Biogeosciences www.biogeosciences.net 1726-4170 1726-4189 7 1 2010 10.5194/bg-7-11-2010 http://www.biogeosciences.net/7/11/2010/ http://www.biogeosciences.net/7/11/2010/bg-7-11-2010.html http://www.biogeosciences.net/7/11/2010/bg-7-11-2010.pdf 11 25 2010-01-05 Natural iron enrichment around the Antarctic Peninsula in the Southern Ocean M. V. Ardelan murato@nt.ntnu.no O. Holm-Hansen C. D. Hewes C. S. Reiss N. S. Silva H. Dulaiova E. Steinnes E. Sakshaug Norwegian University of Science and Technology (NTNU), Department of Biology, Trondheim 7491, Norway Polar Research Program, Marine Biology Research Division, Scripps Institution of Oceanography, University of California-San Diego, La Jolla, CA 92093-0202, USA NOAA Fisheries, Antarctic Ecosystem Research Division, La Jolla, CA 92037, USA Pontificia Universidad Católica de Valparaíso, Escuela de Ciencias del Mar, Chile Woods Hole Oceanographic Institution, Department of Marine Chemistry and Geochemistry, Woods Hole, MA 02543, USA Norwegian University of Science and Technology, Department of Chemistry, Trondheim 7491, Norway As part of the US-AMLR program in January-February of 2006, 99 stations in the South Shetland Islands-Antarctic Peninsula region were sampled to understand the variability in hydrographic and biological properties related to the abundance and distribution of krill in this area. Concentrations of dissolved iron (DFe) and total acid-leachable iron (TaLFe) were measured in the upper 150 m at 16 of these stations (both coastal and pelagic waters) to better resolve the factors limiting primary production in this area and in downstream waters of the Scotia Sea. The concentrations of DFe and TaLFe in the upper mixed layer (UML) were relatively high in Weddell Sea Shelf Waters (~0.6 nM and 15 nM, respectively) and low in Drake Passage waters (~0.2 nM and 0.9 nM, respectively). In the Bransfield Strait, representing a mixture of waters from the Weddell Sea and the Antarctic Circumpolar Current (ACC), concentrations of DFe were ~0.4 nM and of TaLFe ~1.7 nM. The highest concentrations of DFe and TaLFe in the UML were found at shallow coastal stations close to Livingston Island (~1.6 nM and 100 nM, respectively). 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