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

帕尔默南极长期生态研究项目（PAL）旨在了解南极半岛西部海洋和陆地生态系统在季节性到年际大气和海冰动态以及长期气候变化背景下的结构和功能。PAL测量系统（或网格）旨在研究海洋和陆地食物网，主要由硅藻初级生产者、主要食草动物南极磷虾和顶级捕食者阿德利企鹅组成。减毒的微生物食物网也是一个焦点。PAL每年在海洋学站的区域尺度网格上研究这些生态系统，并在帕尔默站进行季节性研究。海冰的范围和变异影响着所有营养水平的生态系统变化。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种群趋势为该地区气候变暖趋势的影响提供了一个清晰的例子。在帕尔默站附近的五个主要种群中，阿德利种群的数量在过去30年里都呈逐渐减少的趋势。半岛垂直于一个强烈的气候梯度，南部是寒冷、干燥的大陆政权，具有南极内部的特征，北部是温暖、潮湿的海洋政权。南北梯度的移动引起了气候变化的巨大环境变率。目前，随着气候梯度向南移动，更多的海洋条件似乎正在取代半岛北部原来的极地生态系统。到目前为止，这种变化似乎与半岛上的生态系统变化相匹配，阿德利种群的减少证明了这一点，这需要更长的积雪季节才能成功招募。主要的假设是，生态系统迁移最明显地体现在上层捕食者（企鹅）和某些极地鱼类在捕食觅食环境中的变化。这是因为这些寿命较长的物种整合了最近的气候趋势，而且单个物种比总体功能群更敏感。类似的变化预计将在未来几年在该系统的海洋部分的较低营养水平上表现出来。然而，这些较低水平的变化可能只有通过长期观测才能观测到，这与沿着半岛的生态系统边界的扩张和收缩的概念相一致。PAL-LTER将继续调查沿半岛低营养水平的生态系统变化，以应对持续的、剧烈的气候变暖和气候梯度的极移。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.