Collaborative Research: Geophysical Campaign to Image CZ Structure Along Hillslope Gradients in the Neotropics

The Amazon forest is the largest stand of tropical rainforest on Earth. It hosts the highest diversity of plants and animals, many not yet documented. The Amazon forest regulates the climate not just over the Amazon but also globally, by sending large amounts of water vapor into the air and by pulling carbon dioxide from the air, both important for maintaining the stability of our climate system. The source of water to support trees in the Amazon is not clear, particularly in the dry season when areas can go without rain for extended periods of time. This project will investigate subsurface water storage in the Amazon, and the extent to which that storage is recharged during wet periods. Geophysical tools will be used to “see” the subsurface structure below the forests. Geophysical tools send waves into the ground and receive the bounced back signal, which can be analyzed to get an image of the material structure below the ground. The project is a collaboration with three Brazilian scientists, trains two US and two Brazilian students, and the work will generate educational materials for universities in both countries. This project will conduct seasonal geophysical campaigns, near the end of wet (April-May) and dry (October-November) seasons, over 2-3 years to image the subsurface structure and seasonal water storage dynamics, at two sites in Brazil (a rainforest and a savanna site), already well established by a collaborating Brazilian team to study vegetation drought resilience. Tasks include 2D seismic refraction and electric resistivity tomography and 1D nuclear magnetic resonance surveys, along hill-valley transects at each site. Detailed analyses and integrative modeling will be used to test hypotheses on the hydrologic function of different subsurface zones and their role in buffering vegetation drought responses. The project will create educational modules on how the belowground dynamics interact with aboveground vegetation in the Amazon.This project is jointly funded by Hydrologic Sciences and the Division of Earth Sciences to support projects that increase research capabilities, capacity and infrastructure at a wide variety of institution types, as outlined in the GEO EMBRACE DCL.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.