15N enrichment in the surface Particulate Organic Nitrogen of the north-eastern Arabian Sea from the middle to the waning phase of the winter monsoon: possible causes

Other literature type English OPEN
Kumar, S. ; Ramesh, R. (2007)

A temporal increase of ~5&permil; in the average nitrogen isotopic composition (&delta;<sup>15</sup>N<sub>PON</sub>) of surface particulate organic nitrogen was observed in the open north-eastern Arabian Sea during January to late February-early March 2003, despite the presence of <i>T. erithraeum</i> (up to ~11%), a diazotroph that fixes atmospheric N<sub>2</sub>, in the latter period. Hydrographic conditions and residence time of nitrate in the water column suggested that this increase could be a combined effect of denitrification in the subsurface layer and inefficient utilization of nitrate entrained in the water column during January.
Share - Bookmark