Aluminum and Manganese Distributions in the Solomon Sea: Results from the 2012 PANDORA Cruise

Much is still unknown about the sources of trace nutrients to the Equatorial Undercurrent (EUC), which ultimately contribute to high-nutrient regions in the Eastern Tropical Pacific. One region that is possibly a source of trace nutrients to the EUC is the Solomon Sea, located east of Papua New Guinea. A study during the summer of 2012, PANDORA, was conducted on board the R/V l’Atalante to determine currents and the geochemical makeup within the basin. Water samples were analyzed for aluminum and manganese using Flow Injection Analysis (FIA). At many stations, aluminum distributions exhibit a sub-surface minimum, located at approximately the same depth as a salinity maximum. Additionally, aluminum is enriched along coastal areas, particularly in the outflow of the Vitiaz Strait, which is concurrent with the findings of Slemons et al. 2010. These regions of high aluminum are also likely regions of iron enrichment. Manganese distributions in the Solomon Sea are similar to data collected north of the region by Slemons et al. 2010, and show a scavenged distribution with local inputs in the surface and concentrations decreasing at depth. This region has strong western boundary currents, and input from coastal margins, two large rivers, island mining sites, and hydrothermal activity, making it an important study-site to determine how trace nutrients are transported to the open ocean.