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
Deep (>0.8km depth) fracture water with residence time estimates on the order of several Ma from the Witwatersrand Basin, South Africa contains up to 40μM of NO 3 -, up to 50mM N 2 (90 times air saturation at surface) and 1 to 400μM NH 3/NH 4 +. To determine whether the oxidized N species were introduced by mining activity, by recharge of…