Short circuits in the nitrogen cycle regulate ecosystem development in the terrestrial Antarctic

南极洲是研究生态系统对气候变化反应的独特重要的“天然实验室”，正确理解那里观察到的生物变化至关重要。它的独特性来自于其生态系统的简单性，表现出有限的物种多样性和食物链的复杂性，以及环境变暖，其变化速度约为温带地区的两倍。这种变暖的主要特征之一似乎是陆地栖息地的“绿化”。这种绿化似乎与氮的可用性有关，而在许多极地环境中，氮往往供应不足。尽管它在调节植物生长方面发挥着核心作用，但我们对南极环境中氮循环的了解仍然非常少。因此，仍然很难理解和预测环境扰动将如何影响或威胁这些独特的陆地社区。此外，我们认为，目前的氮循环模型是不健全的，因为它们没有包括关键齿轮和内部循环。我们的目标是通过详细研究土壤和植物之间对有机氮和无机氮的竞争，大大扩展我们对极地氮循环的认识。最终，这将增强用于预测生态系统对扰动的反应的数学模型。这项工作直接支持与极地地区环境变化和生物多样性有关的政策。这项工作也与世界各地许多其他低投入生态系统（如北方森林、北极苔原、热带雨林）极为相关。

The Antarctic is a uniquely important 'natural laboratory' for examining ecosystem responses to climate change, and it is vital that the biological changes being observed there are properly understood. Its uniqueness comes from a combination of the simplicity of its ecosystems, which exhibit restricted species diversity and food chain complexity, with environmental warming which is occurring at approximately twice the rate of change in temperate regions. One of the major features of this warming appears to be the 'greening-up' of terrestrial habitats. This greening appears to be linked to the availability of nitrogen which is often present in short supply in many polar environments. Despite its central role in regulating plant growth, our knowledge of the nitrogen cycle in Antarctic environments remains extremely poor. Consequently, it remains difficult to understand and predict how envionmental perturbations will affect or threaten these unique terrestrial communities. In addition, we believe that current models of the nitrogen cycle are unsound as they have failed to include key cogs and internal loops. Our aim is to greatly expand our knowledge of polar N cycling by looking in detail at competition between soil and plants for organic and inorganic nitrogen. Ultimately, this will enhance mathematical models used for predicting ecosystem responses to perturbation. The work directly underpins policy relating to environmental change and biodiversity in polar regions. The work is also extremely relevant to many other low-input ecosystems around the world (e.g. boreal forest, Arctic tundra, tropical rainforest).