An 8000-year Precipitation Record from the Central American Dry Corridor

Keywords: lake sediments, stable isotopes, fire history, drought, Costa Rica, Central America
Session Type: Virtual Paper Abstract
Day: Monday
Session Start / End Time: 2/28/2022 02:00 PM (Eastern Time (US & Canada)) - 2/28/2022 03:20 PM (Eastern Time (US & Canada))
Room: Virtual 8

Abstract

The Guanacaste Province of northwestern Costa Rica is located on the southern end of the Central
American Dry Corridor (CADC), a dry and drought-prone subregion of the isthmus that stretches
from Guanacaste northward along the Pacific coast through Nicaragua, Honduras, El Salvador,
and Guatemala. Analyses by Hidalgo et al. (Climate Dynamics, 2019) showed a periodicity of
significant, sustained droughts of about ten years during recent decades, influenced by multiple
drivers including the Caribbean Low Level Jet and the El Nino-Southern Oscillation (see also
Quesada-Hernández et al., Progress in Physical Geography, 2019). Here we present a record of
millennial-scale shifts in precipitation over the last 8000 years in the CADC inferred from the
stable hydrogen isotope compositions of leaf waxes in a sediment core from Laguna San Pablo on
the lower Pacific slope of Volcán Miravalles. Our analyses show that conditions were generally
drier prior to 6500 cal yr BP and after 3200 cal yr BP, a pattern consistent with interpretations
from diatom assemblages in the lake sediments. Hydrogen isotope ratios indicate dry conditions
from ca. 500–250 cal yr BP, during the Little Ice Age, in agreement with lake-sediment records
from the CADC and lake-sediment, speleothem, and marine records from the circum-Caribbean
region.