Collaborative Research: BEST: The Trophic Role of Euphausiids in the eastern Bering Sea: Ecosystem Responses to Changing Sea-ice Conditions

哈维0732667大学。主要研究人员的主要假设是，海冰和相关食物资源的时间和覆盖范围的季节性和年际变化将导致海龟的年龄结构、饮食历史和营养状况的差异，这最终转化为生产率和可获得性的差异，作为更高营养水平的猎物。研究人员的目标包括：1.确定气候驱动的海冰条件变化对主要海鞘动物的脂肪含量和脂肪种类的潜在影响，从而在季节和年际时间尺度上确定营养状况和繁殖潜力。了解在不断变化的空间(即冰盖、冰缘和开阔水域)和时间(即季节性和年际)捕食场下，真姬鼠的摄食史、摄食率和放牧策略。将使用多种方法(即喂养实验、肠道内容物分析)来验证和确定特定脂肪饮食标记物的保留率。应用生物化学方法的最新进展，以确定真姬鼠野外种群的年龄结构，以及气候变化对季节性和间歇性队列种群维持或中断的潜在影响。由阿拉斯加同事进行的平行实验室饲养将允许在队列中校准准确的年龄。该项目是一个更大的项目的一部分，该项目旨在加深对东部白令海大陆架综合生态系统的了解，白令海大陆架是美国沿海水域的一个高产地区。这个生态系统是美国大部分商业渔业的家园，也为阿拉斯加的自给自足的猎人和渔民提供了重要的资源。在连接浮游生物和该地区鱼类资源的食物网中，真甲鱼被认为是关键的一环。了解这些生物的生态对于了解商业和自给性渔业如何应对不断变化的环境至关重要。

Harvey 0732667Univ. of Maryland Center for Environmental Sciences/CBLThe principal investigators' primary hypothesis is that seasonal and interannual variation in the timing and coverage of sea-ice and associated food resources will lead to differences in age structure, diet history and nutritional condition for euphausids, which ultimately translate into differences in production rates and availability as prey to higher trophic levels. Funds are provided to quantify the age structure and diet history of important euphausids together with detailed information on their consumption and growth and to link field collections and analysis with laboratory rearing for age calibrations and shipboard feeding experiments to test the validation and retention of trophic lipid markers as well as the quality and quantity of food resources.The investigators' objectives include:1. To determine the potential impact of climate driven changes in sea-ice conditions on lipid content and lipid classes in major euphausid species and thus nutritional condition and reproductive potential over seasonal and interannual time scales.2. To understand the feeding history, feeding rates and grazing strategies of euphausids under changing spatial (i.e. ice-covered, ice-edge, and open water zones) and temporal (i.e. seasonal and interannual) prey fields. Multiple approaches (i.e. feeding experiments, gut content analysis) will be used for validation and determination of retention of specific lipid dietary markers.3. To apply recent advances in biochemical approaches to determine the age structure in field populations of euphausids and the potential effects of climate change on maintenance or disruption of cohort populations seasonally and interannually. Laboratory rearing conducted in parallel by Alaskan colleagues will allow calibrating precise ages in cohorts.This project is part of a larger program designed to develop understanding of the integrated ecosystem of the eastern Bering Sea shelf, a highly productive region of US coastal waters. This ecosystem is home to a major portion of the commercial fisheries of the US and also provides significant resources to subsistence hunters and fisherman of Alaska. Euphausids are believed to be a critical link in the food web connecting plankton to fish resources in the region. Understanding the ecology of these organisms is critical to understanding how the commercial and subsistence fisheries may respond to a changing environment.