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  • 1
    Language: English
    In: Ecological Engineering, 2010, Vol.36(9), pp.1156-1166
    Description: Fertilizer applications and other non-point sources result in an increasing diffuse N and P pollution of receiving waters degrading water quality by eutrophication with several adverse impacts. Floodplains are regarded as reactive interfaces between uplands and receiving waters. In the present study groundwater quality on its subsurface flow from an upland area through a lowland floodplain towards the receiving water body of the Spree River was monitored biweekly over 2 years with two transects of 18 groundwater observation wells. Within the floodplain reaction rates of the nutrients are unevenly distributed. On a scale smaller than the floodplain, the hyporheic zone is regarded as reactive interface with unproportional high reaction rates. Therefore, phosphate and dissolved iron were measured with high spatial resolution in the pore water of the riverbed and the oxbow bed to investigate turnover processes and their small-scale spatial variability at the immediate surface–subsurface interface. The biogeochemical composition of subsurface water is characterized by little temporal variability while spatial heterogeneity is high on the hectametre scale of the study site as well as on the centimetre scale of the bed sediments. Nitrate is eliminated very efficiently by denitrification in the anoxic aquifer of the floodplain while ammonium and phosphate concentrations increase under anoxic conditions. Phosphate and ammonium originate from the mineralization of organic matter and phosphate is additionally released by reductive dissolution of iron-bound phosphorus and weathering of bedrock. Sorption–desorption processes equalize temporal fluctuations of phosphate concentrations. Phosphate uptake by plants is assumed as an important process at only one of the groundwater observation wells. Redox conditions required for a phosphate sink are opposite to those involved in nitrate removal by denitrification. Thus, redox patchiness of floodplain aquifers favours nitrate and phosphate removal, i.e. a temporal and spatial sequence of anoxic and oxic conditions eliminates nitrogen and causes phosphate storage. On the groundwater's path from the upland to the river further phosphate is released in the bed sediments. It originates from previously settled particulate compounds containing phosphorus. While the release of iron-bound phosphorus clearly predominates in the riverbed sediments the mineralization of organic matter is an important additional phosphorus release process in the oxbow bed sediments.
    Keywords: Phosphate ; Nitrate ; Nutrient Retention ; Floodplain'S Aquifer ; Hyporheic Zone ; Biogeochemical Processes ; Engineering ; Environmental Sciences
    ISSN: 0925-8574
    E-ISSN: 1872-6992
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  • 2
    Language: English
    In: Science of the Total Environment, 2011, Vol.409(10), pp.1824-1835
    Description: Many rivers and streams worldwide are impacted by pharmaceuticals originating from sewage. The hyporheic zone underlying streams is often regarded as reactive bioreactor with the potential for eliminating such sewage-born micropollutants. The present study aims at checking the elimination potential and analyzing the coupling of hydrodynamics, biogeochemistry and micropollutant processing. To this end, two sites at the lowland stream Erpe, which receives a high sewage burden, were equipped and sampled with nested piezometers. From temperature depth profiles we determined that at one of the sites infiltration of surface water into the aquifer occurs while exfiltration dominates at the other site. Biogeochemical data reveal intense mineralization processes and strictly anoxic conditions in the streambed sediments at both sites. Concentrations of the pharmaceuticals indomethacin, diclofenac, ibuprofen, bezafibrate, ketoprofen, naproxen and clofibric acid were high in the surface water and also in the subsurface at the infiltrating site. The evaluation of the depth profiles indicates some attenuation but due to varying surface water composition the evaluation of subsurface processes is quite complex. Borate and non-geogenic gadolinium were measured as conservative wastewater indicators. To eliminate the influence of fluctuating sewage proportions in the surface water, micropollutant concentrations are related to these indicators. The indicators can cope with different dilutions of the sewage but not with temporally varying sewage composition. ► Hyporheic zone underlying streams is often regarded as reactive bioreactor. ► Hyporheic zone has some potential for eliminating sewage-born micropollutants. ► Subsurface pharmaceutical concentrations high due to infiltration of stream water. ► Varying surface water composition complicates evaluation of subsurface processes. ► Borate and non-geogenic gadolinium are useful as conservative wastewater indicators.
    Keywords: Pharmaceuticals ; Ibuprofen ; Hyporheic Zone ; Self-Purification Capacity ; Gadolinium ; Borate ; Hydrology ; Biogeochemistry ; Environmental Sciences ; Biology ; Public Health
    ISSN: 0048-9697
    E-ISSN: 1879-1026
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  • 3
    Language: English
    In: Journal of Hydrology, Oct 10, 2013, Vol.502, p.202(10)
    Description: To link to full-text access for this article, visit this link: http://dx.doi.org/10.1016/j.jhydrol.2013.08.021 Byline: Karin Meinikmann, Jorg Lewandowski, Gunnar Nutzmann Abstract: acents LGD is a key player in nutrient budgets of some lakes. acents Quantification of LGD is challenging due to its spatial heterogeneity. acents Quantity and pattern of LGD jointly control groundwater-borne P loads. Article History: Received 26 April 2013; Revised 8 August 2013; Accepted 14 August 2013 Article Note: (miscellaneous) This manuscript was handled by Corrado Corradini, Editor-in-Chief, with the assistance of Aldo Fiori, Associate Editor
    Keywords: Groundwater
    ISSN: 0022-1694
    Source: Cengage Learning, Inc.
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  • 4
    Language: English
    In: Journal of Hydrology, Dec 19, 2012, Vol.475, p.1(11)
    Description: To link to full-text access for this article, visit this link: http://dx.doi.org/10.1016/j.jhydrol.2012.06.050 Byline: Lisa Angermann (a)(b)(c), Jorg Lewandowski (a), Jan H. Fleckenstein (b)(c), Gunnar Nutzmann (a)(d) Keywords: Flow patterns; Flow direction; Flow velocity; Hyporheic zone; Heat pulse technique Abstract: a* We developed a method to determine flow direction and velocity in the hyporheic zone. a* The method is based on a heat pulse technique with analytical data analysis algorithm. a* Error-proneness and accuracy of the method were assessed in the lab and in situ. a* The first field application gives insight in hyporheic flow patterns of a lowland river. Author Affiliation: (a) Leibniz-Institute of Freshwater Ecology and Inland Fisheries, Department Ecohydrology, Muggelseedamm 310, D-12587 Berlin, Germany (b) Helmholtz Center for Environmental Research - UFZ, Department of Hydrogeology, Permoserstr. 15, D-04318 Leipzig, Germany (c) University of Bayreuth, Department of Hydrology, Universitatsstr. 30, D-95440 Bayreuth, Germany (d) Humboldt-University of Berlin, Geographical Institute, Rudower Chaussee 16, D-12489 Berlin, Germany Article History: Received 27 October 2011; Revised 21 June 2012; Accepted 26 June 2012 Article Note: (miscellaneous) This manuscript was handled by Philippe Baveye, Editor-in-Chief, with the assistance of Nunzio Romano, Associate Editor
    Keywords: Hydrogeology -- Analysis ; Sensors -- Analysis ; Flow (Dynamics) -- Analysis
    ISSN: 0022-1694
    Source: Cengage Learning, Inc.
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  • 5
    Language: English
    In: Limnology and Oceanography, July, 2005, Vol.50(4), p.1106(13)
    Description: We used mesocosms equipped with two-dimensional (2D) pore water samplers (24 rows x 24 columns, 9-mm spatial resolution) to resolve and quantify some of the complex spatial patterns in diagenetic reactions produced by irrigated biogenic structures. The mesocosms were filled with an organic-, iron-, and phosphorus-rich sediment, and chironomids and oligochaetes were added in high densities to three of six mesocosms: the other three mesocosms served as controls. In the mesocosms without macrozoobenthos, a classic redox zonation developed. In the mesocosms with macrozoobenthos, profiles of redox-sensitive dissolved species were less steep in the vicinity of the sediment-water interface, and more irregular throughout the sediment, than in the mesocosms without macrozoobenthos. Furthermore, pore water P concentrations were decreased overall and showed much more small-scale 2D heterogeneity in the mesocosms with macrozoobenthos than to the controls. A comparison of the calculated heterogeneity indices of pore water P concentrations (the ratio of horizontal to vertical flux components) of this laboratory study with in situ-determined indices of previous studies indicates that the presence of macrozoobenthos is the major factor causing heterogeneity. A conceptual model of the effects of macrozoobenthos on biogeochemistry along with pore water and sediment analysis showed a close coupling of P cycling with iron and sulfur cycling. This led to the conclusion that pore water P concentrations and heterogeneity were mainly redox-controlled by association of P with iron oxyhydroxides precipitating along oxidized burrow walls, and not a consequence of mineralization processes occurring in organic-rich "hot spots" of increased P turnover. Decreased P release rates accompanied addition of macrozoobenthos and indicated that redox control of P release by iron oxyhydroxide precipitation and dissolution was of major importance.
    Keywords: Freshwater ; Freshwater ; Freshwater ; Water Quality ; Erosion and Sedimentation ; Ecosystems and Energetics ; Geochemistry of Sediments;
    ISSN: 0024-3590
    Source: Cengage Learning, Inc.
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  • 6
    Language: English
    In: Journal of Hydrology, May 2015, Vol.524, pp.214-226
    Description: Lake eutrophication has long been mainly associated with phosphorus (P) inputs from overland flow. The present study gives evidence that also groundwater can carry significant loads of dissolved P. We quantified P loads from groundwater to Lake Arendsee using near-shore measurements of P concentrations at a high spatial resolution and volume fluxes of lacustrine groundwater discharge (LGD) derived from a previous study. Results show that LGD accounts for more than 50% of the overall external P load, thus fuelling the eutrophication of the lake. Several different approaches of groundwater sampling (groundwater observation wells, temporary piezometers, and domestic wells) reveal a broad spatial heterogeneity of P concentrations in the subsurface catchment of the lake. The highest P concentrations (above 4 mg l ) were found below a settled area along the southern lake shore. Contrary to expectations, other parameters (dissolved iron, ammonium, etc.) were not correlated with P, indicating that natural processes are superimposed by heavy contaminations. Both the intensity of the contamination and its proximity to the lake inhibit nutrient retention within vadose zone and aquifer and allow significant P loads to be discharged into the lake. Although the groundwater quality was investigated intensely, the results eventually give no clear evidence of the location and sources of the pollution. As a consequence, measures to decrease LGD-derived P loads cannot target the contamination at its source in the catchment. They need to be implemented in the riparian area to eliminate groundwater P directly before it enters the lake.
    Keywords: Contamination ; Groundwater Phosphorus Loading ; Urban Areas ; Groundwater Surface Water Interaction ; Lacustrine Groundwater Discharge ; Groundwater Pollution ; Geography
    ISSN: 0022-1694
    E-ISSN: 1879-2707
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  • 7
    Language: English
    In: Remote Sensing of Environment, Nov, 2013, Vol.138, p.119(7)
    Description: To link to full-text access for this article, visit this link: http://dx.doi.org/10.1016/j.rse.2013.07.005 Byline: Jorg Lewandowski, Karin Meinikmann, Thomas Ruhtz, Franziska Poschke, Georgiy Kirillin Abstract: Although lacustrine groundwater discharge (LGD) might be important in water and nutrient budgets, it has often been neglected due to the required effort to measure LGD and due to intense spatial heterogeneity of LGD limiting the validity of measurements. Therefore, fast, easy applicable methods for a first snapshot of the LGD pattern are required and might be the basis for choosing relevant and representative sampling sites. In the present case study, which is actually the first application of an airborne measurement of thermal infrared radiation (TIR) to identify LGD pattern for entire deep freshwater lakes, the measurement was substantiated with thermal profiles in sediments and a water-table map. We found that measurement of TIR is a powerful tool to identify LGD pattern in lake-related studies provided that there is a lack of warm surface inflows. A TIR image taken in March 2012 shows that warm groundwater entering the relatively colder lake water in some near-shore areas is visible as a plume floating on top of the lake water. Prerequisites for the application of TIR to detect LGD pattern are the positive buoyancy of the groundwater relative to lake water and weak mixing in the water column. We propose a dimensionless scale for identifying groundwater floating conditions based on weather conditions. Attributing a surface thermal anomaly to LGD depends on careful consideration of other factors that could produce similar patterns and careful consideration of lake physics. Article History: Received 15 November 2012; Revised 4 March 2013; Accepted 6 July 2013
    Keywords: Groundwater -- Case Studies ; Groundwater -- Measurement ; Nuclear Radiation -- Case Studies ; Nuclear Radiation -- Measurement
    ISSN: 0034-4257
    Source: Cengage Learning, Inc.
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  • 8
    Language: English
    In: Water Research, 15 June 2016, Vol.97, pp.153-161
    Description: An artificial increase of phosphorus (P) retention in lakes with a long residence time and/or a large mobile sediment P pool by adding P binding chemicals can drastically shorten the time these lakes require to reach water quality targets. Suitable tools to optimize timing and extent of external and internal measures are lacking. The one-box model, a mass balance tool for predicting the P trend in the water under different management options was applied to highly eutrophic Lake Arendsee (a = 5.14 km , z  = 49 m), Germany. Mass developments of blue green algae and increasing hypolimnetic oxygen deficiencies are urgent reasons for restoring Lake Arendsee. Detailed studies of P cycling and scenario analyses with the one-box model led to the following conclusions: i) immediate improvement of the trophic state is only possible by in-lake P inactivation because of the long water residence time (56 years); ii) a gradual external P load reduction, even if the effect is delayed, will assure the sustainability of the scheduled Al application beyond one decade; iii) a twofold precipitation reduces the risk of failure compared to a singular application with an overdose related to the relevant internal P pools.
    Keywords: Sediment ; Phosphorus Retention ; One-Box Model ; Eutrophication ; Phosphorus Binding Chemicals ; Lake Restoration ; Engineering
    ISSN: 0043-1354
    E-ISSN: 1879-2448
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  • 9
    Language: English
    In: Water Research, June 15, 2016, Vol.97, p.153(9)
    Description: To link to full-text access for this article, visit this link: http://dx.doi.org/10.1016/j.watres.2015.06.052 Byline: Michael Hupfer, Kasper Reitzel, Andreas Kleeberg, Jorg Lewandowski Abstract: An artificial increase of phosphorus (P) retention in lakes with a long residence time and/or a large mobile sediment P pool by adding P binding chemicals can drastically shorten the time these lakes require to reach water quality targets. Suitable tools to optimize timing and extent of external and internal measures are lacking. The one-box model, a mass balance tool for predicting the P trend in the water under different management options was applied to highly eutrophic Lake Arendsee (a = 5.14 km.sup.2, z.sub.max = 49 m), Germany. Mass developments of blue green algae and increasing hypolimnetic oxygen deficiencies are urgent reasons for restoring Lake Arendsee. Detailed studies of P cycling and scenario analyses with the one-box model led to the following conclusions: i) immediate improvement of the trophic state is only possible by in-lake P inactivation because of the long water residence time (56 years); ii) a gradual external P load reduction, even if the effect is delayed, will assure the sustainability of the scheduled Al application beyond one decade; iii) a twofold precipitation reduces the risk of failure compared to a singular application with an overdose related to the relevant internal P pools. Author Affiliation: (a) Leibniz-Institute of Freshwater Ecology and Inland Fisheries Berlin, Muggelseedamm 301, D-12587 Berlin, Germany (b) University of Southern Denmark Odense, Institute of Biology, Campusvej 55, DK-5230 Odense M, Denmark Article History: Received 3 May 2015; Revised 27 June 2015; Accepted 30 June 2015
    Keywords: Precipitation (Meteorology) – Analysis ; Lake Renewal – Analysis
    ISSN: 0043-1354
    Source: Cengage Learning, Inc.
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  • 10
    Language: English
    In: Journal of Hydrology, 10 October 2013, Vol.502, pp.202-211
    Description: The quantification of lacustrine groundwater discharge (LGD) in water and nutrient balances of lakes is challenging and thus often neglected. However, by carrying large nutrient loads, groundwater might play a key role in a lakés nutrient budget even if its contribution to the water balance is small. In the present study, we quantify the total annual LGD of a lake in northeastern Germany by the calculation of annual groundwater recharge in the subsurface catchment. Furthermore, spatial variability of LGD is expected to have significant influence on the nutrient balance due to heterogeneous nutrient concentrations. To assess its spatial variability, LGD is calculated for single sites based on vertical temperature profiles of the lake bed along the shoreline. The combination of the total LGD and the spatial LGD patterns allows calculating LGD volumes for single shoreline sub-sections. These calculations reveal that a large portion of the total LGD enters the lake within a relatively limited section of the shoreline. Scenarios including different phosphorus concentrations demonstrate the importance of both, quantity and patterns of LGD, when groundwater-borne phosphorus loads are calculated. At high, heterogeneous groundwater nutrient concentrations, it is crucial for lake nutrient budgets to reliably determine LGD patterns and volume.
    Keywords: Groundwater–Surface Water Interaction ; Groundwater Recharge ; Lacustrine Groundwater Discharge ; Water Balance ; Nutrient Budget ; Geography
    ISSN: 0022-1694
    E-ISSN: 1879-2707
    Source: ScienceDirect Journals (Elsevier)
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