Continental margin sediments underlying the NE Pacific oxygen minimum zone are a source of nitrous oxide to the water column. Issue 2 (11th November 2020)

• Record Type: Journal Article
• Authors: Jameson, Brett D.; Berg, Peter; Grundle, Damian S.; Stevens, Catherine J.; Juniper, S. Kim
• Is Part Of: Limnology and oceanography letters. Volume 6:Issue 2(2021)
• Page Start: 68
• Page End: 76
• Publication Date: 2020-11-11
• Subjects: Limnology -- Periodicals; Oceanography -- Periodicals; 551.46
• DOI: 10.1002/lol2.10174
• Languages: English
• ISSNs: 2378-2242

Abstract

Abstract: Continental margin sediments are important sites of marine nitrogen cycling and potential contributors to atmospheric N2 O emissions. We employed trace‐level N2 O microsensors to measure vertical N2 O profiles at submillimeter resolutions in intact cores from outer continental margin sediments underlying the NE Pacific oxygen minimum zone. We used mathematical modeling to estimate depth‐dependent rates of N2 O production and fluxes to the overlying water along a transect of diminishing bottom water oxygen concentrations. Net sediment efflux was observed at all sites on the outer continental margin, with a mean value of 524 nmol m −2 d −1 . N2 O efflux increased with decreased oxygen penetration depth in sediments. Enhanced N2 O production and efflux were obtained when outer continental shelf sediments were experimentally exposed to lower bottom‐water O2 concentrations, to simulate upwelling conditions. Our results underline the need for further investigation of the drivers of N2 O production in continental margin sediments, and the relative importance of these environments to the global N2 O budget.