Starting with the work of Ben Houlton, we have collaborated with the group of Lars Hedin in the Department of Ecology and Evolutionary Biology in isotope studies of terrestrial N cycling. We have also worked on the nitrate N and O isotopes in rain, snow, and ice as tracers of reactive nitrogen sources and processing in the modern and ancient atmosphere.

A photo taken by former graduate student Ben Houlton of a Hawaiian rainforest. See Houlton et al. (2006).
References
Tropical forests account for one third of terrestrial primary production and contribute significantly to the land carbon sink 1,2. The future of this sink relies critically on forest interactions with nutrient cycles 3-5. Humid montane tropical forests are often thought to be rich in phosphorus, but to contain low levels of bioavailable…