Ammonia oxidation is carried out by both Bacteria and Archaea. Oligotrophic ammonia oxidation kinetics and cellular characteristics of a mesophilic crenarchaeon found in the open ocean are now reported; its remarkably high specific affinity for reduced nitrogen suggests that certain ammonia-oxidizing Archaea could successfully compete with heterotrophic bacterioplankton and phytoplankton. Thus, ammonia oxidation may be more prevalent in the marine nitrogen cycle than is currently accounted for.
- Willm Martens-Habbena
- Paul M. Berube
- David A. Stahl
