Vertical Profile of Phosphatase Activity in the Sundarban Mangrove Forest, North East Coast of Bay of Bengal, India

Abstract

Impact of phosphate solubilizing bacteria along with soil phosphatase activity on phosphorous cycle was found to be quiet interesting in the Sundarban mangrove ecosystem. Soil phosphatase activity showed a decreasing pattern with increase in depth [soil phosphatase activity (μg pnp produced g⁻¹ dry wt of soil) = 906.85 – 5.6316 Depth (cm)] from the deep forest region of the Sundarban forest ecosystem. Soil salinity showed a very little effect on soil phosphatase activity whereas soil temperature and pH was found to show significant impact on the soil phosphatase activity. This ensured that the microbes associated with phosphate mineralization present in the Sundarban forest ecosystem are more tolerant to fluctuation in salinity than that of temperature and pH. A direct correlation was perceptible between the number of phosphate solubilizing bacteria and phosphatase activity in the soil during the study period from 2007 to 2012. Soil phosphate concentration was found to be directly governed by the soil phosphatase activity [The regression equation is: avg PO₄⁻³-P (μg g⁻¹ dry wt of soil) = 0.0311 + 0.000606 soil phosphatase activity (μg pnp produced g⁻¹ dry wt of soil); R² = 63.2%, p < 0.001, n = 62].

Keywords:

• phosphate solubilizing bacteria
• soil phosphatase activity
• Sundarban mangrove ecosystem