Search results for "Water table"
showing 10 items of 27 documents
Hydrology is reflected in the functioning and community composition of methanotrophs in the littoral wetland of a boreal lake
2010
In lake ecosystems a major proportion of methane (CH4) emissions originate from the littoral zone, which can have a great spatial variability in hydrology, soil quality and vegetation. Hitherto, spatial heterogeneity and the effects it has on functioning and diversity of methanotrophs in littoral wetlands have been poorly understood. A diagnostic microarray based on the particulate methane monooxygenase gene coupled with geostatistics was used to analyse spatial patterns of methanotrophs in the littoral wetland of a eutrophic boreal lake (Lake Kevaton, Eastern Finland). The wetland had a hydrology gradient with a mean water table varying from −8 to −25 cm. The wettest area, comprising the h…
The effects of long-term drainage and subsequent restoration on water table level and pore water chemistry in boreal peatlands
2014
Summary Degradation by drainage threatens biodiversity and globally important peatland ecosystem functions such as long-term carbon sequestration in peat. Restoration aims at safeguarding peatland values by recovering natural hydrology. Long-term effects of drainage and subsequent restoration, especially related to within-site variation of water table level and pore water chemistry, are poorly known. We studied hydrological variation at 38 boreal Sphagnum peatland sites (pristine, drained and restored) in Finland. The average water table level was significantly lower at Drained than Pristine sites especially near the ditches. We also observed large pore water chemical differences between Dr…
Strategic Behavior and Efficiency in the Common Property Extraction of Groundwater
2002
Groundwater has always been regarded as a common property resource where entry is restricted by land ownership and private exploitation is inefficient. In 1980, Gisser and Sanchez presented a first estimation of this inefficiency, cornparing socially optimal exploitation with private (competitive) exploitation using a model with linear water demand, average extraction cost independent of the rate of extraction and linearly decreasing with respect to the water table level. They characterized the private exploitation of the aquifer assuming that farmers are myopic and choose their rate of extraction to maximize their current profits, whereas optimal exploitation is obtained by maximizing the …
Effect of water level and climatic factors on the radial growth of black alder
2011
Effect of water level and climatic factors on the radial growth of black alder Black alder (Alnus glutinosa (L.) Gaertn.) is a widespread tree species in Europe and the western part of the temperate climate zone. The area of forest in Latvia dominated by this tree species has substantially decreased due to wide-spread forest drainage. To predict future changes due to environmental change, it is extremely important to understand the function of ecosystems with black alder and their dynamics. Tree rings can be used as a proxy of past environmental factors. The aim of the study was to determine the effects of meteorological and hydrological factors on radial growth of black alder at two study …
Nitrous oxide emission budgets and land-use-driven hotspots for organic soils in Europe
2014
Organic soils are a main source of direct emissions of nitrous oxide (N2O), an important greenhouse gas (GHG). Observed N2O emissions from organic soils are highly variable in space and time, which causes high uncertainties in national emission inventories. Those uncertainties could be reduced when relating the upscaling process to a priori-identified key drivers by using available N2O observations from plot scale in empirical approaches. We used the empirical fuzzy modelling approach MODE to identify main drivers for N2O and utilize them to predict the spatial emission pattern of European organic soils. We conducted a meta-study with a total amount of 659 annual N2O measurements, which was…
Spatial characterization of leachate plume using electrical resistivity tomography in a landfill composed of old and new cells (Belfort, France)
2016
International audience; Located near Belfort (France), the Etueffont landfill was in operation from 1976 to 2002 for the disposal and storage of domestic waste produced by 47,650 inhabitants. The site is comprised of the original landfill site called the old landfill (OL), in operation from 1976 to 1999, and a newer section known as the new cell (NC) which operated from 1999 to 2002. The objective of this study is to determine, using electrical resistivity tomography (ERT), the extent of the leachate plume from the OL and to monitor the efficiency of the liner of the NC. The entire Etueffont site was crisscrossed with 21 electrical profile lines which were traced in summer between 2009 and …
Hydrologic and geochemical survey of the lake ‘‘Specchio di Venere’’ (Pantelleria island, Southern Italy)
2007
Hydrological and geochemical studies performed on Lake Specchio di Venere on Pantelleria island (Italy) indicate that this endorheic basin has been formed through upwelling of the water table, and that it is continuously fed by the thermal springs situated on its shores. The lake is periodically stratified both thermally and in salinity, albeit this stratification is rather unstable over time, since meteorological events such as strong rain or wind can determine the mixing of its waters. Periodical analyses of the lake water chemistry show large variations of the salt content due to the yearly evaporation-rain dilution cycle. These processes are also responsible for the saline stratificatio…
Analyse cartographique de données pédologiques et hydrogéologiques appliquée à la gestion responsable de produits phytosanitaires
2014
BASF launched a Responsible Bentazone Management plan in 2011, in order to preserve water resources and sustain its bentazon based herbicide solutions. This molecule is commercialized by the company for several years and is found at concentrations above the standard for drinking water in about 1% of groundwater catchments in France. The action plan aims to reduce contamination situations with recommendations on the use of bentazone (dose, timing of application, restrictions on vulnerable soils on groundwater catchment areas) that complement the commercialization authorization. The study carried out during the internship focused on the diagnosis of a groundwater catchment area located in the…
Sulfuric acid speleogenesis (SAS) close to the water table: Examples from southern France, Austria, and Sicily
2016
Caves formed by rising sulfuric waters have been described from all over the world in a wide variety of climate settings, from arid regions to mid-latitude and alpine areas. H2S is generally formed at depth by reduction of sulfates in the presence of hydrocarbons and is transported in solution through the deep aquifers. In tectonically disturbed areas major fractures eventually allow these H2S-bearing fluids to rise to the surface where oxidation processes can become active producing sulfuric acid. This extremely strong acid reacts with the carbonate bedrock creating caves, some of which are among the largest and most spectacular in the world. Production of sulfuric acid mostly occurs at or…
Modeling belowground water table fluctuations in the Everglades
2010
[1] Humid lands, such as riparian zones, peatlands, and unsubmerged wetlands, are considered among the most biologically diverse of all ecosystems, providing a bountiful habitat for a large number of plant and animal species. In such ecosystems, the water table dynamics play a key role in major ecohydrological processes. The aim of the present study is to test with field data a recent analytical model for the estimation of the long-term probability distribution of the belowground water table position in groundwater-dependent environments. This model accounts for stochastic rainfall and processes such as infiltration, root water uptake, water flow from/to an external water body, and capillar…