Award Abstract # 0842785
SGER: Determining Equatorial Upwelling Rates with a Novel Geochemical Tracer Technique

NSF Org: OCE
Division Of Ocean Sciences
Recipient: UNIVERSITY OF MIAMI
Initial Amendment Date: September 8, 2008
Latest Amendment Date: May 21, 2009
Award Number: 0842785
Award Instrument: Standard Grant
Program Manager: Eric C. Itsweire
OCE
 Division Of Ocean Sciences
GEO
 Directorate for Geosciences
Start Date: October 1, 2008
End Date: September 30, 2010 (Estimated)
Total Intended Award Amount: $0.00
Total Awarded Amount to Date: $124,544.00
Funds Obligated to Date: FY 2008 = $79,476.00
FY 2009 = $45,068.00
History of Investigator:
  • William Johns (Principal Investigator)
    wjohns@rsmas.miami.edu
  • David Kadko (Co-Principal Investigator)
Recipient Sponsored Research Office: University of Miami
1251 MEMORIAL DR
CORAL GABLES
FL  US  33146-2509
(305)421-4089
Sponsor Congressional District: 27
Primary Place of Performance: University of Miami
1251 MEMORIAL DR
CORAL GABLES
FL  US  33146-2509
Primary Place of Performance
Congressional District:
27
Unique Entity Identifier (UEI): KXN7HGCF6K91
Parent UEI: VNZZYCJ55TC4
NSF Program(s): PHYSICAL OCEANOGRAPHY,
BIOLOGICAL OCEANOGRAPHY
Primary Program Source: 01000910DB NSF RESEARCH & RELATED ACTIVIT
01000809DB NSF RESEARCH & RELATED ACTIVIT
Program Reference Code(s): OTHR, 9237, 1324, 0000, EGCH
Program Element Code(s): 161000, 165000
Award Agency Code: 4900
Fund Agency Code: 4900
Assistance Listing Number(s): 47.050

ABSTRACT

In the exploratory project, the investigators propose to develop a novel isotopic technique, based on the isotope Beryllium 7, to infer rates of upwelling along the equator. Beryllium 7 samples will be collected on an NSF-funded research cruise to the equatorial eastern Atlantic in April, 2009. The cruise track is ideal for the proposed study. Several stations away from the equator will be occupied to make numerous mixed layer measurements and several profiles of Beryllium 7 within the areas of upwelling in the cold tongue region, focusing primarily on the region between 5°E and 10°W. The Beryllium 7 profiles will be collected simultaneously with the CTD stations using well established techniques developed by the investigators. The key hypothesis to be tested is the idea that the observed mixed layer Beryllium 7 concentration is an extremely sensitive indicator of the upwelling rate. Two properties of Beryllium 7 make it an ideal tracer for investigation of upwelling. First, its source function and water column distribution (high contrast between mixed layer and sub-mixed layer depth) allow it to be a sensitive indicator of upwelling. Secondly, its characteristic time scale is long enough to integrate upwelling over periods of weeks but still be sensitive to variations on seasonal timescales, unlike tracers with significantly longer half-lives.

Broader Impacts. Upwelling is an important physical process affecting climate dynamics and biogeochemical cycling within the global ocean. Direct measurements of upwelling are difficult because of the relatively small velocities involved, and it must therefore be inferred by indirect methods such as those provided by tracer observations. If successful, this method will provide an important tracer tool to the oceanographic community. The findings will be incorporated into undergraduate and graduate courses that the co-investigator teaches.

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