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

0732983 - Vernet，Maria -斯克里普斯海洋学研究所0732450-货车多佛，辛迪-杜克大学0732711- Smith，克雷格-夏威夷大学0732917-麦考密克，迈克尔-汉密尔顿学院IPY合作研究：拉森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冰架的崩溃，威德尔海西部沿海沃茨的生态系统结构和功能正在发生深刻的变化。这种转变似乎产生了化能自养和光合生产之间的能量流的重新分配，并导致冰架下发现的非凡渗漏生态系统的迅速消亡。 这一活动为研究与气候变化相关的生态系统过渡的基本方面提供了一个理想的机会。我们建议测试以下假设，以阐明发生在海洋生态系统中的变化作为拉森B崩溃的后果：（1）的地理隔离和亚冰架设置的拉森B渗漏导致新的栖息地特征，化能自养依赖类群和功能适应。(2)前拉森B冰架下的底栖生物群落与威德尔海冰区类似深度的组合有着根本的不同，类似于贫营养深海群落。拉森B组合正在经历迅速的变化。(3)以前黑暗，贫营养沃茨的拉森B海湾现在支持一个蓬勃发展的光养社会，生产率和浮游植物组成类似于其他生产领域的威德尔海。为了记录拉森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，船上采样器和停泊的沉积物捕集器。 我们将表征微生物，大型动物和巨型动物组成的渗漏社区;评估模式的表面生产力，出口通量，和底栖动物组成的地区以前覆盖的冰架，并比较这些地区的开放海冰区。 这些变化将被放置在地质，冰川学和气候学的背景下，导致冰架退缩，通过同伴研究项目资助与这项工作的一致。 这些项目将有助于预测冰架崩溃对南极洲其他易受气候变化影响的地区的海洋生态系统可能产生的后果。 这项研究的特点是来自阿根廷、比利时、加拿大、德国、西班牙和英国的国际合作者。 更广泛的影响包括：一名科学作家的参与; Jim Lehrer News Hour（公共广播系统）成员广播科学节目;环境变化暑期课程材料;指导研究生和博士后研究员;通过播客向学生和公众展示科学活动和研究成果。

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.