220 Organic waste recycling: technology and management
age, the outer matrix often becomes pigmented and stratified, developing into a
semi-rigid surface membrane.
Of the seven phyla shown in Table 5.1, the largest division of algae is the
Chlorophyta or green algae. The photosynthetic ability of algae enables them to
utilize sunlight energy to synthesize cellular (organic) material in the presence
of appropriate nutrients. Thus the algae (and also the bacteria) are the major
primary producers of organic matter in aquatic environment.
Figure 5.1. Examples of planktonic algae. Diatoms: (a) Asterionella; (b) Skeletonema.
Dinoflagellates: (c) Ceratium and (d) Peridinium. Green Algae: (e) Chlamydomonas; (f)
Scenedesmus. Blue-green algae: (g) Aphanizomenon and (h) Anabaena. Chrysophytes: (i)
Dinobyron and (j) Synura. Euglenoids: (k) Euglena.