Open AccessA 2000‐year record of Caribbean and tropical North Atlantic hydrographic variability
Author(s) -
Black David E.,
Thunell Robert C.,
Kaplan Alexey,
Peterson Larry C.,
Tappa Eric J.
Publication year - 2004
Publication title -
paleoceanography
Language(s) - English
Resource type - Journals
eISSN - 1944-9186
pISSN - 0883-8305
DOI - 10.1029/2003pa000982
Subject(s) - intertropical convergence zone , tropical atlantic , globigerina bulloides , climatology , upwelling , geology , sea surface temperature , foraminifera , oceanography , hydrography , globigerinoides , precipitation , geography , benthic zone , meteorology
Here we present near‐annually resolved oxygen isotope records from two species of planktic foraminifera from the Cariaco Basin that reflect sea surface temperature (SST) and Intertropical Convergence Zone (ITCZ) precipitation‐related salinity variations over the Caribbean and tropical North Atlantic spanning the last 2000 years. A strong, broad spatial pattern of correlation exists between foraminiferal δ 18 O and SSTs over the period of instrumental overlap, but the correlations weaken as they are extended back in time and instrumental SST records become discontinuous. A long‐term trend in the Globigerinoides ruber δ 18 O record can be explained by two different but equally plausible scenarios. First, the increase in δ 18 O may indicate that tropical summer‐fall SSTs have cooled by as much as 2°C over the last 2000 years, possibly as a result of a long‐term increase in upwelling intensity. Alternately, comparisons to other studies of ITCZ and regional evaporation/precipitation variability suggest that much of the δ 18 O record is influenced by decadal‐ to centennial‐scale variations in the mean annual position of the ITCZ and associated rainfall patterns. Similarities between the G. bulloides δ 18 O record and the 11‐year sunspot cycle support prior studies that suggest solar variability plays a role in influencing the hydrologic balance of the circum‐Caribbean.