The effects of sediment from an industrial outfall area on a marine planktonic ecosystem

-Sediment from Xiamen industrial area was added to marine ecosystem enclosures to test the effects on the planktonic communities in Xiamen Bay, China, in April, 1985. Sediments were added at two concentrations, 11.2 and 112 ppm dry wt. respectively. The species of phytoplankton did not change as compared with the control, but the number of diatoms markedly decreased in the sediment treated enclosures. A suppression of photosynthesis was presumed to be due to light attenuation by the added sediment. Microflagellates, zooplankton and bacteria were resistant to sediment increase in water column.

Experimental Study on the Effect of Sediment Composition Ratio on Shallow Water Delta

1 Introduction Shallow water delta in the middle-newborn Stratum Widely developed with huge oil and gas in China(Hu Shengwu et al.,2013).The control factors on the deltadevelopment like Climate,sea level,tectonic subsidence,sediment supply(flow,type),the geometric characteristics of the upstream river,the energy(wave,

Assessing the Effect of Natural Controls and Land Use Change on Sediment Yield in a Major Andean River:The Magdalena Drainage Basin,Colombia

马格达莱纳河是哥伦比亚安第斯山区的一个世界级的河流网络，该河流年产沙量约为150Mt，是全世界10大主要产沙河流之一。在本研究中，我们探讨主要自然因子和人类活动对马格达莱纳河流域产沙模式的影响，重建该区森林砍伐和农业活动时空模式，探讨土地利用变化与产沙趋势的关系。我们的研究结果表明，整个马格达莱纳河流域的产沙量可以用自然变量（包括径流量和最大河水流量）来解释。这两个因子解释了产沙量58％的变化。含沙率和土地利用的时间分析表明，在过去10～20年里流域侵蚀呈现增加的趋势。许多人类活动的影响，包括森林覆被在20年里减小了近40％．农业和牧场增加了65％、土壤保持差、开矿活动，以及城市化的加速，都促进了该地区域尺度上产沙量的增加。

Numerical simulation of flow and bed morphology in the case of dam break floods with vegetation effect

The purpose of this study is to establish a depth-averaged 2-D hydrodynamic and sediment transport model for the dambreak flows with vegetation effect. The generalized shallow water equations are solved using an explicit finite volume method with unstructured quadtree rectangular grid, and in the hydrodynamic model, a Harten-Lax-Van Leer（HLL） approximate Riemann solver is used to calculate the intercell flux for capturing the dry-to-wet moving boundary. The sediment transport and bed variation equations in a coupled fashion are calculated by including the bed variation and the variable flow density in the flow continuity and momentum equations. The drag force of vegetation is modeled as the sink terms in the momentum equations. The developed model is tested against lab experiments of the dam-break flows over a fix bed and a movable bed in vegetated and non-vegetated channels. The results are compared with experimental data, and good agreement is obtained. It is shown that the reduced velocity under vegetated conditions leads to a decrease of the peak discharge and a rise of the water level of rivers and also an enhancement of the sediment deposition.

Effects of sediment parameters on the low frequency acoustic wave propagation in shallow water

The integral expression for acoustic field due to a point source in shallow waterwhile sediment is either a liquid or a solid is derived. The synthetic full waveforms are simulatedusing real axis integration and FFF method. The effects of the seabed sediment parametersand center frequency of the source on the low frequency acoustic wave propagation in shallowwater are investigated. The conclusion is that the wave groups received in far field are thoseof the mode waves of the source center frequency. The possibility for inversely deducing thecompressional and shear sound speeds of sediment using the least square optimum through themeasured group velocities of a selected mode at different frequencies is discussed.

STUDY ON THE EFFECT OF SEDIMENT MOTION ON TRANSPORT TRANSFORMATION OF HEAVY METAL POLLUTANTS

By combining laboratorial experiments,theoretical analysis and mathematical model,theeffect of sediment motion on transport-transformation of heavy-metal pollutants is studied. (1)Previous studies on adsorption-desorption of heavy-metal pollutants by sedimentparticles are systematically summarized.Based on this summary,subjects that need to be furtherstudied are put forward. In rivers most heavy-metal pollutants concentrate on sediment particles.In order tocontrolling water pollution aused by heavy-metal pollutants following topics should beemphasized:studies on the effect of suspended matter and deposit on transport-transformation of

Zonal differences of runoff and sediment reduction effects for typical management small watersheds in China

In this particular study,99 typical managed small watersheds which representing five water erosion areas in China were selected to study zonality of Runoff Reduction Efficiency(RRE)and of Sediment Reduction Efficiency(SRE).The RRE is the ratio of Effect of Runoff Reduction(ERR)by soil and water conservation measure over management degree in a watershed.And The SRE is the ratio of Effect of Sediment Reduction(ESR)by soil and water conservation measure over management degree in a watershed.First of ah,statistical analysis was applied to test the zonal effects of RRE and SRE between different water erosion regions.The results showed that the mean RRE values in northern regions were significantly greater than those of southern regions;and the mean SRE values in northern regions were significantly greater than those in southern regions.Next,the variation of RRE with runoff depth(H)was studied in direction of both latitude and longitude across regions influenced by East Asian Monsoon.Meanwhile,the variation of SRE with specific sediment yield(Y)was studied in direction of both latitude and longitude across regions influenced by East Asian Monsoon.The results showed that RRE had the inverse variation trend as H in both latitude and longitude direction and SRE had the same variation trend as Y in both latitude and longitude direction.Furthermore,the variation of unit management area Runoff Reduction Rate(RRR)with H and RRE was studied in direction of both latitude and longitude.And the variation of unit management area Sediment Reduction Rate(SRR)with Y and SRE was studied in direction of both latitude and longitude.It was found that RRR had the similar variation trend as H in latitude direction and there was critical point around 37°N greater than which RRR began to be equal to H or even larger;RRR had the similar variation trend as H in longitude direction and there was a critical point around 109°E lees than which RRR began to equal to or greater than H;SRR had the similar variation trend as Y in latitude direction and there was critical point around 36°N greater than which SRR began to be equal to Y or even larger;SRR had the similar variation trend as Y in longitude direction and there was a critical point around 106°E lees than which SRR began to equal to or greater than Y.The zonality of RRE,RRR,SRE and SRR was determined by the combined influence of climate variation and special landform in regions controlled by East Asian Monsoon in China.

Review on utilization of biochar for metal-contaminated soil and sediment remediation

Biochar is a carbon-neutral or even carbon-negative material produced through thermal decomposition of plant-and animal-based biomass under oxygen-limited conditions.Recently, there has been an increasing interest in the application of biochar as an adsorbent, soil ameliorant and climate mitigation approach in many types of applications.Metal-contaminated soil remediation using biochar has been intensively investigated in small-scale and pilot-scale trials with obtained beneficial results and multifaceted effects.But so far, the study and application of biochar in contaminated sediment management has been very limited, and this is also a worldwide problem. Nonetheless, there is reason to believe that the same multiple benefits can also be realized with these sediments due to similar mechanisms for stabilizing contaminants. This paper provides a review on current biochar properties and its use as a sorbent/amendment for metal-contaminated soil/sediment remediation and its effect on plant growth, fauna habits as well as microorganism communities. In addition, the use of biochar as a potential strategy for contaminated sediment management is also discussed, especially as regards in-situ planning. Finally, we highlight the possibility of biochar application as an effective amendment and propose further research directions to ensure the safe and sustainable use of biochar as an amendment for remediation of contaminated soil and sediment.