SUBPROJECT - B3
Sensitivity of oceanic biological nitrogen fixation to changes in dissolved oxygen
Nitrogen (N2) fixation is a key control on the oceanic nitrogen inventory. High NO3- and low O2 concentrations favour N-loss: resulting low N/P ratios are hypothesised to promote N2 fixation. This project examined direct ([O2]) and indirect (N/P) effects of O2 on rates of N2 fixation and the functional gene diversity of N2-fixing microorganisms (diazotrophs). A metagenomic approach was used to determine the extent to which phylogenetically-related diazotroph ecotypes are adapted to specific nutrient stoichiometry and O2 concentrations.