scholarly journals Homogeneous Glacial Landscapes Can Have High Local Variability of Strontium Isotope Signatures: Implications for Prehistoric Migration Studies

2021 ◽  
Vol 8 ◽  
Author(s):  
Erik Thomsen ◽  
Rasmus Andreasen ◽  
Tine L. Rasmussen
Keyword(s):  
Surface Water ◽  
Surface Waters ◽  
Viking Age ◽  
Surprising Result ◽  
Sr Isotopes ◽  
Substantial Impact ◽  
Vital Importance ◽  
Prehistoric Migration ◽  
The Impact ◽  
Local Variability

Increasingly, strontium (Sr) isotopes are used to distinguish locals and migrants in prehistoric studies, by measuring 87Sr/86Sr in human remains and comparing these values to the distribution of the bioavailable 87Sr/86Sr in the study area, often in surface water. However, it has recently been shown that agricultural lime can have a substantial impact on the 87Sr/86Sr ratio and strontium concentration in surface water in areas where soils are low- to non-calcareous. Agricultural lime is rich in strontium with low 87Sr/86Sr ratios, such that interpretations of prehistoric migration based on surface waters affected by agricultural lime often overestimate the number of migrants in a given area. However, the impact of agricultural lime was questioned in a new study, which argues that strontium derived from agricultural lime is retained in the topsoil of the fields and therefore do not contaminate the surface water. In the present study and in a companion study in this volume, we show that strontium derived from agricultural lime is highly mobile in soils, and so contaminate surface waters extensively. We also show that the 87Sr/86Sr ratios are consistently higher in waters from “pristine areas” (where no agricultural lime has been applied within a distance of 150 m from the sample locality) than in water from farmland, thus confirming that it is of vital importance for accurate mapping of isoscapes to avoid sampling waters contaminated by agricultural lime. Our new measurements of 87Sr/86Sr ratios in central Jutland, Denmark, raise the highest measured values to 0.7186. High values between 0.7140 and 0.7156 occur repeatedly and it is apparent that nearly all prehistoric human finds in Jutland, previously believed to have journeyed from afar are more likely of local origin. Furthermore, we show that carbonate-rich areas along the coast of southwest Zealand carry high 87Sr/86Sr values (0.7112–0.7132), where we would expect low values. This surprising result indicates that nearly all humans buried at the Viking Age site, Trelleborg could well have originated locally, in contrast to past studies, which have suggested that about 50% of the burials were of individuals who came from afar.

An investigation into advanced oxidation of three chlorophenoxy pesticides in surface water

2009 ◽  
Vol 59 (8) ◽  
pp. 1665-1671 ◽  
Author(s):  
Jitka MacAdam ◽  
Simon A. Parsons
Keyword(s):  
Surface Water ◽  
Effective Treatment ◽  
Surface Waters ◽  
Advanced Oxidation ◽  
Pesticide Degradation ◽  
Fenton's Reagent ◽  
Pesticide Concentration ◽  
Low Levels ◽  
Stoichiometric Ratios ◽  
The Impact

The performance of Fenton's reagent in removing 2,4-D, MCPA and mecoprop from surface water has been evaluated here. Initial trials were undertaken at a pesticide concentration of 4.5 × 10−5 mol l−1 in deionised water at pH 3 and two different stoichiometric ratios of pesticide: Fe(II): H2O2 (1:1:10, 1:10:10) were evaluated. At the 1:1:10 ratio, ∼10 minutes were required to achieve a 50% removal of the pesticide. At the higher ratio the removal achieved after 1 minute, was >90%. Subsequent experiments studied the performance of Fenton (4.5 × 10−4 mol l−1 Fe(II): 4.5 × 10−4 mol l−1 H2O2) in surface water spiked with pesticides and the impact of pH on the rate and degree of pesticide degradation was investigated. The removal was significantly improved at pH 3 in comparison to pH 6.5. The effect of Fenton on DOC removal from surface water was followed. Experiments investigated the performance of Fenton at pesticide concentrations of 7.5 × 10−9 mol l−1 in surface water. Fenton was shown to be an effective treatment for removing low levels of pesticides from surface waters at pH 3 & 4.

Is carbonate sediment dissolution a significant source of dissolved organic matter to Florida Bay?

2020 ◽  
Author(s):  
Mary Zeller ◽  
Bryce Van Dam ◽  
Chris Lopes ◽  
Ashley Smyth ◽  
Christopher Osburn ◽  
...  
Keyword(s):  
Organic Matter ◽  
Surface Water ◽  
Organic Carbon ◽  
Surface Waters ◽  
Florida Bay ◽  
Source Surface ◽  
Carbonate Sediments ◽  
Seagrass Meadows ◽  
Autochthonous Organic Matter ◽  
The Impact

<p>Florida Bay is subtropical embayment characterized by dense Thalassia testudinum seagrass meadows, the prevalence of carbonate-rich sediments, and relatively long residence times (~1 yr). Florida Bay seagrass meadows store appreciable quantities of allochthonous and autochthonous organic matter (OM) as so-called ‘blue carbon’, the fate of which is therefore tied to that of the carbonate minerals it is bound to.  Dissolved organic carbon (DOC) concentrations are also relatively high (~7-12 mg/L), despite potential photo-oxidative loss in this shallow and long residence time system, as well as low internal DOC production due to the ecosystem’s documented oligotrophy.  These carbonate sediments can dissolve through net acid production via sediment heterotrophic processes as well as sulfide oxidation, processes which may be enhanced via O<sub>2</sub> pumping through seagrass roots.  </p><p>This study investigated the impact of carbonate dissolution on the release of sediment-associated OM to surface waters, and the relative contribution of this process to surface water DOC quantity and quality.  We undertook a three-part experimental approach, with analyses including EEMs, δ13C-DOC, and FT-ICR-MS, to better understand the sources and fate of DOC in Florida Bay. 1) We conducted a spatial survey of surface waters, pore waters, and acid-leachable (representing the ‘carbonate-bound’ OM fraction) sedimentary OM.  2)  We conducted a DOM photodegradation study using two potential source surface waters, from a main tributary (Taylor Slough) and a central mangrove island.  3) We conducted benthic flux experiments using intact sediment cores facilitating direct measurements of the quality and quantity of DOC release from sediments. The flux information was placed into the context of sediment dissolution rates, estimated from coinciding determinations of alkalinity and inorganic carbon.</p><p>While analyses are ongoing, our initial results indicate a high degree of similarity between the fluorescence signature (PARAFAC components and fluorescence indices) of acid-leachable sedimentary OM, and that of DOC in pore water and surface water throughout Florida Bay.  Taken together, our study points to sediment dissolution as an important, yet understudied, process affecting organic carbon cycling in carbonate-dominated systems like Florida Bay.</p>

scholarly journals Surface Water Evolution (2001–2017) at the Cambodia/Vietnam Border in the Upper Mekong Delta Using Satellite MODIS Observations

2020 ◽  
Vol 12 (5) ◽  
pp. 800 ◽  
Author(s):  
Filipe Aires ◽  
Jean-Philippe Venot ◽  
Sylvain Massuel ◽  
Nicolas Gratiot ◽  
Binh Pham-Duc ◽  
...  
Keyword(s):  
Surface Water ◽  
Surface Waters ◽  
Land Reclamation ◽  
Mekong Delta ◽  
Temporal Distribution ◽  
Global Scale ◽  
Time Frequency ◽  
Surface Water Resources ◽  
Interdisciplinary Approaches ◽  
The Impact

Studying the spatial and temporal distribution of surface water resources is critical, especially in highly populated areas and in regions under climate change pressure. There is an increasing number of satellite Earth observations that can provide information to monitor surface water at global scale. However, mapping surface waters at local and regional scales is still a challenge for numerous reasons (insufficient spatial resolution, vegetation or cloud opacity, limited time-frequency or time-record, information content of the instrument, lack in global retrieval method, interpretability of results, etc.). In this paper, we use 17 years of the MODIS (MODerate-resolution Imaging Spectro-radiometer) observations at a 8-day resolution. This satellite dataset is combined with ground expertise to analyse the evolution of surface waters at the Cambodia/Vietnam border in the Upper Mekong Delta. The trends and evolution of surface waters are very significant and contrasted, illustrating the impact of agriculture practices and dykes construction. In most of the study area in Cambodia. surface water areas show a decreasing trend but with a strong inter-annual variability. In specific areas, an increase of the wet surfaces is even observed. Ground expertise and historical knowledge of the development of the territory enable to link the decrease to ongoing excavation of drainage canals and the increase of deforestation and land reclamation, exposing flooded surfaces previously hidden by vegetation cover. By contrast, in Vietnam, the decreasing trend in wet surfaces is very clear and can be explained by the development of dykes dating back to the 1990s with an acceleration in the late 2000s as part of a national strategy of agriculture intensification. This study shows that coupling satellite data with ground-expertise allows to monitor surface waters at mesoscale (<100 × 100 km2), demonstrating the potential of interdisciplinary approaches for water ressource management and planning.

scholarly journals EVALUATION OF THE HEAVY METALS CONTAMINATION OF THE WATER OF THE MOULOUYA MEDIUM

2021 ◽  
Vol XLVI-4/W5-2021 ◽  
pp. 193-196
Author(s):  
H. Ech-Chafay ◽  
M. Najy ◽  
A. El Ghazouany ◽  
O. Akkaoui ◽  
M. Lachhab ◽  
...  
Keyword(s):  
Heavy Metals ◽  
Surface Water ◽  
Surface Waters ◽  
Concentration Gradient ◽  
Human Activities ◽  
Anthropogenic Impact ◽  
Heavy Metals Contamination ◽  
The Impact ◽  
Metallic Pollution

Abstract. This work is part of a program to study and monitor the impact of human activities in the cities of Missour and Outat El Haj on the quality of the surface waters of the average Moulouya (Morocco).The aim of this study is to evaluate in time and space, the degree of metallic pollution of surface water of the average Moulouya during the period (September 2014, January, April and July 2015). The results of this study suggest that the waters of the ten stations in the study area are relatively contaminated with heavy metals. The contents of the analyzed metals are high and variable in the wastewater of the cities of Missour and Outat El Haj and in the waters of the Moulouya average.The anthropogenic impact on the ecosystems selected for this work is highlighted by: the high metallic contamination of the water of the stations located downstream of wastewater discharges of the cities of Missour and Outat El Haj, and the variation of the contents according to an increasing concentration gradient from station M1 to M9.

scholarly journals MODELING AND ASSESSMENT OF THE IMPACT OF LAND USE IN THE WESTERN RIF REGION, MOROCCO, ON WATER QUALITY

2021 ◽  
Vol XLVI-4/W5-2021 ◽  
pp. 225-230
Author(s):  
G. Fattah ◽  
F. Ghrissi ◽  
J. Mabrouki ◽  
N. Al-Jadabi
Keyword(s):  
Land Use ◽  
Surface Layer ◽  
Surface Water ◽  
Surface Waters ◽  
Chemical Parameters ◽  
Physical And Chemical ◽  
The Impact ◽  
Different Sources

Abstract. The Western Rif is a rural area characterized by rock extraction and agriculture. As a result, the surface of the land in the region is exposed to different sources of contamination which alters the quality of the soil. Leaching of the soil and runoff to surface water may impact the quality of surface water used by local people. A mapping of the land use by GIS of an area located at the level of the western Rif was carried out then an analysis of the interactions between the uses of the land; the practices, the quality of the surface layer of the soil and the quality of the water were made. Thanks to the processing of satellite images and to samples on the ground and assays of the physic-chemical parameters of soils and water (T °, pH, MES, turbidity, Nitrate, nitrite, phosphorus, nitrogen, etc.). The results of these analyzes revealed that these activities lead to an alteration in the quality of the surface layer of the soil, its characterization of which changes depending on the land use. Surface water is endowed with the components identified in the soil. This reveals that land use has generally negative physical and chemical impacts on surface waters.

scholarly journals Seasonal dynamics of carbonate chemistry, nutrients and CO2 uptake in a sub-Arctic fjord

Elem Sci Anth ◽  
2020 ◽  
Vol 8 ◽  
Author(s):  
Elizabeth M. Jones ◽  
Angelika H. H. Renner ◽  
Melissa Chierici ◽  
Ingrid Wiedmann ◽  
Helene Hodal Lødemel ◽  
...  
Keyword(s):  
Surface Water ◽  
Surface Waters ◽  
Phytoplankton Bloom ◽  
Biogeochemical Cycling ◽  
Atmospheric Co2 ◽  
Subsurface Water ◽  
Series Data ◽  
Co2 Uptake ◽  
Arctic Fjord ◽  
The Impact

Environmental change can have a significant impact on biogeochemical cycles at high latitudes and be particularly important in ecologically valuable fjord ecosystems. Seasonality in biogeochemical cycling in a sub-Arctic fjord of northern Norway (Kaldfjorden) was investigated from October 2016 to September 2018. Monthly changes in total inorganic carbon (CT), alkalinity (AT), major nutrients and calcium carbonate saturation (Ω) were driven by freshwater discharge, biological production and mixing with subsurface carbon-rich coastal water. Stable oxygen isotope ratios indicated that meteoric water (snow melt, river runoff, precipitation) had stratified and freshened surface waters, contributing to 81% of the monthly CT deficit in the surface layer. The timing and magnitude of freshwater inputs played an important role in Ω variability, reducing AT and CT by dilution. This dilution effect was strongly counteracted by the opposing effect of primary production that dominated surface water Ω seasonality. The spring phytoplankton bloom rapidly depleted nitrate and CT to drive highest Ω (~2.3) in surface waters. Calcification reduced AT and CT, which accounted for 21% of the monthly decrease in Ω during a coccolithophore bloom. Freshwater runoff contributed CT, AT and silicates of terrestrial origin to the fjord. Lowest surface water Ω (~1.6) resulted from organic matter remineralisation and mixing into subsurface water during winter and spring. Surface waters were undersaturated with respect to atmospheric CO2, resulting in modest uptake of –0.32 ± 0.03 mol C m–2 yr–1. Net community production estimated from carbon drawdown was 14 ± 2 g C m–2 yr–1 during the productive season. Kaldfjorden currently functions as an atmospheric CO2 sink of 3.9 ± 0.3 g C m–2 yr–1. Time-series data are vital to better understand the processes and natural variability affecting biogeochemical cycling in dynamic coastal regions and thus better predict the impact of future changes on important fjord ecosystems.

The Digital Divide and K-12 Student Computer Use

10.28945/2926 ◽  
2005 ◽  
Author(s):  
James N. Morgan ◽  
Craig A. VanLengen
Keyword(s):  
Digital Divide ◽  
Computer Use ◽  
Census Data ◽  
Internet Access ◽  
Demographic Characteristics ◽  
The Internet ◽  
Substantial Impact ◽  
Limited Basis ◽  
K 12 ◽  
The Impact

The divide between those who have computer and Internet access and those who do not appears to be narrowing, however overall statistics may be misleading. Measures of computer availability in schools often include cases where computers are only available for administration or are available only on a very limited basis (Gootman, 2004). Access to a computer and the Internet outside of school helps to reinforce student learning and emphasize the importance of using technology. Recent U.S. statistics indicate that ethnic background and other demographic characteristics still have substantial impact on the availability and use of computers by students outside of the classroom. This paper examines recent census data to determine the impact of the household on student computer use outside of the classroom. Encouragingly, the findings of this study suggest that use of a computer at school substantially increases the chance that a student will use a computer outside of class. Additionally, this study suggests that computer use outside of the classroom is positively and significantly impacted by being in a household with adults who either use a computer at work or work in an industry where computers are extensively used.

Groundwater protection and diffuse nitrogen emissions to surface waters – which catchment areas have to be considered?

2007 ◽  
Vol 7 (3) ◽  
pp. 103-110
Author(s):  
C. Schilling ◽  
M. Zessner ◽  
A.P. Blaschke ◽  
D. Gutknecht ◽  
H. Kroiss
Keyword(s):  
Surface Water ◽  
Total Nitrogen ◽  
Surface Waters ◽  
Flow Path ◽  
Emission Model ◽  
Catchment Scale ◽  
Danube Basin ◽  
Nitrogen Emissions ◽  
Nitrogen Levels ◽  
Catchment Areas

Two Austrian case study regions within the Danube basin have been selected for detailed investigations of groundwater and surface water quality at the catchment scale. Water balance calculations have been performed using the conceptual continuous time SWAT 2000 model to characterise catchment hydrology and to identify individual runoff components contributing to river discharge. Nitrogen emission calculations have been performed using the empirical emission model MONERIS to relate individual runoff components to specific nitrogen emissions and for the quantification of total nitrogen emissions to surface waters. Calculated total nitrogen emissions to surface waters using the MONERIS model were significantly influenced by hydrological conditions. For both catchments the groundwater could be identified as major emission pathway of nitrogen emissions to the surface waters. Since most of the nitrogen is emitted by groundwater to the surface water, denitrification in groundwater is of considerable importance reducing nitrogen levels in groundwater along the flow path towards the surface water. An approach was adopted for the grid-oriented estimation of diffuse nitrogen emissions based on calculated groundwater residence time distributions. Denitrification in groundwater was considered using a half life time approach. It could be shown that more than 90% of the total diffuse nitrogen emissions were contributed by areas with low groundwater residence times and short distances to the surface water. Thus, managing diffuse nitrogen emissions the location of catchment areas has to be considered as well as hydrological and hydrogeological conditions, which significantly influence denitrification in the groundwater and reduce nitrogen levels in groundwater on the flow path towards the surface water.

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