SURFACE-SUBSURFACE CONNECTIVITY IN KARST LANDSCAPES: IMPLICATIONS FOR TERRESTRIAL WATER AND CARBON FLUXES

Karst systems worldwide are experiencing lowered water levels and pollution, and it is predicted that climate and land use change will exacerbate both of these conditions. In this project we are studying how the hydrologic connectivity between terrestrial ecosystems and underlying geology affects subsurface carbon storages and fluxes in karst landscapes, using the James Cave field site in Pulaski, Co., Virginia. In 2007, we instrumented James Cave to study karst hydrology, and since then our group has collected almost ten years of data on the timing, magnitude, and chemistry of recharge (drip water) within the cave. To understand couplings between hydrologic (e.g., evapotranspiration and recharge) and carbon fluxes, we recently installed three vertical profiles of soil water content and CO₂ sensors in the soil profile above the cave. In this presentation, we will focus on using these high-resolution data to better understand the dynamic role of hydrologic connectivity on carbon fluxes within the karst “critical zone”.