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This dataset is of the trace element composition (Al, Fe, P, Ca, Si) of suspended particulate matter samples collected in the Indian Ocean. Samples were collected in the upper 1000 m of the water column along U.S. CLIVAR/CO2 Repeat Hydrography zonal section I05 in 2009 in the South Indian subtropical gyre. The eastern Indian Ocean and South Indian subtropical gyre are characterized by a transition from a biologically productive system with significant fluvial sediment transport and aerosol deposition in the Bay of Bengal to an oligotrophic gyre with potentially significant input of particles from continental margin sources but relatively low aeolian trace metal inputs. These data are the first ocean section of trace particulate chemistry in the South Indian and Southern Oceans. High resolution sampling in the upper ocean along CLIVAR sections provides an opportunity to determine likely sources for biogenic and lithogenic particles and investigate the processes that drive their cycling. Suspended particulate matter (SPM) was collected by pressure-filtering (<55 kPa, filtered compressed air) seawater through acid-washed, 0.4 μm track-etched polycarbonate filters (Millipore). Backing filters of mixed cellulose ester were used for even sample loading in polypropylene filter holders. The average filtration volume was 9 L. Filters were gently rinsed with deionized water adjusted to pH 8 with ammonium hydroxide (3 x ~5 mL) with a low vacuum applied while avoiding loss or redistribution of particles in order to remove residual seasalt, avoiding salt interferences in ED-XRF analyses. SPM samples were analyzed using energy-dispersive x-ray fluorescence (ED-XRF) on a Thermo Fisher Quant’X under a vacuum atmosphere and calibrated with both commercial and custom made thin film standards. 

This dataset is of the trace element composition (Al, Fe, P, Ca, Si) of suspended particulate matter samples collected in the Indian Ocean along zonal I09N/I08S section from the Bay of Bengal to the subtropical front. The eastern Indian Ocean and South Indian subtropical gyre are characterized by a transition from a biologically productive system with significant fluvial sediment transport and aerosol deposition in the Bay of Bengal to an oligotrophic gyre with potentially significant input of particles from continental margin sources but relatively low aeolian trace metal inputs. These data are the first ocean section of trace particulate chemistry in the South Indian and Southern Oceans. High resolution sampling in the upper ocean along CLIVAR sections provides an opportunity to determine likely sources for biogenic and lithogenic particles and investigate the processes that drive their cycling. Suspended particulate matter (SPM) was collected by pressure-filtering (<55 kPa, filtered compressed air) seawater through acid-washed, 0.4 μm track-etched polycarbonate filters (Millipore). Backing filters of mixed cellulose ester were used for even sample loading in polypropylene filter holders. The average filtration volume was 9 L. Filters were gently rinsed with deionized water adjusted to pH 8 with ammonium hydroxide (3 x ~5 mL) with a low vacuum applied while avoiding loss or redistribution of particles in order to remove residual seasalt, avoiding salt interferences in ED-XRF analyses. SPM samples were analyzed using energy-dispersive x-ray fluorescence (ED-XRF) on a Thermo Fisher Quant’X under a vacuum atmosphere and calibrated with both commercial and custom made thin film standards. SPM samples were analyzed using energy-dispersive x-ray fluorescence (ED-XRF) on a Thermo Fisher Quant’X under a vacuum atmosphere and calibrated with both commercial and custom made thin film standards. 

This dataset is of the trace element composition (Al, Fe, P, Ca, Si) of suspended particulate matter samples collected in the Indian Ocean. Samples were collected in the upper 1000 m of the water column along U.S. CLIVAR/CO2 Repeat Hydrography meridional section IO9N in 2009 from the Bay of Bengal to the subtropical front. The eastern Indian Ocean and South Indian subtropical gyre are characterized by a transition from a biologically productive system with significant fluvial sediment transport and aerosol deposition in the Bay of Bengal to an oligotrophic gyre with potentially significant input of particles from continental margin sources but relatively low aeolian trace metal inputs. These data are the first ocean section of trace particulate chemistry in the South Indian and Southern Oceans. High resolution sampling in the upper ocean along CLIVAR sections provides an opportunity to determine likely sources for biogenic and lithogenic particles and investigate the processes that drive their cycling. Suspended particulate matter (SPM) was collected by pressure-filtering (<55 kPa, filtered compressed air) seawater through acid-washed, 0.4 μm track-etched polycarbonate filters (Millipore). Backing filters of mixed cellulose ester were used for even sample loading in polypropylene filter holders. The average filtration volume was 9 L. Filters were gently rinsed with deionized water adjusted to pH 8 with ammonium hydroxide (3 x ~5 mL) with a low vacuum applied while avoiding loss or redistribution of particles in order to remove residual seasalt, avoiding salt interferences in ED-XRF analyses. SPM samples were analyzed using energy-dispersive x-ray fluorescence (ED-XRF) on a Thermo Fisher Quant’X under a vacuum atmosphere and calibrated with both commercial and custom made thin film standards.