Is colonization of sea ice by diatoms facilitated by increas

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TitleIs colonization of sea ice by diatoms facilitated by increased surface roughness in growing ice crystals?AbstractColonization by ice algae at the bottom of the sea ice is important ecologically as these algae are the major carbon source for zooplankton and the Polar food chains from early spring and until ice break-up several months later. At that time, ice algae can seed the water column promoting the pelagic production. We collected a time-series of ice growth, surface roughness, ice algae biomass (Chl-a), photosynthetic performance, primary production, irradiance, species composition, under ice ADCP data, nutrients, and ice algae spatial distribution in Kangerlussuaq, Greenland. A significant increase in biomass, primary production, and photosynthetic performance was observed at the bottom of the first-year sea ice. This colonization was not related to any change in light or nutrient availability, but instead occurred over a few days after which all parameters remained stable and constant. Colonization was concurrent with active ice growth associated with a period of very cold air temperatures as low as minus 35 degrees C. This new ice growth featured ice crystals and dendrites that significantly increased the surface roughness of the bottom, which facilitated the colonization. The dendrites are about 0.5 mm high and with a similar distance between the crests. The species composition of ice algae was similar in the water below and at the ice bottom, though biomass remained significantly lower in the water, and was dominated by Fragilariopsis oceanica and Navicula vanhoeefi. It is concluded that the colonization of the bottom of the sea ice is solely related to the increase in surface roughness initiated in the growing ice. © 2016, Springer-Verlag Berlin Heidelberg.Funding DetailsAU, Aarhus Universitet; Carlsbergfondet; FNU, DFF, Natur og Univers, Det Frie Forskningsrad

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1st AuthorLund-Hansen, L.AuthorLund-Hansen, L.Hawes, I.Nielsen, M.Sorrell, B.Year2017JournalPolar BiologyVolume40Number3Pages593-602DOI10.1007/s00300-016-1981-3URLhttps://www.scopus.com/inward/recor.....937e36db3bba536b67724fe82Author KeywordsChl-aColonizationIce algaePhotosynthetic performanceSurface roughness

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TypeArticleCitationLund-Hansen, L., Hawes, I., Nielsen, M. and Sorrell, B. (2017). Is colonization of sea ice by diatoms facilitated by increased surface roughness in growing ice crystals? Polar Biology, 40(3): 593-602