Geochemistry of continental shelf waters and sediments east coast of Tamilnadu bay of Bengal

Abstract

Continental shelf studies are important in order to understand the newlinephysicochemical properties of sea water as well as biogeochemical systems newlineexisting in the marine environment Lying within the tropical zone the east newlinecoast Tamilnadu receives strong monsoonal rains and hence any variation in newlinethe intensity and amount of precipitation would reflect in the seawater and newlinesediment deposition characteristics along the continental shelf The present newlinestudy quantifies the spatial and vertical heterogeneity in the distribution of newlineseawater properties and geochemical parameters that influence their newlinedistributional trends in seafloor sediments during the 2009 post North East newlineNE and South West SW monsoon periods along the continental shelf from newlineChennai to Nagapattinam East Coast Tamilnadu This study was conducted newlineto assess the status of the coastal biogeochemical environment and for this newlinepurpose seawater samples were collected from the sea surface and also at newlinevarying depths surface to 150 m depth at six different locations newlineThe nutrient analyses and the CTD data reveal a distinct variation newlinewith water depth along the continental slope and also the physicochemical newlineproperties of seawater are not homogenous The observed values of nutrients newlinefor the post NE monsoon period are low compared to the SW monsoon newlineperiod Contour plots indicate seasonal and spatial variations in physicochemical newlineparameters along the continental shelf of the east coast of India newlineThese observations are also reflected by the stable isotope oxygen data newlineSalinity temperature and stable isotope oxygen reconstruction showed that the newlineparameters increased towards the central regions of the coastal stretch newlineespecially along Tarangampadi and ChidambaramO values reflect a newlinepositive gradient with other biogeochemical parameters dissolved oxygen newlinesalinity pH and temperature It is very obvious that there exist a dynamic and newlinekinetic interaction between the saline waters and the sediment passing newlinethrough the seawater column at different depths and settling on the seafloor newline newline newline newline newline newline newline newline newline newline newline newline newline newline newline newline