Editor's Summary

17 July 2008

Nitrogen fixation: the forest paradox

In contrast to marine environments, nitrogen fixation in temperate and tropical forests seems not to obey the law of supply and demand. Symbiotic trees that fix atmospheric nitrogen are more abundant in the tropics, where nitrogen is readily available in the soil, than in mature temperate forests where it is scarce. A possible explanation of this paradox is offered in a model that takes account of two extra factors: temperature and phosphorus abundance. In phosphate-limited soils, nitrogen-fixers may gain an advantage in the form of enhanced phosphate acquisition. And at high latitudes, the temperature may limit nitrogen fixation.

Letter: A unifying framework for dinitrogen fixation in the terrestrial biosphere

Benjamin Z. Houlton, Ying-Ping Wang, Peter M. Vitousek & Christopher B. Field

doi:10.1038/nature07028

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