Environmental Microbiology of Aquatic and Waste Systems

4.1 Taxonomy of Microorganisms in Aquatic Environments 85

Table 4.9

The various algal groups (Compiled from Sze

198

6 and Trainor

197

8 )

S. No.

Group

Pigments

Storage

Zoospores

Walls,

Morphology

Example

Habitat

1.

Chlorophyceae (Green algae)

Chlorophyll a,b,

Starch

Variale, when present

Cellulose, chitin, calcium carbonate

Unicellular to multicellular

Spirogyra, Chlamydomonas

Freshwater, oceans, soils

Xanthophyll

2.

Rhodophyceae (Red algae)

Chlorophyll a,d

Floridean starch (like glycogen)

None

Cellulose

Multicellular: large, up to 5 m long

Gelidium

(agar,

microbial cultiva­tion) and

Chondrus

(carageenan – food thickening)

Few freshwater, mostly marine:warmer waters, especially along coastlines

Carotene a, bPhycobilins (masks other pigments)

3.

Phaemyceae (Brown algae)

Chlorophyll a,c

Laminarin, mannitol, fat

Alginic acid, cellulose

Multicellular: large, up to 5 m long

Ectocarpus

Mostly marine in north temperate regions

Carotene a, bXanthophylls

4.

Bacillariophyceae (Diatoms)

Chlorophyll a,c

Glucans, Oil

No moving member at any stage

Celluose, pectin in above structure

Unicels, colonial or filametous

Tabelaria

spp.(freshwater)

Marine and freshwater

Xanthophylls

5.

Xanthophyceae (Yellow green algae)

Chlorophyll a,c

Chrysolaminarin, Oil

Celluose, pectin in above structure

Unicells, colonies, branched and unbranched filaments

Vaucheria

sp.

Mostly temperate freshwater

Carotene a, bXanthophylls

6.

Chrysophyceae (Golden algae)

Chlorophyll c

Chrysolaminarin

Adults nonmotile or motile with a flagellum

Naked or cellulose

Typically Unicellular; few colonies, branched and unbranched filaments

Synura

sp. (imparts

fish odor to water)

Cold freshwater in northern hemisphere

Carotene a, bXanthophylls

7.

Dinophyceae (Dinoflagellates; dark­brown algae)

Chlorophyll c

Starch or oils

Often only cell membrane; sometimes a pellicle

Motile adult flagellates, colonies or filamentous

Freshwater and marine

Carotene bXanthophylls

Girdle in which one flagellum lodged; other flagellum trails