Wong, Michelle: Travel Grant - 2016-2017

Nitrogen fixation, the primary source of new nitrogen (N) to tropical forests, is exclusively catalyzed by the nitrogenase enzyme, which almost always requires molybdenum (Mo). Increasing evidence in recent years suggests that Mo availability may be low in highly weathered tropical soils and can constrain N-fixation rates. The tropical forests of the Amazon Basin represents a significant fraction of the global carbon balance and a significant portion of where N-fixation occurs. However, measured rates of N-fixation in the Amazon are very few and highly variable. This study will establish a Mo gradient where N-fixation rates will be measured at Tanguro Ranch, Mato Grosso in Brazil, where other aspects of N cycling are well established.