Ecological Significance of Planktonic Marine Archaebacteria

本研究的主要目的是研究一种新发现的丰富的海洋微浮游生物成分：浮游海洋古细菌的生理特性、代谢活性及其生态意义。近年来的研究结果表明，浮游海洋古细菌分布广泛，在海洋原核生物组合中可能相对丰富。现有数据表明，这些微生物可能显著影响海洋浮游生物的碳和能量通量。此外，由于所有其他已知的古细菌都具有独特的代谢和生理特性，因此浮游海洋古细菌很可能具有影响其生态功能的独特特性，并在定性上区别于其他原核微浮游生物。本研究将探讨浮游古细菌的定性特性及其对圣巴巴拉海峡微浮游生物生物量和产量的定量贡献。选择性检测浮游古细菌存在、代谢物和活动的方法将用于评估它们的生态意义。古细菌的相对丰度和分布将用于估计它们对浮游生物生物量的贡献。估算特定古细菌细胞代谢物（rRNA，脂质）中放射性标记的结合技术将用于确定浮游古细菌代谢池中营养物质的相对通量。这项研究将为一种普遍存在但鲜为人知的海洋浮游生物成分提供新的信息。本研究的最终目的是将浮游海洋古细菌的独特特性、生物量和代谢活动与它们影响海洋能量和物质流动的生物相互作用和生物地球化学过程联系起来。＊＊＊

9529804 Delong The primary objective of this research is to investigate the physiological properties, metabolic activities and ecological significance of a newly discovered abundant component of marine picoplankton: planktonic marine archaebacteria. Recently results have demonstrated that planktonic marine archaebacteria are widely distributed and can be relatively abundant in marine prokaryote assemblages. Available data suggest that these microorganisms may significantly influence carbon and energy flux in marine picoplankton. In addition, since all other known archaebacteria have unique metabolic and physiological properties, it is quite possible that planktonic marine archaebacteria have unique characteristics which influence their ecological function, and qualitatively distinguish them from other prokaryotic picoplankters. This study will investigate the qualitative properties of planktonic archaebacteria, and their quantitative contributions to picoplanktom biomass and production in the Santa Barbara Channel. Methods that selectively detect planktonic archaebacterial presence, metabolites, and activities will be used to assess their ecological significance. Measurements of archaebacteria relative abundance and distribution will be used to estimate their contribution to picoplankton biomass. Techniques that estimate incorporation of radiolabel into specific archaebacterial cellular metabolites (rRNA, lipids) will be used to determine the relative flux of nutrients into planktonic archaebacterial metabolic pools. This study will provide new information on a ubiquitous but, little understood component of marine picoplankton. The ultimate goal of this research is to relate the unique properties, biomass, and metabolic activities of planktonic marine archaebacteria to the biological interactions and biogeochemical processes through which they influence flows of energy and matter in the sea. ***