Does Caribbean SST drive decadal to centennial-scale variability in the Central American Monsoon? Evidence from stalagmites from Mona Island, Puerto Rico

This research is based on broader study investigating drivers of decadal to centennial-scale variations in the Central American Monsoon (CAM), a sub-region of the broader North American Monsoon. In the context of the Global Monsoon system, the precipitation patterns of CAM are of particular interest because of the placement/shifting of the ITCZ through time, its proximity to the AMOC system, and that existing precipitation records from this area have revealed a heterogenous pattern throughout the past 2 kyr.

Here we present new carbon and oxygen isotopic records of two speleothems, MO-AL-3 and MO-CU-2, recently collected from Mona Island, Puerto Rico. These speleothems together cover the last 2 kyr BP, thus significantly expanding the hydrologic history of the Northeastern Caribbean from speleothem records. Previous studies, mostly from the Western Caribbean, have revealed that Caribbean SSTs as well as solar and volcanic forcing are involved, to different degrees, as driving mechanisms determining the strength of the InterAmerican monsoon systems over the late Holocene. The study of precise, independent chronologies extracted from speleothems, and comparing them to local and regional coral/sclerosponge SST reconstructions, allows for an improved understanding of precipitation patterns of the Caribbean overtime. This new record allows the investigation of decadal to centennial-scale precipitation variability, as well as its linkage to past human civilizations. There is also potential to contribute to the recent discussion of whether the AMO is an internal oscillation or externally forced.