Biogeochemical processes in the continental slope of Bay of Bengal: I. Bacterial solubilization of inorganic phosphate

Abstract

Microorganisms play a vital role in the biogeochemical cycles of various marine environments, but studies on occurrence and distribution of such bacteria in the marine environment from India are meager. We studied the phosphate solubilizing property of bacteria from the deep sea sediment of Bay of Bengal, India, to understand their role in phosphorous cycle (and thereby the benthic productivity of the deep sea environment). Sediment samples were obtained from 33 stations between 10° 36' N - 20° 01' N and 79° 59' E - 87° 30' E along 11 transects at 3 different depths i.e. ca. 200 m, 500 m, 1000 m in each transect. Total heterotrophic bacterial (THB) counts ranged from 0.42 to 37.38×104 CFU g-1 dry sediment weight. Of the isolates tested, 7.57% showed the phosphate solubilizing property. The phosphate solubilizing bacterial genera were Pseudomonas, Bacillus, Vibrio, Alcaligenes, Micrococcus, Corynebacterium and Flavobacterium. These strains are good solubilizers of phosphates which ultimately may play a major role in the biogeochemical cycle and the benthic productivity of the Exclusive Economic Zone (EEZ) of Bay of Bengal, because this enzyme is important for the slow, but steady regeneration of phosphate and organic carbon in the deep sea.