1Alfred Wegener Institute for Polar and Marine Research, Am Handelshafen 12, 27570 Bremerhaven, Germany
2Karlsruhe Institute of Technology, Institute for Synchrotron Radiation, Hermann-von-Helmholtz-Platz 1, 76344 Eggenstein-Leopoldshafen, Germany
3Norwegian Polar Institute, Polar Environmental Centre, 9296 Tromsø, Norway
4School of Ocean Sciences, Bangor University, Menai Bridge, Anglesey, LL59 5AB, UK
Abstract. We report for the first time on the discovery of calcium carbonate crystals as ikaite (CaCO3·6H2O) in sea ice from the Arctic (Kongsfjorden, Svalbard) as confirmed by morphology and indirectly by X-ray diffraction as well as XANES spectroscopy of its amorophous decomposition product. This finding demonstrates that the precipitation of calcium carbonate during the freezing of sea ice is not restricted to the Antarctic, where it was observed for the first time in 2008. This observation is an important step in the quest to quantify its impact on the sea ice driven carbon cycle.