Release into the environment of metals by two vascular salt marsh plants   总被引：6，自引：0，他引：6  

Weis P  Windham L  Burke DJ  Weis JS 《Marine environmental research》2002,54(3-5):325-329

Metals in contaminated salt marshes are mainly locked in the anaerobic layer of sediments, where they are tightly bound as sulfides and organic complexes. Vascular plants survive in saturated soils in part by pumping O2 into their root zones, changing their microenvironment to an oxic one. This, along with chelating exudates, mobilizes metals, allowing uptake by the roots. We compared the common reed Phragmites australis and cordgrass Spartina alterniflora in lab and field studies for ways in which they handle trace metals. Both plants store most of their metal burden in their roots, but some is transported to aboveground tissues. Spartina leaves contain approximately 2-3 x more Cr, Pb, and Hg than Phragmites leaves, but equivalent Cu and Zn. Furthermore, Spartina leaves have salt glands, so leaf excretion of all metals is twice that of Phragmites. In-depth studies with Hg indicate that Hg excretion correlates with Na release but not with transpiration, which is 2.2 x higher in Phragmites; and that more Hg accumulates in early-appearing leaves than in upper (i.e. later) leaves in both species. Spartina thus makes more metals available to salt marsh ecosystems than Phragmites by direct excretion and via dead leaves which will enter the food web as detritus.  相似文献   

假单胞菌(Pseudomonas sp.cn4902)磷酸甘油磷酸酯酶基因克隆与鉴定     

刘广发  张会永  谢金镇 《海洋与湖沼》2005,36(4):313-318

采用随机克隆、功能筛选、逐次排除和同源比较的基因克隆新策略进行克隆假单胞菌(Pseudomonas sp．cn4902)磷酸甘油磷酸酯酶基因的研究。结果表明，该结构基因长819bp，与铜绿假单胞菌的磷酸甘油磷酸酯酶基因的核苷酸一致性达61．5％，氨基酸同源性为56．2％。该基因已输入GenBank数据库，收录号AF348165。将该基因转化大肠杆菌，受体菌在含NaCl 1．0mol／L的培养基中甘油含量升高2．9倍，最终菌浓度提高3．6倍。可见这是一个与生物耐盐性相关的主基因，以其转化、培育耐盐农作物的前景十分光明。  相似文献   

柴达木盆地第三系咸水湖相生油岩古沉积环境地球化学特征   总被引：9，自引：0，他引：9  

叶爱娟  朱扬明 《海洋与湖沼》2006,37(5):472-480

在系统分析柴达木盆地西部第三系咸水湖相生油岩样品的微量元素、有机物、粘土矿物组成的基础上,揭示了研究区生油岩的无机元素和有机质组成特征;并结合沉积环境的无机与有机地球化学指标,重建了生油岩沉积时的古沉积环境。生油岩的B、Cl-及伽玛蜡烷含量表明,沉积时的水介质条件是半咸水—咸水环境,并伴随湖盆沉积中心北迁过程各层位地层的盐度发生规律性时空]化;生油岩的Fe2 /Fe3 、S2-、Pr/Ph比值、藿烷碳数分布模式及黄铁矿含量反映其沉积时的沉积环境为强还原性;粘土矿物组合特征及含量揭示这些生油岩的沉积相带介于中心咸湖相和边缘咸湖相之间。  相似文献   

The impact of salt water inflows on the distribution of polycyclic aromatic hydrocarbons in the deep water of the Baltic Sea     

Gesine Witt  Wolfgang Matthus 《Marine Chemistry》2001,74(4):246

Salt-water inflows into the Baltic Sea are important events for renewing the deep and bottom waters of the deep basins of the Baltic Sea. These events occur only at irregular intervals. The last strong event was in January 1993 followed by minor inflows in winter 1993/1994. As a result of these inflows, the deep water of the central Baltic basins was completely renewed.Based on extensive observations of polycyclic aromatic hydrocarbons (PAHs) in water, fluffy layer material and surface sediments between 1992 and 1998, the transformation of PAHs and the modification of their distribution in the Baltic deep water is discussed in connection with the spreading of the inflowing highly saline and oxygen-rich water along its pathway from the sills into the central basins. In the course of the inflows in 1993/1994, the PAH concentration in the deep water of the different basins increased significantly. The concentrations were elevated, at least by a factor of 2 and as much as seven to eight times (for the four-ring PAHs) compared to the previous and the following years. Two hypotheses for the causes were discussed: the inflowing salt water may have entrained more highly polluted surface water in the western Baltic Sea, or it may have entrained contaminated fluffy layer material or sediment particles along the route of transport.  相似文献   

Nature of the connection between the Northern and Southern Zechstein Basins across the Mid North Sea High     

M.K. Jenyon  P.M. Cresswell  J.C.M. Taylor 《Marine and Petroleum Geology》1984,1(4):355-363

The seismic expression of a salt-filled channel which cuts across the Mid North Sea High in Quadrant 37 is described, with features interpreted as being produced by salt-edge dissolution forming both eastern and western margins of the channel. The apparent half-graben nature of the channel is shown to be only superficial, and due to complex faulting associated with, but not defining, its western margin. The shallower faulting here is a Mesozoic to early Tertiary growth fault related to local dissolution of Zechstein salt. The dissolution effect appears in turn to have been localized by the presence of a deeper fault that was already downthrown to the east in Zechstein times, when it seems to have limited the eastward progradation of Zechstein shelf carbonates and anhydrites, and had probably ceased to move significantly before the onset of the Late Cimmerian erosional phase. The origin of this arcuate fault is tentatively ascribed to subsidence around a granite batholith. Zechstein salt originally spread some distance to the east and west of the channel; it was dissolved from the edges inwards, mainly before the Late Cretaceous, giving rise to a thicker Mesozoic sequence on parts of the flanks of the channel than in the middle. Besides providing an interesting structural case history, the features described have implications regarding Zechstein sedimentation, reservoir potential, the tectonic history of the North Sea, and the nature of the Mid North Sea High itself.  相似文献   

中国北方盐田和盐湖高盐水域藻类的初步研究   总被引：3，自引：0，他引：3  

马志珍 《海洋与湖沼》1995,26(3):317-322

于１９８６年３月－１９９０年９月，对中国北方一些盐田和盐湖的高盐水域（盐度６１．０－３２０．０）中的藻类（主要是浮游藻）进行调查。在青岛东风盐场和天津汉沽盐场每月２次定点采集藻类标本水样７２份以及随机在山西解地、青海尕海，新疆达板城盐湖和巴里坤湖采集水样５份。鉴定出蓝藻５种，绿藻８种，硅藻８种。结果表明，均是典型的耐盐或喜盐种类，但其种的多样与水体的盐度呈负相关，藻类种群生物量以春季和秋季最为丰富  相似文献   

Comparative tolerance of two estuarine annelids to fluoranthene under normoxic and moderately hypoxic conditions     

Weinstein JE  Sanger DM 《Marine environmental research》2003,56(5):637-648

The tolerance of the oligochaete Monopylephorus rubroniveus and the polychaete Streblospio benedicti to sediment-associated fluoranthene was characterized under normoxic (>80% dissolved oxygen saturation) and moderately hypoxic ( approximately 50% dissolved oxygen saturation) conditions. Under both conditions, M. rubroniveus was highly tolerant of fluoranthene. Streblospio benedicti was considerably less tolerant of fluoranthene compared with M. rubroniveus. In addition, S. benedicti was less tolerant to fluoranthene under moderately hypoxic conditions, although no differences in sensitivity between the two oxygen conditions were observed based upon median lethal tissue residues. Bioaccumulation factors were higher for S. benedicti exposed to moderate hypoxia, suggesting that behavioral adaptations to compensate for the lower dissolved oxygen increased its bioaccumulation of fluoranthene. The results of the present laboratory study demonstrate that (1). changes in annelid tolerance to fluoranthene under varying oxygen conditions is a species-dependent phenomenon and (2). the differential tolerance of these two annelids to these combined stressors is consistent with their relative abundances in the field.  相似文献   

Retention of arsenic and phosphorus in iron-rich concretions of Tagus salt marshes   总被引：1，自引：0，他引：1  

Miguel Caetano  Carlos Vale 《Marine Chemistry》2002,79(3-4)

Iron-rich concretions are frequently found around plant roots in Tagus estuary (Portugal) where radial delivery of O₂ takes place. Salt marsh sediments exhibit cracks that are an additional feature to introduce O₂ and other solutes in the upper sediments. Metal concentrations in salt marsh sediments are clearly above the background levels reflecting the anthropogenic sources from a large city with 2.5 million inhabitants, and several industrial centres. In order to evaluate how both oxidised structures influences the redistribution of redox sensitive elements in salt marsh sediments, concretions were collected from roots of Halimione portucaloides below the oxygenated zone. These tubular cylindrical structures were analysed for Fe, Al, Mn, As, and P along 1-cm radial transect in a millimetre scale from the inner part to the adjacent anoxic sediment. In addition, oxidised cracks were analysed for the same spatial resolution, from the sediment–water interface to anoxic layers (2-cm transept). The parallelism between Fe, As, and P concentrations at this microscale is the most noticeable aspect. Iron and As presented very high concentrations in the 4-mm concretions (3.4 mmol g⁻¹ and 3.1 μmol g⁻¹, respectively) and decreased sharply to the host sediment. Oxygen released from roots oxidise the solid sulphides, and the reduced Fe and As are transported towards the root by both diffusion and pore water flow associated with the root water uptake. Subsequently, Fe(III) precipitates and As is retained by sorption and/or coprecipitation. These elements are also enriched in the first 2-mm of oxidised cracks, but in lower concentrations (50% and 30%, respectively). Manganese concentrations in concretions were low (11.8 μmol g⁻¹), indicating that Fe dominates the sediment chemistry. Phosphorus and iron concentrations in the ascorbate fraction were higher in the oxidising surfaces of concretions (10.7 μmol g⁻¹ and 1.6 mmol g⁻¹, respectively) and of cracks (5.1 μmol g⁻¹ and 0.47 mmol g⁻¹). The parallelism of Fe and As distributions includes not only their similar redox chemistries, but also that to phosphate, including control by coprecipitation of the host iron phases. The mechanisms involved in the mobilisation of As and P are however different, whereas As comes from the oxidation of iron sulphides; dissolved P derives from reduction of ferri-hydroxide phases.  相似文献   

Salt Diapirs, Salt Brine Seeps, Pockmarks and Surficial Sediment Creep and Slides in the Canary Channel off NW Africa     

J. Acosta  E. Uchupi  A. Muñoz  P. Herranz  C. Palomo  M. Ballesteros 《Marine Geophysical Researches》2003,24(1-2):41-57

Circular to elliptical mounds in the Canary Channel with reliefs of 75 to 375 m and diameters of 4 to 8 km partially surrounded by moats with reliefs of 25 to 75 m, were formed by piercement of the seafloor by Mesozoic evaporites. Several long gullies, < 1km wide, with abrupt terminations and pockmarks associated with these mounds were probably eroded by dense brine and hydrocarbon seeps. The salt brines that eroded the gullies were formed where salt diapirs intersect the seafloor, or in the subsurface by circulating ground water heated by igneous activity along the Canary Ridge. If the brines originated in the subsurface they reached the seafloor along faults. Displacement of the surficial sediments by sliding and creep is probably the result of the expulsion of hydrocarbons and/or vertical motion of the Mesozoic evaporites. Microtopographic features along or near the east flank of the Canary Ridge are the creation of uplift of the ridge, hydrothermal activity, mass wasting processes and turbidity currents.  相似文献   

我国海水制盐工艺改革的设计研究     

周仲怀  徐丽君  于银亭  王建华  于廷芳  王继业  殷丽 《海洋科学》1997,21(6):43-46

从技术上和工艺上的可能性、可行性和合理性，论证了海水制盐工艺改革的必要性，并且提出了实现海水制盐工艺改革的各种设计方案。它对我国的海水制盐工业的发展将具有深远意义。  相似文献