A mid-twentieth century reduction in tropical upwelling inferred from coralline trace element proxies

Matthew K. Reuer, Edward A. Boyle, Julia E. Cole

Research output: Contribution to journalArticle

54 Scopus citations

Abstract

The Cariaco Basin is an important archive of past climate variability given its response to inter- and extratropical climate forcing and the accumulation of annually laminated sediments within an anoxic water column. This study presents high-resolution surface coral trace element records (Montastrea annularis and Siderastrea siderea) from Isla Tortuga, Venezuela, located within the upwelling center of this region. A two-fold reduction in Cd/Ca ratios (3.5-1.7 nmol/mol) is observed from 1946 to 1952 with no concurrent shift in Ba/Ca ratios. This reduction agrees with the hydrographic distribution of dissolved cadmium and barium and their expected response to upwelling. Significant anthropogenic variability is also observed from Pb/Ca analysis, observing three lead maxima since 1920. Kinetic control of trace element ratios is inferred from an interspecies comparison of Cd/Ca and Ba/Ca ratios (consistent with the Sr/Ca kinetic artifact), but these artifacts are smaller than the environmental signal and do not explain the Cd/Ca transition. The trace element records agree with historical climate data and differ from sedimentary faunal abundance records, suggesting a linear response to North Atlantic extratropical forcing cannot account for the observed historical variability in this region.

Original languageEnglish (US)
Pages (from-to)437-452
Number of pages16
JournalEarth and Planetary Science Letters
Volume210
Issue number3-4
DOIs
StatePublished - May 30 2003

Keywords

  • Barium
  • Cadmium
  • Cariaco Basin
  • Coral reefs
  • Paleoclimatology
  • Trace elements

ASJC Scopus subject areas

  • Geophysics
  • Geochemistry and Petrology
  • Earth and Planetary Sciences (miscellaneous)
  • Space and Planetary Science

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