نتایج جستجو برای: accumulation igeo sediment

تعداد نتایج: 184755  

Journal: :Environmental Nanotechnology, Monitoring and Management 2021

Oil spillage is one of the common pollution events global water-soil ecosystems. A comprehensive investigation on heavy metals surface water and sediments was conducted after oil spill incident in Sela River its tributaries Sundarbans mangrove forest ecosystems, Bangladesh. Water sediment samples were collected from preselected sampling points River, elemental (Pb, Cd, Cr, Co, Cu, Ni, Fe, As, H...

2017
Mary J. Kraus Thomas M. Bown

A new method uses alluvial paleosols to calculate sediment accumulation rates for thin (25 m) stratigraphic intervals and allows the reliable interpolation of ages for stratigraphic levels within a thick stratigraphic interval bounded by established dates. Sediment accumulation rates calculated for a 650 m composite section in the Eocene Willwood Formation of Wyoming span time intervals ranging...

Journal: :The Science of the total environment 2009
Damien A Devault Magali Gérino Christophe Laplanche Frédéric Julien Peter Winterton Georges Merlina François Delmas Puy Lim José Miguel Sánchez-Pérez Eric Pinelli

The aim of the present study was to understand the effect of reservoir configurations on sediment pesticide fate. Two dams were selected on the River Garonne, in southwest France: Carbonne and Golfech, both with reservoirs subject to accumulation of herbicide-contaminated sediment. They are situated upstream and downstream respectively of an agricultural and urban area: the Mid-Garonne. The res...

Journal: :Environmental toxicology and chemistry 2012
Jon P Kochersberger G Allen Burton Kevin W Custer

Stream-deposited sediment is one of the major stressors affecting stream biota. Several methods exist to quantify stream sediment embeddedness, but they are relatively qualitative and operationally defined. The authors developed a short-term in situ embeddedness chamber method to measure aquatic insect recruitment and associated sediment accumulation in a more quantitative, better replicated ma...

Journal: :Journal of environmental radioactivity 2009
Jun Zhu Curtis R Olsen

Measured monthly atmospheric depositional fluxes of cosmogenically produced (7)Be ranged from 1 to 67 mBq/cm(2) in Boston, Massachusetts between September 2000 and August 2007. These fluxes exhibited seasonality and supported a decay-corrected (7)Be atmospheric depositional running inventory that ranged from 36 to 144 mBq/cm(2). Annual (7)Be deposition exhibited an increasing trend that may ref...

2018
BRITAS KLEMENS ERIKSSON ELLEN WEERMAN HAN OLFF THEUNIS PIERSMA SERENA DONADI

Ecosystem engineering research has recently demonstrated the fundamental importance of non-trophic interactions for food-web structure. Particularly, by creating benign conditions in stressful environments, ecosystem engineers create hot beds of elevated levels of recruitment, growth, and survival of associated organisms; this should fuel food webs and promote production on the ecosystem scale....

2002
TOSHIHIRO USUI ISAO KOIKE NORIO OGURA

To evaluate the effect of the tidal cycle on the pore water nitrate dynamics in intertidal sediment, concentrations of inorganic nitrogen in water and sediment were monitored during tidal cycles in the mud flat of Tama Estuary, Japan. During submergence, nitrate concentration was highest in the overlying water and decreased monotonically with increasing depth in the sediment, suggesting that th...

2004
JOHN I. HEDGES FENG SHENG HU ALLAN H. DEVOL HILAIRY E. HARTNETT ELIZABETH TSAMAKIS RICHARD G. KEIL

We report here a test of the hypothesis that the extent of organic matter preservation in continental margin sediments is controlled by the average period accumulating particles reside in oxic porewater immediately beneath the water/sediment interface. Oxygen penetration depths, organic element compositions, and mineral surface areas were determined for 16 sediment cores collected along an offs...

2010
Guang C. Chen Yong Ye

Sesarmid crabs are important ecosystem engineers in mangroves because they remove a large proportion of mangrove leaf litter. However, the effects on mangrove sediments of sesarmid crab foraging on mangrove leaves has been poorly quantified. Through a laboratory experiment, the present study aimed to quantify changes in nutrient concentrations and enzyme activities in mangrove sediment due to f...

Journal: :مهندسی عمران فردوسی 0
حسین آسیائی حسین منتصری

the mechanism of flow and sediment transport in channel bend is much complex. because of secondary current, the sediment moves away from outer bank toward inner bank and therefore outer bank of the bend is one of best positions for lateral diversion. in this paper, the mechanism of sediment transport was simulated with ssiim software in the u shape channel with lateral intake. in order to verif...

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