Roles of Heterotrophic Bacteria and Protists in the Arctic Ocean Carbon Cycle

9400218由这笔赠款支持的谢尔研究由北极系统科学全球变化研究计划赞助，由海洋科学部和极地方案办公室联合赞助。这项研究将围绕着对北冰洋从未被广泛研究的部分进行一次独特的、密集的、多学科的研究考察。1994年美国/加拿大北冰洋部分是与加拿大的一项合作努力，将有大约60名科学家在1994年夏天在一艘加拿大破冰船和一艘美国破冰船上工作。NSF资助的项目将集中在水文地理学、生物学、古生物和海冰研究上。从北冰洋几个地区收集的数据将是有史以来最早的数据之一，对于增进我们对北极如何成为全球气候条件变化的指标以及它如何影响较温和海洋和地区的物理、化学和生物特征的理解，将具有非常重要的意义。俄勒冈州立大学和特拉华大学的研究人员之间的这项合作研究工作是AOS生物学计划的关键组成部分。研究将测量微型浮游动物的丰度、生物量和大小分布，以及它们对浮游植物和其他浮游动物的捕食估计。工作的重点将是北冰洋水柱和海冰中的异养细菌和原生生物。目前关于这些微生物的丰度和活性以及它们对初级生产的影响的信息很少。研究人员将量化细菌的数量、生物量和生产力的分布，并将这些参数与不稳定的有机底物(溶解自由+结合氨基酸和糖)的原位浓度进行比较；量化纳米级和微型浮游生物类中捕食性原生动物的丰度、大小频率分布和生物量；以及测量原生生物对细菌和藻类细胞的放牧影响。还将进行不同底物浓度和温度的培养实验，以确定对异养细菌生长的影响。了解这些过程将有助于解决异养和自养微生物对北极碳循环的影响。***

9400218 Sherr Research supported by this grant is under the auspices of the Arctic Systems Science (ARCSS) Global Change Research Program and is jointly sponsored by the Division of Ocean Sciences and the Office of Polar Programs. The research will be centered around a unique and intensive, multidisciplinary research expedition to parts of the Arctic Ocean that have never been extensively studied. The 1994 U.S./Canada Arctic Ocean Section is a collaborative effort with Canada that will involve approximately 60 scientists on a Canadian and a U.S. icebreaker during summer 1994. NSF-funded projects will focus on hydrography, biology, paleo-, and sea-ice studies. Data collected will be amongst the first ever from several regions of the Arctic Ocean and will be highly relevant to improving our understanding of how the Arctic is an indicator of changing global climate conditions and how it affects the physical, chemical, and biological features of the more temperate oceans and regions. This collaborative research effort between investigators at Oregon State University and the University of Delaware represents a critical component of the AOS biology program. Research will measure microzooplankton abundances, biomass, and size distributions, together with estimates of their grazing on phytoplankton and other zooplankton. Work will focus on heterotrophic bacteria and protists in the water column and sea ice of the Arctic Ocean. Present information is sparse on the abundance and activity of these microbes and about their influence on primary production. The investigators will quantify the distribution of numbers, biomass, and productivity of bacteria and compare these parameters to the in situ concentrations of labile organic substrates (dissolved free + combined amino acids and sugars); quantify the abundance, size frequency distribution, and biomass of phagotrophic protists in the nano- and microplankton size classes; and measure the grazing impact of protists on bacteria and on algal cells . Incubation experiments will also be performed where substrate concentrations and temperatures are varied to ascertain the effect on heterotrophic bacterial growth. Understanding these processes will help resolve role heterotrophic and autotrophic microbes' influence on the Arctic carbon cycle. ***