The environmental controls that govern the end product of bacterial nitrate respiration

• DOI: 10.1126/science.1254070
• Publication Date: 2014-08-07T18:46:21Z
• Authors: Beate Kraft; Halina E. Tegetmeyer; Ritin Sharma; Martin G. Klotz; Timothy G. Ferdelman; Robert L. Hettich; Jeanine S. Geelhoed; Marc Strous
• Keywords: Biogeochemical Cycle; Nitrogen Cycle; Nitrospira; Microbial Metabolism

In the biogeochemical nitrogen cycle, microbial respiration processes compete for nitrate as an electron acceptor. Denitrification converts into nitrogenous gas and thus removes fixed from biosphere, whereas ammonification ammonium, which is directly reusable by primary producers. We combined multiple parallel long-term incubations of marine nitrate-respiring communities with isotope labeling metagenomics to unravel how specific environmental conditions select either process. Microbial generation time, supply nitrite relative nitrate, carbon/nitrogen ratio were identified key controls that determine whether will be reduced or ammonium. Our results define ecophysiology a feedback loop global change, eutrophication, wastewater treatment.