Carbon and Pigments in the Oceanic Ice Domain

Wednesday, May 14, 2014 - 07:00
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Brine channels of the global pack ice system import nutrients from below, provide habitat for primary producers and constitute a reservoir for organic detritus. Our ice biogeochemistry team is currently developing a global three dimensional simulation capability for these processes. Inorganics enter sea ice from the marine mixed layer, driving photosynthesis given light availability. The ensuing pack internal ecosystem generates carbonaceous waste with several critical effects on the polar environment -dissolved organic matter determines brine network permeability in Arctic sea ice, plus trapping and retention of iron in the Antarctic counterpart. In parallel with this work, DOE aerosol modelers are now improving distributions of soot deposition onto the pack. But in many locations, ice algal chlorophyll is likely to compete as an absorber. In a second phase, we will transport black carbon through overlying snow cover and into a common biogeochemical brine transport system. Absorption by the anthropogenic material will be compared with that of the ice algae themselves. We will map areas of soot versus biopigment dominance in the sense of single scattering, then couple into a full radiation transfer scheme to attribute the various contributions to polar climate change amplification. Early progress will be described in both these areas. The work prepares us to study more traditional issues such as chlorophyll warming of the pack periphery and carbonate expulsion from the ice bottom.

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