Temporal and vertical distributions of IP25 and other lipid biomarkers in sea ice from Resolute Bay, Nunavut, Canada

Abstract

IP25 (Ice Proxy with 25 carbon atoms) is a highly branched isoprenoid biomarker, specifically produced by marine diatoms in Arctic sea ice. Temporal and vertical IP25 concentrations were measured in sea ice from a second location in the Canadian Arctic, Resolute Bay, Nunavut. Sea ice samples were collected as part of the Arctic ICE project in collaboration with scientists of the University of Manitoba from April to June 2011. Comparisons were made between other established lipid biomarkers of diatom origin and general organic production, along with previously established temporal and vertical distributions in sea ice collected from the Amundsen Gulf, from January to June 2008. IP25 was present in sea ice from a second location in the Canadian Arctic over the spring sea ice bloom period and concentrations correlated well with those of chlorophyll a (r = 0.81; n = 10; P < 0.05). IP25 and chlorophyll a were present throughout sea ice cores. Accumulation of IP25 and chlorophyll a were highest (89% - 99%) in the lower 3 cm, whereas vertical distributions of fatty acids were more distributed throughout the sea ice cores. Overall accumulation of IP25 in the lower section of the sea ice was found to be affected by snow cover.