Heavy metals in surficial coastal sediments of the Ligurian Sea   总被引：1，自引：0，他引：1  

Bertolotto RM  Tortarolo B  Frignani M  Bellucci LG  Albanese S  Cuneo C  Alvarado-Aguilar D  Picca MR  Gollo E 《Marine pollution bulletin》2005,50(3):348-356

  相似文献   

A Rapid X-ray Flare from Markarian 501     

Catanese M  Sambruna RM 《The Astrophysical journal》2000,536(1):L39-L42

The tree code for the approximate evaluation of gravitational forces is extended and substantially accelerated by including mutual cell-cell interactions. These are computed by a Taylor series in Cartesian coordinates and in a completely symmetric fashion, such that Newton's third law is satisfied by construction and that therefore momentum is exactly conserved. The computational effort is further reduced by exploiting the mutual symmetry of the interactions. For typical astrophysical problems with N=105 and at the same level of accuracy, the new code is about 4 times faster than the tree code. For large N, the computational costs are found to scale almost linearly with N, which can also be supported by a theoretical argument, and the advantage over the tree code increases with ever larger N.  相似文献   

Ecological evaluation of an experimental beneficial use scheme for dredged sediment disposal in shallow tidal waters     

van der Wal D  Forster RM  Rossi F  Hummel H  Ysebaert T  Roose F  Herman PM 《Marine pollution bulletin》2011,62(1):99-108

An experiment was performed to test an alternative dredging strategy for the Westerschelde estuary. Clean sand dredged from the navigation channel was disposed seawards of an eroding intertidal flat in order to modify morphology and hydrodynamics, improving the multi-channel system with ecologically productive shallow water habitat. Five years of intensive monitoring revealed that part of the disposed sediment moved slowly towards the flat, increasing the very shallow subtidal and intertidal area, as planned. The sand in the impact zone became gradually finer after disposal, possibly due to reduced current velocities. Nevertheless, no changes in macrobenthic biomass, density, species richness and composition were detected in the subtidal zone, also demonstrating rapid macrobenthic recovery. In the intertidal zone, no ecological effects could be revealed superimposed on trends associated with long-term sediment fining. Thus, despite morphological success and absence of detected negative ecological impacts of the experiment, new beneficial habitat was not created.  相似文献   

Benthic macroinvertebrates as indicators of environmental deterioration in a large microtidal estuary   总被引：1，自引：0，他引：1  

Wildsmith MD  Rose TH  Potter IC  Warwick RM  Clarke KR 《Marine pollution bulletin》2011,62(3):525-538

This study tested the hypothesis that, during recent years, the benthic macroinvertebrate fauna of the large basin of the Swan-Canning Estuary has changed in ways consistent with deteriorating environmental conditions in that estuary. Between 1986/7 and 2003/4, the compositions of that fauna altered markedly at the species and even family levels. Thus, the densities and number of species of molluscs, and especially of crustaceans, which are particularly susceptible to environmental stress, declined, while those of the more tolerant polychaetes increased. However, taxonomic distinctness declined consistently only at one of the four widely-spaced sampling sites and the dispersion of samples did not differ markedly between periods, indicating that the benthic fauna has not undergone such extreme changes as in the nearby Peel-Harvey Estuary. It is thus proposed that benthic macroinvertebrates can act as important indicators of the severity of environmental degradation in microtidal estuaries in regions where such perturbations are increasing.  相似文献   

Biological neutralization of chlor-alkali industry wastewater     

Jain RM  Mody KH  Keshri J  Jha B 《Marine pollution bulletin》2011,62(11):2377-2383

The present work reports biological neutralization of chlor-alkali industrial effluent by an alkaliphilic bacterium, isolated from the Gujarat coast, which was identified as Enterococcus faecium strain R-5 on the basis of morphological, biochemical and partial 16S rRNA gene sequencing. The isolate was capable of bringing down the pH of waste water from 12.0 to 7.0 within 3 h in the presence of carbon and nitrogen sources, with simultaneous reduction in total dissolved solutes (TDS) up to 19-22%. This bacterium produced carboxylic acid, as revealed by FT-IR analysis, which facilitated neutralization of alkaline effluent. The presence of unconventional raw materials viz. Madhuca indica flowers or sugar cane bagasse as carbon and nitrogen sources could effectively neutralize alkaline effluent and thus making the bioremediation process economically viable. The time required for neutralization varied with size of inoculum. To the best of our knowledge, this is the first report on biological neutralization of a chlor-alkali industrial effluent.  相似文献   

The use of benthic macroinvertebrates to establish a benchmark for evaluating the environmental quality of microtidal, temperate southern hemisphere estuaries     

Tweedley JR  Warwick RM  Valesini FJ  Platell ME  Potter IC 《Marine pollution bulletin》2012,64(6):1210-1221

Establishment of a benchmark against which deleterious changes to an estuary can be evaluated requires validating that it has not been subjected to detrimental anthropogenic perturbations and then identifying the biological features which are indicative of a pristine condition and can thus be employed as indicators for detecting and monitoring departures from the natural state. The characteristics of the benthic macroinvertebrate fauna of an essentially pristine, seasonally-open estuary in Western Australia (Broke Inlet) have been determined and compared with those previously recorded for a nearby eutrophic, seasonally-open estuary (Wilson Inlet). Density was far lower in Broke than Wilson. Compositions differed radically at all taxonomic levels, with polychaetes contributing less, and crustaceans more, to the abundance in Broke. Average taxonomic distinctness was greater for Broke than both Wilson and 16 other temperate southern hemisphere estuaries, whereas the reverse was true for variation in taxonomic distinctness, emphasizing that Broke Inlet is pristine.  相似文献   

Diseases leading to accelerated decline of reef corals in the largest South Atlantic reef complex (Abrolhos Bank, eastern Brazil)     

Francini-Filho RB  Moura RL  Thompson FL  Reis RM  Kaufman L  Kikuchi RK  Leão ZM 《Marine pollution bulletin》2008,56(5):1008-1014

Although reef corals worldwide have sustained epizootics in recent years, no coral diseases have been observed in the southwestern Atlantic Ocean until now. Here we present an overview of the main types of diseases and their incidence in the largest and richest coral reefs in the South Atlantic (Abrolhos Bank, eastern Brazil). Qualitative observations since the 1980s and regular monitoring since 2001 indicate that coral diseases intensified only recently (2005–2007). Based on estimates of disease prevalence and progression rate, as well as on the growth rate of a major reef-building coral species (the Brazilian-endemic Mussismilia braziliensis), we predict that eastern Brazilian reefs will suffer a massive coral cover decline in the next 50 years, and that M. braziliensis will be nearly extinct in less than a century if the current rate of mortality due to disease is not reversed.  相似文献   

Sulphur partitioning in sediments and biodeposits below mussel rafts in the Ria de Arousa (Galicia, NW Spain)     

Otero XL  Calvo de Anta RM  Macías F 《Marine environmental research》2006,61(3):305-325

Forty four core samples were analyzed to determine sediment particle size, total organic carbon (TOC), total inorganic carbon (TIC), total nitrogen and total sulphur. Sequential extraction of S was also carried out, differentiating AVS (acid volatile sulphide), elemental S, organic S and pyrite S. The results obtained show that the presence of mussel rafts causes intense changes in the physicochemical composition and properties of the sea floor in the Ria de Arousa. The percentage of silt and clay, TOC, TIC and total N were significantly higher in the biodeposit than in the sediment. In contrast, there were no differences between the biodeposit and the sediment in terms of pH (8.0-8.7) and redox potential. The sediment and biodeposit were always anoxic, with values of redox potentials below -100 mV. In accordance with these conditions, the dominant fraction of S was pyrite S (FeS(2)). The AVS fraction and elemental S were present at low concentrations, except in the uppermost part of each core. Pyrite was relatively stable when the biodeposit and sediment were maintained in suspension for 8 days in oxic sea water; unlike the AVS fraction, which disappeared within a few hours.  相似文献   

清营汤配方颗粒联合阿维A胶囊治疗寻常型银屑病血热证60例临床观察          下载免费PDF全文

谢敬  席建元  李小鹏 《应用海洋学学报》2018,34(7):18-20

目的：观察清营汤配方颗粒联合阿维A胶囊治疗寻常型银屑病血热证的临床疗效。方法：将120例寻常型银屑病血热证患者随机分为治疗组和对照组各60例,对照组予以阿维A胶囊口服,治疗组在对照组治疗的基础上加用清营汤配方颗粒治疗。观察2组综合疗效及治疗前后皮损面积与严重指数（PASI）评分。结果：总有效率治疗组为91.67%,对照组为78.33%,2组比较,差异有统计学意义（P<0.05）;2组PASI评分治疗前后组内比较及治疗后组间比较,差异均有统计学意义（P<0.05）。结论：清营汤配方颗粒联合阿维A胶囊治疗寻常型银屑病血热证疗效满意。  相似文献   

Numerical implementation of a backward probabilistic model of ground water contamination   总被引：4，自引：0，他引：4  

Neupauer RM  Wilson JL 《Ground water》2004,42(2):175-189

Backward location and travel time probabilities can be used to characterize known and unknown sources or prior positions of ground water contamination. Backward location probability describes the position of the observed contamination at some time in the past; backward travel time probability describes the amount of time prior to observation that the contamination was released from its source or was at a particular upgradient location. The governing equation for backward probabilities is the adjoint of the governing equation for contaminant transport, but with new load terms. Numerical codes that have been written to solve the forward equations of contaminant transport, e.g., the advection-dispersion equation, can also be used to solve the adjoint equation for location and travel time probabilities; however, the interpretation of the results is different and some new approximations must be made for the load terms. We present the governing equations for backward location and travel time probabilities, and provide appropriate numerical approximations for these load terms using the cell-centered finite difference method, one of the most popular numerical methods in ground water hydrology. We discuss some additional numerical considerations for the backward model including boundary conditions, reversal of the flow field, and interpretation of the results. We illustrate the implementation of the backward probability model using hypothetical examples in one- and two-dimensional domains. We also present a three-dimensional application of a pump-and-treat remediation capture zone delineation at the Massachusetts Military Reservation. The illustrations are performed using MODFLOW-96 for flow simulations and MT3DMS for transport simulations.  相似文献