glacial water mass geometry and the distribution of d 13 c of s co 2 in the western atlantic
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Glacial Water Mass Geometry and the Distribution of d 13 C of S CO 2 in the Western Atlantic. William Curry Delia Oppo Department of Geology and Geophysics Woods Hole Oceanographic Institution. Fate of Fossil Fuel CO 2 in the Ocean. Shackleton (1977). M12392 Atlantic d 13 C - PowerPoint PPT PresentationTRANSCRIPT
Glacial Water Mass Geometry and the Glacial Water Mass Geometry and the Distribution of Distribution of 1313C of C of COCO22 in the in the
Western AtlanticWestern Atlantic
William Curry
Delia Oppo
Department of Geology and Geophysics
Woods Hole Oceanographic Institution
Shackleton (1977)
Fate of Fossil Fuel COFate of Fossil Fuel CO22 in the Ocean in the Ocean
M12392
Atlantic 13C
Glacial = -1.2 ‰ PDB
Shackleton (1977)
Y71-6-12MGY71-6-12MG
Pacific Pacific 1313CC
Same as AtlanticSame as Atlantic
During GlacialDuring Glacial
Shackleton (1977)
NADW High Salinity – High 13C
AABW Low Salinity – Low 13C
Conservative MixingConservative Mixing
NADW
GEOSECS
NADW
Kroopnick (1985)
Benthic ForaminiferaBenthic Foraminifera
13C of CO2 13C of CaCO3
Cibicidoides sp.Cibicides sp.Planulina sp.
Data sources:Duplessy et al., 1984
Curry and Lohmann, 1990Mackensen et al., 1993
McCorkle and Keigwin, 1994
AAIWAAIW
UCPDWUCPDW
LCPDWLCPDW
NADWNADW
South AtlanticWater Masses
Sedimentation Rates:
~ 10 cm kyr-1 above 1500 m
~ 5 cm kyr-1 below 2000 m
Cibidicoides at Brazil MarginCibidicoides at Brazil Margin
Curry and Oppo (in press)
NADW
GNAIW
North versus South AtlanticNorth versus South Atlantic
Curry and Oppo (in press)
GNAIWGNAIW
Core locationsCore locations
New Brazil Margin Cores (Curry and Oppo)
New Blake Ridge Cores (Keigwin)
Curry and Oppo (in press)
Curry and Oppo (in press)
Curry and Oppo (in press)
Curry and Oppo (in press)
Curry and Oppo (in press)
North versus South AtlanticNorth versus South Atlantic
Curry and Oppo (in press)
GNAIWGNAIW
Mauritzen et al. (2002)
Vertical Mixing Along the MARVertical Mixing Along the MAR
North versus South AtlanticNorth versus South Atlantic
Curry and Oppo (in press)
GNAIWGNAIW
SummarySummary
• Carbon isotope tracers show the presence of three water masses a reduced volume and shoaling of NADW – GNAIW.
•GNAIW southward penetration to 26º S. Intermediate water mass northward penetration unconstrained by carbon isotopes.
• Bathymetric and meridional gradients in 13C much larger because of changes in end member water mass properties.
• Bathymetric gradients in 13C imply that lateral advection remained strong with respect to expected strong vertical mixing.
What’s in the What’s in the 1818O Data?O Data?
North versus South AtlanticNorth versus South Atlantic
Curry and Oppo (in press)
GNAIWGNAIW
30 ºS to 30 ºN
T = 4 ºC
1818O gradient at Constant DensityO gradient at Constant Density
0.6 permil
Sea surface salinity distributions are determined in large part by E-P patterns
Global SSS and E-P distributions
Source: R.Schmitt,WHOISource: HydroBase2
Large Scale Ocean CirculationLarge Scale Ocean Circulation
Vema ChannelVema Channel
Curry and Lohmann (1982)
Shackleton (1977)
Glacial Southern Ocean
13C slightly higher than
Atlantic and Pacific
(-0.9‰ > -1.2‰ PDB)
Curry and Lohmann (1982)
Curry and Lohmann (1982)
Bathymetric
Changes in 13C –
Decreased NADW