Collaborative Research: Developing Records of Hydroclimate Variability in the Southeastern United States from the Middle Holocene to Present-Day

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The Southeastern United States is an important agricultural region, but recent flooding and drought events have caused billions of dollars in economic loss. There is a lack of understanding about what drives changes in precipitation-evaporation (hydroclimate) trends, in part because there are fewer paleoclimate records from this region compared to the rest of the United States. This project will collect sediment cores from four lakes, two in northern Georgia and Alabama and two in the south. These regions are expected to respond differently depending on what predominantly controls hydroclimate. This project will establish if these lakes have records that are suitable for further, in-depth study of the past 5000 years and can ultimately identify what is an important control of hydroclimate and how it changed through time.This project’s central hypothesis is that from 4000 years BP onwards, hydroclimate in the Southeastern United States has been predominantly controlled by the Pacific North American pattern which manifests as a precipitation dipole at the selected study sites. This project will focus attention on: 1) dating the collected sediment sequences from depocenter and transect cores, 2) establishing whether sediment accumulation is sufficient enough to test the hypothesis, and 3) documenting the stratigraphic sequences in the collected cores. Preliminary work on physical (grain size), geochemical (carbon and nitrogen), and biological (pollen) parameters in the sediments will also establish the feasibility of pursuing additional study.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.