McMurdo Dry Valleys: A Cold Desert Ecosystem

麦克默多干谷的极端环境将是 长期生态研究（LTER）项目 南极洲麦默多站以西约100公里处。 的 干谷是世界上最极端的沙漠之一。 的 常年冰封的湖泊，短暂的溪流， 山谷内的土壤区域经受低温， 非常有限的降水和盐的积累。 的 山谷中的生物系统相对简单，没有 维管植物或脊椎动物和很少的昆虫。 营养 相互作用和地球化学养分循环在很大程度上是 仅限于微生物种群和微型无脊椎动物。 物种多样性和丰富度很低， 如此极端的环境。 尽管如此简单，复杂 物种之间的相互作用以及生物和 物理化学环境存在于湖泊，溪流和 土壤 此外， 生态系统提高了干旱河谷的整体生产力 的风景. 所有的生态系统都在不同程度上受到 气候和物质运输，但没有地方比这更明显 比在干燥的山谷里要多。 一个极端的明显影响 环境与生态系统的一般简单性相结合 结构使干燥的山谷成为研究这些的理想地点 基本关系。 两个中心假设将是重点 本研究主要内容如下：1）干旱河谷的结构与功能 生态系统主要受物理限制的控制， 2)干旱河谷生态系统的结构和功能是 改性材料运输。 干谷LTER将解决 这些假设和LTER研究的五个核心领域 通过系统的环境数据计划强调 收集，长期实验和模型开发。 努力将集中在生物过程的整合 在湖泊、溪流和河流之间的物质运输， 包括麦克默多干谷的陆地生态系统 景观

The extreme environment of the McMurdo Dry Valleys will be the focus of a Long Term Ecological Research (LTER) project located approximately 100 km west of McMurdo Station, Antarctica. The dry valleys are among the most extreme deserts in the world. The perennially ice-covered lakes, ephemeral streams, and extensive areas of soil within the valleys are subject to low temperatures, very limited precipitation, and salt accumulation. The biological systems in the valleys are relatively simple, with no vascular plants or vertebrates and very few insects. Trophic interactions and biogeochemical nutrient cycles are largely limited to microbial populations and micro-invertebrates. Species diversity and abundance are low as would be predicted for such extreme environments. Despite this simplicity, complex interactions among species and between the biological and physico-chemical environment exist in the lakes, streams and soils. Furthermore, interactions between various components of the ecosystem enhance the overall productivity of the dry valley landscapes. All ecosystems are shaped to varying degrees by climate and material transport, but nowhere is this more apparent than in the dry valleys. The obvious effects of an extreme environment coupled with the general simplicity of ecosystem structure makes the dry valleys an ideal location to study these basic relationships. Two central hypotheses will be the focus of this research: 1) The structure and function of dry valley ecosystems are primarily controlled by physical constraints, and 2) The structure and function of dry valley ecosystems are modified by material transport. The dry valley LTER will address these hypotheses and the five core areas of LTER research emphasis through a program of systematic environmental data collection, long-term experiments, and model development. Efforts will focus on the integration of the biological processes within and material transport between the lakes, streams and terrestrial ecosystems comprising the McMurdo Dry Valley landscape.