Microbial and chemical data on sea-ice brines

Sea-ice brines were collected from sackholes drilled into the ice cover of Kanajorsuit Bay in 2013 and Kobbefjord in 2014 near Nuuk, Greenland, along with sea-ice cores and under-ice seawater samples. Data obtained include concentrations of bacteria, viruses, particulate organic carbon and nitrogen, extracellular polysaccharides, chlorophyll a and phaeophytin pigments, and total suspended particulate matter, along with temperature, salinity, snow thickness, ice thickness and sackhole depth. Experimental work conducted on the samples, with additional details on sample characteristics, are published in Firth et al. (2016) [DOI 10.12952/journal.elementa.000120]. The purpose of the experiments was to assess the use of compatible solutes as a microbial strategy for surviving the fluctuations in salinity that occur seasonally in sea-ice brines and search for links to primary production. We found that compatible solutes are taken up and stored as brine salinity increases, and released and respired as salinity freshens. We found novel links to primary production mediated by bacterial nitrification but not by algal photosynthesis, as chlorophyll levels were negligible in the brines sampled.