Open AccessAn Atlantic meridional transect of surface water dimethyl sulfide concentrations with 10–15 km horizontal resolution and close examination of ocean circulation
Author(s) -
Belviso Sauveur,
Morrow Rosemary,
Mihalopoulos Nikolaos
Publication year - 2000
Publication title -
journal of geophysical research: atmospheres
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.67
H-Index - 298
eISSN - 2156-2202
pISSN - 0148-0227
DOI - 10.1029/1999jd900955
Subject(s) - oceanography , subtropical front , thermohaline circulation , zonal and meridional , geology , north atlantic deep water , climatology , latitude , water mass , subtropics , dimethyl sulfide , ocean gyre , tropical atlantic , anticyclone , upwelling , sea surface temperature , environmental science , sulfur , chemistry , geodesy , organic chemistry , biology , fishery
Underway measurements of dimethyl sulfide (DMS) in the Atlantic surface waters have been made during the ALBATROSS campaign from 65°N to 45°S along about 30°W. The main patterns of DMS variability in subtropical waters of both hemispheres were the existence of (1) a poleward negative gradient of DMS (0.04 nM/°latitude) paralleling the temperature and salinity meridional trends and opposite to that of chlorophyll a (chl a ) and particulate DMSP (pDMSP), and (2) sharp DMS enhancements, up to twenty fold the background levels, coinciding almost systematically with thermohaline frontal zones. We observed that DMS concentrations and TOPEX/Poseidon sea level anomalies (SLAs) were clearly in opposition of phase in the subtropical and tropical waters of the Atlantic. Neither meridional changes in pDMSP nor in chl a concentrations account for these large‐scale (15°–20° latitude) DMS variations. It is suggested that the spatial distribution of DMS is highly sensitive to the upper ocean dynamics. The tropical Atlantic is a zone of contrasted DMS levels with two broad maxima associated (1) with the cyclonic circulations generated by the North Equatorial currents and (2) with the South Equatorial Current, a situation very much resembling the autumnal meridional distribution of surface pC0 2 . A close examination of the South Atlantic subtropical front (38°–43°S) show that DMS and in situ validated satellite chl a have a distinct spatial distribution suggesting important spatial segregation of biogeochemical processes in the frontal zones. These observations at different spatial scales provide indications for the existence of a DMS‐climate link through frontogenesis and surface ocean circulation in the Atlantic.