Publication Date:
2022-05-26
Description:
Author Posting. © The Author(s), 2017. This is the author's version of the work. It is posted here under a nonexclusive, irrevocable, paid-up, worldwide license granted to WHOI. It is made available for personal use, not for redistribution. The definitive version was published in Deep Sea Research Part I: Oceanographic Research Papers 130 (2017): 1-11, doi:10.1016/j.dsr.2017.10.005.
Description:
Modeling studies have shown that mesoscale and submesoscale processes can
stimulate phytoplankton productivity and export production. Here, we present observations from
an undulating, towed Video Plankton Recorder (VPR-II) in the tropical Atlantic. The VPR-II
collected profiles of oxygen, fluorescence, temperature and salinity in the upper 140 m of the
water column at a spatial resolution of 1 m in the vertical and 〈2 km in the horizontal. The data
reveal remarkable "hotspots", i.e. locations 5 to 10 km wide which have elevated fluorescence
and decreased oxygen, both of which are likely the result of intense submesoscale upwelling.
Based on estimates of source water, estimated from identical temperature and salinity surfaces,
hotspots are more often areas of net respiration than areas of net production — although the
inferred changes in oxygen are subject to uncertainty in the determination of the source of the
upwelled waters since the true source water may not have been sampled. We discuss the spatial
distribution of these hotspots and present a conceptual model outlining their possible generation
and decline. Simultaneous measurements of O2/Ar in the mixed layer from a shipboard mass
spectrometer provide estimates of rates of surface net community production. We find that the
subsurface biological hotspots are often expressed as an increase in mixed layer rates of net
community production. Overall, the large number of these hotspots support the growing evidence
that submesoscale processes are important drivers in upper ocean biological production.
Description:
Funding for this work came from the National Science
Foundation (R.H.R.S. and D.J.M) (OCE-0925284, OCE-1048897, and OCE- 1029676) and the
National Aeronautics and Space Administration (D.J.M.) (NNX08AL71G and NNX13AE47G).
Keywords:
Net Community Production
;
Photosynthesis
;
Respiration
;
Oxygen
;
Fluorescence
;
Patchiness
;
Hotspots
;
O2/Ar
Repository Name:
Woods Hole Open Access Server
Type:
Preprint
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