alkenone

:  any of various long-chain unsaturated ketones that are produced by phytoplanktonic algae (such as the coccolithophores) ◆Analysis of the chemical structure of alkenones present in marine sediment is used as a method to determine past sea temperatures. To further the current climate debate, the chapter “Deep Sea Mud” explains how compounds such as alkenones, left by the marine alga Emiliania huxleyi, among other species, provide a temperature proxy. — Karen Bushaw-Newton, Bioscience, 1 Sept. 2009