Antarctic Marine Archaebacteria; Biological Properties and Ecological Significance

德隆9418442古细菌是一组进化上截然不同的原核生物。直到最近，考古菌被认为只在少数不同的环境中茁壮成长，这些环境要么非常热，要么非常咸，要么严格意义上的厌氧环境。最近的研究表明，在南极帕尔默站附近的沿海水域，远洋海洋考古细菌可以构成南极原核生物生物量的主要部分(30%)。由于帕尔默站附近的表层水域产生了迄今为止最高的远洋考古细菌生物量估计，该地区特别适合研究这些不寻常的微生物。拟议工作的主要目标是确定南极安弗斯岛沿海水域中上层海洋考古细菌的生态意义、分布和丰富，以及代谢和生理活动。将利用分子生物学技术量化南极海洋考古细菌物种的时空丰度和变异性。将开发高度灵敏的半自动方法来量化野外样本中的考古细菌群和物种特定的核糖体RNA和DNA。为了更好地了解它们的生理活动，将使用“王国特有的”代谢抑制剂的方法来估计远洋古细菌对总的原核异养活性的贡献。该项目将提供有关南极远洋考古细菌季节和空间变异性的资料，这些细菌可构成南极沿海原核生物生物量的主要部分。最后，该项目还将加强对这些丰富的南极沿海水域“古浮游生物”的生物地球化学活动和生态作用的了解，并可能为它们对独特的南极环境的具体适应提供线索。

Delong 9418442 Archaebacteria are an evolutionarily distinct group of prokaryotes. Until very recently, archaebacteria were thought to thrive only in a few disparate niches, consisting of either very hot, very salty, or strictly anaerobic environments. Recent studies show that pelagic marine archaebacteria can constitute a major fraction (30%) of Antarctic prokaryote biomass in coastal waters off Palmer Station, Antarctica. Since surface waters off Palmer Station have yielded the highest biomass estimates of pelagic archaebacteria to date, this area is uniquely suited for studing these unusual microorganisms. The main objective of the proposed work is to characterize the ecological significance, distribution and aboundance, and the metabolic and physiological activities, of pelagic marine archaebacteria in coastal waters off Anvers Island, Antarctica. Molecular biological techniques will be used to quantify the spatial and temporal abundance and variability of Antarctic marine archaebacterial species. Highly sensitive, semiautomated methods will be developed to quantify archaebacterial group and species-specific ribosomal RNA and DNA in field samples. To better understand their physiological activities, methods employing "kingdom-specific" metabolic inhibitors will be used to estimate the contribution of pelagic archaebacteria to total prokaryotic heterotrophic activity. The project will provide information on the seasonal and spatial variability of pelagic Antarctic archaebacteria, which can comprise a major fraction of Antarctic coastal prokarytoic biomass. Finally, this project will also enhance understanding of the biogeochemical activities and ecological roles of these abundant "archaeoplankton" in coastal Antarctic waters, and may provide clues as to their specific adaptations to the unique Antarctic environment.