Cross-Site: Microbial Loop Dynamics and Regulation of Bacterial Physiology in Subtropical and Polar Marine Habitats

跨站点：亚热带和极地海洋栖息地的微生物循环动力学和细菌生理学调节

• 批准号: 9526986
• 负责人: David Karl
• 金额: $ 15.81万
• 依托单位: University of Hawaii
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 1996
• 资助国家: 美国
• 起止时间: 1996-01-01 至 1998-12-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=9526986&HistoricalAwards=false
• 关键词: Cross; Site; Microbial; Loop; Dynamics

The microbial loop has been shown to play an important role in marine and freshwater plankton ecosystems in all climatic zones. Earlier research in two contrasting habitats: an Antarctic coastal/ shelf/oceanic ecosystem and a subtropical oceanic ecosystem, have shown significant differences in the ecological role of the microbial loop and the physiology of bacterioplankton. These two habitats are isolated from input of terrestrially derived organic matter and so provide excellent opportunities to study bacterial metabolism of autochthonous organic matter of phytoplankton origin. Strong contrasts in plankton community parameters make these two sites ideal for this comparison. This study will be embedded within on-going programs at each of these two sites (US-JGOFS Hawaii Ocean Time-series in the North Pacific and Palmer LTER in Antarctica) that provide both logistical support and supporting data on a wide range of hydrographic, chemical and biological parameters, with extensive documentation of spatial and temporal variation. Preliminary field results show that bacterial communities in th ese two areas are physiologically distinct, that bacterial physiology is regulated by the structure of the microbial community and particularly by grazer recycling of nitrogen, that organic compounds rare in seawater, especially histidine, play a large role in regulation of bacterial ectoenzyme expression, and that photolysis of dissolved organic matter by solar ultraviolet radiation also plays a role in regulation of bacterial ectoenzymes. More thorough investigation of these phenomena in ecologically distinct microbial communities will facilitate understanding of the complex interactions between bacterioplankton and the rest of the microbial community.

微生物环已被证明在所有气候带的海洋和淡水浮游生物生态系统中发挥重要作用。早期对南极海岸/陆架/海洋生态系统和亚热带海洋生态系统这两个不同生境的研究表明，微生物环的生态作用和浮游细菌的生理作用存在显著差异。这两个生境与陆源有机质的输入是隔离的，因此为研究浮游植物来源的原生有机质的细菌代谢提供了良好的机会。浮游生物群落参数的强烈对比使这两个地点成为进行这种比较的理想地点。这项研究将纳入这两个站点(北太平洋的美国-JGOFS夏威夷海洋时间序列和南极洲的Palmer LTER)正在进行的方案，这些方案提供后勤支助和关于广泛的水文、化学和生物参数的辅助数据，并提供大量的空间和时间变化记录。初步的野外研究结果表明，这两个地区的细菌群落在生理上是不同的，细菌的生理受微生物群落的结构，特别是氮的掠食循环的调节，海水中稀有的有机化合物，特别是组氨酸，在调节细菌胞外酶的表达方面发挥了很大的作用，而太阳紫外线对溶解有机物的光解也对细菌胞外酶的调节起到了作用。更深入地研究不同生态微生物群落中的这些现象，将有助于理解浮游细菌与其他微生物群落之间的复杂相互作用。