An integrated approach to sediment quality assessment: the Venetian lagoon as a case study
40
Citation
29
Reference
10
Related Paper
Citation Trend
Abstract:
Abstract Recent research trends in sediment quality assessment have demonstrated the need for an integrated approach which combines chemical characterisation with biological effects evaluation, both in the laboratory (toxicity bioassays) and in situ (macrobenthic community structure investigations). The Sediment Quality Triad organises these three aspects of sediment quality assessment in a single approach, where each component is complementary to the others. Considering the lack of previous studies, this preliminary work aimed to verify the potential of an integrated approach in a complex ecosystem, the Venetian lagoon. Five sampling stations along a presumed quality gradient were chosen. The chemical analyses of heavy metals and organic pollutants have been compared with the results of the toxicity bioassays (Microtox ® solid phase, saline extracts and pore water, and sea urchin Paracentrotus lividus sperm cell bioassay performed with saline extracts) and with the characterisation of the infaunal community structure. The results of this first application pointed out the complementarity of the three approaches and the ability of the integrated approach in discriminating different levels of environmental stress. Nevertheless, deeper investigations both on the response of the macrobenthic community to natural variability and on the environmental toxicity of several sulphur compounds (i.e. elemental sulphur) will be necessary.Based on the analysis of measured data in Shantou Bay, Guangdong province, there is a good interrelation between quartz component and suspended sediment concentration. With the increasing of suspended sediment concentration, the percentage of quartz decreases, while the amount of quartz material increases. The reason for this phenomenon is the number of fine grain size sediment goes up quickly with sediment concentration increasing, which reduces the median grain size of suspended sediment. By setting up relational expressions of quartz to sediment conncentration and the rising rate and descending rate of water level to sediment concentration, the year occurrence number of wearing sediment concentration and characteristic values of quartz and suspended sediment concentration are calculated.
Cite
Citations (0)
This paper revealed clearly the different coupling characteristics of sediment nitrogen and phos- phorus with sediment losses in slopeland of purple soil,and also the influence of rainfall intensity(RI)and slope on the characteristics with simulated rainfall method.It is found that sediment nitrogen losses de- creased with the increase of slope and RI,but sediment phosphorus losses were lightly influenced by both RI and slope.Correlation analysis demonstrated that with the increase of sediment losses,sediment nitrogen losses decreased,but sediment phosphorus losses increased.Both sediment nitrogen and sediment temporal- ly showed peak values,while sediment phosphorus did not.The accumulated amount of sediment nutrient losses increased with the increase of the accumulated amount of sediment losses,but sediment phosphorus loss was obviously higher than sediment nitrogen loss.In addition,there were differences in sediment nutri- ent enrichment ratios(Er),that is,the higher the amount of sediment losses,the lower sediment nitrogen Er,and the higher sediment phosphorus Er.Further,since sediment phosphorus Er was higher than sedi- ment nitrogen Er,sediment phosphorus was more coupling stable than sediment nitrogen,so as more likely to exhibit latent effect of its influence on the water environment of the downsream.
Phos
Cite
Citations (0)
Cite
Citations (12)
It analyzed the surface sediment phosphorus species using SMT method and the release poten- tial in the West Lake of Fuzhou.The results showed that the total phosphorus concentrations of the surface sediment are from 711 to 1 654 mg/kg and the inorganic phosphorus was the major phosphorus species in the sediment.The active organic and the Al/Fe bounded phosphorus occupied from 70% to 90% of the total phosphorus,which indicated the sediment had a large phosphorus releases potential.A gradient of the reac- tive soluble phosphorus occurred at the sediment-water interface which indicated that SRP could diffuse from sediment into the overlying water.The results suggested that a considerable potential P could be released from the sediment to the water when the burden of the outside became less which would influence the water quality of West Lake.
Cite
Citations (0)
Cite
Citations (1)
Based on analyzing natural environment characteristics of different producing runoff and producing sediment regions in the Yellow River basin,principles and indexes of determining more sediment and coarse sediment region have been mainly discussed and area of more sediment and coarse sediment region is calculated.It is to research coupling relations among different producing runoff and sediment regions in the Yellow River basin and runoff and sediment in the middle reaches of the Yellow River.Ratio that producing runoff volume and sediment delivery occupy total runoff and sediment in the four stations(Huaxian,Zhuangtou,Longmen and Hejin)are calculated,they are that producing annual runoff volume and sediment delivery occupy total runoff and sediment in four stations of the Yellow River 12.9% and 63.4% respectively,in which 87% of coarse sediment in the four stations comes from the more sediment and coarse sediment region.Controlling more sediment and coarse sediment region is a key for reducing sediment of four stations.It is estimated that controlling 10 000 km 2 more sediment and coarse sediment region can reduce 8% of total sediment and 10% coarse sediment respectively.
Sedimentary budget
Cite
Citations (2)
Abstract: A capitelid small polychaete, Capitella sp. I, is a head-side down deposit feeder, which often occurs densely in organically enriched sediment. In this study, we observed burrowing and feeding behaviors of this species, and conducted laboratory experiments, examining the impact of reworking activities of the worms on the physics and chemistry of the organically enriched sediment. The laboratory experiments revealed that the worms fed not only the subsurface sediment but also the surface sediment selectively. The burrowing and feeding activities of the worms in the sediment were activated by the addition of organic matter on the sediment surface. The reworking activities of the worms include burrowing into the sediment, spouting the subsurface layers of the sediment onto the sediment surface, feeding on the sediment and excreting the sediment as fecal pellets on the sediment surface. The amount of spouted sediment on the sediment surface caused by burrowing activities was approximately 2.6 times larger than the amount of sediment reworked by excretion of fecal pellets. We estimated that approximately 162gDW per day of the sediment could be reworked by 30, 000 adult worms with 1 mm of maximum width of thoracic segments. This reworking rate indicated that one square meter of the subsurface sediment with 2 cm in thickness, 75% of water content and 1.7 of specific gravity should be reworked within 52.5 days.
Deposition
Detritivore
Bioturbation
Cite
Citations (7)
Sediments play an important role in phosphorus (P) dynamics in eutrophic lakes. P concentrations are higher in surface sediments compared to deeper layers, representing a pool of P that can be released into the water column. Effective sediment depth for P release is different among lakes and little is known about this depth. Through experimental evaluation of P release in sediment cores, characterization of sediment porosity and distribution of P fractions in the sediment profile from a monomictic eutrophic lake, we determined which sediment layers produce release of P. The release of P in sediment layers of different depths varied between 0.89 and 2.07 mg P/m2×d with the highest P flow found in the sediment layer of 0-15 cm. The porosity of the sediment strata varied between 68 and 80%, with higher porosity in the surface sediment and decreasing porosity with depth of the sediment profile. We found that P bound to Fe/Mn (BD-P), Al/Fe oxides (NaOH-SRP), and organic matter (NaOH-NRP) were higher in the layer of 0-15 cm than in deeper layers. Sediment porosity, P release, total P and concentrations of the different P species in the sediment profile declined with sediment depth, stabilizing at the depth of 15 cm in the sediment profile. Therefore, we conclude that the effective sediment depth for release of P in this monomictic eutrophic lake is found up to 15 cm.
Cite
Citations (0)
Sedimentation
Cite
Citations (8)