Water subsidies from mountains to deserts : their role in sustaining groundwater-fed oases in a sandy landscape

Abstract

The study indicates a reliance of ecosystem productivity on Andean snowmelt, which is increasingly being diverted to one of the largest irrigated regions of the continent. Deep soil coring, plant measurements, direct water-table observations, and stable isotopic analyses (2H and 18O) of meteoric, surface, and ground waters, were used to compare woodland stands, bare dunes, and surrounding shrublands. The isotopic composition of phreatic groundwaters closely matched the signature of water brought to the region by the Mendoza River, suggesting that mountain-river infiltration, rather than in situ rainfall deep drainage was the dominant mechanism of groundwater recharge.