On nitrogen and phosphorus in the western Bay of Bengal

Abstract

Nitrate, nitrite, ammonia, total nitrogen, inorganic phosphate and total phosphorus concentrations have been estimated at some stations in the Bay of Bengal. Organic nitrogen and phosphorus have been detected up to 3000 m depth. This is due to the settling of unoxidized or partially oxidized organic matter indicating that oxidation processes are only partially regulated by the supply of oxygen. Presence of only 1 oxygen minimum in the Bay of Bengal, as compared to 2 in the Northern Arabian Sea, can be related to the difference in photosynthetic production between the 2 regions. Presence of denitrification in the low oxygen layers of the Bay of Bengal leads to the suggestion that this process is present all over the Northern Indian Ocean resulting in about 40% loss in the inorganic nitrogen compounds.