Rivers are freshwater lotic ecosystems. Rivers are quite large in terms of their size, speed of flowing water, amount of water, 02 quantity and physical and chemical conditions. Their biotic and abiotic components are as follows:
1. Biotic components - These include
(i) Producers - They include phytoplanktons, blue-green algae, green algae, water moss and diatoms.
(ii) Consumers - The consumers are cephalopteryx, helodes, phalacrocera, etc.
(iii) Decomposers - Bacteria and fungi are the micro-organisms that feed on the dead organic material.
2. Abiotic components -These comprise organic substances, inorganic materials and climatic factors of a region.