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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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Notes | Approved | no | |||
Call Number | THL @ christoph.kuells @ Oehler2019 | Serial | 192 | ||
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Author | Bahir, M.; Ouhamdouch, S.; Carreira, P.M. | ||||
Title | Isotopic and geochemical methods for studying water–rock interaction and recharge mode: application to the Cenomanian–Turonian and Plio-Quaternary aquifers of Essaouira Basin, Morocco | Type | Journal Article | ||
Year | 2018 | Publication | Mar. Freshwater Res. | Abbreviated Journal | |
Volume | 69 | Issue | 8 | Pages | 1290-1300 |
Keywords | geochemistry, semi-arid area, stable isotopes, water resources. | ||||
Abstract | Study of the Cenomanian–Turonian and Plio–Quaternary aquifers of Essaouira basin (Western Morocco), based on the interpretation of geochemical (major elements) and isotopic (18O, 2H, 13C and 14C) data, has aided the understanding of the hydrodynamics of these aquifers, which is greatly affected by tectonics. Hydrochemical characteristics based on the bivariate diagrams of major ions (Cl–, SO42–, NO3–, HCO3–, Na+, Mg2+, K+ and Ca2+) and electrical conductivity and mineral saturation indices indicate that the origins of groundwater mineralisation are the result of: (1) evaporite dissolution; (2) cation exchange reactions; (3) and evaporation processes. Radiogenic isotopes (3H and 14C) have highlighted the presence of significant recent recharge in the eastern part of the basin, with groundwater moving according to the general flow path (south-east to north-west). Stable isotope data from the Essaouira basin plot along the Global Meteoric Water Line and below the Local Meteoric Water Line. This suggests that groundwater has been recharged under several different climate regimes. | ||||
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Notes | Approved | no | |||
Call Number | THL @ christoph.kuells @ | Serial | 191 | ||
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Author | Alexakis, D.; Gotsis, D.; Giakoumakis, S. | ||||
Title | Evaluation of soil salinization in a Mediterranean site (Agoulinitsa district—West Greece) | Type | Journal Article | ||
Year | 2015 | Publication | Arabian Journal of Geosciences | Abbreviated Journal | |
Volume | 8 | Issue | 3 | Pages | 1373-1383 |
Keywords | Agricultural soil . Soil quality . Soil salinization | ||||
Abstract | Soil salinization is an environmental problem having significant impacts on the soil–water–plant system. This problem is more frequent in coastal areas due to seawater intrusion into the land. Assessing the soil salinization is a critical issue for the agricultural areas situated in the Mediterranean basin. This paper examines the deterioration of soil quality in the cultivated land of a Mediterranean site (Agoulinitsa district—West Greece). Soil samples were collected in both pre-irrigation and post-irrigation seasons. Electrical conductivity (EC), pH and the ions Br−, Ca2+, Cl−, F−, K+, Li+, Mg2+, Na+, NH4 +, NO2 −, NO3 −, PO4 3− and SO4 2− were determined by the 1:2 (soil/water ratio on weight basis) method. The salts which were present in both seasons in the soils of the area studied are KCl, MgCl2, NaCl, CaSO4 and K2SO4. The wide spatiotemporal variation of EC in the cultivated land in both seasons demonstrates that soil salinity is controlled mainly by seawater intrusion and anthropogenic factors such as the application of salt-rich water which is directly pumped from the drainage ditches. Seawater intrusion provides the affected soil with elevated contents of Ca2+, Cl−, K+, Mg2+, Na+ and SO4 2−. Classification of the soils by using criteria given by the literature is discussed. Practices to prevent, or at least ameliorate, salinization in the cultivated land of Agoulinitsa district are proposed. |
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Publisher | Springer | Place of Publication | Editor | ||
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ISSN | 1866-7511 | ISBN | Medium | ||
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Notes | Approved | no | |||
Call Number | THL @ luqianxue.zhang @ Alexakis2015 | Serial | 42 | ||
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Author | de Paz, J.-M.; Sánchez, J.; Visconti, F. | ||||
Title | Combined use of GIS and environmental indicators for assessment of chemical, physical and biological soil degradation in a Spanish Mediterranean region | Type | Journal Article | ||
Year | 2006 | Publication | Journal of environmental management | Abbreviated Journal | |
Volume | 79 | Issue | 2 | Pages | 150-162 |
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Abstract | Soil is one of the main non-renewable natural resources in the world. In the Valencian Community (Mediterranean coast of Spain), it is especially important because agriculture and forest biomass exploitation are two of the main economic activities in the region. More than 44% of the total area is under agriculture and 52% is forested. The frequently arid or semi-arid climate with rainfall concentrated in few events, usually in the autumn and spring, scarcity of vegetation cover, and eroded and shallow soils in several areas lead to soil degradation processes. These processes, mainly water erosion and salinization, can be intense in many locations within the Valencian Community. Evaluation of soil degradation on a regional scale is important because degradation is incompatible with sustainable development. Policy makers involved in land use planning require tools to evaluate soil degradation so they can go on to develop measures aimed at protecting and conserving soils. In this study, a methodology to evaluate physical, chemical and biological soil degradation in a GIS-based approach was developed for the Valencian Community on a 1/200,000 scale. The information used in this study was obtained from two different sources: (i) a soil survey with more than 850 soil profiles sampled within the Valencian Community, and (ii) the environmental information implemented in the Geo-scientific map of the Valencian Community digitised on an Arc/Info GIS. Maps of physical, chemical and biological soil degradation in the Valencian Community on a 1/200,000 scale were obtained using the methodology devised. These maps can be used to make a cost-effective evaluation of soil degradation on a regional scale. Around 29% of the area corresponding to the Valencian Community is affected by high to very high physical soil degradation, 36% by high to very high biological degradation, and 6% by high to very high chemical degradation. It is, therefore, necessary to draw up legislation and to establish the policy framework for actions focused on preventing soil degradation and conserving its productive potential. |
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Publisher | Elsevier | Place of Publication | Editor | ||
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ISSN | 0301-4797 | ISBN | Medium | ||
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Notes | Approved | no | |||
Call Number | THL @ luqianxue.zhang @ dePaz2006 | Serial | 47 | ||
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Author | Kurunc, A.; Ersahin, S.; Sonmez, N.K.; Kaman, H.; Uz, I.; Uz, B.Y.; Aslan, G.E. | ||||
Title | Seasonal changes of spatial variation of some groundwater quality variables in a large irrigated coastal Mediterranean region of Turkey | Type | Journal Article | ||
Year | 2016 | Publication | Science of the Total Environment | Abbreviated Journal | |
Volume | 554 | Issue | Pages | 53-63 | |
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Abstract | Soil and groundwater degradations have taken considerable attention, recently. We studied spatial and temporal variations of groundwater table depth and contours, and groundwater pH, electrical conductivity (EC), and nitrate (NO3) content in a large irrigated area in Western Mediterranean region of Turkey. These variables were monitored during 2009 and 2010 in previously constructed 220 monitoring wells. We analyzed the data by geostatistical techniques and GIS. Spatial variation of groundwater table depth (GTD) and groundwater table contours (GTC) remained similar across the four sampling campaigns. The values for groundwater NO3 content, EC, and pH values ranged from 0.01 to 454.1 g L−1 , 0.06 to 46.0 dS m−1 and 6.53–9.91, respectively. Greatest geostatistical range (16,964 m) occurred for GTC and minimum (960 m) for groundwater EC. Groundwater NO3 concentrations varied both spatially and temporally. Temporal changes in spatial pattern of NO3 indicated that land use and farming practices influenced spatial and temporal variation of groundwater NO3. Several hot spots occurred for groundwater NO3 content and EC. These localities should be monitored more frequently and land management practices should be adjusted to avoid soil and groundwater degradation. The results may have important implications for areas with similar soil, land use, and climate conditions across the Mediterranean region. |
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Corporate Author | Thesis | ||||
Publisher | Elsevier | Place of Publication | Editor | ||
Language | Summary Language | Original Title | |||
Series Editor | Series Title | Abbreviated Series Title | |||
Series Volume | Series Issue | Edition | |||
ISSN | 0048-9697 | ISBN | Medium | ||
Area | Expedition | Conference | |||
Notes | Approved | no | |||
Call Number | THL @ luqianxue.zhang @ Kurunc2016 | Serial | 45 | ||
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