نتایج جستجو برای: wind sediments

تعداد نتایج: 111368  

Journal: :Chemosphere 2007
Clare A Atkinson Dianne F Jolley Stuart L Simpson

Experiments were undertaken to examine the key variables affecting metal release and sequestration processes in marine sediments with metal concentrations in sediments reaching up to 86, 240, 700, and 3000 mg kg(-1) (dry weight) for Cd, Cu, Pb and Zn, respectively. The metal release and sequestration rates were affected to a much greater extent by changes in overlying water pH (5.5-8.0) and sed...

2017
Adriana Humanes Gerard F. Ricardo Bette L. Willis Katharina E. Fabricius Andrew P. Negri

Coral reproduction is vulnerable to both declining water quality and warming temperatures, with simultaneous exposures likely compounding the negative impact of each stressor. We investigated how early life processes of the coral Acropora tenuis respond to increasing levels of suspended sediments in combination with temperature or organic nutrients. Fertilization success and embryo development ...

2010
Hai Xu Bin Liu Feng Wu

The Rb/Sr ratios of lake sediments have been suggested as indicators of weathering intensity by increasing work. However, the geochemistry of Rb/Sr ratios of lake sediments is variable between different lakes. In this study, we investigated the spatial and temporal patterns of Rb/Sr ratios, as well as those of other major elements in surface sediments of Lake Qinghai. We find that the spatial p...

Journal: :international journal of environmental research 2010
ch. yu sh. xu m. gang l. zhou g. chen

the concentrations and speciation of mo, together with fe, cu, and zn, in nver river sediments impacted with mo mining activities in western liaoning, northeast china, were investigated withgeochemical method. using the x-ray fluorescence and x-ray diffraction, the characterizations of metals in tailings ponds deposited along the nver river bank were analyzed. analysis and comparison of the con...

Journal: :تحقیقات جغرافیایی 0
مهدی دهقان طزرجانی جغرافیای طبیعی و اقلیم شناسی دانشگاه یزد کمال امیدوار اقلیم شناسی دانشگاه یزد

in the current research, wind energy potential at yazd synoptic stations, which contain wind data with 10 years statistic period and beyond, including yazd synoptic station (1976-2006), tabass (1987-2006), robate poshte badam (1992-2006), bafgh (1993-2006) and marvast (1997-2006), has been studied. wind data were obtained from the recorded data at yazd meteorology organization. the data were re...

Journal: :فیزیک زمین و فضا 0
مرتضی فتاحی هیئت علمی موسسه ژئوفیزیک مریم حیدری موسسه ژئوفیزیک دانشگاه تهران

luminescence dating is now an important element in the suite of quaternary geochronological methods. the major area of growth in the past two decades has been its application to quaternary sediments, where the method provides an absolute age for the last exposure of the constituent grains to daylight.such deposits are generally composed of wind-blown sediment grains that have been exposed to su...

Journal: :Applied and environmental microbiology 1997
J D Coates J Woodward J Allen P Philp D R Lovley

Although polycyclic aromatic hydrocarbons (PAHs) have usually been found to persist under strict anaerobic conditions, in a previous study an unusual site was found in San Diego Bay in which two PAHs, naphthalene and phenanthrene, were oxidized to carbon dioxide under sulfate-reducing conditions. Further investigations with these sediments revealed that methylnaphthalene, fluorene, and fluorant...

Journal: :Frontiers in microbiology 2015
Antje Gittel Johanna Donhauser Hans Røy Peter R. Girguis Bo B. Jørgensen Kasper U. Kjeldsen

Alkanes are major constituents of crude oil and are released to the marine environment by natural seepage and from anthropogenic sources. Due to their chemical inertness, their removal from anoxic marine sediments is primarily controlled by the activity of anaerobic alkane-degrading microorganisms. To facilitate comprehensive cultivation-independent surveys of the diversity and distribution of ...

2015
Brandano Marco

Sedimentary facies and foraminiferal assemblages of sediments sampled into seven Posidonia oceanica meadows from Western Mediterranean Sea were investigated. Six sampling sites are localised in Italy (Maratea, Ponza Island, Santa Marinella, Giglio Island, Osalla and Alghero), and one in France (Argentella, Crovani Bay, Corsica). The role of P. oceanica meadows in the sedimentary processes was i...

2014
Bo Gao Huaidong Zhou Yong Huang Yuchun Wang Jijun Gao Xiaobo Liu

The concentrations, distribution, accumulation, and potential ecological risk of heavy metals (Cr, Cu, Zn, Ni, As, Pb, Cd, and Hg) in sediments from the Three Gorges Reservoir (TGR) tributaries were determined and studied. Pb isotopic compositions in sediments were also measured to effectively identify the potential Pb sources. The results showed that the average concentrations of heavy metals ...

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