Nitrous oxide variability at sub-kilometre resolution in the Atlantic sector of the Southern Ocean

PeerJ

Sophie Fielding¹  Karen J. Heywood²  Jan Kaiser²  Imke Grefe² 

[1] British Antarctic Survey, Cambridge, United Kingdom;Centre for Ocean and Atmospheric Sciences, University of East Anglia, Norwich, United Kingdom;

关键词: Nitrous oxide;    Southern Ocean;    High-resolution measurements;    Air-sea gas exchange;    Marine biogeochemistry;    Laser spectroscopy;   

DOI  :  10.7717/peerj.5100

来源: DOAJ

【 摘 要 】

The Southern Ocean is an important region for global nitrous oxide (N2O) cycling. The contribution of different source and sink mechanisms is, however, not very well constrained due to a scarcity of seawater data from the area. Here we present high-resolution surface N2O measurements from the Atlantic sector of the Southern Ocean, taking advantage of a relatively new underway setup allowing for collection of data during transit across mesoscale features such as frontal systems and eddies. Covering a range of different environments and biogeochemical settings, N2O saturations and sea-to-air fluxes were highly variable: Saturations ranged from 96.5% at the sea ice edge in the Weddell Sea to 126.1% across the Polar Frontal Zone during transit to South Georgia. Negative sea-to-air fluxes (N2O uptake) of up to −1.3 µmol m−2 d−1 were observed in the Subantarctic Zone and highest positive fluxes (N2O emission) of 14.5 µmol m−2 d−1 in Stromness Bay, coastal South Georgia. Although N2O saturations were high in areas of high productivity, no correlation between saturations and chlorophyll a (as a proxy for productivity) was observed. Nevertheless, there is a clear effect of islands and shallow bathymetry on N2O production as inferred from supersaturations.

【 授权许可】

Unknown