Tag: zoology

The red sea is the saltiest sea and connects to the ocean without any river meeting the sea. It is named so because of the abundant occurrence of red coloured planktonic cyanophyceae called Trichodesmium erythraeum. This cyanophyceae imparts red colour to red sea. This results in the algal bloom or red bloom.

Cyanobacteria are also called as Blue green algae. They are unicellular, colonial, filamentous prokaryotes. They are found in marine and terrestrial habitats. The colonies are surrounded by a gelatinous sheath. They are photosynthetic bacteria. They often form blooms in water bodies and results in eutrophication. Some Cyanobacteria like Nostoc can fix atmospheric nitrogen in specialized cells called heterocysts and make it available to plants.

BGA is chefly used as fertilizer in paddy fields for paddy crops.

Azolla forms a symbiotic association with Anabaena for nitrogen fixation.

Green manures are fertilizers consisting of growing plants that are ploughed back into the soil.All the above are good examples of green manure.

Sesbania rostrate is mainly used as green manure to improve the fertility of the soil due to its fast growth, high biomass production and the ability to convert atmospheric nitrogen into a usable form for plants.