NOAA/WDS Paleoclimatology - San Lázaro Basin, Eastern Pacific 2,300 Year Sediment Geochemical Data

San Lázaro Basin (SLB) oceanographic record is highly sensitive to El Niño and the Southern Oscillation (ENSO) and the Pacific Decadal Oscillation (PDO) variability due to its location below the dynamic boundary between the northern, cooler and fresher waters of the California Current System (CCS) and the southern, warmer and saltier surface waters from subtropics and tropics. Warm sea surface temperatures (SST) and the ensuing stratified surface water column favor carbonate productivity, mostly dominated by the export of coccolithoforids as observed during El Niño events, while cool SSTs and a lesser stratified water column favor a relatively higher export of organic carbon. Here we show how during the last two millenia, the mechanisms that drive the organic carbon and carbonate export depend on the timescale considered. The organic carbon and carbonate records show opposite trends for the past 2 Kyr and in the multicentennial periodicities most probably as the result of the precessional forcing and decreasing insolation of the Northern Hemisphere, which has been shown to further affect the migration of the Inter Tropical Convergence Zone and the Polar Jet stream. In the shorter time-scales, interanual to centennial, the SLB records exhibit an ENSO-like variability; while decadal to multidecadal variability is correlated with instrumental and reconstructed PDO records. Here we further show how interannual variability seems to have increased during the Little Ice Age, most likely related to large ENSO events, in contrast with an apparent reduction in this type of variability between 400 to 1350 CE suggesting a changing sensitivity of the ENSO teleconnection in the southern CCS for the past 2 millennia.