Collaborative Research: The Role of Microbial Food Webs in Carbon Fluxes and Shelf-Basin Exchange in the Arctic Ocean

陆架-盆地相互作用（SBI）计划和其他大型多学科项目最近完成了实地工作，以研究北冰洋的碳循环。这些方案包括对微生物现存量和生产量的测量，因为微生物在构建海洋食物网和调节海洋中无机碳和有机碳通量方面具有根本重要性。据推测，异养细菌和微生物环路的其余部分在高纬度海洋中的初级生产过程比大多数海洋制度少，因为常年冷水抑制微生物活性。SBI计划的一些数据表明，通过微生物循环的碳通量在北极西部低于温暖的海洋系统，而其他数据表明有机碳降解超过了初级生产率。这些观测结果对我们理解北极生产性陆架沃茨和有机碳贫乏盆地之间的碳输出和交换具有重要意义。然而，关于数据的有效性和解释、SBI研究结果的普遍性以及微生物过程对北极碳系统的影响等问题仍存在一些悬而未决的问题。在北冰洋不同区域，通过微生物循环的能量流结构是什么？将分析SBI和其他北极研究中关于微生物和相关生物地球化学参数的所有数据，以组成泛北极综合报告，并确定北冰洋生态系统各区域之间可能的联系。微生物活动对北极西部碳系统的影响是什么？微生物速率将与净群落生产率和DOM输出速率进行比较，这些速率是根据西北极DIC和DOC的时空变化估计的。迁移在使北冰洋有机物的生产和降解脱钩方面发挥什么作用？一个明确的，北冰洋环流和海洋地球化学的三维模型将被用来评估运输的生产和呼吸的空间和时间脱钩的作用，这项工作将有助于最大限度地利用SBI和其他程序收集的数据集，其中大部分还没有得到彻底的分析和综合。此外，数据合成和建模工作将提供一个框架，以考虑气候变化如何影响北极的碳通量和食物网动态。这种综合将是衡量这一重要生态系统潜在变化轨迹的重要里程碑。

The Shelf-Basin Interaction (SBI) program and other large, multi-disciplinary projects have recently completed field work to examine carbon cycling in the Arctic Ocean. These programs included measurements of microbial standing stocks and production because of the fundamental importance of microbes in structuring marine food webs and in modulating fluxes of inorganic and organic carbon in the oceans. It has been hypothesized that heterotrophic bacteria and the rest of the microbial loop process less primary production in high latitude oceans than in most oceanic regimes because perennially cold water inhibits microbial activity. Some of the data from the SBI program indicate that the flux of carbon through the microbial loop is lower in the western Arctic than in warmer marine systems, whereas other data indicate organic carbon degradation exceeds rates of primary production. These observations have major implications for our understanding of carbon export and exchange between productive shelf waters and organic carbon-poor basins of the Arctic. However, several unresolved issues remain about the validity and interpretation of the data, the generality of the SBI findings, and the impact of microbial processes on the Arctic carbon system.To address these issues, this effort will examine the following questions:1. What is the structure of energy flow through the microbial loop in various regions of the Arctic Ocean?All data on microbes and related biogeochemical parameters from SBI and other Arctic studies will be analyzed in order to compose a pan-Arctic synthesis and to identify possible linkages between regions of the Arctic Ocean ecosystem.2. What is the impact of microbial activity on the carbon system in the western Arctic?Microbial rates will be compared with rates of net community production and DOM export as estimated from temporal and spatial variations in DIC and DOC in the western Arctic.3. What is the role of transport in decoupling the production and degradation of organic matter in the Arctic Ocean?An explicit, three dimensional model of Arctic Ocean circulation and biogeochemistry will be used to evaluate the role of transport in the spatial and temporal decoupling of production and respiration.This work will help maximize use of the datasets collected by SBI and other programs, of which much has not been thoroughly analyzed and synthesized. In addition, the data synthesis and modeling efforts will provide a framework in which to consider how climate change may affect carbon fluxes and food web dynamics in the Arctic. This synthesis will be an essential mile post for gauging the trajectory of potential changes in this important ecosystem.