نتایج جستجو برای: surface sediment

تعداد نتایج: 666636  

Journal: :international journal of environmental research 2012
m.m. serbaji c. azri k. medhioub

eight selected heavy metals (cu, zn, pb, cd, cr, mn, fe and al) in surface and sub-surfacesediments in the northern coast of sfax (tunisia) were studied in order to assess the sediment quality and tohighlight the anthropogenic contributions to heavy metal distributions in the two study sediment levels.multiple chemometric approaches based on geographic information system (gis), enrichment facto...

Journal: :journal of agricultural science and technology 2011
a. kouhpeima s. feiznia h. ahmadi s. a. a. hashemi

sediment yield data, collected for most regions in iran has been insufficient and not so reliable and there is still not any sufficiently reliable methodology available for sediment yield assessment in the country as a whole. on the other hand, an attainment of reliable sediment yield data is a must and key requirement for the design of effective sediment management as well as control strategie...

2009
Halim A. Ergül Sayhan Topcuoğlu

Total mass flux (TMF), total organic matter (TOM), carbonate (CaCO3), lithogenic matter, biogenic silica (BSi), organic carbon (Corg), organic nitrogen (Norg) fluxes and sedimentation rates were determined seasonally using a sediment trap deployed in oxic layer on eastern coast of the Black Sea from July 2002 to October 2003. TOM, CaCO3, Corg and Norg percentages in surface sediment and chlorop...

2003
Peter Berg Hans Røy Felix Janssen Volker Meyer Bo Barker Jørgensen Markus Huettel Dirk de Beer

This paper presents a new non-invasive technique for measuring sediment O2 uptake that, in its concept, differs fundamentally from other methods used to date. In almost all natural aquatic environments, the vertical transport of O2 through the water column toward the sediment surface is facilitated by turbulent motion. The new technique relies on measuring 2 parameters simultaneously and at the...

2006
J. Taylor Perron Michael P. Lamb Charles D. Koven Inez Y. Fung Elowyn Yager Máté Ádámkovics

[1] Branching valley networks near the landing site of the Huygens probe on Titan imply that fluid has eroded the surface. The fluid was most likely methane, which forms several percent of Titan’s atmosphere and can exist as a liquid at the surface. The morphology of the valley networks and the nature of Titan’s surface environment are inconsistent with a primary valley formation process involv...

2017
Hanna Barchanska Marcin Sajdak Kornelia Szczypka Angelika Swientek Martyna Tworek Magdalena Kurek

The aim of this study was to monitor the sediment, soil and surface water contamination with selected popular triketone herbicides (mesotrione (MES) and sulcotrione(SUL)), atrazine (ATR) classified as a possible carcinogen and endocrine disrupting chemical, as well as their degradation products, in Silesia (Poland). Seventeen sediment samples, 24 soil samples, and 64 surface water samples colle...

2012
Isabela C. Torres Patrick W. Inglett Mark Brenner William F. Kenney Ramesh Reddy

Lake sediments contain archives of past environmental conditions in and around water bodies and stable isotope analyses (dC and dN) of sediment cores have been used to infer past environmental changes in aquatic ecosystems. In this study, we analyzed organic matter (OM), carbon (C), nitrogen (N), phosphorus (P), and dC and dN values in sediment cores from three subtropical lakes that span a bro...

2014
Nicholas P. Webb Gregory S. Okin Shannon Brown

Representation of surface roughness effects on aeolian sediment transport is a key source of uncertainty in wind erosion models. Drag partitioning schemes are used to account for roughness by scaling the soil entrainment threshold by the ratio of shear stress on roughness elements to that on the vegetated land surface. This approach does not explicitly account for the effects of roughness confi...

2007
EKKEHARD HOLZBECHER

Models on flow and transport in surface water sediments currently neglect compaction, although it is well understood that compaction is one of the major processes below the free fluid-sediment interface. Porosity changes in the sediment layers, as a result of compaction, are measured in almost all probes: porosity decreases with the distance from the surface water-sediment interface. This paper...

Journal: :Environment international 2002
C K Yap A Ismail S G Tan H Omar

Total concentrations and speciation of cadmium (Cd), copper (Cu), lead (Pb) and zinc (Zn) in surface sediment samples were correlated with the respective metal measured in the total soft tissue of the green-lipped mussel Perna viridis, collected from water off the west coast of Peninsular Malaysia. The aim of this study is to relate the possible differences in the accumulation patterns of the h...

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