Selective incorporation of dissolved organic matter (DOM) during sea ice formation

This study investigated the incorporation of DOM from seawater into >2 day-old sea ice in tanks filled with seawater alone or amended with DOM extracted from the microalga, Chlorella vulgaris. Optical properties, including chromophoric DOM (CDOM) absorption and fluorescence, as well as concentrations of dissolved organic carbon (DOC), dissolved organic nitrogen (DON), dissolved carbohydrates (dCHOs) and dissolved uronic acids (dUAs) were measured. Enrichment factors (EFs), calculated from salinity-normalized concentrations of DOM in bulk ice, brine and frost flowers relative to under-ice water, were generally >1. The enrichment factors varied for different DOM fractions: EFs were the lowest fo…