text: Lipid:In marine sediments, a stable lipid called IP25 (Ice Proxy with 25 carbon atoms), which is biosynthesized by sea-ice dwelling diatom, has been found to be generally related to spring sea-ice cover in the Arctic region, Thus this proxy could be used to reconstruct sea-ice coverage. A different biomarker, IPSO25 (Ice Proxy Southern Ocean with 25 carbon atoms) has been documented as a useful proxy for the sea-ice cover in the Antarctic region.