Periphyton (assemblages of algae and microbes) are sentinel indicators of the quality of many habitats of the Everglades.
Periphyton are found attached to macrophyte stems, floating as mats in the water column, and as a benthic layer on top of the soil. Long considered an integral part of the animal food web, periphyton respond rapidly to changes in water quality and hydroperiod.
Like macrophytes, "native" periphyton are adapted to oligotrophic (low nutrient) conditions, while a variety of other periphyton are common in eutrophic (high nutrient) waters. Another important control on periphyton and algae is light availability: at intermediate and high plant densities (such as in high nutrient areas), emergent marsh macrophytes shade periphyton, and (to some extent) prevent healthy communities from developing. Capable of senescing during dry periods and coming back to high growth levels upon rehydration, there are a variety of different types of periphyton species & communities, depending on the subregion of the Everglades and its local environmental conditions.