Root exudation by plants plays important role in carbon sequestration, formation of soil organic matter, weathering of soil minerals, and many other soil processes. In this study, young mesquite trees and grasses were planted into the granular basalt that will be used as soil in the Biosphere 2 Landscape Evolution Observatory. This material has no inherent organic matter present. Plants were placed in two locations at Biosphere 2 that were maintained at 4 degrees temperature difference to simulate changes predicted to happen as a result of global warming. Several containers with the same material but without the plants were co-located with planted treatments. Soil containers with plants were equipped with moisture and temperature sensors, CO2 sensors, as well as solution samplers. Small aliquots of soil solution were withdrawn over time. These samples were analyzed to determine both total dissolved organic matter content and concentrations of a number of low molecular weight organic acids. Release of root exudates by the plants was followed as a function of time and soil moisture content.