Enhanced Nitrogen Loss by Eddy-Induced Vertical Transport in the Offshore Peruvian Oxygen Minimum Zone.
Callbeck, Cameron M., Lavik, Gaute, Stramma, Lothar , Kuypers, Marcel M. M. and Bristow, Laura A.
(2017)
Enhanced Nitrogen Loss by Eddy-Induced Vertical Transport in the Offshore Peruvian Oxygen Minimum Zone.
PLoS ONE, 12
(1).
e0170059.
DOI 10.1371/journal.pone.0170059.
|
Text
journal.pone.0170059.pdf - Published Version Available under License Creative Commons: Attribution 4.0. Download (1326Kb) | Preview |
Abstract
The eastern tropical South Pacific (ETSP) upwelling region is one of the ocean’s largest sinks of fixed nitrogen, which is lost as N2 via the anaerobic processes of anammox and denitrification. One-third of nitrogen loss occurs in productive shelf waters stimulated by organic matter export as a result of eastern boundary upwelling. Offshore, nitrogen loss rates are lower, but due to its sheer size this area accounts for ~70% of ETSP nitrogen loss. How nitrogen loss and primary production are regulated in the offshore ETSP region where coastal upwelling is less influential remains unclear. Mesoscale eddies, ubiquitous in the ETSP region, have been suggested to enhance vertical nutrient transport and thereby regulate primary productivity and hence organic matter export. Here, we investigated the impact of mesoscale eddies on anammox and denitrification activity using 15N-labelled in situ incubation experiments. Anammox was shown to be the dominant nitrogen loss process, but varied across the eddy, whereas denitrification was below detection at all stations. Anammox rates at the eddy periphery were greater than at the center. Similarly, depth-integrated chlorophyll paralleled anammox activity, increasing at the periphery relative to the eddy center; suggestive of enhanced organic matter export along the periphery supporting nitrogen loss. This can be attributed to enhanced vertical nutrient transport caused by an eddy-driven submesoscale mechanism operating at the eddy periphery. In the ETSP region, the widespread distribution of eddies and the large heterogeneity observed in anammox rates from a compilation of stations suggests that eddy-driven vertical nutrient transport may regulate offshore primary production and thereby nitrogen loss.
Document Type: | Article |
---|---|
Keywords: | oxygen minimum zone; tropical Pacific; nitrogen loss; eddies |
Research affiliation: | OceanRep > SFB 754 > B4 OceanRep > SFB 754 OceanRep > SFB 754 > A5 OceanRep > GEOMAR > FB1 Ocean Circulation and Climate Dynamics > FB1-PO Physical Oceanography |
Refereed: | Yes |
Open Access Journal?: | Yes |
DOI etc.: | 10.1371/journal.pone.0170059 |
ISSN: | 1932-6203 |
Projects: | SFB754 |
Expeditions/Models/Experiments: | |
Date Deposited: | 26 Jan 2017 12:15 |
Last Modified: | 06 Feb 2020 09:04 |
URI: | http://oceanrep.geomar.de/id/eprint/35923 |
Actions (login required)
![]() |
View Item |
Document Downloads
More statistics for this item...
Copyright 2013 | GEOMAR Helmholtz-Zentrum für Ozeanforschung Kiel | All rights reserved
Questions, comments and suggestions regarding the GEOMAR repository are welcomed
at bibliotheksleitung@geomar.de !