Journal Article10.1126/SCIENCE.1086435
A Reservoir of Nitrate Beneath Desert Soils
Michelle Ann Walvoord,Fred M. Phillips,David A. Stonestrom,R. Dave Evans,P. C. Hartsough,P. C. Hartsough,Brent D. Newman,Robert G. Striegl +7 more
TL;DR: Consideration of the subsoil reservoir raises estimates of vadose-zone nitrogen inventories by 14 to 71% for warm deserts and arid shrublands worldwide and by 3 to 16% globally.
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Abstract: A large reservoir of bioavailable nitrogen (up to approximately 10(4) kilograms of nitrogen per hectare, as nitrate) has been previously overlooked in studies of global nitrogen distribution. The reservoir has been accumulating in subsoil zones of arid regions throughout the Holocene. Consideration of the subsoil reservoir raises estimates of vadose-zone nitrogen inventories by 14 to 71% for warm deserts and arid shrublands worldwide and by 3 to 16% globally. Subsoil nitrate accumulation indicates long-term leaching from desert soils, impelling further evaluation of nutrient dynamics in xeric ecosystems. Evidence that subsoil accumulations are readily mobilized raises concern about groundwater contamination after land-use or climate change.
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Citations
Denitrification across landscapes and waterscapes: a synthesis.
Sybil P. Seitzinger,John A. Harrison,John Karl Böhlke,Alexander F. Bouwman,Richard Lowrance,Bruce J. Peterson,Craig R. Tobias,G. Van Drecht +7 more
TL;DR: It is suggested that terrestrial, freshwater, and marine systems in which denitrification occurs can be organized along a continuum ranging from (1) those in which nitrification and Denitrification are tightly coupled in space and time to (2) thoseIn aquatic ecosystems, N inputs influenceDenitrification rates whereas hydrology and geomorphology influence the proportion of N inputs that are denitrified.
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Impact of land use and land cover change on groundwater recharge and quality in the southwestern US
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