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Berlin Brandenburg

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  • 1
    Language: English
    In: Vadose Zone Journal, 2011, Vol.10(3), p.943
    Description: Dissolved organic carbon (DOC) export from watersheds and soil organic carbon (SOC) storage are intimately linked in the terrestrial carbon cycle. However, predictions of hot spots and hot moments of DOC and SOC in watersheds remain uncertain because of high spatiotemporal variability and changing controls. In this study, we investigated the linkage between SOC storage and landform units across the 7.9-ha Shale Hills Critical Zone Observatory (CZO) and its implications for potential hot spots of DOC. We also examined the trends of DOC in soil pore water along two hillslopes of contrasting soils and topography and the impacts of rainfall, stream discharge, and stream temperature on DOC export to identify possible hot moments. Based on the SOC distribution throughout the entire catchment, swales (particularly south-facing swales) were identified as hot spots because they exhibited significantly higher SOC storage and more active hydrology as compared to the rest of the catchment. Along the two hillslopes reported here, average soil pore water DOC concentrations were noticeably higher (35 + or - 12%) along the swale as compared to the planar hillslope. Soil pore water DOC concentrations were elevated at the soil-bedrock interface at the ridgetop and at the Bw-Bt horizon interface in the valley floor, suggesting transport-driven hot spots along restrictive layer interfaces. Stream water DOC concentration at the catchment outlet averaged 6.2 + or - 5.3 mg L (super -1) from May 2008 to October 2010, which was significantly correlated with stream discharge and stream water temperature. Transport-driven hot moments of stream water DOC were observed during the periods of snowmelt and late summer to early fall wet-up, which together contributed approximately 55% of total stream water DOC exported in 2009. This reflected the control of DOC export by flushing (linked to discharge) and biological activity (related to temperature) and its variation during different seasons of a year. This study showcased the impacts of complex soil and topography interactions--coupled with changing weather and seasonal biological activity--on the spatiotemporal dynamics of DOC export in a temperate forested catchment and its link to SOC distribution.
    Keywords: Geochemistry Of Rocks, Soils, And Sediments ; Hydrogeology ; Appalachians ; Carbon ; Carbon Cycle ; Central Pennsylvania ; Concentration ; Drainage Basins ; Geochemical Cycle ; Geochemistry ; Ground Water ; Huntingdon County Pennsylvania ; Hydrochemistry ; Hydrologic Cycle ; Hydrology ; Moisture ; North America ; Organic Carbon ; Pennsylvania ; Pore Water ; Quantitative Analysis ; Shale Hills ; Solutes ; Spatial Distribution ; Statistical Analysis ; Surface Water ; Time Factor ; United States ; Unsaturated Zone ; Valley And Ridge Province ; Variance Analysis;
    ISSN: Vadose Zone Journal
    E-ISSN: 1539-1663
    Source: CrossRef
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  • 2
    Language: English
    In: Vadose Zone Journal, 2011, Vol.10(3), p.928
    Description: We investigated variations of Mg concentration, delta D and delta O in precipitation, soil water along a planar hillslope, groundwater, and first-order stream water at the Susquehanna Shale Hills Critical Zone Observatory (SSHO). Water flows vertically in the unsaturated zone of the hillslope, but hydrological saturation periodically causes lateral flow along interfaces of permeability contrast between the A-B and B-C soil horizons. Changes in soil water Mg concentration respond to hydrological changes and are ultimately controlled by the kinetics of clay mineral dissolution, but are buffered by the soil exchange capacity. Clay dissolution predominantly occurs within the A and B horizons, and Mg released from these zones of "low-flow" diffuses or flows into the "high-flow" zones at horizon interfaces. The Mg concentrations are low in these high-flow zones because fresher (younger) water flows in through macropores. The amplitude of seasonal variations in water isotopes (data from 2008-2010) decreases in the following order: precipitation (delta D: 286 per mil) 〉〉 soil water (delta D: 86 per mil) 〉 shallow groundwater (delta D: 26 per mil), indicating water becomes progressively older along the flowpath. Fractures and preferential high-flow paths make the watershed hydrologically responsive: the average time water stays in the shallow subsurface is inferred to be 〈2 yr. The stream water chemistry is affected by inputs of old groundwater that is relatively high in Mg concentration but relatively limited in range in delta D, as well as by inputs from young soil water that is relatively low in Mg concentration with a wide range in delta D. The relative contributions of these two sources to the stream change seasonally.
    Keywords: Isotope Geochemistry ; Hydrogeology ; Geomorphology ; Alkaline Earth Metals ; Appalachians ; Central Pennsylvania ; Controls ; Critical Zone ; D/H ; Geochemistry ; Geomorphology ; Ground Water ; Huntingdon County Pennsylvania ; Hydrochemistry ; Hydrogen ; Hydrologic Cycle ; Hydrology ; Isotope Ratios ; Isotopes ; Magnesium ; Metals ; Meteoric Water ; Moisture ; Monitoring ; North America ; O-18/O-16 ; Observatories ; Oxygen ; Pennsylvania ; Ph ; Preferential Flow ; Reactive Transport ; Shale Hills ; Soils ; Stable Isotopes ; Surface Water ; Susquehanna River Basin ; Transport ; United States ; Unsaturated Zone ; Valley And Ridge Province ; Weathering;
    ISSN: Vadose Zone Journal
    E-ISSN: 1539-1663
    Source: CrossRef
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  • 3
    Language: English
    In: Vadose Zone Journal, 2013, Vol.12(4), p.0
    Description: To better understand flow pathways and patterns in the subsurface, a stable isotope monitoring network was established at the Susquehanna-Shale Hills Critical Zone Observatory (SSHCZO). Soil water samples were collected approximately biweekly using suction-cup lysimeters installed at multiple depths along four different transects in the catchment. Groundwater and stream water were collected daily in the valley using automatic samplers, while precipitation samples were collected automatically on an event basis. The 3+ years (2008-2012) of monitoring data showed strong seasonal precipitation isotope compositions, which were imprinted in seasonal patterns of soil water at different spatial locations and depths. The groundwater isotope composition remained relatively constant throughout the year and closely matched the yearly amount-weighted precipitation average, suggesting groundwater received recharge water in each season, although recharge mechanisms differed between growing and nongrowing seasons. Soil water samples showed clear attenuation with depth, with the largest variability in the shallow soil water (〈 or =30 cm) mirroring precipitation inputs, moderate variability in the intermediate depths (40-100 cm), and the least variability in the deep soil water (〉 or =120 cm) where the average remained near the groundwater average. Soil water isotope composition profiles also provided clear evidence for preferential flow occurring both laterally and vertically in different seasons and at various soil depths in the catchment. Putting all together, the extensive dataset of soil water isotopic compositions obtained in this study have provided a number of insights into complex subsurface hydrologic processes that are transferable to other similar landscapes.
    Keywords: Isotope Geochemistry ; Hydrogeology ; Appalachians ; Central Pennsylvania ; D/H ; Huntingdon County Pennsylvania ; Hydrodynamics ; Hydrogen ; Hydrologic Cycle ; Hydrology ; Isotope Ratios ; Isotopes ; Juniata River Basin ; Meteoric Water ; North America ; O-18/O-16 ; Observatories ; Oxygen ; Pennsylvania ; Preferential Flow ; Shavers Creek ; Snowmelt ; Soil Profiles ; Soils ; Stable Isotopes ; Susquehanna-Shale Hills Critical Zone Observatory ; Topography ; United States ; Unsaturated Zone ; Valley And Ridge Province ; Water;
    ISSN: Vadose Zone Journal
    E-ISSN: 1539-1663
    Source: CrossRef
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  • 4
    Language: English
    In: Vadose Zone Journal, 2011, Vol.10(3), pp.974-987
    Description: European Union policy on soil threats and soil protection has prioritized new research to address global soil threats. This research draws on the methodology of Critical Zone Observatories (CZOs) to focus a critical mass of international, multi disciplinary expertise at specific field sites. These CZOs...
    Keywords: Environmental Sciences Related To Agriculture And Land-Use ; Miljö- Och Naturvårdsvetenskap
    ISSN: 1539-1663
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  • 5
    Language: English
    In: Vadose Zone Journal, 01 November 2018, Vol.17(1)
    Description: The Susquehanna Shale Hills Critical Zone Observatory (SSHCZO) was established to investigate the form, function, and dynamics of the critical zone developed on sedimentary rocks in the Appalachian Mountains in central Pennsylvania. When first established, the SSHCZO encompassed only the Shale...
    Keywords: Agriculture
    ISSN: 1539-1663
    E-ISSN: 1539-1663
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  • 6
    Language: English
    In: Vadose Zone Journal, 01 October 2018, Vol.17(1)
    Description: The footprint of the Susquehanna Shale Hills Critical Zone Observatory was expanded in 2013 from the forested Shale Hills subcatchment (0.08 km) to most of Shavers Creek watershed (163 km) in an effort to understand the interactions among water, energy, gas, solute, and sediment. The main stem...
    Keywords: Agriculture
    ISSN: 1539-1663
    E-ISSN: 1539-1663
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