Aquatic ecology and Biodiversity

Unit 12- Aquatic biodiversity and conservation

12.1. Aquatic biodiversity
Biodiversity is the variability and variation of all living organisms including animal and plant species. Biodiversity is a measure of the richness of life from the habitat down to the gene. There are about 1.7 million species have been identified and upto 100 million total species present on earth. Of the 1.7 million species, if we ignore viruses, bacteria, fungi, arachnids, insects and half the protozoan’s and plant species, we are left with approximately 5.0 lakh species considered to be marine. Biodiversity makes up the structure of the ecosystems and habitats that support essential living resources including wildlife, fisheries and forests. It helps to provide basic human needs such as food, shelter, and medicine. Biodiversity also has recreational, cultural, spiritual and aesthetic values. Biodiversity reflects the number, variety and variability of living organisms in space and time.
The Global Convention on Biological Diversity, signed in 1992 at the Earth Summit, describes biodiversity as the "variability among all living organisms from all sources, including terrestrial, marine and other aquatic ecosystems and ecological complexes of which they are part, this includes diversity within species, between species and of ecosystems. Biological diversity basically meant number of species however, refers to the variability within nature and encompasses three levels- genetic, species and ecosystem diversity. These three levels are closely interconnected and thus cover all animals and plants (including viruses) belonging to the kingdoms - Animalia; Plantae; Monera (prokaryotes: bacteria, cyanobacteria);Protista (plant and animal-like protists) and Fungia (fungi and moulds) their genetic variation and the ecosystems which they form part of an ecosystem.