Sediment grain size

Where D is in cm yr and Depth in m. Although these two relationships explain some of the variability in D, it is clear that other environmental factors are also important, including sediment grain-size (Wheatcroft 1992) and the organic carbon flux (Trauth et al. 1997). 

Fig. 1. Log-ratio-based normalization trends for Gulf of Trieste sediments. Grain-size fractions measured in %, chemical components scaled to relative abundance.

The abiotic stress affecting microbial activity and growth in an interfacial microenvironment include factors such as light, moisture, temperature, pH, soil/sediment grain size, carbon/nitrogen content, and redox potential [40-43, 46,47,49-51,56-58]. 

As noted above, the SQT originally focused on sediment chemistry, toxicity, and community structure. It has been expanded to include bioaccumulation, sediment stability, CBR and TIE analyses. Schmidt et al. (2002) have provided a means for inclusion of data on habitat. Habitat is a key factor controlling the distributions of biota, which has been implicitly but not explicitly considered to date in the SQT (e.g., via measurements of sediment grain size and TOC). Habitat should be explicitly considered as part of the SQT in future. 

Aelion C. M. (1996) Impact of aquifer sediment grain size on petroleum hydrocarbon distribution and biodegradation. J. Contamin, Hydrol. 22(1—2), 21—109. 

Since it is well known that sediment grain-size and organic content influence trace metal concentrations, it would be expected that temporal variability in trace metal concentrations would also be found. This is indeed the case (French, 1993a), but additional controls appear to also exert an influence zinc exhibits a temporal variability even after grain-size correction in Severn Estuary sediments (French, 1993b), probably reflecting... 

The most important sediment characteristic is usually the sediment grain-size. The abundance of Rb in sediments is an established and... 

Comparison of trace-metal distribution maps for Cu, Zn, and Pb with a sediment grain-size map shows that the primary control is the association of Cu, Zn, and Pb with the fine-grained fraction. 

D Sediment grain size diameter-a specific length scale used in calculation of roughness... 

Studies showed that the sediment grain size and TOC influenced the heavy metal distributions. According to the profound analysis of the heavy metal concentrations in the sediments of SYS, it was safe to reach a conclusion that the grain size of sediment was the most important factor controlling the heavy metal distributions in SYS. 

The sediments grain size is controlled by the distance from the material source, the transportation medium, transportation mode and the sediments environmental characteristics. B2 and the A line stations were near to the Han River Estuary, so that the sand and silt schlepped by the Han River contributed enormously to high concentrations. Additionally, due to the effects of the ancient Yellow River and Yangtze River in the Wiirm glaciations, a thick layer of sand sediments developed in the west coast area north of the Yangtze... 

Seabed sediment grain size parameters in costal zone are important to describe depositional environment and reflect the coupling mechanism of dynamic-deposition-topography action. Therefore, based on a combination of characteristics of seabed sediment grain size parameters, it can help understand sedimentary environment, such as sediments deposition condition, sediment sources, sediment transport trends etc. 

Lake sediment grain-size parameters was directly reflected the sedimentary hydrodynamic conditions, thus speculated that the changes of sedimentary environment, sediment grain-size and there is close relationship between climate (Yang etc., 1999). Magnetic susceptibility is more like a reflection of lake basin land environment information. That are... 

Sediment Grain-size/pm 2 < Ra 214pb 22SAC 212pb 40 K 137Cs... 

Artificial radionuclides in bottom sediments of the Don River Estuary-Azov Sea (Black Sea) were measured to examine the storage and migration of radionuclides within this inland sea and to estimate the annual dose received by individuals in the local population who regularly consume fish (Matishov et al. 2002). The specific activity of surface sediments was 0.5—100 Bq/kg dry wt. [mean = (33.8 25.9) Bq/kg dry wt., the number of samples = 57] for Cs, 0.2-5.7 Bq/kg dry wt. [mean= (2.1 1.4) Bq/kg dry wt., the number of samples = 34] for Sr and 0.31-0.51 Bq/kg dry wt. (the number of samples = 2) for Pu in 1997—1999. Cs specific activities increase with distance from the mouth of the Don River and correlate negatively with the sediment grain size (square of the correlation coefficient, / = 0.77, the number of data points, n = 21). The annual Cs-derived dose received by an individual through the tropic chain water—fish-humans (approximately 10 Sv/a) is well below regulatory recommended limits. 

There are two distinct erodibility attributes for a given sediment. These are critical shear stress (i.e., the critical level of hydraulic shear stress that is sufficient to dislodge the solid particles), and the erosion rate (i.e., the flux rate of sediment into the water column) as a function of shear stress. Perhaps the most important determinant of erodibility is sediment grain size. Due to larger grain size and lesser interparticle forces, the erosion of coarse sediments is qualitatively quite different than erosion of cohesive sediments. It is also much better understood and empirically characterized. 

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