Oceans arc the largest and most stable marine ecosystems. Oceans cover approximately 70 per cent of the earth's surface. Ocean water is saline and highly rich in minerals and gases. The biotic and abiotic components are discussed below.
1. Biotic components - They are classified as
(i) Producers - They consists of phytoplanktons, e.g., diatoms, dinotkgellatesred, brown algae, etc.
(ii) Consumers - Crustaceans, molluscs, fishes, etc., are the primary consumers. The secondary consumers are herring, mackerel, shad, etc.. whereas the tertiary consumers include fishes like cod, haddock, halibut, etc.
(iii) Decomposers - Saprophytic bacteria and fungi are the decomposers of ocean ecosystem.
2. Abiotic components - The main abiotic components are light, heat, pH, inorganic and organic substances.