Nitrogen in Tropical Forest

摘要

Pollution from nitrogen deposition is well documented in temperate ecosystems and it has been predicted that the globalization of nitrogen deposition will eventually lead to its enrichment in tropical forests. Hietz et al. (p. 664) report a comprehensive data set showing a clear change in the nitrogen cycle in two tropical forests-one in Panama and one in Thailand. The data set provides evidence for nitrogen enrichment from stable isotope analysis of leaves collected for more than 40 years and of tree rings spanning approximately 100 years. Spatial data on nitrogen emissions and tropospheric NO_2 suggest that the type of enrichment seen may be widespread in tropical forests.