Collaborative Research: Capturing the Elusive 37:4 Alkenone-predominating Lacustrine Haptophyte: Alkenone Biosynthesis, Genetics and Culture Manipulation

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Haptophyte algae are recently credited as the most abundant and diverse primary producers in the world?s oceans, rendering their metabolic and carbon fixation pathways issues of utmost importance. Alkenone lipids produced by haptophyte algae of the order Isochrysidales occur ubiquitously in the world?s ocean and in numerous lakes and are an invaluable tool for paleotemperature reconstructions. However, the mismatch between cultured haptophytes and observed alkenone distributions in sediments has hindered the use of alkenones as a paleotemperature proxy in lakes. In order to confidently apply the alkenone unsaturation for paleotemperature reconstructions in lakes, it is necessary to fully understand the biology and biochemistry of the lacustrine alkenone-producing haptophytes using a consortium of techniques including culturing, lipid and molecular characterization. This proposal builds on our success in obtaining the first stable enrichment culture for a lacustrine haptophyte alga that produces predominantly C37:4 alkenones, the alkenone abundant in freshwater and brackish environments. Systematic sampling of lake water and plankton and in situ measurements of environmental parameters at Lake George, ND combined with extensive manipulation of our haptophyte culture will permit identification of the triggers for haptophyte algal blooms.Our study will promote multidisciplinary collaboration (organic geochemistry, molecular biology, phycology, paleoclimatology, limnology) to studying important biological, geochemical and paleoclimatological problems, and allow cross-discipline training of graduate and undergraduate students. Close interaction with Brown University's existing NSF funded GK-12 program will bring high school teachers to participate in field trips and laboratory research, and lectures given at local schools, will broadly disseminate our research. Data generated from this research will also be incorporated into organic geochemistry and molecular biology courses targeted at the advanced undergraduate/graduate level and help support a full-time graduate student focusing on lacustrine haptophytes.