LTER: PALMER, ANTARCTICA LTER: Climate Change, Ecosystem Migration and Teleconnections in an Ice-Dominated Environment

南极洲帕尔默长期生态研究项目（PAL）旨在了解南极洲西部半岛海洋和陆地生态系统的结构和功能，以及季节到年际的大气和海冰动态，以及长期气候变化。PAL测量系统（或网格）旨在研究海洋和陆地食物网，主要包括硅藻初级生产者，占主导地位的食草动物南极磷虾和顶端捕食者阿德利企鹅。一个弱化的微生物食物网也是一个焦点。PAL研究这些生态系统，每年在一个区域规模的网格海洋站和季节性在帕尔默站。海冰的范围和变异性影响着所有营养级的生态系统变化。近年来，由于该地区普遍变暖，海冰范围已经缩小。该地区依赖冰的阿德利企鹅的长期人口趋势为该地区气候变暖趋势的影响提供了一个明确的例子。在帕尔默站附近研究的五个主要殖民地的阿德利种群都显示出30年来数量的逐渐减少。半岛垂直于一个强烈的气候梯度，南部是寒冷干燥的大陆气候，这是南极内陆的特征，北部是温暖潮湿的海洋气候。南北梯度的变化引起了气候变化的巨大环境变异性。目前，随着气候梯度南移，更多的海洋条件似乎正在取代半岛北方原有的极地生态系统。到目前为止，这种转变似乎匹配的生态系统的转变沿着半岛，阿德利种群的下降，需要更长的积雪季节成功招聘证明。主要的假设是，生态系统的迁移是最清楚地表现在上层捕食者（企鹅）和某些极地鱼类捕食环境中的变化。这是因为这些寿命较长的物种整合了最近的气候趋势，并且因为单个物种比聚集的功能群更敏感。类似的变化预计将在未来几年内在该系统的海洋部分的较低营养级中表现出来。然而，这些较低水平的变化可能只能通过长期观测观察到的生态系统的边界沿着半岛的扩张和收缩的概念一致。PAL-LTER将继续调查沿着半岛较低营养水平的生态系统变化，以应对持续、急剧的气候变暖和气候梯度的向极转移。 除了长期的研究活动，研究生培训，K-12教师的参与和基于网络的教育是PAL-LTER的一个组成部分。

The Palmer, Antarctica, Long-Term Ecological Research Project (PAL) seeks to understand the structure and function of the Western Antarctic Peninsula's marine and terrestrial ecosystems in the context of seasonal-to-interannual atmospheric and sea ice dynamics, as well as long-term climate change. The PAL measurement system (or grid) is designed to study marine and terrestrial food webs consisting principally of diatom primary producers, the dominant herbivore Antarctic krill, and the apex predator Adelie penguin. An attenuated microbial food web is also a focus. PAL studies these ecosystems annually over a regional scale grid of oceanographic stations and seasonally at Palmer Station. Sea ice extent and variability affects ecosystem changes at all trophic levels. In recent years, sea ice extent has diminished in response to a general warming in the region. Long-term population trends of ice-dependent Adelie penguins in the region provide a clear example of impact of the climate warming trend in the in the region. Adelie populations at the five major colonies studied near Palmer Station have all shown a gradual decrease in numbers over thirty years. The Peninsula runs perpendicular to a strong climatic gradient between the cold, dry continental regime to the south, characteristic of the Antarctic interior, and the warm, moist, maritime regime to the north. North-south shifts in the gradient give rise to large environmental variability to climate change. Currently more maritime conditions appear to be replacing the original polar ecosystem in the northern part of the peninsula as the climatic gradient shifts southward. To date, this shift appears matched by an ecosystem shift along the peninsula, as evidenced by declines in Adelie populations that require longer snow-cover seasons for successful recruitment. The main hypothesis is that ecosystem migration is most clearly manifested by changes in upper level predators (penguins) and certain polar fishes in predator foraging environments. This is because these longer lived species integrate recent climate trends and because individual species are more sensitive indicators than aggregated functional groups. Analogous modifications are expected to be manifested at lower trophic levels in the marine parts of the system in the years ahead. However, these lower level changes are likely to be observed only through long-term observations consistent with the concept of expansion and contraction of ecosystem boundaries along the Peninsula. The PAL-LTER will continue to investigate ecosystem changes at lower trophic levels along the Peninsula, in response to the continued, dramatic climate warming and pole ward shifts in the climatic gradient. In addition to the long-term research activities, graduate student training, the involvement of K-12 teachers and web-based education are an integral part of the PAL-LTER.