COLLABORATIVE RESEARCH: What Controls the Transfer of Diatom Organic Matter to age-0 Pollock Prey in the Bering Sea Ecosystem?

白令海的高产量和经济上重要的白鳕商业渔业依赖于对食物网途径知之甚少。有机碳的主要生产者，特别是硅藻，被大型甲壳类浮游动物消耗，而浮游动物又被幼鳕鱼消耗。该系统的主流范式表明，了解大型甲壳类浮游动物生物量的变化有助于估计鳕鱼幼鱼的存活率；然而，最近的数据显示，大型甲壳类浮游动物的碳需求存在两个数量级的不确定性。这种不确定性影响了管理渔业的能力。已经提出了该系统的订正模型，其中考虑到硅藻产生的有机物的数量和质量，以及这将如何限制对商业渔业的支持。在投资于主要的实地工作来测试这种方法之前，该项目将评估硅藻有机物生产的预期变化幅度和相关误差，包括用于估计它的单个术语，即丰度、生长速度和细胞碳。这项工作将基于实验室实验和历史数据分析。该项目将通过部分支持培训博士后助理，为STEM劳动力的发展做出贡献。本科生将通过毕格罗海洋科学实验室的REU项目和毕格罗项目的科尔比学院学期来学习这门科学。K-12外展将通过参与成功和长期存在的海豚岛海洋实验室探索大厅计划来促进。与公众的联系将通过博客来完成，毕格罗？《咖啡科学》和《毕格罗通讯》。本项目将开展的研究的长期目标是改进商业渔业管理的机制和预测模型。关于低营养水平的碳在白令海生态系统中流向何处的机制关系尚无共识，因此通常使用初级生产和渔业之间的简单比例关系。根据白令海生态系统研究（BEST）的估计，对0岁大的狭鳕猎物，即大型甲壳类浮游动物（LCZ）进行自下而上的控制，可以帮助限制初级生产者与狭鳕渔业之间的这种耦合，但LCZ的碳需求存在两个数量级的不确定性。需要一个新的概念模型，本项目将开始细化问题，重点关注硅藻，硅藻的分布不像LCZ那样斑块状，是LCZ的主要猎物。在了解硅藻损失过程的规模方面存在着重大的知识差距；要理解白令海东部初级生产与渔业之间的基本联系，合乎逻辑的下一步是回答：用于支持高营养生物的硅藻初级生产的比例是多少？该比例与哪些生物地球化学变量共变？在实地测试此方法之前，必须了解硅藻有机物生产的预期变化幅度和相关误差，包括用于估计的单个术语（即丰度、生长速度、细胞碳）。该项目将结合从高纬度地区分离的硅藻的培养研究与文献和BEST项目数据来实现这一最初目标。

The highly productive and economically important Walleye Pollock commercial fishery of the Bering Sea depends on poorly understood food web pathways. Primary producers of organic carbon, notably diatoms, are consumed by large crustacean zooplankton, which, in turn, are consumed by juvenile pollock. The dominant paradigm for the system suggests that understanding changes in the biomass of large crustacean zooplankton can help estimate the survival of juvenile pollock; however, recent data show two orders of magnitude uncertainty in the carbon demand of large crustacean zooplankton. Such uncertainties impact the ability to manage the fishery. A revised model for the system has been proposed that involves consideration of both the quantity and quality of organic matter produced by diatoms and how this would constrain support for the commercial fishery. Before investing in a major field effort to test this approach, this project will assess the expected magnitude of change and associated errors, for diatom organic matter production, including the individual terms that are used to estimate it, i.e. abundance, growth rate, and cell carbon. This effort will be based on laboratory experiments and historical data analysis. The project will contribute to STEM workforce development through partial support for the training of a post-doctoral associate. Undergraduates would be entrained into the science through an REU program at Bigelow Laboratory for Ocean Sciences and through the Colby College Semester at Bigelow program. K-12 outreach will be facilitated through participation in the successful and long-standing Dauphin Island Sea Lab Discovery Hall program. Outreach to the general public will be accomplished through a blog, Bigelow?s Café Scientifique, and the Bigelow newsletter. The long-term goal for the research that this project would initiate is improved mechanistic and predictive models for commercial fisheries management.There is no consensus on the mechanistic relationship of where carbon from the lower trophic levels goes in the Bering Sea ecosystem, hence simple proportionality relationships between primary production and fisheries are used routinely. Bottom-up control on age-0 walleye pollock prey, i.e. large crustacean zooplankton (LCZ), could help constrain this coupling between the primary producers and pollock fishery, but there is a two-order-of-magnitude uncertainty in the LCZ carbon demand based on estimates from the Bering Sea Ecosystem Study (BEST). A new conceptual model is required and this project will begin to refine the issue by focusing on diatoms, which have a less patchy distribution than LCZ and are a key prey item of LCZ. A major knowledge gap exists in the understanding of the magnitude of diatom loss processes; the logical next step to understanding the fundamental linkage between primary production and fisheries in the eastern Bering Sea is to answer: what is the proportion of diatom primary production available for supporting higher trophic organisms and with which biogeochemical variables does this covary? Before testing this approach in a field setting, the expected magnitude of change and associated error for diatom organic matter production, including the individual terms that go into that estimate (i.e. abundance, growth rate, cell carbon), must be understood. This project will combine culture studies using diatoms isolated from high-latitude regions with literature and BEST program data to meet this initial objective.