학술논문
Continental margin sediments underlying the NE Pacific oxygen minimum zone are a source of nitrous oxide to the water column
Document Type
Report
Column
Column
Source
Limnology and Oceanography Letters. April 2021, Vol. 6 Issue 2, p68, 9 p.
Subject
Language
English
Abstract
Scientific Significance Statement Nitrous oxide (N[sub.2]O) is a potent greenhouse gas that also contributes to stratospheric ozone depletion. Continental margin sediments represent an understudied, yet potentially important marine contributor to [...]
: Continental margin sediments are important sites of marine nitrogen cycling and potential contributors to atmospheric N[sub.2]O emissions. We employed trace‐level N[sub.2]O microsensors to measure vertical N[sub.2]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 N[sub.2]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[sup.−2] d[sup.−1]. N[sub.2]O efflux increased with decreased oxygen penetration depth in sediments. Enhanced N[sub.2]O production and efflux were obtained when outer continental shelf sediments were experimentally exposed to lower bottom‐water O[sub.2] concentrations, to simulate upwelling conditions. Our results underline the need for further investigation of the drivers of N[sub.2]O production in continental margin sediments, and the relative importance of these environments to the global N[sub.2]O budget.
: Continental margin sediments are important sites of marine nitrogen cycling and potential contributors to atmospheric N[sub.2]O emissions. We employed trace‐level N[sub.2]O microsensors to measure vertical N[sub.2]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 N[sub.2]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[sup.−2] d[sup.−1]. N[sub.2]O efflux increased with decreased oxygen penetration depth in sediments. Enhanced N[sub.2]O production and efflux were obtained when outer continental shelf sediments were experimentally exposed to lower bottom‐water O[sub.2] concentrations, to simulate upwelling conditions. Our results underline the need for further investigation of the drivers of N[sub.2]O production in continental margin sediments, and the relative importance of these environments to the global N[sub.2]O budget.