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

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).