Aerobic microbial activity in surface sediments containing high or low concentrations of zinc taken from Dublin Bay,Ireland     

A.H. Pickaver  M.C. Lyes 《Estuarine, Coastal and Shelf Science》1981,12(1):13-22

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The transport of bacteria in the sediments of a temperate marsh     

Parke A. Rublee  Susan M. Merkel  Maria A. Faust 《Estuarine, Coastal and Shelf Science》1983,16(5):501-509

The number of bacteria in sediments, interstitial water and overlying tidal water of an oligohaline marsh system are about 10⁹, 10⁶ and 10⁶ cells cm^?3, respectively. Average cell size in the overlying water (about 0·06 μm³), is much smaller than that in sediments and interstitial water (about 0·18 μm³). Most bacterial cells in sediments are bound to sediment particles and less than 1% of the cells were displaced by percolating water through sediment columns. Concentration of bacteria in flooding tidal waters is generally higher than that in ebbing waters. Movement of bacterial biomass does not appear to be a significant mechanism of particulate organic transport in marsh sediments and marsh sediments do not appear to be a source of suspended bacteria for estuaries.  相似文献   

Autotrophic and heterotrophic abundance and activity associated with a nearshore front off the Georgia coast,U.S.A.     

T.R. Jacobsen  L.R. Pomeroy  J.O. Blanton 《Estuarine, Coastal and Shelf Science》1983,17(5):509-520

The nearshore frontal zone off the coast of Georgia was found to be an area of high phytoplankton and bacterioplankton abundance and activity. Phytoplankton and bacterioplankton populations on the seaward side of the frontal zone had significantly higher photosynthetic and heterotrophic potentials than the nearshore side of the front. Phytoplankton species composition changed across the front, verifying that the front is a barrier to cross shelf mixing. Nearshore, large chain forming diatoms dominated, while smaller single cell diatoms and cyanobacteria dominated the seaward side of the front. Increased bacterioplankton activity was found associated with phytoplankton photosynthetic activity. Light appeared to be the major factor controlling photosynthesis across the frontal zone. Nitrogen, phosphorus and silica were present in similar concentrations, well above levels that would limit photosynthesis, on both sides of the front. Therefore the outflow of nutrients from rivers or estuaries did not influence primary production directly.  相似文献   

Applicability and Limits of Bioremediation of Contaminated Groundwater by Organic Compounds     

Taboure Aboubacar  LIN Xueyu 《世界地质(英文版)》2001,4(1)

This paper gives in some ways a broad look at the Bioremediation Technology in the treatment of polluted groundwater. Environmentalists and Hydrologeologists around the world, especially in the developed countries welcomed this revolutionizing technique at a moment when other methods were becoming rather expensive and sources of secondary and more challenging pollution problems across sole fresh groundwater. Bioremediation of contaminated groundwater is based on the use of bacteria which breakdown organic matters to more stable forms, which will not create nuisance or give off foul odors. The Applicability of this technology at a specific site lies in the understanding of the site's hydrogeologic, physiochemical backgrounds and the knowledge of the properties of the designated bacteria colonies, which would likely stabilize the contaminants. These are key points, which determine the success of the all process. Only, by complying with all those measures, Bioremediation can meet all the expectations.  相似文献   

Effects of Heavy Metal Contamination on Microbial Biomass and Community Structure in Soils   总被引：5，自引：0，他引：5  

杨元根  刘丛强  徐磊  吴攀  张国平 《中国地球化学学报》2004,23(4):319-328

Theeco environmentalpollutioncausedbyminingdevelopmentisaworldwideproblem ,whichhasarousedever increasingattentionofscientists.Inadditiontovegetationdestructionanderosionofcultivatedlanddirectlycausedbyminingdevelopment,scientistshaveplacedmorefocusontheenvironmentalproblemsinducedbythereleaseofharmfulsubstances ( particularlyheavymetals) .Especiallyundersurfaceconditions,thepiled upminewastes (minetailings)undergoweatheringundertheactionofaseriesofgeochemicalfactorssuchasthemineralogyofmineta…  相似文献   

Tepee-shaped agglutinated microbialites: an example from a Famennian carbonate platform on the Lennard Shelf, northern Canning Basin, Western Australia   总被引：1，自引：0，他引：1  

Nancy Chow  Annette D. George† 《Sedimentology》2004,51(2):253-265

Distinctive, metre‐scale antiformal structures are well developed in a Famennian carbonate platform in the Chedda Cliffs area of the Lennard Shelf reef complexes. The structures are distinguished by chevron‐shaped crests and thickened cores and contain abundant non‐skeletal allochems (ooids/pisoids, peloids and intraclasts) of silt to pebble size and variably developed laminations and fenestrae. The internal morphology and pervasive occurrence of fenestral clotted and wavy laminated fabrics suggest that these structures are microbial mounds composed of agglutinated stromatolites and thrombolites. Microbial fabrics most probably originated through sediment trapping and binding by microbial mats with early lithification involving microbial calcification and cementation of trapped sediment. The facies and stratigraphic context of the mounds support a shallow subtidal, transitional backreef to reef‐flat setting; however, alone these mounds do not provide unequivocal environmental information. Other large antiformal structures in Famennian platforms on the Lennard Shelf, previously described as tepee structures, show morphological similarities to the Chedda Cliffs mounds, which suggests that these other structures may also be microbial mounds. The presence of microbial mounds in platform successions further highlights the importance of microbial communities in the Lennard Shelf reef complexes.  相似文献   

土壤石油污染的生物修复技术   总被引：8，自引：3，他引：8  

叶为民  孙风慧 《上海国土资源》2002,(4):22-24,57

采用生物修复技术对土壤石油有机污染进行治理以效率高、安全性好、无二次污染、易于管理而受重视。文章结合国内外的最新研究成果。对生物修复的处理过程、技术工艺等方面进行了论述。  相似文献   

微生物采油及其作用机理   总被引：9，自引：0，他引：9  

王岚 《世界地质》2002,21(2):139-141

微生物采油经过70多年发展，已成为继热驱，化学驱，气驱之后的第四种提高采收率的方法，其提高采收集方式有地面法和地下法两种，特点是成本低，效果好，无污染。其采油机理为：一是改变原油组成，二是改善驱油环境，最终使原油流向井底，提高采收率。  相似文献   

Late diagenetic calcitization of anhydrite from the Mississippian of Saskatchewan, western Canada     

Alan C. Kendall 《Sedimentology》2001,48(1):29-55

Mississippian nodular anhydrites beneath an unconformity in the subsurface of southern Saskatchewan are locally replaced by calcite, pyrite and celestite. Triassic clastics above the unconformity are green, rather than red, and a usually developed subunconformity alteration zone (where carbonates are dolomitized, and porosity is filled with anhydrite) is absent. The unconformity lacks karstic features (unlike in the USA), and probably formed in a hyperarid climate. Mississippian anhydrites near the unconformity are not preferentially dissolved, nor were they extensively hydrated. Anhydrite calcitization occurred only after the unconformity was shallowly buried by redbeds, and it probably involved sulphate-reducing bacteria. Hydrogen sulphide, generated by bacteria, reduced redbed pigments. The replacement calcite contains pseudomorphs and relicts of anhydrite, and pseudomorphs of secondary gypsum. These indicate calcitization occurred only after original Mississippian gypsum was altered to anhydrite and this, in turn, was partially converted back to secondary gypsum beneath the unconformity. Replacement occurred concurrently with the formation elsewhere of the dolomitized zone beneath the unconformity. Sulphur isotopic ratios of replacement pyrite are depleted relative to Mississippian sulphate values, consistent with the activities of sulphate-reducing bacteria. Carbon isotopic ratios of replacive calcites, however, do not support this interpretation, and are identical to those of Mississippian limestones. Simple replacement of sulphate by pore-water bicarbonate (in equilibrium with host limestones) is unlikely because protons generated during the reaction should have created acidic conditions in which calcite would have dissolved. A full explanation of the calcitization remains elusive, but may involve replacement occurring in an active groundwater system and/or bacterial sulphate reduction occurring upstream of the site of calcitization.  相似文献   

Microbially induced cementation of carbonate sands: are micritic meniscus cements good indicators of vadose diagenesis?   总被引：4，自引：0，他引：4  

Heiko Hillgärtner  Christophe Dupraz  & Wolfgang Hug 《Sedimentology》2001,48(1):117-131

Characteristic fabrics such as micrite envelopes, calcified filaments and micritic grain-to-grain bridges are observed in a modern subtidal firmground (Wood Cay, Bahamas) and in a variety of firm- and hardgrounds of Lower Cretaceous and Upper Jurassic platform carbonates (Swiss and French Jura Mountains). Their similarity to microbial fabrics described in grapestones and in intertidal to continental vadose environments suggests that microbial activity played an important role in the initial stabilization and cementation of carbonate sands. 'Meniscus-type cements' (to distinguish them from vadose meniscus cements), which clearly formed in subtidal environments, are related to filament calcification, trapping of percolating micrite and microbially induced carbonate formation. Such meniscus-type cements are commonly micritic, but meniscus-shaped precipitation of fibrous aragonite or sparitic calcite around organic filaments is also observed. Therefore, an interpretation of vadose early diagenesis should not be based on meniscus cements alone. Similarly, subtidally formed filamentous structures can strongly resemble alveolar septal structures and be interpreted incorrectly as related to subaerial exposure.  相似文献