THE LITTORAL ZONE

ALGAE AND ZOOPLANKTON

Attached algal habitats in a generalized river ecosystem

Algae and bacteria on a sand grain

Diagram of an epiphyte biofilm and nutrient flow within the community

SEM micrographs of periphyton biofilms on Chara

Model of a periphyton community showing

relationships between algae and bacteria

Intact biofilm

showing clusters of algae and bacteria

Model of interactions

between phytoplankton/

bacterioplankton and epiphytic algae

& bacteria

Comparison between

periphyton habitats

relative to surface

areas for attachment

Variations in particle size around an obstacle in a stream

As periphyton communities

develop, nutrient demand

increases but diffusion

rates from the water

decreases

Seasonal variation in epipelic diatoms and cyanobacteria in two English lakes

Seasonal carbon content of epiphytes on Scirpus subterminalis in Lawrence Lake

Generalized relationship between submerged macrophytes and periphyton

Interactions between the littoral zone and open water in lakes

Spatial variations in periphyton

Primary production of periphyton and phytoplankton

Epipelic algal production in Marion Lake, BC

Periphyton production on emergent and submerged epiphytes

Model of macrophyte, periphyton, and phytoplankton production in a lake

Number of littoral-dominated versus pelagic-dominated lakes on earth

Chydorids in beds of Scirpus subterminalis

Wetzel’s SummaryRIVERS RESERVOIRS LAKES WETLANDS

Periphyton diversity

Low (channel)Moderate (wetlands)

Low Low in epilithic algaeHigh in epiphytic algae

Very high

Periphyton biomass and production

Low in-channelModerate to high in wetlands and backwaters

Low High to very high

Very high

Herbivory pressures on periphyton

Moderate to high

Low Low to moderate

Low

Littoral zooplankton

Low Very low High Relatively low