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Author Oehler, T.; Tamborski, J.; Rahman, S.; Moosdorf, N.; Ahrens, J.; Mori, C.; Neuholz, R.Ã.©; Schnetger, B.; Beck, M.
Title DSi as a Tracer for Submarine Groundwater Discharge Type Journal Article
Year 2019 Publication Frontiers in Marine Science Abbreviated Journal
Volume 6 Issue Pages 563
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Abstract Submarine groundwater discharge (SGD) is an important source of nutrients and metals to the coastal ocean, affects coastal ecosystems, and is gaining recognition as a relevant water resource. SGD is usually quantified using geochemical tracers such as radon or radium. However, a few studies have also used dissolved silicon (DSi) as a tracer for SGD, as DSi is usually enriched in groundwater when compared to surface waters. In this study, we discuss the potential of DSi as a tracer in SGD studies based on a literature review and two case studies from contrasting environments. In the first case study, DSi is used to calculate SGD fluxes in a tropical volcanic-carbonate karstic region (southern Java, Indonesia), where SGD is dominated by terrestrial groundwater discharge. The second case study discusses DSi as a tracer for marine SGD (i.e., recirculated seawater) in the tidal flat area of Spiekeroog (southern North Sea), where SGD is dominantly driven by tidal pumping through beach sands. Our results indicate that DSi is a useful tracer for SGD in various lithologies (e.g., karstic, volcanic, complex) to quantify terrestrial and marine SGD fluxes. DSi can also be used to trace groundwater transport processes in the sediment and the coastal aquifer. Care has to be taken that all sources and sinks of DSi are known and can be quantified or neglected. One major limitation is that DSi is used by siliceous phytoplankton and therefore limits its applicability to times of the year when primary production of siliceous phytoplankton is low. In general, DSi is a powerful tracer for SGD in many environments. We recommend that DSi should be used to complement other conventionally used tracers, such as radon or radium, to help account for their own shortcomings.
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ISSN 2296-7745 ISBN Medium
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Call Number THL @ christoph.kuells @ Oehler2019 Serial 192
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Author Kloppmann, W.; Petelet-Giraud, E.; Guerrot, C.; Cary, L.; Pauwels, H.
Title Extreme Boron Isotope Ratios in Groundwater Type Journal Article
Year 2015 Publication Procedia Earth and Planetary Science Abbreviated Journal
Volume 13 Issue Pages
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Abstract Kloppmann, W. , Petelet-Giraud, E. , Guerrot, C. , Cary, L. , & Pauwels, H. (2015). Extreme Boron Isotope Ratios in Groundwater. Procedia Earth and Planetary Science, 13 . doi: 10.1016/j.proeps.2015.07.069
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Call Number THL @ christoph.kuells @ Serial 193
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Author Sarker, M.M.R.; Van Camp, M.; Islam, M.; Ahmed, N.; Walraevens, K.
Title Hydrochemistry in coastal aquifer of southwest Bangladesh : origin of salinity Type Journal Article
Year 2018 Publication Environmental Earth Sciences Abbreviated Journal
Volume 77 Issue 2 Pages 20
Keywords Hydrochemistry,Stable isotope,Seawater intrusion,Coastal aquifer,Bangladesh,DAR-ES-SALAAM,SEAWATER INTRUSION,DELTA PLAIN,GROUNDWATER,DRINKING,TANZANIA,DROUGHT,COMPLEX
Abstract In the coastal region of Bangladesh, groundwater is mainly used for domestic and agricultural purposes, but salinization of many groundwater resources limits its suitability for human consumption and practical application. This paper reports the results of a study that has mapped the salinity distribution in different aquifer layers up to a depth of 300 m in a region bordering the Bay of Bengal based on the main hydrochemistry and has investigated the origin of the salinity using Cl/Br ratios of the samples. The subsurface consists of a sequence of deltaic sediments with an alternation of more sandy and clayey sections in which several aquifer layers can be recognized. The main hydrochemistry shows different main water types in the different aquifers, indicating varying stages of freshening or salinization processes. The most freshwater, soft NaHCO3-type water with Cl concentrations mostly below 100 mg/l, is found in the deepest aquifer at 200-300 m below ground level (b.g.l.), in which the fresh/saltwater interface is pushed far to the south. Salinity is a main problem in the shallow aquifer systems, where Cl concentrations rise to nearly 8000 mg/l and the groundwater is mostly brackish NaCl water. Investigation of the Cl/Br ratios has shown that the source of the salinity in the deep aquifer is mixing with old connate seawater and that the saline waters in the more shallow aquifers do not originate from old connate water or direct seawater intrusion, but are derived from the dissolution of evaporite salts. These must have been formed in a tidal flat under influence of a strong seasonal precipitation pattern. Long dry seasons with high evaporation rates have evaporated seawater from inundated gullies and depressions, leading to salt precipitation, while subsequent heavy monsoon rains have dissolved the formed salts, and the solution has infiltrated in the subsoil, recharging groundwater.
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ISSN 1866-6280 ISBN Medium
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Notes Approved no
Call Number THL @ christoph.kuells @ Sarker2018 Serial 194
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Author Satrio, S., Prasetio, R., Hadian, M., Syafri, I.
Title Stable Isotopes and Hydrochemistry Approach for Determining the Salinization Pattern of Shallow Groundwater in Alluvium Deposit Semarang, Central Java Type Journal Article
Year 2016 Publication Indonesian Journal on Geoscience Abbreviated Journal
Volume 4 Issue Pages
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Call Number THL @ christoph.kuells @ Serial 195
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Author Bouchaou, L.; Michelot, J.L.; Vengosh, A.; Hsissou, Y.; Qurtobi, M.; Gaye, C.B.; Bullen, T.D.; Zuppi, G.M.
Title Application of multiple isotopic and geochemical tracers for investigation of recharge, salinization, and residence time of water in the Souss–Massa aquifer, southwest of Morocco Type Journal Article
Year 2008 Publication Journal of Hydrology Abbreviated Journal
Volume 352 Issue 3 Pages 267-287
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Abstract Groundwater and surface water in Souss–Massa basin in the west-southern part of Morocco is characterized by a large variation in salinity, up to levels of 37gL−1. The high salinity coupled with groundwater level decline pose serious problems for current irrigation and domestic water supplies as well as future exploitation. A combined hydrogeologic and isotopic investigation using several chemical and isotopic tracers such as Br/Cl, δ18O, δ2H, 3H, 87Sr/86Sr, δ11B, and 14C was carried out in order to determine the sources of water recharge to the aquifer, the origin of salinity, and the residence time of water. Stable isotope, 3H and 14C data indicate that the high Atlas mountains in the northern margin of the Souss–Massa basin with high rainfall and low δ18O and δ2H values (−6 to −8‰ and −36 to −50‰) is currently constitute the major source of recharge to the Souss–Massa shallow aquifer, particularly along the eastern part of the basin. Localized stable isotope enrichments offset meteoric isotopic signature and are associated with high nitrate concentrations, which infer water recycling via water agricultural return flows. The 3H and 14C data suggest that the residence time of water in the western part of the basin is in the order of several thousands of years; hence old water is mined, particularly in the coastal areas. The multiple isotope analyses and chemical tracing of groundwater from the basin reveal that seawater intrusion is just one of multiple salinity sources that affect the quality of groundwater in the Souss–Massa aquifer. We differentiate between modern seawater intrusion, salinization by remnants of seawater entrapped in the middle Souss plains, recharge of nitrate-rich agricultural return flow, and dissolution of evaporate rocks (gypsum and halite minerals) along the outcrops of the high Atlas mountains. The data generated in this study provide the framework for a comprehensive management plan in which water exploitation should shift toward the eastern part of the basin where current recharge occurs with young and high quality groundwater. In contrast, we argued that the heavily exploited aquifer along the coastal areas is more vulnerable given the relatively longer residence time of the water and salinization processes in this part of the aquifer.
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ISSN 0022-1694 ISBN Medium
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Notes Approved no
Call Number THL @ christoph.kuells @ Bouchaou2008 Serial 17
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