, Seminole and Orange county, according to a Jacksonville.com article. Dead freshwater turtles have also been found in Lake County, and the FWC is investigating other areas, as well.
Roughly 3.5 million Floridians live alongside of the St. Johns River, Florida’s second largest ecosystem (after the Everglades). Humans use this ecosystem not only for recreation like fishing, boating, jet-skiing and sailing, but also as both an economic thoroughfare and driver.
St. Johns Riverkeeper, Lisa Rinaman believes these turtle deaths could be the result of massive amounts of sewage being discharged in the St. Johns River.
“Our concern was this high level of sewage sludge that’s being applied on adjacent lands there in the headwaters. In particular, some of the areas where they are seeing a high number of turtle deaths,” Rinaman told the Florida Times Union.
“They were having trouble breathing. They were lethargic,” Rinaman said of the freshwater turtles in the article. “They would crawl out and just kind of give up and couldn’t go any where.”
According to the Daytona Beach News-Journal, some of these turtles were found downstream of an area that’s permitted to use the sewage sludge as fertilizer.
Advocacy Director of St. Johns Riverkeeper, Shannon Blankinship said these reports started in January in the headwaters near Sanford and Lake Monroe, but it seems to be flowing further into the river.
“It seems as if the map just keeps moving,” Blankinship said. “It started in the headwaters, then creeped to the Shands Bridge, and then Greencove Springs. Each report each day was moving a little bit further north.”
Although she said reports have decreased since the start of the investigation, Blankinship says there are still new reports coming in every week.
Tissue samples from the turtles were sent in for testing, but results for toxins like pesticides and herbicides came back negative.
The St. Johns River, on the other hand, was found to have much higher levels of phosphorus and algae bloom outbreaks have been rampant in recent weeks.
Jacksonville.com says that microcysts, bacteria related to harmful algal blooms, such as blue or green algae, are still prevalant in the river and of great concern.
“These deaths were coming at the same time we were receiving reports of overwhelming algae blooms, specifically in Blue Cypress Lake. We believe that this was related to the sewage sludge on property,” said Blankinship.
And with Florida’s summer storms along the way, more trouble could be looming for St. Johns and its freshwater turtle population.
“[The sewage sludge]… happening in conjunction with really high summer rain, it’s expected that the water quality is really going to suffer,” Blankinship warned.
Lisa Rinaman and the FWC are also worried that whatever is causing the turtles harm could also lead to a human health crisis.
“It definitely is a red flag. We want to figure out what’s going on for the sake of the turtles, but also to make sure there is not a larger human health issue to be concerned about,” Rinaman said in the T.U. article.
More samples were recently sent to labs in Michigan to test the quality of the turtles’ organs at the time of death, but results have yet to be determined.
“It may be years before we have a definitive cause with the turtles,” said Blankinship.