Climate-driven changes in impacts of benthic predators in the northern Bering Sea

提供资金用于研究海冰变化可能影响北极浅层大陆架上以底栖生物为主的非常富有生产力的食物网的机制--由于底层水温升高，移动的海底捕食者的范围和数量扩大。要解决的主要问题是：白令海中北部的底栖生物食物网是否受到捕食者自上而下的控制？白令海中北部的冰盖趋势是否影响了镜象的越冬生存和/或预繁殖条件，使竞争对手螃蟹和底栖鱼的数量得以扩大？为了回答这些问题，PI将收集所需的数据，以模拟捕食者对白令海中北部主要底栖生物猎物的总体影响。这些捕食者包括Spi、底层鱼、雪蟹、海星和腹足类，模拟蟹和底层鱼种群的变化对主要吸温性捕食者(SPEI)能量平衡的影响，预计随着冰盖和底层水温度的变化而发生，并继续该地区长期(1950-2004年)的底栖群落记录，这将有助于上述建模和分析。此外，这些数据还将表明，在一些站点测量到的沉积物有机质供应量是否在整个区域出现下降，以及这些下降是否对应于在冰缘春季水华期间和之后浮游植物直接降雨量的减少。在对大型海洋生态系统的食物网进行建模方面，一个尚未解决的主要挑战是整合在不同时间和空间尺度上运作的不同组织级别，这可能对大型海洋生态系统对整个捕食者群落的承载能力至关重要，并确定该系统的变化如何影响顶级捕食者的能量平衡和分布。在这一问题的新方法中，这项研究将结合空间上明确的、基于个体的SPAI觅食能量学模型，以及较不详细的底栖猎物和较少移动的捕食者的空间模型。

Funds are provided to investigate a mechanism by which sea-ice change might affect the very productive, benthic-dominated food webs on shallow arctic shelves - expansion of the ranges and numbers of mobile benthic predators owing to increased temperature of bottom water. The main questions to be addressed are:Is the benthic food web in the north-central Bering Sea limited by top-down control by predators?Are the overwinter survival and/or prebreeding condition of Spectacled Eider (SPEI) being impacted by climate-driven trends in ice cover that are allowing populations of competing crabs and groundfish to expand?To answer these questions, the PIs will:Collect data needed to model the total impact of predators on their mainbenthic prey in the north-central Bering Sea. These predators include SPEI, groundfish, snow crabs, sea stars, and gastropods,Simulate impacts on the energy balance of the main endotherm predator (SPEI) of variations in crab and groundfish populations expected to occur with changes in ice cover and resulting temperature of bottom water, andContinue a long-term (1950-2004) record of benthic communities in this area that will contribute to the modeling and analyses listed above. Additionally, these data would also indicate whether declines in organic matter supply to sediments that have been measured at a subset of stations have occurred throughout the area, and whether these declines correspond to a decrease in direct precipitation of phytoplankton during and after the ice-edge spring bloom. A major unsolved challenge in modeling food webs of large marine ecosystems is integrating across levels of organization that operate at different temporal and spatial scales that might be critical to the carrying capacity of a large marine ecosystem for the entire predator community and determining how changes in that system affect the energy balance and distribution of top predators. In a novel approach to this problem, this study will integrate a spatially-explicit, individual-based model of the foraging energetics of SPEI with less detailed spatial models of benthic prey and less mobile predators.