P2C2: A Speleothem and Cave Monitoring Research Program to Reconstruct the Paleoclimatology of the Yucatan Peninsula--Testing Modes and Causes of Variability in the North American

Despite the observed intensification of the hydrological cycle including the increased incidence of drought, flooding and extreme events such as tropical cyclones, the historical record is insufficiently long and uncertain to enable the firm attribution of specific observed extreme hydrological events to an anthropogenic cause and/or to internal modes of climate variability. This project aims at producing precipitation records from stalagmites located in the Yucatan Peninsula (Caribbean and Gulf of Mexico regions), and at examining underlying causal mechanisms of tropical hydroclimate change by integration of these records with climate model simulations.

The researchers will analyze multiple tracers including Oxygen and Carbon isotopes and trace elements to reconstruct precipitation variability in the Caribbean and Gulf of Mexico regions during key climate periods: the Holocene, the last glacial and during marine isotope stages 8-9. In addition, they will expand an environmental and geochemical monitoring system of surface and cave conditions that started in the year 2014, to investigate the relationship between local precipitation amount, and the Oxygen isotopes of precipitation and stalagmite isotopic and elemental composition.

The new monitoring system will include fieldwork to understand the role of vegetation shifts and prior calcite precipitation on the carbon isotopic composition of stalagmites. The monitoring, in conjunction, with the new stalagmite paleoclimate records from the Yucatan Peninsula would help test various hypotheses concerning the environmental controls of the stable isotopic and elemental composition of stalagmites, the role of drought in the development of the Maya civilization, and potential links between Heinrich events (cold intervals) and precipitation declines in the northern Caribbean and Gulf of Mexico region.

The potential Broader Impacts include a characterization and better understanding of hydroclimate variability and tropical cyclones beyond the instrumental record in a densely and vulnerable geographic area (Caribbean and Gulf of Mexico). Other Broader Impacts include the scientific training, mentorship and professional development of two Ph.D students including one female Native American student at UMASS and a second student that the researchers will recruit through the AGU-Bridge program.

The project will also support two early and mid-career researchers. Additionally, the researchers and students will engage in public outreach activities including scientific lectures for the Rio Secreto Cave (Yucatan Peninsula, Mexico) staff. Previous cave monitoring work and paleoclimate studies from this cave have been successfully incorporated in the cave conservation efforts, and in the information shared by tour-guides with thousands of visitors per year.

This paleoclimate research program will foster international collaborations and engagement with local researchers and communities.

This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.