A comparative study of nitrous oxide and methane in freshwater and marine ecosystems in and around India

Abstract

The earth s environment is being severely affected by anthropogenic activities, particularly newlineby the use of chemical fertilizers which can lead to eutrophication and oxygen deficiency newline(Mallin et al., 2006; Diaz and Rosenberg, 2008) in freshwater and marine ecosystems. newlineThese oxygen deficient environments primarily affects the biogeochemical transformation newlineof the various elements during the remineralization of organic matter, where the sequential newlineuse of the various available electron acceptors results into the accumulation of reduced newlinespecies (NH4 newline+, N2O, H2S and CH4) in severely oxygen depleted zones (Galy-Lacaux et al., newline1997; Naqvi et al., 2000). These sites then act as sources/sinks of the Greenhouse gases newline(GHG s) and are identified as regional hot spots (especially of N2O and CH4). Ecosystems newlineexperiencing seasonal oxygen deficiency such as those observed in freshwater reservoirs newlineand the coastal upwelling systems provide natural laboratories to investigate the newlinebiogeochemical cycling of carbon and nitrogen throughout the redox gradients ranging newlinefrom oxic to anoxic. newline