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1.
Ana P. Mucha M. Teresa S. D. Vasconcelos Adriano A. Bordalo 《Estuarine, Coastal and Shelf Science》2004,59(4):663
Vertical distribution (0–15 cm) of the macrobenthic community and its relationships to natural sediment characteristics and trace metal contents and bioavailability were studied at five locations in the lower Douro estuary, Portugal. An analysis of vertical metal distribution, for the interpretation of anthropogenic impact on the estuarine sediments, was also investigated. Sediment characterisation included organic matter, grain size, metals (Al, Fe, Cu, Pb, Cr, Ni, Cd, Zn and Mn), acid volatile sulphide (AVS) and simultaneously extracted metals (SEM). The macrobenthic community had low diversity (14 species), was dominated by small size opportunists and seemed to be controlled mainly by natural factors such as grain size distribution, Al and Fe contents and sediment depth. The vertically heterogeneous distribution of macrobenthic community appears to affect redox status of the sediments and consequently metal bioavailability. Despite anthropogenic contamination in terms of Zn, Cu, Pb, Cr and Ni having already been detected in the north bank, the analysis of vertical distribution was essential for the identification of current anthropogenic contamination in terms of Zn, Pb and Cd in the south bank. 相似文献
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Ana P. Mucha C. Marisa R. Almeida Adriano A. Bordalo M. Teresa S.D. Vasconcelos 《Estuarine, Coastal and Shelf Science》2010
This work aimed to evaluate, in vitro, the capability of roots of two salt marsh plants to release low molecular weight organic acids (LMWOAs) and to ascertain whether Cu contamination would stimulate or not organic acids exudation. The sea rush Juncus maritimus and the sea-club rush Scirpus maritimus, both from the lower Douro river estuary (NW Portugal), were used. Plants were collected seasonally, four times a year in 2004, during low tide. After sampling, plant roots were washed for removal of adherent particles and immersed for 2 h in a solution that matched salinity (3) and pH (7.5) of the pore water from the same location to obtain plant exudates. In one of the seasons, similar experiments were carried out but spiking the solution with different amounts of Cu in order to embrace the range between 0 and 1600 nM. In the final solutions as well as in sediment pore water LMWOAs were determined by high performance liquid chromatography. Plants were able to release, in a short period of time, relatively high amounts of LMWOAs (oxalate, citrate, malate, malonate, and succinate). In the sediment pore water oxalate, succinate and acetate were also detected. Therefore, plant roots probably contributed to the presence of some of these organic compounds in pore water. Exudation differed between the plant species and also showed some seasonally variation, particularly for S. maritimus. The release of oxalate by J. maritimus increased with Cu increase in the media. However, exudation of the other LMWOAs did not seem to be stimulated by Cu contamination in the media. This fact is compatible with the existence of alternative internal mechanisms for Cu detoxification, as denoted by the fact that in media contaminated with Cu both plant species accumulated relatively high amounts (29–83%) of the initially dissolved Cu. This study expands our knowledge on the contribution of globally dominant salt marsh plants to the release of LMWOAs into the environment. 相似文献
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Almeida CM Mucha AP Delgado MF Caçador MI Bordalo AA Vasconcelos MT 《Marine environmental research》2008,66(3):311-318
The presence of polycyclic aromatic hydrocarbons (PAHs) may change the mechanisms of metal uptake, thus influencing kinetics and extent of metal phytoextraction. Studies on the subject are scarce, particularly for salt marsh plants. The aim of this work was to investigate the effect of PAHs on the uptake of Cu by Halimione portulacoides, a plant commonly found in salt marshes. Experiments were carried out in the laboratory, either in hydroponics (sediment elutriate) or in sediment soaked in elutriate, which were prepared with sediment and water from a salt marsh of the Cavado river estuary (NW Portugal). Groups of H. portulacoides (grown in a greenhouse) were exposed to those media during six days. Cu(2+) (as Cu(NO(3))(2)), 10(2) and 10(4)mugl(-1), was added to the media as well as 1.6mugl(-1) of the sixteen EPA priority PAHs (0.1mugl(-1) of each PAHs). Cu was assayed in solutions, sediments and different plant tissues before and after experiments. After exposure, photosynthetic efficiency and levels of chlorophylls were also measured, indicating that plant stress indicators were identical in all plants independently of the media to which the plants were exposed. PAHs influenced both the soluble Cu fraction and Cu uptake by plants. The amounts of metal accumulated in both roots and stems were significantly higher when the 10(4)mugl(-1) of Cu enriched elutriate was amended with PAHs. Thus, results suggest that PAHs may modify Cu solubility, the Cu sorption by plants and/or the passive penetration of Cu into the root cells. Therefore, the combined effects of different types of pollutants should be taken in consideration when studying the remediation potential of plants, namely in terms of phytoextraction. 相似文献
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Prof. Dr. V. Mucha DrSc. I. Daubner CSc 《Aquatic Sciences - Research Across Boundaries》1971,33(1):252-268
Zusammenfassung Eine dringliche Notwendigkeit des Aufschwunges der Hydromikrobiologie tritt namentlich in den letzten 25 Jahren der heftigen
Entwicklung der Industrie sowie der Landwirtschaft und von Siedlungen in den Vordergrund. Von der Bereitschaft der Hydromikrobiologen
h?ngt in hohem Masse nicht nur der Schutz der Oberfl?chengew?sser vor unzul?ssiger Verunreinigung und Kontaminierung ab, sondern
auch die Schaffung von Unterlagen für Techniker hinsichtlich der Reinigung von Abw?ssern und F?rderung ihrer Selbstreinigungsvorg?nge.
Zu diesem Zwecke muss man sich wom?glich die neuesten theoretischen Kenntnisse und in der Praxis bew?hrte Methoden der Forschungs-
und Routinearbeit aneignen. Als Beispiel kann die mikroskopische Z?hlung von Mikroben auf Membranfiltern angeführt werden,
mit der die Gesamtzahl der Mikroben in einer Einheit von Wasser sehr genau bestimmt werden kann. Diese Methode soll weiter
entwickelt und auf breiterer Basis zur Geltung gebracht werden.
Gleichfalls bedeutend ist die zweckdienliche Benützung von Membranfiltern zur Kultivation von heterotrophen Mikroben aus dem
Wasser sowie deren prim?re und biochemische Identifizierung direkt auf Membranfiltern.
Das Problem der pathogenen Mikroben in Oberfl?chengew?ssern sowie in Grundw?ssern erscheint auch derzeit nicht nur aus humanmedizinischer,
sondern auch aus veterin?rer Hinsicht progredient wichtig. Deswegen soll man diesem Problem eine erh?hte Aufmerksamkeit widmen,
um die Verbreitung von Enteroinfektionen durch das Wasser als Zwischentr?ger zu verhüten.
Die Bedeutung der Familie Pseudomonadaceae in den Oberfl?chenw?ssern wird derzeit noch untersch?tzt. Es handelt sich hier
um Mikroben, die nicht nur tote organische Stoffe rasch zerlegen, sondern z.T. auch um Arten, die für Menschen, Tiere und
Pflanzen bedingt oder unbedingt pathogen sind. Ausserdem sind diese Arten oder einige ihrer St?mme Antagonisten vonE. coli und einiger Serotypen von Salmonellen. Eine wichtige Tatsache ist auch, dass sie sich bei der Belüftung des Wassers zum Nachteil
der Enterobacteriaceae vermehren.
Die Adaption der Mikroben an ein ihnen fremdes Milieu ist in theoretischer und praktischer Hinsicht ein wichtiges Problem.
Auf Grund morphologischer, physiologischer und biochemischer Ver?nderungen bei Bakterien der Familie Enterobacteriaceae kann
eine bessere M?glichkeit der Beurteilung ihres Indikatorwertes oder ihrer Pathogenit?t im Wasser im Hinblick auf die direkten
und indirekten Bedürfnisse des Menschen erwartet werden. Dazu sind nicht nur ?ltere, sondern haupts?chlich neuere Methoden
notwendig, einschliesslich in erster Reihe die Elektronenmikroskopie und biochemische Methoden für die Bestimmung von metabolischen
und enzymatischen Ver?nderungen der Zellen.
Die Aufgaben der modernen Hydromikrobiologie sind umfangreich und stellen Ansprüche an die Mikrobiologen mit Hinblick auf
theoretische Kenntnisse sowie auf praktische Erfahrungen und Notwendigkeiten. Darum müssen auch im Rahmen der Arbeitsgemeinschaft
Donauforschung der Societas Internationalis Limnologiae (SIL) in den einzelnen Donaustaaten Arbeitsbedingungen geschaffen
werden, welche die Verteilung der Forschungs- und der praktischen Aufgaben an mikrobiologische Laboratorien je nach ihrer
Ausstattung und Bereitschaft der Spezialisten erm?glichen würden.
Summary The importance of aquatic microbiology for the control of water pollution and as a basis for the work of technicians concerned with the purification of sewage and the encouragement of self-purification, has increased greatly during the last 25 years. For this purpose new theoretical knowledge and methods are necessary. An example of this is the microscopic counting of bacteria on membrane filters, their use in the cultivation of heterotrophic bacteria, indicators of faecal pollution, with the basic biochemical identification of colonies on the membrane filter. The problem of pathogenic bacteria in water is becoming increasingly important from both the medical and vetinerary point of view. Among the facultatively pathogenic bacteria, more consideration should be given to the family Pseudomonadaceae. These bacteria are antagonistic to some Enterobacteriaceae (e.g.E. coli, Salmonellae, Shigellae, Serratiae). The study of the adaptation of bacteria to the aquatic environment has both theoretical and practical importance. This includes morphological and physiological changes which make the identification of many bacteria more difficult (e.g. faecal indicators). To solve these problems the Danube Research Group (Arbeitsgemeinschaft Donauforschung der SIL) should create suitable work-conditions for hydromicrobiologists.相似文献
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Study of the influence of different organic pollutants on Cu accumulation by Halimione portulacoides
C. Marisa R. Almeida A. Claúdia Dias Ana P. Mucha A.A. Bordalo M. Teresa S.D. Vasconcelos 《Estuarine, Coastal and Shelf Science》2009
The influence of each of four organic pollutants selected from among those commonly found in coastal areas, 1,1-dichloro-2,2-bis(p-chlorophenyl) ethylene (DDE), monobutyltin (MBT), Triton X-100 and polycyclic aromatic hydrocarbons (PAHs), on Cu accumulation by Halimione portulacoides was investigated. Experiments were carried out in a laboratory setting, either in hydroponics (sediment elutriate) or in a salt marsh sediment (Cávado River, NW Portugal) soaked in elutriate. Groups of H. portulacoides were exposed to media for 6 days spiked with 10 mg/L Cu(II) and with one of the selected pollutants, at an environmentally realistic concentration. DDE and MBT did not cause any major change on Cu accumulation by H. portulacoides, whereas PAHs slightly increased accumulation only in hydroponics i.e. in the absence of sediment. On the other hand, the non-ionic surfactant Triton X-100 markedly favoured Cu accumulation on plant roots both in the presence and absence of sediment. The addition of DDE, MBT and Triton X-100 also favoured Cu solubility from sediments. Therefore, the simultaneous presence of pollutants from different nature (inorganic and organic) in the estuarine environment may result in a composition of water column, pore water, sediment or biota different of that expected considering the effect of each individual pollutant. 相似文献
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A. E. Volvach V. I. Kostenko M. G. Larionov L. N. Volvach D. M. Mucha A. S. Nabatov A. M. Reznichenko 《Bulletin of the Crimean Astrophysical Observatory》2012,108(1):158-162
As part of the scientific cooperation between Ukraine and Russia, a series of studies on the preparation of the ground segment of the RadioAstron mission has been carried out. A scientific program of measurements to be performed using the 22-m RT-22 radio telescope (Crimean Astrophysical Observatory) has been prepared. A substantial part of this program is the study of compact structures in extragalactic sources. Ground-based VLBI test experiments at 6 and 18 cm intended for testing a model of the ground segments of the RadioAstron mission have been carried out at RT-22 of the Crimean Astrophysical Observatory in Simeiz and RT-70 (P-2500) in Evpatoriya. The processing of the data recorded by each antenna resulted in obtaining and calibrating responses of cross-correlation functions using the ASC LPI correlator. The results of the experiment demonstrate the readiness of RT-22 and RT-70 to participate in the ground-space radio interferometer sessions in the RadioAstron mission. 相似文献
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A new expression has been derived for calculation of the magnetic force acting in the space of an oriented matrix of the high-gradient magnetic separator. The matrix geometry and the interaction of the individual matrix elements is taken into consideration. The new method for making visible the elevation of the paramagnetic fluid in the neighbourhood of the matrix rod element, which depends on the magnetic field intensity, allows of verifying theoretical calculations of the magnetic force and determining the direction of its highest effect. 相似文献
9.
L. Bláhová Z. Navrátilová M. Mucha E. Navrátilová V. Neděla 《International Journal of Environmental Science and Technology》2018,15(4):697-706
The removal of Cu(II) and Pb(II) was studied on two types of slags (blast furnace and steelmaking slag) and their modifications prepared by leaching with demineralized water (with contact time 24 and 48 h) and 0.001 mol L?1 HCl solution. The slags and their modifications were characterized by x-ray fluorescence spectroscopy, x-ray diffraction, infrared spectroscopy, and the specific surface area was measured. Environmental scanning electron microscope was used to study the microscopic changes of the slags. The highest removal amounts of Cu(II) were found on the blast furnace slag leached for 48 h. This fact can be explained by the higher specific surface area of the leached blast furnace slag; the removal of Cu(II) is supposed to take place by co-precipitation of its hydroxides or hydroxo-complexes on the slag surface. On the contrary, the modified steelmaking slags exhibit no improvement of the removal properties. The used treatment of the slags decreased the sorption capacities for Pb(II). The original steelmaking slag showed to be the best adsorbent for both metal cations. 相似文献
10.
AP® GIS&T Study Group 《The Journal of geography》2018,117(4):165-173
This article presents the findings of a study to determine the degree of consistency in what is taught and learned in high school and college-level introductory courses in geographic information science and technology (GIS&T). A content analysis identified sixteen topics that are generally representative of the knowledge, skills, and abilities developed in introductory undergraduate courses. The findings were used to propose a standard college-level survey course in GIS&T that could inform future efforts to introduce more academically rigorous GIS&T coursework in high schools, such as through the Advanced Placement Program. 相似文献