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

附着藻类最近被认为是世界上最丰富和最多样化的初级生产者。海洋，使其代谢和碳固定途径的问题至关重要。由等鞭金藻目的附着藻类产生的烯酮脂质在世界上普遍存在？它是古温度重建的宝贵工具。然而，培养的附着植物和观察到的沉积物中的烯酮分布之间的不匹配，阻碍了在湖泊中使用烯酮作为古温度代理。为了有信心地应用烯酮不饱和度在湖泊古温度重建，有必要充分了解生物学和生物化学的湖泊产生烯酮的附着植物使用的财团的技术，包括培养，脂质和分子表征。这一建议建立在我们成功地获得了第一个稳定的富集培养的湖泊附着植物，主要产生C37：4烯酮，烯酮丰富的淡水和半咸水环境。在乔治湖，对湖水和浮游生物进行系统采样，并对环境参数进行原位测量，结合对我们的附着植物培养的广泛操作，将允许识别附着植物藻类水华的触发因素。我们的研究将促进多学科的合作（有机地球化学、分子生物学、藻类学、古气候学、湖沼学）研究重要的生物学、地球化学和古气候学问题，并允许研究生和本科生的跨学科培训。与布朗大学现有的NSF资助的GK-12项目的密切互动将使高中教师参与实地考察和实验室研究，并在当地学校进行讲座，将广泛传播我们的研究。从这项研究中产生的数据也将被纳入有机地球化学和分子生物学课程针对高级本科生/研究生水平，并帮助支持全日制研究生专注于湖泊附着植物。

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.