Project title: Temperature and nitrogen modulated nitrous oxide cycling
Summary: A novel sink for the greenhouse gas nitrous oxide (N2O) may have been found in pristine, nitrogen limited streams in Iceland and the same could also be true for regions of the cold, Southern Ocean. This sink seems to be temperature regulated, with N2O being consumed at colder temperatures. In the cold it is more energy efficient to break the bond of N2O than it is to break the triple bond of N2. N2O could therefore be used as an alternative nitrogen source in cold, pristine ecosystems. This opens up a few interesting questions:
Is N-fixation in cold temperatures more dependent on N2O?
Is the fixation of N2O a physiological response of diazotrophs that normally fix N2O?
Are cold and N-limited ponds, streams, and their adjacent soils characteristically under saturated with N2O?
By examining the nitrogen cycle in the controlled setting of long-term experimentally warmed ponds, in a gradient of geothermally heated streams in Iceland, and/or the Southern Ocean, and in low N impacted sites in UK uplands, these questions will be addressed.