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Vadose zone oxygen (O2) dynamics during drying and wetting cycles : An artificial recharge laboratory experiment

Dutta, Tanushree; Brangarí, Albert C. LU ; Fernandez-Garcia, Daniel; Rubol, Simonetta; Tirado-Conde, Joel and Sanchez-Vila, Xavier (2015) In Journal of Hydrology 527. p.151-159
Abstract
Vadose zone oxygen dynamics control all subsurface redox reactions and play a decisive role in maintaining groundwater quality. Although drying and wetting events are common in artificial recharge, their effects on subsurface oxygen distribution are poorly documented. We monitored oxygen concentration in the unsaturated zone in a mid-scale (1 m high) laboratory soil lysimeter, which was subjected to short wetting and drying cycles that simulated a highly permeable shallow aquifer recharged by river water. Ten cycles of varying duration were performed for a period of 85 days. Measurements of oxygen in the liquid and the gas phases were recorded every 20 s using non-invasive optical fibers (PreSens). The results provided high-resolution (in... (More)
Vadose zone oxygen dynamics control all subsurface redox reactions and play a decisive role in maintaining groundwater quality. Although drying and wetting events are common in artificial recharge, their effects on subsurface oxygen distribution are poorly documented. We monitored oxygen concentration in the unsaturated zone in a mid-scale (1 m high) laboratory soil lysimeter, which was subjected to short wetting and drying cycles that simulated a highly permeable shallow aquifer recharged by river water. Ten cycles of varying duration were performed for a period of 85 days. Measurements of oxygen in the liquid and the gas phases were recorded every 20 s using non-invasive optical fibers (PreSens). The results provided high-resolution (in time) oxygen concentration maps. The infiltration rate revealed a decreasing trend during wetting cycles associated with biological clogging. Such a decrease with time was accompanied by a depletion of O2 concentration, occurring within the first few hours of the infiltration. During drying, O2 concentrations recovered rapidly at all depths owing to air flushing, resulting in a stratified vertical profile consistent with the biological consumption of O2 along the air infiltration path. Furthermore, drying periods caused a potential recovery of the infiltration capacity while preserving the soil biological activity. Scraping also led to the recovery of the infiltration capacity of the soil but was less effective than drying. Our experiment suggests that the small-scale heterogeneity played a key role in accurately mapping pore-scale O2 concentrations and should be considered in modeling O2 fluxes of unsaturated soils under natural or managed recharge conditions (Less)
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author
publishing date
type
Contribution to journal
publication status
published
subject
keywords
Oxygen concentration dynamics, Precision sensing, Managed Aquifer Recharge, Infiltration, Drying–wetting cycles, Biological processes
in
Journal of Hydrology
volume
527
pages
151 - 159
publisher
Elsevier
external identifiers
  • scopus:84929095975
ISSN
0022-1694
DOI
10.1016/j.jhydrol.2015.04.048
language
English
LU publication?
no
id
873a57f0-b8a6-401e-9ef5-79a0f0b26625
date added to LUP
2018-04-16 14:07:15
date last changed
2018-08-19 04:42:18
@article{873a57f0-b8a6-401e-9ef5-79a0f0b26625,
  abstract     = {Vadose zone oxygen dynamics control all subsurface redox reactions and play a decisive role in maintaining groundwater quality. Although drying and wetting events are common in artificial recharge, their effects on subsurface oxygen distribution are poorly documented. We monitored oxygen concentration in the unsaturated zone in a mid-scale (1 m high) laboratory soil lysimeter, which was subjected to short wetting and drying cycles that simulated a highly permeable shallow aquifer recharged by river water. Ten cycles of varying duration were performed for a period of 85 days. Measurements of oxygen in the liquid and the gas phases were recorded every 20 s using non-invasive optical fibers (PreSens). The results provided high-resolution (in time) oxygen concentration maps. The infiltration rate revealed a decreasing trend during wetting cycles associated with biological clogging. Such a decrease with time was accompanied by a depletion of O2 concentration, occurring within the first few hours of the infiltration. During drying, O2 concentrations recovered rapidly at all depths owing to air flushing, resulting in a stratified vertical profile consistent with the biological consumption of O2 along the air infiltration path. Furthermore, drying periods caused a potential recovery of the infiltration capacity while preserving the soil biological activity. Scraping also led to the recovery of the infiltration capacity of the soil but was less effective than drying. Our experiment suggests that the small-scale heterogeneity played a key role in accurately mapping pore-scale O2 concentrations and should be considered in modeling O2 fluxes of unsaturated soils under natural or managed recharge conditions},
  author       = {Dutta, Tanushree and Brangarí, Albert C. and Fernandez-Garcia, Daniel and Rubol, Simonetta and Tirado-Conde, Joel and Sanchez-Vila, Xavier},
  issn         = {0022-1694},
  keyword      = {Oxygen concentration dynamics,Precision sensing,Managed Aquifer Recharge,Infiltration,Drying–wetting cycles,Biological processes},
  language     = {eng},
  month        = {05},
  pages        = {151--159},
  publisher    = {Elsevier},
  series       = {Journal of Hydrology},
  title        = {Vadose zone oxygen (O2) dynamics during drying and wetting cycles : An artificial recharge laboratory experiment},
  url          = {http://dx.doi.org/10.1016/j.jhydrol.2015.04.048},
  volume       = {527},
  year         = {2015},
}