scholarly journals Storage and routing of water in the deep critical zone of a snow dominated volcanic catchment

2019 ◽  
Author(s):  
Alissa White ◽  
Bryan Moravec ◽  
Jennifer McIntosh ◽  
Yaniv Olshansky ◽  
Ben Paras ◽  
...  
Keyword(s):  
High Elevation ◽  
Critical Zone ◽  
Precipitation Pattern ◽  
Fracture Density ◽  
Stable Water Isotopes ◽  
Ion Chemistry ◽  
Major Ion ◽  
Welded Tuff ◽  
Isotopic Analyses ◽  
Perched Aquifer

Abstract. This study combines major ion and isotope chemistry, age tracers, fracture density characterizations, and physical hydrology measurements to understand how the structure of the critical zone (CZ) influences its function, including water routing, storage, mean water residence times, and hydrologic response. In a high elevation rhyolitic tuff catchment in the Jemez River Basin Critical Zone Observatory (JRB-CZO) within the Valles Caldera National Preserve of northern New Mexico, a periodic precipitation pattern creates different hydrologic flow regimes during spring snowmelt, summer monsoon rain, and fall storms. Hydrometric, geochemical, and isotopic analyses of surface water and groundwater from distinct stores, most notably a perched aquifer in consolidated collapse breccia and deeper groundwater in a fractured tuff aquifer, enabled us to untangle the interactions of these groundwater stores and their contribution to streamflow across one complete water year. Despite seasonal differences in groundwater response due to water partitioning, major ion chemistry indicates that deep groundwater from the highly fractured site is more representative of groundwater contributing to streamflow across the entire water year. Additionally, comparison of streamflow and groundwater hydrographs indicates hydraulic connection between the fractured welded tuff aquifer and streamflow while the perched aquifer within the collapse breccia deposit does not show this same connection. Furthermore, analysis of age tracers and stable water isotopes indicates that groundwater is a mix of modern and older waters recharged from snowmelt and downhole neutron probe surveys suggest that water moves through the vadose zone both as vertical infiltration and subsurface lateral flow, depending on lithology. We find that in complex geologic terrain like that of the JRB-CZO, differences in CZ architecture of two hillslopes within a headwater catchment control water storage and routing through the subsurface and suggest that the perched aquifer does not contribute significantly to streams while deep fractured aquifers contribute most to streamflow.

scholarly journals Distinct stores and the routing of water in the deep critical zone of a snow-dominated volcanic catchment

2019 ◽  
Vol 23 (11) ◽  
pp. 4661-4683 ◽  
Author(s):  
Alissa White ◽  
Bryan Moravec ◽  
Jennifer McIntosh ◽  
Yaniv Olshansky ◽  
Ben Paras ◽  
...  
Keyword(s):  
Shallow Groundwater ◽  
Critical Zone ◽  
Shallow Aquifer ◽  
Precipitation Pattern ◽  
Fractured Aquifer ◽  
Aquifer System ◽  
Major Ion ◽  
Welded Tuff ◽  
Aquifer Systems ◽  
Isotopic Analyses

Abstract. This study combines major ion and isotope chemistry, age tracers, fracture density characterizations, and physical hydrology measurements to understand how the structure of the critical zone (CZ) influences its function, including water routing, storage, mean water residence times, and hydrologic response. In a high elevation rhyolitic tuff catchment in the Jemez River Basin Critical Zone Observatory (JRB-CZO) within the Valles Caldera National Preserve (VCNP) of northern New Mexico, a periodic precipitation pattern creates different hydrologic flow regimes during spring snowmelt, summer monsoon rain, and fall storms. Hydrometric, geochemical, and isotopic analyses of surface water and groundwater from distinct stores, most notably shallow groundwater that is likely a perched aquifer in consolidated collapse breccia and deeper groundwater in a fractured tuff aquifer system, enabled us to untangle the interactions of these groundwater stores and their contribution to streamflow across 1 complete water year (WY). Despite seasonal differences in groundwater response due to water partitioning, major ion chemistry indicates that deep groundwater from the highly fractured site is more representative of groundwater contributing to streamflow across the entire water year. Additionally, the comparison of streamflow and groundwater hydrographs indicates a hydraulic connection between the fractured welded tuff aquifer system and streamflow, while the shallow aquifer within the collapse breccia deposit does not show this same connection. Furthermore, analysis of age tracers and oxygen (δ18O) and stable hydrogen (δ2H) isotopes of water indicates that groundwater is a mix of modern and older waters recharged from snowmelt, and downhole neutron probe surveys suggest that water moves through the vadose zone both by vertical infiltration and subsurface lateral flow, depending on the lithology. We find that in complex geologic terrain like that of the JRB-CZO, differences in the CZ architecture of two hillslopes within a headwater catchment control water stores and routing through the subsurface and suggest that shallow groundwater does not contribute significantly to streams, while deep fractured aquifer systems contribute most to streamflow.

RAPID CHANGES IN MAJOR ION CHEMISTRY OF SEAWATER AND THE END-PERMIAN MASS EXTINCTION

2017 ◽  
Author(s):  
Tim K. Lowenstein ◽  
◽  
Javier Garcia Veigas ◽  
Dioni I. Cendón ◽  
Lluís Gibert Beotas
Keyword(s):  
Mass Extinction ◽  
Ion Chemistry ◽  
Major Ion Chemistry ◽  
Major Ion ◽  
Rapid Changes ◽  
Permian Mass Extinction

scholarly journals Analyzing the major drivers of NEE in a Mediterranean alpine shrubland

2010 ◽  
Vol 7 (9) ◽  
pp. 2601-2611 ◽  
Author(s):  
B. R. Reverter ◽  
E. P. Sánchez-Cañete ◽  
V. Resco ◽  
P. Serrano-Ortiz ◽  
C. Oyonarte ◽  
...  
Keyword(s):  
Net Ecosystem Exchange ◽  
High Elevation ◽  
Photosynthetic Photon Flux Density ◽  
Photon Flux ◽  
Photon Flux Density ◽  
Precipitation Pattern ◽  
Key Factors ◽  
Cold Temperatures ◽  
Carbon Sequestration Potential ◽  
Sequestration Potential

Abstract. Two years of continuous measurements of net ecosystem exchange (NEE) using the eddy covariance technique were made over a Mediterranean alpine shrubland. This ecosystem was found to be a net source of CO2 (+ 52 ± 7 g C m−2 and + 48 ± 7 g C m−2 for 2007 and 2008) during the two-year study period. To understand the reasons underlying this net release of CO2 into the atmosphere, we analysed the drivers of seasonal variability in NEE over these two years. We observed that the soil water availability – driven by the precipitation pattern – and the photosynthetic photon flux density (PPFD) are the key factors for understanding both the carbon sequestration potential and the duration of the photosynthetic period during the growing season. Finally, the effects of the self-heating correction to CO2 and H2O fluxes measured with the open-path infrared gas analyser were evaluated. Applying the correction turned the annual CO2 budget in 2007 from a sink (− 135 ± 7 g C m−2) to a source (+ 52 ± 7 g C m−2). The magnitude of this change is larger than reported previously and is shown to be due to the low air density and cold temperatures at this high elevation study site.

Major ion chemistry and water quality assessment of groundwater in the Shigaze urban area, Qinghai-Tibetan Plateau, China

2019 ◽  
Vol 20 (1) ◽  
pp. 335-347 ◽  
Author(s):  
Yingzhi Li ◽  
Jiutan Liu ◽  
Zongjun Gao ◽  
Min Wang ◽  
Leqi Yu
Keyword(s):  
Water Quality ◽  
Tibetan Plateau ◽  
Quality Assessment ◽  
Major Ions ◽  
Water Quality Assessment ◽  
Ion Chemistry ◽  
Major Ion Chemistry ◽  
Major Ion ◽  
The Mean ◽  
Over Time

Abstract Shigaze city is situated in the southwestern Tibetan Plateau and is the second largest city in the Tibet Autonomous Region. Groundwater is the major source of domestic and drinking water for urban inhabitants. In this study, the major ion chemistry and a water quality assessment of groundwater were studied using geochemical methods and fuzzy comprehensive assessment. Groundwater was classified as slightly alkaline soft and hard freshwater, and the influence of anthropogenic activities on groundwater was relatively weak. The dominant cations and anions were Ca2+ and Mg2+ and HCO3− and SO42−, respectively. Overall, the mean concentrations of major ions in groundwater increase gradually over time, except for NO3−; however, the mean value of pH decreases over time. Most groundwater samples belong to the type of HCO3-Ca, and the groundwater has a trend of evolution from HCO3-Ca to the mixed type. Rock weathering was the main hydrogeochemical process controlling groundwater hydrochemistry, and the dissolution of carbonate and silicate minerals were the primary contributors to the formation of the major ion chemistry of groundwater. Major ions of groundwater in the urban area of Shigaze are below the standard limits, and the groundwater is excellent for drinking according to the fuzzy comprehensive assessment.

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