A5034994294- Groundwater and Isotope Geochemistry
- Groundwater flow and contamination studies
- Geology and Paleoclimatology Research
- Isotope Analysis in Ecology
- Microbial bioremediation and biosurfactants
- Soil and Water Nutrient Dynamics
- Atmospheric and Environmental Gas Dynamics
- Peatlands and Wetlands Ecology
- Amazonian Archaeology and Ethnohistory
- Hydrocarbon exploration and reservoir analysis
- Toxic Organic Pollutants Impact
- Hydrology and Watershed Management Studies
- Water Treatment and Disinfection
- Methane Hydrates and Related Phenomena
- Coastal wetland ecosystem dynamics
- Karst Systems and Hydrogeology
- Groundwater and Watershed Analysis
- Environmental remediation with nanomaterials
- Wastewater Treatment and Nitrogen Removal
- Geological and Tectonic Studies in Latin America
- Microbial Community Ecology and Physiology
- Radioactive contamination and transfer
- Tree-ring climate responses
- Water Quality and Resources Studies
- Geography and Environmental Studies
University of Waterloo
2015-2024
University of Guelph
2018-2021
GGD Amsterdam
2018
University of Tübingen
2018
PLUS Foundation
2012
Sapienza University of Rome
2011
University of Massachusetts Amherst
2009
University of Neuchâtel
2003-2008
Shell (United States)
2008
Arizona State University
2008
Abstract This study explores the use of multiple isotopic tracers to evaluate processes involved in nitrate attenuation ground water. δ 15 N and 18 O are used provide information about role denitrification on attenuation, 34 S, O, 13 C reduced sulfur carbon as electron donors for reduction. The focus this is a zone significant NO 3 −1 occurring sand aquifer impacted by septic system contamination. pattern, water flow system, changes other chemical parameters suggest that depletion caused...
Abstract Stable isotopes, 15 N and 18 O, have been used as tracers to differentiate a contaminant nitrate plume emanating from single domestic septic system, in ground‐water system characterized by high similar content outside inside of the plume. A good delineation origin was obtained using analysis nitrate. The ofthe nonplunie is agreement with sources nitrate: solid cattle manure, synthetic fertilizer (NH 4 ‐NO 3 ), soil organic nitrogen, at study site. O did not provide enough isotopic...
Three types of functionally different artificial neural network (ANN) models are calibrated using a relatively short length groundwater level records and related hydrometeorological data to simulate water table fluctuations in the Gondo aquifer, Burkina Faso. Input delay (IDNN) with static memory structure globally recurrent (RNN) inherent dynamical proposed for monthly modeling. The simulation performance IDNN RNN is compared results obtained from two variants radial basis function (RBF)...
Abstract Radiocarbon-dated macrofossils are used to document Holocene treeline history across northern Russia (including Siberia). Boreal forest development in this region commenced by 10,000 yr B.P. Over most of Russia, advanced or near the current arctic coastline between 9000 and 7000 retreated its present position 4000 3000 Forest establishment retreat was roughly synchronous Russia. Treeline advance on Kola Peninsula, however, appears have occurred later than other regions. During...
Experimental flooding of a boreal forest wetland caused the to change from being small, natural carbon sink, with respect atmosphere, −6.6 g C m-2 yr-1 large source +130 yr-1. This was by death vegetation, which eliminated photosynthetic CO2 sink and stimulated microbial production CH4 decomposition plant tissues peat. Another type activity that increased methylation inorganic mercury much more toxic methyl (MeHg) form. The MeHg prior became an even larger (39 fold) after flooding....
Abstract During the last 40 years, nitrate (NO 3 − ) has become one of most common ground water contaminants. Stream riparian zones are considered important ecological ecotones that decrease NO load discharging into streams. This study uses /Cl ratios, natural abundances 15 N and 18 O in , an situ tracer experiment to evaluate reducing processes occurring within a narrow grassed buffer strip bordering stream agricultural watershed. The ratios (1.9‐0.0 [M/M]) indicate both consuming mixing...
The determination of compound-specific stable isotope ratios is a promising new tool to assess biodegradation organic compounds in groundwater. In this study, the occurrence carbon fractionation during dechlorination tetrachloroethene (PCE) ethene was evaluated PCE-contaminated aquifer and microcosm that based on material from site. microcosm, all steps were accompanied by fractionation. largest occurred cis-1,2-dichloroethene (cDCE) vinyl chloride (VC), resulting large enrichment 13C...
There is an exceptional group of alpine peatlands in the world situated arid grasslands central Andes.The northern Chile occur most part their range.Members Juncaceae are primary peat-forming plant species.Fresh and mildly saline groundwaters originate from glaciers, snowmelt rain water sources for peatlands.Paleoecological investigations suggest that some recent features landscape having developed within last three thousand years or less.These unique, extremely fragile sensitive to climate...
Abstract Carbon isotopes of soil organic matter (SOM) were used to evaluate and establish the chronology vegetation dynamics an ecosystem presently composed savannas surrounded by forests. The study was carried out on a 200-km transect along highway BR 319, border Amazonas Rondônia states, in southern Amazon, Brazil. Large ranges δ 13 C values observed SOM collected from profiles savanna (−27 −14‰) forest regions (−26 −19‰), reflecting changing distribution C-depleted 3 C-enriched 4 response...
Abstract The efficiency with which riparian zones remove nitrate (NO − 3 ) from contaminated ground water can vary landscape setting. This study was conducted to determine the influence of flood plain geometry, lithology, hydrologic flow path, and transport on mechanisms depletion water. Patterns NO −N, chloride, dissolved organic carbon (DOC) concentrations δ 15 N‐NO 18 O‐NO values in combination detailed piezometric head measurements were investigated a river floodplain connected large...
During the last decade radiocarbon dating has been used extensively in distinct regions of Brazil to provide information about soil chronology paleoenvironmental studies. This paper presents 14 C data organic matter (SOM), humin fraction, and charcoal several profiles under natural vegetation from different locations (north, central, southeast regions). The main objective is compare obtained total SOM with humin, oldest fraction SOM. In order validate ages these are compared age collected at...
Carbon isotope fractionation during dechlorination of chlorinated ethenes was investigated using a methanogenic microbial enrichment culture. Subcultures were amended with trichloroethene (TCE), cis-1,2-dichloroethene (cis-DCE), and vinyl chloride (VC), respectively. ratios concentrations reactants all products monitored two experiments. All steps accompanied by significant fractionation. The the described Rayleigh type model, following factors (εP/R) obtained: −6.6 −2.5‰ for TCE, −14.1...
Dissolved organic carbon (DOC) is important in the acid‐base chemistry of acid‐sensitive freshwater systems; complexation, mobility, persistence, and toxicity metals other pollutants; lake metabolism. Carbon isotopes ( 13 C 14 C) are used to study origin, transport, fate DOC a softwater catchment central Ontario. Precipitation, soil percolates, groundwaters, stream, beaver pond, waters, sediment pore water were characterized chemically isotopically. In addition total DOC, isotopic...
The study investigated carbon and chlorine isotope fractionation during aerobic oxidation reductive dechlorination of vinyl chloride (VC) cis-1,2-dichloroethene (cDCE). experimental data followed a Rayleigh trend. For oxidation, the average enrichment factors were −7.2‰ −8.5‰ for VC cDCE, respectively, while only −0.3‰ both compounds. These values are consistent with an initial transformation by epoxidation which significant primary effect small secondary is expected. dechlorination, larger...
This paper presents carbon isotope data on soil organic matter (SOM) collected along an ecosystem transect that includes a wooded savannah (cerrado), tropical semideciduous forest (cerradão), tran sition type and forest. The study area is located in the Rondonia state, southwestern Brazilian Amazon region. 14 C of total charcoal indicate these soils at least Holocene age. transition sites are characterized by δ 13 depth profiles gener ated typically 3 plants, indicating no major changes...