Around the stems and other underwater parts of the glades plants are
cylindrical masses of yellowish-green _periphyton_. So incredibly
abundant are these masses of living material that in late summer the
water appears as though clogged with mossy-looking sausages and floating
pancakes. Largely algae, but containing perhaps 100 different organisms,
the periphyton supports a complex web of glades life. It is the
beginning of many food chains in the fresh-water marsh. The larvae of
mosquitoes and other invertebrates, larval frogs (tadpoles) and
salamanders, and other small, free-swimming creatures feed upon the tiny
plants and minute animals living in the masses of periphyton. These
periphyton feeders are in turn fed upon by small fish, frogs, and other
vertebrates, which are food for big fish, birds, mammals, and reptiles;
most of these larger creatures are preyed upon by the alligator.
The periphyton is perhaps most important for its role in maintaining the
physical environment of the marsh. The water flowing over the limestone
of the glades is hard with calcium. The algae remove this calcium and
convert it to marl (_see_ glossary), which precipitates to the bottom.
Sawgrass is rooted in this marl; accumulated dead sawgrass forms peat;
other marsh plants, including willows and the trees of the bayheads,
spring up from the peat. Acid from the peat and from decaying plant
matter of the tree islands dissolves some of the marl and underlying
bedrock—and the cycle is complete.
Every plant, every animal, every physical element is involved in this
web of life—as soil builder, predator, plant-eater, scavenger, agent of
decay, or converter of energy and raw materials into food. Damage to or
removal of any of these components—pollution of the water, lowering of
the water table, elimination of a predator, or any interference in the
energy cycle—could destroy the glades as we know them.
[Illustration: BEGINNING OF FOOD CHAIN]
ALGAE AND ONE-CELLED ANIMALS
INVERTEBRATE LARVAE
PERIPHYTON MASS
SAWGRASS
SAWGRASS DIES AND MAKES PEAT
Every other plant-and-animal community in the park—hammock, mangrove
swamp, pineland, etc.—is an association of large and small organisms
sharing a physical environment. It is impossible to understand either
the park as a whole or the life of a single creature without being aware
of these interrelationships.