Multi-element regulation of the tropical forest carbon cycle

Tropical ecosystems dominate the exchange of carbon dioxide between the atmosphere and terrestrial biosphere, yet our understanding of how nutrients control the tropical carbon (C) cycle remains far from complete. In part, this knowledge gap arises from the marked complexity of the tropical forest biome, in which nitrogen, phosphorus, and perhaps several other elements may play roles in determining rates of C gain and loss. As studies from other ecosystems show, failing to account for nutrient-C interactions can lead to substantial errors in predicting how ecosystems will respond to climate and other environmental changes. Thus, although resolving the complex nature of tropical forest nutrient limitation-and then incorporating such knowledge into predictive models - will be difficult, it is a challenge that the global change community must address.