Summary of Abstract Submission

Abstract Submission No. IO50-04-0020PresentationOral


Venkatesh Chinni*1, Sunil Kumar Singh1, Ravi Bhushan1, R. Rengarajan1

1 Physical Research Laboratory, India


Iron (Fe) is an essential trace element for marine organisms. Low concentrations of Fe limits primary production and nitrogen fixation in large parts of the oceans and finally influence the oceans ecosystem. Here, we present the dissolved iron (DFe) concentrations in water columns of Indian ocean. The clean sampling and measurement techniques are validated by comparing the vertical profile of DFe at cross over stations in the Indian Ocean and by analyzing GEOTRACES and SAFe reference samples. A total of 38 full vertical profiles have been collected during GEOTRACES-INDIA cruise SK-304, 311 and 312 along different meridional sections in the Indian Ocean between 18oN to 15oS. The DFe shows variable concentrations in surface waters ranging from 0.06 nM to 1.8 nM. The high surface concentrations ( > 0.4 nM) observed in Arabian sea (AS) waters are due to the deposition of dust from nearby sources and also from new iron which brought to the surface during upwelling. In the subsurface waters, DFe concentrations got elevated and reach a maximum of 1.5 nM suggesting remineralization of sinking organic material / presence of excess ligand concentrations and its concentrations remain constant throughout the water column. In some regions of Indian Ocean, elevated concentrations of iron has been noticed which could be resulting from resuspension of sediments or/and release of pore waters. The hydrothermal vents also seems to supply significant concentrations of iron in the deep Indian Ocean waters.