Size : Range 1.0 μm to many feet
Characteristics :
Algae are photosynthesis eukaryotes with a wide variety of shapes and both sexual and asexual reproductive forms. The algae of interest to microbiologists are members of the kingdom protista and are usually unicellular. Algae are photosynthetic protists that together with cyanobacteria produce about 75% of the planet's oxygen. They are abundant in fresh and salt water, soil and in association with plants. As photosynthesizers, algae need light and air for food production and growth, but they do not generally require organic compounds from the environment. As result of photosynthesis, algae produce oxygen and carbohydrates, which are ingested by other organisms, including animals. Thus they play an important role in the balance of nature. Gelidium ( red algae ), Vaucheria ( Yellow-green algae ), Ochromonas ( golden algae ), Sargassum ( brown algae ), Diatoms, Euglena, chlorella ( green algae ) Cryptomonas and Gymnodinium ( the dinoflagellates ) are the representative examples of each important group of algae.
* Algae are simple eukaryotic organisms.
* They are unicellular as well as multicellular.
* They occur predominantly in aquatic environments or in damp soil.
* All the algal cells contain chlorophyll and are capable of photosynthesis.
* They reproduce asexually and by sexual processes.
Practical Significance :
a. Algae are important to the production of food in aquatic environments.
b. They are used as food supplement and in pharmaceutical preparations eg. Spirulina in the extraction of proteins.
c. They are used for the production of agar agar a solidifying agent for microbiolo