Biology and Ecology of Microalgae

Microalgae are mainly photo-synthetic single-celled organisms living in aquatic environments or humid or aerial terrestrial environments. Microalgae are eukaryotic organisms that possess the main characteristics of the vegetable eukaryotic cell. Like all organisms, microalgae are classified into several taxonomic groups according to traditional or phylogenetic systematics. The presence of additional pigments, called supernumerary pigments, is used as a distinguishing criterion to define the main algal phyla. These phyla, of which there are three, are, respectively, the phylum of Chlorophyta, Chromophyta and Rhodophyta. Cyanobacteria have long been considered microalgae and classified as Cyanophyceae or “blue algae” or “blue-green algae”. Cyanobacteria are the most important group of photosynthetic bacteria. Microalgae are present in many environments, whether aquatic, terrestrial or atmospheric. In the aquatic environment, marine microalgae can be distinguished from freshwater microalgae or freshwater algae. Microalgae are varied unicellular organisms living in different environments or habitats.