LTER Palmer, Antarctica (PAL): Land-Shelf-Ocean Connectivity, Ecosystem Resilience and Transformation in a Sea-Ice Influenced Pelagic Ecosystem

帕尔默南极洲LTER(长期生态研究)站点自1990年以来一直在运行。所有LTER站点的目标是对生态问题进行与政策相关的研究，这些问题需要数十年的数据，并覆盖大片地理区域。对于帕尔默南极LTER来说，问题的中心是南极洲半岛以西的海洋生态系统如何应对与地球上任何地方一样迅速变化的气候。例如，过去35年的卫星观测表明，海冰覆盖的平均持续时间现在约为90天(3个月！)比以前更短了。开放水域的延长对生态系统研究的许多方面都有影响，该区域内的阿德利企鹅同时减少，经常被认为是南极洲气候变化影响的典范。自动水下(和可能是空中)航行器、海底系泊和数值模拟等尖端技术，再加上每年一次的海洋巡航和每周一次的环境采样，使帕尔默南极长期热辐射研究能够扩大和连接评估气候影响所需的时间和空间尺度。该奖项首次包括研究鲸鱼在季节性海冰生态系统中作为主要捕食者的作用。该团队还将专注于西南极半岛(WAP)沿岸的海底峡谷，这是生物活动增强的特殊地区。目前该奖项的主要研究问题是：海冰范围和持续时间的季节性、年际变化和长期趋势如何影响海洋生态系统和生物地球化学循环的结构和动态？这一广泛问题中的具体焦点包括：1.长期变化和生态系统转型。作为生态系统状态的函数，生态系统对外部扰动的敏感性或弹性是什么？2.横向连通性和垂直分层。淡水、热量和营养物质的横向输送对当地海洋分层和生产力有何影响？它们如何推动生态系统的变化？3.自上而下的控制和基线的变化。生态系统如何应对捕鲸活动的停止和随后鲸鱼种群的长期恢复？4.食物网结构和生物地球化学过程。食物网结构的时空变化如何影响碳和养分的循环、输出和储存？该奖项的更广泛影响利用了当地的教育合作伙伴关系，包括三明治、麻省理工学院、新英格兰水族馆，以及美国国家科学基金会资助的哥伦比亚地球研究所的极地学习和应对气候变化教育伙伴关系，以在北极和南极、海洋和陆地科学家和学生、政府和非政府组织之间建立新的协同效应。帕尔默南极LTER还将进行适当的跨LTER地点比较，并在信息管理方面发挥领导作用，以便在南极、海洋和LTER社区内外进行知识建设。

The Palmer Antarctica LTER (Long Term Ecological Research) site has been in operation since 1990. The goal of all the LTER sites is to conduct policy-relevant research on ecological questions that require tens of years of data, and cover large geographical areas. For the Palmer Antarctica LTER, the questions are centered around how the marine ecosystem west of the Antarctica peninsula is responding to a climate that is changing as rapidly as any place on the Earth. For example, satellite observations over the past 35 years indicate the average duration of sea ice cover is now ~90 days (3 months!) shorter than it was. The extended period of open water has implications for many aspects of ecosystem research, with the concurrent decrease of Adèlie penguins within this region regularly cited as an exemplar of climate change impacts in Antarctica. Cutting edge technologies such as autonomous underwater (and possibly airborne) vehicles, seafloor moorings, and numerical modeling, coupled with annual oceanographic cruises, and weekly environmental sampling, enables the Palmer Antarctica LTER to expand and bridge the time and space scales needed to assess climatic impacts. This award includes for the first time study of the roles of whales as major predators in the seasonal sea ice zone ecosystem. The team will also focus on submarine canyons, special regions of enhanced biological activity, along the Western Antarctic Peninsula (WAP).The current award's overarching research question is: How do seasonality, interannual variability, and long term trends in sea ice extent and duration influence the structure and dynamics of marine ecosystems and biogeochemical cycling? Specific foci within the broad question include: 1. Long-term change and ecosystem transitions. What is the sensitivity or resilience of the ecosystem to external perturbations as a function of the ecosystem state? 2. Lateral connectivity and vertical stratification. What are the effects of lateral transports of freshwater, heat and nutrients on local ocean stratification and productivity and how do they drive changes in the ecosystem? 3. Top-down controls and shifting baselines. How is the ecosystem responding to the cessation of whaling and subsequent long-term recovery of whale stocks? 4. Foodweb structure and biogeochemical processes. How do temporal and spatial variations in foodweb structure influence carbon and nutrient cycling, export, and storage? The broader impacts of the award leverage local educational partnerships including the Sandwich, MA STEM Academy, the New England Aquarium, and the NSF funded Polar Learning and Responding (PoLAR) Climate Change Education Partnership at Columbia's Earth Institute to build new synergies between Arctic and Antarctic, marine and terrestrial scientists and students, governments and NGOs. The Palmer Antarctic LTER will also conduct appropriate cross LTER site comparisons, and serve as a leader in information management to enable knowledge-building within and beyond the Antarctic, oceanographic, and LTER communities.