Meet Your Algae
The Hidden World in North Florida’s Springs
By Rachel Damiani
Many springs-lovers have been dismayed to watch the spread of algae in the storied crystal-clear waters of North Florida’s springs, but algae are not a recent stranger. These tiny organisms simply remained unseen. Now that they’re becoming obvious, it’s a good time to meet them. Under a microscope, hidden algae are alive, stark like a little moon in the night sky or subtle like an etching on a marble statue. The elegance of some single-celled algae’s design even inspired Victorian artists to arrange them in unique patterns on microscope slides.
“They are actually quite lovely when you look at them under a microscope, like anything in biology,” said the University of Florida’s Matthew Cohen, an associate professor of forest water resources and watershed systems. “It’s a living thing. It’s not scary, evil, bad. As far as the algae are concerned, it’s just doing its thing.”
In 1957, UF ecologist Howard Odum identified algae in Silver Springs on aquatic vegetation. A slimy coat painted the green plants brown. Under a microscope, this ‘brown slime’ is alive. The algae in North Florida’s springs can be categorized in to multiple classes, including diatoms.
A diatom fixates the sun’s energy and converts it into food through photosynthesis, an impressive feat for a single cell. These tiny organisms are enclosed in a glass-like, silica layer, according to Edward Phlips, a UF fisheries and aquatic sciences professor who specializes in algal physiology and ecology.
“Diatoms are such an important part of all environments and certainly springs are no exception,” said Phlips.
The word diatom derives from Greek, diatomos, “cut in two.” The diatom’s tiny ‘glass house’, or frustule, has two symmetrical sections, a top and a bottom, known as thecae. Like a handmade gift box for a precious ring, the two pieces are slightly different sizes, so that the top cover can perfectly fit over the bottom. The frustule has small pores, according to Phlips, allowing the diatom to interact with its environment.
The diatoms are quite tasty to snails, according to Cohen. Elimia snails graze aquatic vegetation like little lawn mowers, “scraping and scooping” brown slime with an adapted mouth piece.
“You can see where they’ve gone by the brown slime that is gone,” said Dr. Robert Knight, founding director of the nonprofit Howard T. Odum Florida Springs Institute and former graduate student of Odum.
Not only do snails eat diatoms, they also snack on blue-green, yellow-green, and green algae. These algae orders are aptly named for the pigment contained in their chloroplasts, the light-to-food converters in the organism.
While diatoms prefer to work alone, blue-green, yellow-green, and green algae may opt for teamwork. With enough time and sufficient nutrients, these single-celled algae aggregate together, connected cell to cell to form long hair-like threads, known as filamentous algae, according to Phlips.
Lyngbya wollei, a blue-green alga, is one of the dominant filamentous species in North Florida’s springs. L. wollei has a tough encasement that is difficult for snails and other organisms to eat, according to Phlips.
Not only do filamentous algae, like L. wollei, grow attached to aquatic vegetation, they also form mats on the spring floor, or benthic layer, smothering aquatic plants and diatoms, according to Knight. The explosive and visible growth of filamentous algae is worrisome to many spring-lovers.
“For anybody that’s been around the springs for very long and seen how they’ve changed, it’s very disquieting or very sad to see how much algae is in our springs,” said Knight.
Researchers are actively exploring the underlying cause for the recent increase in filamentous algae and its effect on the food web. According to Cohen’s published results, the snail population has declined with lowered dissolved oxygen content in spring water. Without snails to mow the algae, the filamentous algal population can explode. Additional research explores how increased nutrients in spring water may fuel algal growth.
Although some of Florida’s springs have a near complete takeover of filamentous algae, other springs are still dominated by algae that is invisible to the naked eye, according to Cohen.
Tiny glass houses of hope and other unseen algae reign in crystal waters, still.
Note: The author would like to thank Dr. Kent Vliet and Michael Frick in UF’s Department of Biology for assistance with algae collecting equipment and microscope use.
About Project Blue Ether
WUFT News is publishing this multi-week series on water by University of Florida students, led by award-winning environmental journalist and author Cynthia Barnett, who is a visiting professor at the University of Florida College of Journalism and Communications.