Monday, 6 January 2014

Fragile Springs- Life in the springs requires a delicate balance (With Turtles) - via Herp Digest

By Kristine Crane, Halifax Media Services,

December 3, 2013---One Sunday morning in early September, a bale of turtles swam and sunned themselves on the banks of the Santa Fe River near Blue Springs in High Springs.

Jerry Johnston, a turtle expert and biology professor at Santa Fe College, was at the springs that morning with a small group of volunteers for his annual “turtle dive” to collect as many turtles as possible to track where they congregate. The volunteers — a mix of students, biologists and interested residents — scooped up turtles one by one, hugging them against their chests before carrying the turtles to the shore for marking.

This year, the turtle count was a record high: 497. Last year, the divers caught about 30 turtles.

“It is something that has never been seen before,” Johnston said. “It’s a combination of things happening in the river and things happening in Blue Springs.”

The main reason the turtles are there is because they had to look elsewhere for food after the river darkened due to the influx of water from Tropical Storm Debby.

In Blue Springs, they found abundant food in the form of hydrilla, a native grass that grows when water has high levels of nitrates, Johnston explained. The nitrate level of Blue Springs is 2.2 parts per milliliter, which is nearly seven times the healthy standard of 0.35 for waters in the Florida Outstanding Waterway set by the Florida Department of Environmental Protection. Too much nitrate can set off an explosion of algea growth that robs the water of oxygen as it decays ­— resulting in a dead zone.

The turtles are telling part of an ecological story that spreads far beyond the waters of Blue Springs. High nitrate levels permeate most of the springs in north Central Florida, and hydrilla, like algae, is just one sign of it. “If you don’t have hydrilla, the high nitrates will trigger massive rates of algae, which is what we see in a lot of our springs,” Johnston explained.

Most of the turtles that were caught at the springs are Suwannee Cooters, a rare species but one that dominates in north Central Florida. The turtles are good for the springs because they eat the hydrilla, which crowds out other native plants and is on the federal noxious weeds list.

“That’s why the people at Blue love the turtles. (The turtles are) helping them manage the springs,” Johnston said.

Johnston considers preserving turtle diversity also something of an evolutionary duty.

“When you look at an individual turtle on a log, I like to look at it as a lottery winner. It’s a success story,” Johnston said. “He probably had about 1,000 brothers and sisters die at the egg stage or during the first two years of life. They have no defense: When they are eggs, raccoons and crows dig up the nest and eat them. As hatchlings, fish, birds and snapping turtles eat them.”

So making it as a turtle in life is no small feat — but without the springs, Johnston fears their demise.

“The turtles are the ambassadors of the river and springs.”

The turtles are on the surface of a deeper problem that starts in cities such as Jacksonville, where utilities have over-pumped the water supply, and includes farms surrounding the springs and individuals who excessively water their lawns. All are using water from the Floridan aquifer, a mother vessel 100,000 square miles long that “is being tapped by miles and miles of wells, small and large,” as Bob Knight describes it.

Knight is the founding director of the Howard T. Odum Florida Springs Institute and a lifelong advocate of springs conservation. As a 5-year-old visiting his grandparents in Florida, Knight recalls being entranced by the springs in clear-bottomed boats. He returned as an adult to study the area’s springs, naming his institute after Odum, his mentor and the man who wrote the first monograph of Silver Springs in 1956.

Knight wrote a 50-year retrospective of the springs and is dedicating his time now to saving the springs.

“I’m focused on trying to stop the damage,” he said. “The springs are going down at an unbelievable pace.”

Todd Kincaid, the founding director of “GeoHydros,” a geological modeling company, said, “There is less water in the aquifer than people thought. As a consequence, we are running out. You really have to know your water budget. It’s like a bank account.” Being in “water debt” eventually catches up to you, and that’s part of the problem.

Another related issue is that there have been faulty modeling systems for measuring water flow, Kincaid continued.

The models presumed geology based on sand instead of karst limestone.

“The caves dominate the groundwater exchange path … the old models assumed that the rock was sand, and no caves,” he said.

Conduits in the karst geology mean that pockets of water escape to the springs more quickly than previously thought, and are able to contaminate them more rapidly. And the Santa Fe River, in particular, has a uniquely rocky bottom. Kincaid is at the forefront of working on models that take this geology into account.

Meanwhile, Knight and other activists are pushing water districts to curtail permits, mainly to farmers who are contributing to the problem of over-usage of water, and putting nitrates into the springs through fertilizers and other chemicals.

The nitrates are largely what’s believed to be causing the degradation of plant life and some wildlife such as fish and snails in the springs.

Knight has a single-minded devotion to saving the springs “because I love the springs,” he said. “I think it’s a very important part of our lives. They are degrading right before our eyes.”

There’s an economic argument for saving the springs, too, he said, calling the springs “a renewable recreational resource.”

“Florida’s economy is based on its natural environment,” Knight continued.

“If you’re killing the environment, you’re killing the golden goose that makes the economy grow.”

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