Significant mixed layer nitrification in a natural iron-fertilized bloom of the Southern Ocean

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Collective effects in complex plasma

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Revisiting carbon flux through the ocean's twilight zone

Citation only. Published in Science 316: 567-570, doi: 10.1126/science.1137959Funding was obtained primarily through the NSF, Ocean Sciences Programs in Chemical and Biological Oceanography, with additional support from the U.S. Department of Energy, Office of Science, Biological and Environmental Research Program, and other national programs, including the Australian Cooperative Research Centre program and Australian Antarctic Division

Biogenic silica recycling in sea ice inferred from Si-isotopes: constraints from Arctic winter first-year sea ice

We report silicon isotopic composition (d30Si vs. NBS28) in Arctic sea ice, based on sampling of silicic acid from both brine and seawater in a small Greenlandic bay in March 2010. Our measurements show that just before the productive period, d30Si of sea-ice brine similar to d30Si of the underlying seawater. Hence, there is no Si isotopic fractionation during sea-ice growth by physical processes such as brine convection. This finding brings credit and support to the conclusions of previous work on the impact of biogenic processes on sea ice d30Si: any d30Si change results from a combination of biogenic silica production and dissolution. We use this insight to interpret data from an earlier study of sea-ice d30Si in Antarctic pack ice that show a large accumulation of biogenic silica. Based on these data, we estimate a significant contribution of biogenic silica dissolution (D) to production (P), with a D:P ratio between 0.4 and 0.9. This finding has significant implications for the understanding and parameterization of the sea ice Sibiogeochemical cycle, i.e. previous studies assumed little or no biogenic silica dissolution in sea ice.BELCANT