Nitrous oxide cycling

Nitrous oxide cycling

We propose to advance quantitative understanding of the microbiological and biogeochemical controls of ODZ N 2 O cycling using both stable isotopic data at natural abundance and 15 N-label rate measurements using in situ incubation technologies in the Bay of Bengal. Genomic and metatranscriptomic data will be used to reveal the key players and the corresponding metabolic pathways of N 2 O cycling along O 2 and productivity gradients. The combination of these approaches will decipher the relative contribution of the sources of N 2 O and their controls. We will participate in 2 cruises in spring/summer 2025. The first will be a piggy-back onto the ONR funded cruise in 2025 (ASTraL program: The Arabian Sea Transition Layer) and for which are requesting a 4 day addition. The second cruise in summer 2025 will be a dedicated 30 day cruise (this request). During the second cruise, we will apply transformative approaches that minimize sampling and handling artifacts to provide more accurate biogeochemical rate estimates. Two new instruments will be deployed, the “Incubating Productivity System (IPS)” and the “Microbial Sampler – Submersible Incubation Device (MS-SID)”. We will also use the MS-SID to collect and preserve samples in situ for nucleic acid extractions and cell enumeration.