Arsenic biogeochemical cycle through microbial activity and biodiversity status of Shimsha River in Karnataka, India

The biodiversity status of fishes was assessed according to International Union for Conservation of Nature (IUCN) criteria from Shimsha River in Karnataka. However, with a growing population the freshwater fishes, resources are under great pressure and affected 30% livelihood. The results showed that populations of the majority of fish species had a significant decline over the past five decades. The most significant categories of threats derive from: pollution from agriculture pesticides, habitat loss and degradation, over exploitation, eutrophication, dynamiting, chemical and herbal poisons, use of insecticides as poisons, destruction and modification of habitats and misguided human perceptions and a wide array of prohibited fishing methods are rampant and that led to destruction of biodiversity habitat of fishes. Microbial reduction as was evidenced in all the enrichments carried out in anaerobiosis.