نتایج جستجو برای: sediment distribution

تعداد نتایج: 641164  

Journal: :محیط زیست طبیعی 0
حامد ارفع نیا کارشناس ارشد گروه علوم خاک، دانشکدۀ کشاورزی، دانشگاه بوعلی سینا فرخ اسدزاده استادیار گروه علوم خاک، دانشکدۀ کشاورزی، دانشگاه ارومیه

measurement of availability and mobility of heavy metals in river sediments is required in order to understand the behavior of these metals and to prevent potential toxic hazards. leaching column experiments were conducted for four sediment samples to determine the degree of mobility and the distribution of zn, cd, ni, cu, and pb because of an application of spiked heavy metals in sediments. se...

2006
Leonard S. Sklar William E. Dietrich Efi Foufoula-Georgiou Bruno Lashermes Dino Bellugi

[1] Bed load sediment particles supplied to channels by hillslopes are reduced in size by abrasion during downstream transport. The branching structure of the channel network creates a distribution of downstream travel distances to a given reach of river and thus may strongly influence the grain size distribution of the long-term bed load flux through that reach. Here we investigate this hypoth...

ژورنال: اقیانوس شناسی 2020

In order to investigate the sedimentary texture, diversity and density of benthic molluscs, 55 stations at 9 transect were collected in the Nayband Bay.Samples were taken with a Van Veen grab (0.022 m2) in 3 replications in each site.Using a Particle Size Analyzer instrument revealed that the sediment texture was dominated by sand with 7 sub distinct sub sediment. Semelidae,Veneridae and Tellin...

Journal: :international journal of environmental research 2014
p. temporetti g. beamud e. pedrozo

the parameters used to determine the trophic state of a water body are: total phosphorus (tp),transparency (secchi disk depth) and chlorophyll a. however, these parameters show strong seasonalfluctuations which may hinder the estimation of trophic state. some authors have proposed that sediments be used as an additional tool to evaluate the trophic state of a water body. the aim of this study w...

Journal: :Geomorphology 2014
Brian W Miller Martin W Doyle

Researchers have independently documented the effects of land use on rivers and threats to river management institutions, but the relationship between changes in institutional context and river condition is not well described. This study assesses the connections between resource management institutions, land use, and rivers by integrating social science, geospatial analysis, and geomorphology. ...

Water and sediment samples have been collected from five different stations, located along Djendjen River between February and June, 2016 so that the concentrations of Cd, Ni, Zn, and Cu could be determined. The extent of the sediment pollution has been assessed, using the multiple pollution indices, namely Contamination Factor (CF), Pollution Load Index (PLI), and the geoaccumulation index (Ig...

Journal: Pollution 2018

Water and sediment samples have been collected from five different stations, located along Djendjen River between February and June, 2016 so that the concentrations of Cd, Ni, Zn, and Cu could be determined. The extent of the sediment pollution has been assessed, using the multiple pollution indices, namely Contamination Factor (CF), Pollution Load Index (PLI), and the geoaccumulation index (Ig...

2008

Lake Tanganyika is an ancient, tropical, fresh water lake associated with the Great African Rift. Due to active deforestation in many areas surrounding Lake Tanganyika, there is a measurable increase in sediment discharge entering the lake. Certain protected areas (protected from fire and deforestation) allow for comparison of sediment discharge, including grain size distribution and lithologic...

Journal: Desert 2011
H R Azimzadeh M R Ekhtesasi

Different types of sediment trap have been introduced so far to be used in erosion measuring stations, each with its own advantages and disadvantages in trapping aeolian particles. These traps have different collection and retention efficiency due to aerodynamic conditions. Some characteristics such as isokinetic feature of the trap, collection efficiency, time needed to download sediment, capa...

2017
Matthew P. J. Oreska Karen J. McGlathery John H. Porter

Most information on seagrass carbon burial derives from point measurements, which are sometimes scaled by meadow area to estimate carbon stocks; however, sediment organic carbon (Corg) concentrations may vary with distance from the meadow edge, resulting in spatial gradients that affect the accuracy of stock estimates. We mapped sediment Corg concentrations throughout a large (6 km2) restored s...

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