Remote determination of chromophoric dissolved organic matter in lakes,China

Chromophoric dissolved organic matter (CDOM) strongly influences the water-leaving radiance from aquatic ecosystems. In most inland waters, the remote determination of CDOM absorption presents a central challenge due to their complex optical conditions. However, identifying the temporal and spatial variability of CDOM is fundamental to the understanding of aquatic biogeochemical dynamics. In the present study, semi-analytical and empirical modeling approaches were used to examine CDOM absorption in four, shallow, inland water bodies using the spectral bands and sensitivities of major satellite observational systems. Of the models examined, an empirical multiband model was found to provide the highest correlation with measured CDOM absorption. The spectral characteristics of the MERIS sensors yielded the best results with respect to the other available satellite sensors. High detrital load was observed to be a major impediment to estimating CDOM absorption, while lakes with elevated phytoplankton biomass did not present similar problems.     

Automatic mapping of snow cover depletion curves using optical remote sensing data under conditions of frequent cloud cover and temporary snow

Snow cover depletion curves are required for several water management applications of snow hydrology and are often difficult to obtain automatically using optical remote sensing data owing to both frequent cloud cover and temporary snow cover. This study develops a methodology to produce accurate snow cover depletion curves automatically using high temporal resolution optical remote sensing data (e.g. Terra Moderate Resolution Imaging Spectroradiometer (MODIS), Aqua MODIS or National Oceanic and Atmospheric Administration (NOAA) Advanced Very High Resolution Radiometer (AVHRR)) by snow cover change trajectory analysis. The method consists of four major steps. The first is to reclassify both cloud‐obscured land and snow into more distinct subclasses and to determine their snow cover status (seasonal snow cover or not) based on the snow cover change trajectories over the whole snowmelt season. The second step is to derive rules based on the analysis of snow cover change trajectories. These rules are subsequently used to determine for a given date, the snow cover status of a pixel based on snow cover maps from the beginning of the snowmelt season to that given date. The third step is to apply a decision‐tree‐like processing flow based on these rules to determine the snow cover status of a pixel for a given date and to create daily seasonal snow cover maps. The final step is to produce snow cover depletion curves using these maps. A case study using this method based on Terra MODIS snow cover map products (MOD10A1) was conducted in the lower and middle reaches of the Kaidu River Watershed (19 000 km²) in the Chinese Tien Shan, Xinjiang Uygur Autonomous Region, China. High resolution remote sensing data (charge coupled device (CCD) camera data with 19·5 m resolution of the China and Brazil Environmental and Resources Satellite (CBERS) data (19·5 m resolution), and the Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) data with 15 m resolution of the Terra) were used to validate the results. The study shows that the seasonal snow cover classification was consistent with that determined using a high spatial resolution dataset, with an accuracy of 87–91%. The snow cover depletion curves clearly reflected the impact of the variation of temperature and the appearance of temporary snow cover on seasonal snow cover. The findings from this case study suggest that the approach is successful in generating accurate snow cover depletion curves automatically under conditions of frequent cloud cover and temporary snow cover using high temporal resolution optical remote sensing data. Copyright © 2007 John Wiley & Sons, Ltd.     

The River Arno catchment,northern Tuscany: chemistry of waters and sediments from the River Elsa and River Era sub‐basins,and sulphur and oxygen isotopes of aqueous sulphate

Within the hydrologic balance of the River Arno catchment (northern Tuscany), the Rivers Elsa and Era are important tributaries entering the main river from the left bank in the lower part of the watershed. Waters and bed sediments were sampled in June 2000 during low discharges in the Rivers Elsa and Era, as well as in major tributary streams. Water samples were analysed for major chemistry and sulphur isotope composition of sulphate, and sediment samples were analysed for major composition and selected trace elements of environmental concern (Zn, Cu, Pb, Cr and Ni). The main results for the waters are: (1) Na and Cl in solution show consistent downstream positive trends in the main rivers, thus supporting progressive contributions of anthropogenic salts; the highest concentration values are observed in tributaries; (2) as shown by sulphur isotopes, sulphate in solution is mainly controlled by dissolution of evaporites (Elsa basin) or oxidation of reduced organic/biogenic sulphur (Era basin), with anthropogenic contributions in most streams not higher than 10% in both the basins. A δ³⁴S signature in the range ?2 to +3‰ is estimated for pollutant sulphate in the basins studied. The main results for the sediments are: (1) major chemistry is essentially controlled by the lithotypes drained by the waters; (2) pollution by heavy metals does not reach high levels; (3) compared with local fine‐grained rocks, copper is more frequently anomalous, whereas lead and zinc show only occasional anomalies; (4) local high concentrations of chromium and nickel can be attributed to upstream occurrences of ophiolites. Copyright © 2006 John Wiley & Sons, Ltd.     

Investigation of water pollution in the Yalvac basin into Egirdir Lake,Turkey

The aim of this study is to understand the effects of pollution of anthropogenic origin on water quality in Yalvac Basin, part of the Egirdir Lake catchment. Surface discharge from the basin to the lake is 63 m³/year and underground discharge is 114 m³/year. Possible water pollution is categorized into domestic, industrial and agricultural origin. Domestic and industrial wastewaters, including effluents from leather tanneries are discharged, without being purified, into Yalvac Stream, which flows into Egirdir Lake directly or via the drainage canal. Surface waters flowing into the lake are used in winter for irrigation of agricultural areas. In agricultural areas natural and synthetic fertilizers and pesticides are used extensively. Lake Egirdir is used as a source of drinking water. Sampling sites were established for surface and underground waters, taking into account the known point sources of pollution. These sites were sampled in May and October of 2002, and analysed chemically. Cr³⁺ and Pb²⁺ concentrations exceed standard limits, meaning that pollution caused by effluent from the tanneries is adversely affecting the water quality in the lake.     

Geochemistry of Thermal Waters of Continental Margin of Far East of Russia

Studied waters belong to warm(T=30-50℃),alkaline(pH=8.9-9.3),low mineralized(TDS235 mg/1)Na-HCO_3 or Na-SO_4-HCO_3 thermal waters with high content of SiO_2(up to 81 mg/l)and F(up to 3.9 mg/1),occur on modern volcano-tectonic rejuvenated areas of Eastern Sikhote-Alin orogenic belt.Low~3He concentration as well as N_2/O_2 and N_2/Ar ratios exclude influence of deep mantle fluid.New rare earth element data constrain our understandmg of water-rock interaction occurring in the water source region.Meteoric origin of waters is proved by stable isotope values varying from-71‰to-136.1‰and from-10.8‰to-18.8‰forδ~2U andδ~(18)O respectively.REE patterns reflect high pH,resultfing from water-rock interaction and oxidative conditions.Calculations of deep aquifer temperature using Na-K and quartz geothermometers show 116.8-131.1°C and 82.2-125.8℃respectively.Presence of deep faults both with abnormal thermal gradient(~45-50 K/km)define unique geochemical shape of thermal waters of Sikhote-Alin,area,where no present volcanic activity is registered.     

地下水监测工程承压-自流监测井密封技术

针对地下水监测工程施工中面临的承压-自流监测井密封、监测、取样、洗井等紧迫难题,研发了承压-自流监测井密封技术。该技术是在监测井管口安装一个具有多个功能组件的密封不锈钢盖板来实现自流监测井长期监测的各项需求。本文介绍了承压-自流监测井密封技术原理、系统组成和安装流程及方法。通过山西忻州市地下水监测井现场示范及其他地区50余口井的工程应用,证实该技术可有效解决自流监测井井口密封、水样采集、洗井清淤和维护探头等一系列问题,具有密封效果好、不污染水质、操作便捷和成本低等优点,可实现不同特征自流监测井地下水数据长期自动采集与传输,并可为类似井的封孔工作提供解决思路。     

The development of a rapid screening technique to measure antibiotic activity in effluents and surface water samples

Use of antibiotics in medicine, farming and aquaculture results in a continual supply of these pharmaceuticals and their breakdown products reaching the environment. A method has been developed to use for screening environmental samples to establish whether they contain antibiotics. The assay is based on a commercially available test kit and uses some modifications of the test procedure and SPE techniques to deliver a fast, semi-quantifiable result. Development of the assay and results from spiked and environmental samples are discussed.     

Stable isotope composition of Hellenic bottled waters

Bottled waters are an increasingly significant product in the human diet. In this work, we present a dataset of stable isotope ratios for bottled waters sampled in Greece. A total of 25 domestic brands of bottled still waters, collected on the Greek market in 2009, were analysed for δ¹⁸O and δ²H. The measured stable isotope ratios range from − 9.9‰ to − 6.9‰ for δ¹⁸O and from − 67.50‰ to − 46.5‰ for δ²H. Comparison of bottled water isotope ratios with natural spring water isotope ratios demonstrates that on average the isotopic composition of bottled water tends to be similar to the composition of naturally available local water sources, showing that bottled water isotope ratios preserve information about the water sources from which they were derived and suggesting that in many cases bottled water should not be considered as an isotopically distinct component of the human diet. This investigation also helped to determine the natural origin of bottled water, and to indicate differences between the natural and production processes. The production process may influence the isotopic composition of waters. No such modification was observed for sampled waters in this study. The isotopic methods applied can be used for the authentication of bottled waters and for use in the regulatory monitoring of water products.     

黄骅海域浮游植物群落结构的季节变化

2010年在黄骅海域进行浮游植物和理化环境的4个季度的生态调查.共发现浮游植物3门28属75种,其中赤潮种34种,种类数量的季节变化为秋季(2010-10)＞冬季(2010-12)＞夏季(2010-08)＞春季(2010-04).浮游植物生态类型可划分为广温近岸类群、暖水类群和暖温类群,广温近岸类群是浮游植物的优势类群.浮游植物细胞数量的季节变动范围为(46.42×104～190.68×104)个/m3,季节变化为秋季＞夏季＞春季＞冬季,浮游植物数量的季节变化呈单峰特征,硅藻是浮游植物的优势种群.Jacard相似度指数的范围为0.19～0.42,季节更替明显.夏季浮游植物细胞数量与磷酸盐显著正相关,相关系数为0.548(p＜0.05),地表径流是浮游植物细胞数量的重要影响因素.秋季浮游植物细胞数量与温度极显著负相关,相关系数-0.744(p＜0.01);与无机氮显著相关,相关系数0.482.温度和无机氮是影响浮游植物数量的因素.     

Measurements of biomass and activity of neustonic microorganisms

Microlayer samples from a coastal marine area near Marseilles (France) collected in 1979 and 1980 have been analysed for POC, PON, chlorophyll a, ATP, cell counts, carbon fixation and in some cases for heterotrophic activity. Comparison of microlayer data with those of underlying water showed in most cases enrichment of organic matter and microorganisms in the surface microlayer. Carbon fixation values were comparable to those observed at 0·50 m except in the slicks, where phytoneustonic activity was higher than that of the underlying phytoplankton. Though total heterotrophic activity was higher in the surface film, the turnover time was not significantly different in both microlayer and underlying water. Our data show that enrichment is highly dependent on sea conditions; whenever slicks are present, the surface film seems to function like an eutrophic system, including active living material, although detritus is regularly present in large amounts.