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

0732983-韦尔内特，玛丽亚-斯克里普斯海洋研究所0732450-凡多佛，辛迪-杜克大学0732711-史密斯，克雷格-夏威夷大学0732917-麦考密克，迈克尔-汉密尔顿学院国际海洋年合作研究：拉森冰架系统的突然环境变化，多学科方法-海洋生态系统。随着拉森B冰架的坍塌，韦德尔海西部沿海水域正在发生生态系统结构和功能的深刻变化。这种转变似乎正在化学自养和光合作用生产之间产生能量流的重新分配，并导致在冰架下发现的非凡的渗漏生态系统迅速消亡。这次活动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。我们建议检验以下假设来解释拉森B渗漏导致的海洋生态系统的变化：(1)拉森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、依赖化学自养的类群和功能适应。(2)前拉森B冰架下的底栖动物群落与韦德尔海冰带相似深度的群落有根本的不同，类似于贫营养深海群落。拉森B组合正在经历快速变化。(3)拉森B湾以前黑暗、营养稀少的水域现在支持着蓬勃发展的光养群落，其生产力和浮游植物组成与威德尔海的其他生产区相似。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运载工具、船上采样器和系泊沉积物捕集器。我们将确定SEEP群落的微生物、大型动物和大型动物组成的特征；评估以前被冰架覆盖的地区的表层生产力、出口通量和底栖动物组成的模式，并将这些地区与开阔的海冰区进行比较。这些变化将被放在导致冰架退缩的地质、冰川和气候背景下，通过与这一努力相一致的配套研究项目来进行。这些项目将有助于预测冰架坍塌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造成的后果。这项研究以来自阿根廷、比利时、加拿大、德国、西班牙和英国的国际合作者为特色。更广泛的影响包括一名科学作家的参与；Jim Lehrer新闻小时(公共广播系统)成员广播科学部分；夏季环境变化课程的材料；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.