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Rasmus Andreasen

What role does the N. Atlantic subtropical cell play in warming the shallow underwater of the Caribbean Sea on decadal to centennial time scales? Constraints from radiocarbon records across the tropical Atlantic

Publikation: Bidrag til tidsskrift/Konferencebidrag i tidsskrift /Bidrag til avisTidsskriftartikelForskning

  • B. E. Rosenheim, University of South Florida St. Petersburg, St Petersburg, FL, United States brosenheim@usf.edu
  • ,
  • A. Fernandez, Tulane University, New Orleans, LA, United States alvaro.bremer@erdw.ethz.ch
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  • P. K. Swart, Department of Marine Geosciences - RSMAS, University of Miami, Miami, FL, United States pswart@rsmas.miami.edu
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  • T. Lapen, department of earth and atmospheric sciences, University of Houston, Houston, TX, United States tjlapen@central.uh.edu
  • ,
  • R. Andreasen
  • K. Karnauskas, Geology & Geophysics, Woods Hole Oceanographic Institution, woods hole, MA, United States kkarnauskas@whoi.edu
Coral and sclerosponge skeletons provide long time-series of ocean DIC D14C values, a tracer of oceanic circulation, effectively extending the observational record back in time. Here, we present new coral and sclerosponge D14C records from the Atlantic that provide useful constraints on the dynamics of the subtropical cells (STCs). The STCs are shallow meridional wind-driven circulations that transport heat and water masses from the subtropics to the tropics. We use a coral from the Cape Verde Islands and a sclerosponge from the Bahamas to investigate the circulation patterns of the off-equatorial upwelling regions of STCs, which are not well understood. We find an abrupt change in bomb curve of the Cape Verde record that is related to ventilation rate of the STC, and we use these data to show that the strength of the northern STC was likely constant through the latter half of the 20th century. Finally, we present the first 14C record of equatorial upwelling in the Atlantic using a coral from Principe Island in the Gulf of Guinea. We find that the water that upwells in the equator has a 14C signature that is markedly different than the water that is brought to the surface in the off-equatorial sites, suggesting that the northern and southern STCs interior pathways are not well connected in the Atlantic.
TidsskriftAmerican Geophysical Union, Fall Meeting 2015
StatusUdgivet - 1 dec. 2015
Eksternt udgivetJa

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