Microbes and Plants - Freshwater Ecology: Concepts and Environmental Applications - page 137

Characteristics of Major Groups of Freshwater Algae a TABLE 8.3

Approximate
No. of species

Group (common name) Dominant pigments Cell wall Habitats (% freshwater) Ecological importance

Cyanobacteria Chl a , phycobilins Peptidoglycan Oligotrophic to eutrophic, 1,200-5,000 (50%) Some fix nitrogen, some toxic,

benign to harsh environments floating blooms characteristic

of nutrient-rich lakes

Rhodophyceae (red algae) Chl a , phycobilins Cellulose Freshwater species in streams 1,500-5,000 (5%) Rare in freshwaters except

Batrachospermum in streams

Chrysophyceae Chl a , chl c , carotenoids Chrysolaminarin Freshwater, temperate, plankton 300-1,000 (80%) Dinobryon a common dominant

in phytoplankton

Bacillariophyceae (diatoms) Chl a , chl c , carotenoids Silica frustule Plankton and benthos 5,000-12,000 (20%) An essential primary producer,

both in freshwaters and globally

Dynophyceae Chl a , chl c , carotenoids Cellulose Primarily planktonic 230-1,200 (7%) Some toxic, some phagotrophic,

involved in many symbiotic
interactions

Euglenophyceae Chl a , chl b , Protein Commonly in eutrophic waters, 400-1,000 Can be phagotrophic, indicative

associated with sediments of eutrophic conditions

Chlorophyceae (green algae) Chl a , chl b , Naked, cellulose or Oligotrophic to eutrophic, 6,500-20,000 (87%) Very variable morphology, very

calcified planktonic to benthic important primary producers;

filamentous types in streams,
unicellular in plankton

Charophyceae Chl a , chl b , Cellulose, many Benthic, still to slowly flowing 315 (95%) Often calcareous deposits

calcified water

a See Figs. 8.4-8.6, 8.8, and 8.9 for representative genera and some morphological characteristics [after South and Whittick (1987) and Vymazal (1995)].