FR &EM

ABSTRACT Phosphorus (P) is a limiting nutrient in some freshwater ecosystems. Phosphate solubilizing bacteria (PSB) are candidates for enhancing P availability in rhizoplane, but their P release potential in freshwater environments needs further evaluations. This study conducted in floodplain wetlands correlated PSB abundance, decline in sediment pH, and natural mobilization of sediment Ca–P. PSB were abundantly present in floodplain wetland waters, sediments, and in river and ponds, showing low to moderate Ca–P solubilization activity; PSB from Churni River and Bhomra wetland sediments had comparatively higher activity than those from other environments. In laboratory sediment microcosms, PSB were effective in enhancing available P concentration in interstitial water indicating their P release potential. However, P-fractionation of incubated sediments showed only a short-term decline in Ca–P by PSB, suggesting that Ca–P might not be their sole or preferred metabolic target. Despite low to moderate activity in culture medium, high population density and efficacy in P release in sediment suggest significant role of PSB in P cycling in freshwater environments.

India has vast inland water resources having immense potential for aquaculture potential. Assessment of water quality parameters is a pre-requisite to any scientific intervention as they are of prime importance in fisheries perspective. However, monitoring water quality parameters of such vast area is not an easy task with the conventional tools and methods. In the present study, water quality parameters and chlorophyll pigment concentration were assessed using IRS P-6 remote sensing imagery in the Cauvery watershed of Karnataka State, India. Images captured by optical satellite sensors are often obscured by atmospheric effects. Hence, the images were rectified by Dark pixel subtraction method before analysing data in order to extract useful information from the imagery. The study revealed that there was significant correlation between spectral reflectance and in-situ water quality parameters. Near infra-red band (0.77-0.86 µm), was useful to assess the water quality parameters like...