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

已提供资金调查海冰变化可能影响北极浅水架上以底栖生物为主的高产食物网的机制-由于底层水温度升高，移动的底栖捕食者的范围和数量扩大。 要解决的主要问题是：是在白令海中北部的底栖食物网限制由上而下的控制捕食者？眼镜绒鸭（SPEI）的越冬生存和/或繁殖条件是否受到气候驱动的冰盖趋势的影响，这些趋势允许竞争螃蟹和底栖鱼的种群扩大？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的主要底栖猎物的总体影响。这些捕食者包括SPEI、底栖鱼、雪蟹、海星和腹足类，模拟预期随着冰盖变化和由此产生的底层水温度变化而发生的螃蟹和底栖鱼种群变化对主要内温捕食者（SPEI）能量平衡的影响，继续对这一地区的底栖生物群落进行长期（1950-2004年）记录，以协助上述建模和分析。 此外，这些数据还将表明，在整个地区的一个子站测量的沉积物中的有机物供应是否下降，以及这些下降是否对应于冰缘春季水华期间和之后浮游植物直接降水的减少。 大型海洋生态系统食物网建模的一个主要未解决的挑战是整合在不同时空尺度上运作的组织水平，这可能对整个捕食者群落的大型海洋生态系统的承载能力至关重要，并确定该系统的变化如何影响能量平衡和顶级捕食者的分布。 在一个新的方法来解决这个问题，本研究将整合一个空间上明确的，基于个人的模型的觅食能量的SPEI与不太详细的空间模型的底栖猎物和移动的捕食者。

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.