The Everglades periphyton may not attract much attention, respect. It is essential to the health of River of Grass


Perry who? It’s not an unreasonable question for someone hearing for the first time about the Everglades superstar named Periphyton.

While not a majestic scene stealer, this humble substance is essential to life in the River of Grass. It may not soar like a snail kite, ripple like saw grass, or glide like an alligator, but it’s just as important to the Everglades — and wetlands in general — as those shapes. better known lives.

Extremely spongy stuff is softly spongy underfoot, like a super soft carpet, says Paul Gray, scientific director of Audubon Florida. He should know. Gray is usually barefoot when researching, so he’s walked a lot.

But what is this four-syllable substance? There doesn’t seem to be a widely used common name, says Gray, “most people don’t pay attention to it as far as I know,” although aquatic ecologist and professor Evelyn Gaiser says she’s heard some call it “pond scum” or “swamp vomit.”

The word comes from the Greek for “around” perished and “plant” – phytonwhich makes sense, as it can indeed grow around plants, like watery wool sweaters.

What makes periphyton difficult to describe is that it is not a thing; it’s a lot.

“A complicated community…many, many species that all interact in various ways,” says Gaiser, George M. Barley Jr. Endowed Chair of Everglades Research at Florida International University. Other periphyton assemblages live around the world, from the Great Lakes to New Zealand.

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Its Everglades mats contain an enormous distribution of tiny characters: algae, cyanobacteria, fungi and diatoms – single-celled, silica-shelled organisms – although the groupings may vary.

But just because they’re small, they shouldn’t be overlooked, Gaiser said.

“We have a lot of organisms in the Everglades that are often referred to as ‘charismatic megafauna'” – the large, photogenic creatures like roseate spoonbills and alligators – “I always think of periphyton as charismatic microfauna.” Under a microscope, “You would be marvelously amazed by its beauty and intricacies just as you would with megafauna.

“It’s a whole ecosystem,” she said. “Every little function that you would have in a forest is also happening in the periphyton (and) there’s a tremendous amount of co-dependency,” she said. “If something is wrong with one player, something is wrong with the whole.”

Stephen Davis, scientific director of the Everglades Foundation, says, “The way I describe it is a fundamental part of the pristine Everglades marsh. And by intact, I mean an area that is not degraded, phosphorus polluted, or over-dried… It’s really a microcosm-like system within the larger marsh ecosystem.”

Because it’s extremely sensitive to pollution, especially phosphorus, its health can be used to diagnose the condition of the entire system, Davis said.

Periphyton feeds on tiny fish and crayfish as well as a host of microorganisms, Davis says — “many things that are just too small to see,” he said. “A lot of these organisms that are closer to the bottom of the food chain, so of course they get eaten up by bigger things, so the energy from the periphyton mat moves up the food web.”

As for threats, phosphorus pollution, which can come from development and agriculture, is by far the biggest, says Davis, but so is salinity. “Some of the areas that used to be freshwater marshes are increasingly exposed to saltwater.”

Drought can also be a threat, although in the early stages of a drought, periphyton helps ‘Glades stay alive. “When some of these swamps dry out, these periphyton mats break down and become a sort of wet blanket over a swamp that would otherwise dry out very quickly and possibly lead to the disappearance of many aquatic organisms,” such as the crayfish, for example. , Davis said. “It helps keep them moist during what would otherwise be a devastating time and can also help protect those soils from burning if we catch a fire during a drought.”

Not only can periphyton protect soils in the Everglades, it can help create them, he says. “These mats sort of accumulate as layers at the bottom of some marshes (and) they can form soil.”

Yet for all that, he’s easily overlooked, says Gray, and that’s a shame. “We all know that it’s all based on primary productivity – sunlight shining on plants, then green plants turning it into biomass,” he said. “But we’re used to looking at things like trees, which are very large organisms, but they’re growing at a rate of 1% per day – and that’s if they’re growing fast.”

For comparison, “periphyton communities can double their biomass in a day. All they have to do is divide their cells. They really have this incredible productivity (and) their annual production can be way more than all those super big plants.” because they process their biomass so quickly,” Gray said. “Periphyton is really an amazing thing, but people don’t notice it because it’s so small.”

Gaiser says she’s always thrilled when periphyton catches the eye. “It’s a bit of a hidden wonder.”

Periphyton Fun Facts

He is moving. It can grow attached to plants or rocks, but periphyton can also drift, float and sink. “He’s moving,” Gaiser said. “It can fill up with gas…and it’ll bounce, float and then come back down,” she said. “I saw a whole patch of swamp heave up in the middle of the day.”

It does not appear to harm the plants it covers. “We can go out and take what we call a jumper – where the periphyton gets so thick around the stem that it looks like the plant is wearing a jumper – and if you cut that jumper off and take the little plant out, the plant will be the happiest, the light green, which is doing very well.

Its diatoms are magnificent. These microscopic members of the periphyton community live in glassy silica shells that can be quite striking, Gaiser says. Under a microscope, “they take beautiful pictures,” she said.

It’s super temperature resistant. Periphyton can freeze and bounce as well as set while cooking. “We’ve actually seen water boiling under fires in the Everglades with periphyton and it survives the boil,” Gray said.

But it’s super sensitive to pollution. “Once the phosphorus levels hit around 10 or 15 parts per billion, it kills it,” Gray said. “It can survive anything but nutrients.”

Ethnobotany of periphyton? Ancient indigenous peoples of Mexico’s Yucatan Peninsula “may have used periphyton as a kind of slow organic fertilizer by harvesting it from Everglades-like wetlands and then putting it on their farmlands,” Gaiser said. .


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