During sea ice formation, a portion of seawater is trapped in the ice matrix, resulting in concentrated brine. The nutrients in sea ice brine are expected to behave conservatively as a function of brine salinity. However, it is often found that the salinity-normalized nutrients in sea ice brine are depleted compared to those in the surface seawater, which is normally attributed to biological activity. Here we ask the question, are there other factors that can affect nutrient concentration in sea ice? We want to test a hypothesis that phosphate, which is one of the major nutrients, could be removed by ikaite precipitation in sea ice. According to the previous laboratory study, phosphate can be strongly coprecipitated with ikaite. However, no field work on this aspect so far is available. In this project carried out at SERF, we are interested to know at which degree the precipitation of ikaite will affect phosphate abundance in sea ice and whether this coprecipitation of phosphate with ikaite results in phosphate being a limiting nutrient for biological activity.

Field site: Sea-ice Environmental Research Facility (SERF), University of Manitoba, Winnipeg, Canada

PI: F.Wang

Project lead: Y.Hu

Project participants: Yubin Hu (CEOS); Wieter Boone (CEOS); Dr. Feiyue Wang (CEOS)

Fieldwork summary/photo blog

Link to project summary report