Colorado mountains
From Long-Term Data to Understanding: Toward a Predictive Ecology
2015 LTER ASM Estes Park, CO - August 30 - September 2, 2015

Partitioning Nitrification Derived N2O Emission from Ammonia Oxidizing Bacteria (AOB) and Ammonia Oxidizing Archaea (AOA)

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Poster Number: 
Presenter/Primary Author: 
Di Liang
Phil Robertson

N2O is a potent greenhouse gas and its global warming potential is 298 times higher than carbon dioxide (CO2). In 2013, 74% of the total N2O emission in the U.S. was due to agricultural soil management. Therefore, understanding the sources of N2O emission is critical for developing future mitigation practices and achieving a more sustainable agriculture. Nitrification, a process that oxidizes ammonia into nitrite, is considered as one of the major sources of N2O emitted from soil. Previous studies showed that both soil AOB and AOA were able to produce N2O via nitrification but their relative contributions are still poorly understood. We used acetylene (C2H2), an inhibitor that inactivates AOA and AOB ammonia monooxygenase (AMO), and Octyne, an inhibitor that specifically inhibits AOB AMO, to investigate how AOA vs. AOB contribute to N2O emissions in an agricultural soil. In short-term laboratory incubations of freshly collected soils, we found that AOA contributed 33% of total nitrification (NO2- + NO3-) over 12 hours in aerobic soil slurries and 30% of accumulated N2O.

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