Collaborative Research in IPY: Abrupt Environmental Change in the Larsen Ice Shelf System, a Multidisciplinary Approach - Marine Ecosystems.

0372983 - Vernet， Maria - Scripps海洋研究所0372950 - Van Dover， Cindy - Duke大学0372711 - Smith， Craig - University of hawaii 0372917 - McCormick， Michael - Hamilton学院IPY合作研究：larsen冰架系统的环境突变，多学科方法-海洋生态系统。随着拉森B冰架的崩塌，威德尔海西部沿海水域的生态系统结构和功能正在发生深刻的变化。这种转变似乎在化学自养和光合作用之间产生了能量流的重新分配，并导致了在冰架下发现的非凡的渗透生态系统的迅速消亡。这一事件为研究与气候变化相关的生态系统转型的基本方面提供了一个理想的机会。为了解释Larsen B崩塌对海洋生态系统的影响，我们提出了以下假设：(1)Larsen B渗漏的生物地理隔离和亚冰架环境导致了新的栖息地特征、化学自养依赖的分类群和功能适应。(2)前Larsen B冰架下的底栖生物群落与威德尔海冰带相似深度的底栖生物群落有着根本的不同，类似于贫营养深海群落。Larsen B组合正在经历快速变化。(3)拉森B湾以前黑暗、营养不良的水域现在支持一个繁荣的光养群落，其产量和浮游植物组成与威德尔海的其他生产区域相似。为了记录Larsen B生态系统中发生的快速变化，我们将使用远程操作的车辆，船上采样器和系泊沉积物陷阱。我们将描述渗漏群落的微生物，大型动物和巨型动物组成部分；评估以前被冰架覆盖地区的地表生产力、输出通量和底栖动物组成模式，并将这些地区与开放的海冰区进行比较。这些变化将被置于导致冰架退缩的地质、冰川学和气候学背景下，通过与这项工作协同资助的配套研究项目。这些项目将共同帮助预测冰架崩塌对易受气候变化影响的南极洲其他地区的海洋生态系统可能造成的后果。这项研究有来自阿根廷、比利时、加拿大、德国、西班牙和英国的国际合作者参与。更广泛的影响包括科学作家的参与；吉姆·莱勒新闻时间（公共广播系统）的成员播放科学片段；环境变化暑期课程教材；研究生和博士后的指导；并通过播客向学生和公众展示科学活动和发现。

0732983 - Vernet, Maria - Scripps Institute of Oceanography0732450 - Van Dover, Cindy - Duke University0732711 - Smith, Craig - University of Hawaii0732917 - McCormick, Michael - Hamilton CollegeCollaborative Research in IPY: Abrupt Environmental Change in theLarsen Ice Shelf System, a Multidisciplinary Approach - MarineEcosystems.A profound transformation in ecosystem structure and function is occurring in coastal waters of the western Weddell Sea, with the collapse of the Larsen B ice shelf. This transformation appears to be yielding a redistribution of energy flow between chemoautotrophic and photosynthetic production, and to be causing the rapid demise of the extraordinary seep ecosystem discovered beneath the ice shelf. This event provides an ideal opportunity to examine fundamental aspects of ecosystem transition associated with climate change. We propose to test the following hypotheses to elucidate the transformations occurring in marine ecosystems as a consequence of the Larsen B collapse: (1) The biogeographic isolation and sub-ice shelf setting of the Larsen B seep has led to novel habitat characteristics, chemoautotrophically dependent taxa and functional adaptations. (2) Benthic communities beneath the former Larsen B ice shelf are fundamentally different from assemblages at similar depths in the Weddell sea-ice zone, and resemble oligotrophic deep-sea communities. Larsen B assemblages are undergoing rapid change. (3) The previously dark, oligotrophic waters of the Larsen B embayment now support a thriving phototrophic community, with production rates and phytoplankton composition similar to other productive areas of the Weddell Sea. To document rapid changes occurring in the Larsen B ecosystem, we will use a remotely operated vehicle, shipboard samplers, and moored sediment traps. We will characterize microbial, macrofaunal and megafaunal components of the seep community; evaluate patterns of surface productivity, export flux, and benthic faunal composition in areas previously covered by the ice shelf, and compare these areas to the open sea-ice zone. These changes will be placed within the geological, glaciological and climatological context that led to ice-shelf retreat, through companion research projects funded in concert with this effort. Together these projects will help predict the likely consequences of ice-shelf collapse to marine ecosystems in other regions of Antarctica vulnerable to climate change. The research features international collaborators from Argentina, Belgium, Canada, Germany, Spain and the United Kingdom. The broader impacts include participation of a science writer; broadcast of science segments by members of the Jim Lehrer News Hour (Public Broadcasting System); material for summer courses in environmental change; mentoring of graduate students and postdoctoral fellows; and showcasing scientific activities and findings to students and public through podcasts.