We found a match
Your institution may have access to this item. Find your institution then sign in to continue.
- Title
Decadal oxygen change in the eastern tropical North Atlantic.
- Authors
Hahn, Johannes; Brandt, Peter; Schmidtko, Sunke; Krahmann, Gerd
- Abstract
Repeat shipboard and multi-year moored observations obtained in the oxygen minimum zone (OMZ) of the eastern tropical North Atlantic (ETNA) were used to study the decadal change in oxygen for the period 2006-2015. Along 23°W between 6 and 14° N, oxygen decreased with a rate of -5.9±3.5 μmol kg-1 decade-1 within the depth covering the deep oxycline (200-400 m), while below the OMZ core (400-1000 m) oxygen increased by 4.0±1.6 μmol kg-1 decade-1 on average. The inclusion of these decadal oxygen trends in the recently estimated oxygen budget for the ETNA OMZ suggests a weakened ventilation of the upper 400 m, whereas the ventilation strengthened homogeneously below 400 m. The changed ventilation resulted in a shoaling of the ETNA OMZ of -0.03±0.02 kgm-3 decade-1 in density space, which was only partly compensated by a deepening of isopycnal surfaces, thus pointing to a shoaling of the OMZ in depth space as well (-22±17m decade-1/. Based on the improved oxygen budget, possible causes for the changed ventilation are analyzed and discussed. Largely ruling out other ventilation processes, the zonal advective oxygen supply stands out as the most probable budget term responsible for the decadal oxygen changes.
- Subjects
NORTH Atlantic Ocean; OXYGEN content of seawater; DEOXYGENATION; SEAWATER salinity; OCEAN temperature
- Publication
Ocean Science, 2017, Vol 13, Issue 4, p551
- ISSN
1812-0784
- Publication type
Article
- DOI
10.5194/os-13-551-2017