Groundwater influences on atmospheric dust generation in deserts
Groundwater resources are being overexploited in arid and semi-arid environments globally, which necessitates a deeper understanding of the roles that groundwater plays in earth system processes. Of particular importance is the elucidation of groundwater's effect on the generation of atmospheric dust. While many spatially extensive, highly productive dust sources are influenced to some degree by water resource use, including groundwater pumping and other modifications to shallow groundwater tables (< 10 m from the surface), links between near-surface groundwater processes and dust production have only recently been identified. Processes associated with shallow groundwater tables include the vertical movement of salts to the soil surface, the maintenance of near-surface soil moisture, and the support of groundwater-dependent vegetation. Through these processes shallow groundwater dynamics can have both positive and negative feedbacks towards dust generation, and in extreme cases can lead to desertification in semi-arid systems. Here we combine a diverse set of analytical techniques, including remote sensing, ecological evaluation, and fallout radionuclide tracers to characterize groundwater-dependent ecosystems and evaluate the stability of surfaces under variable groundwater conditions. The interdisciplinary approach we describe here is critical to understand the impacts that groundwater management has on earth surface processes. (c) 2008 Elsevier Ltd. All rights reserved.
Keywords: atmospheric dust, groundwater, radionuclides, remote sensing, vegetation, water resources