Degradation and Transformation of Aquatic Humic Substances by Laccase-producing Fungi Cladosporium cladosporioides and Polyporus versicolor     

H. Claus  Z. Filip 《洁净——土壤、空气、水》1998,26(3):180-185

A phenoloxidase-producing fungus – Cladosporium cladosporioides – was isolated from water of a bog lake. At high concentrations of carbon (333 mM) and nitrogen (12 mM), the fungus demonstrated the formation of a laccase and a high ligninolytic activity. After addition of riverine or groundwater humic substances into culture media (ca. 1 mg mL^–1), the fungus showed the ability of degrading (utilizing) of about 60% of these substances. However, the exact quantification of the degree of degradation was difficult because of adsorption of humic matter on fungal mycelium. Reisolated humic substances were lower in aromatic and higher in aliphatic structures. A crude enzyme from the C. cladosporioides culture showed only low activity in decolorizing humic substances, whereas decolorization up to 50% was observed when using a laccase preparation from Polyporus versicolor, and especially in the presence of a redox mediator.  相似文献   

Coordinated Ocean-ice Reference Experiments (COREs)     

Stephen M. Griffies  Arne Biastoch  Claus Böning  Frank Bryan  Gokhan Danabasoglu  Eric P. Chassignet  Matthew H. England  Rüdiger Gerdes  Helmuth Haak  Robert W. Hallberg  Wilco Hazeleger  Johann Jungclaus  William G. Large  Gurvan Madec  Anna Pirani  Bonita L. Samuels  Markus Scheinert  Alex Sen Gupta  Camiel A. Severijns  Harper L. Simmons  Jianjun Yin 《Ocean Modelling》2009,26(1-2):1-46

Coordinated Ocean-ice Reference Experiments (COREs) are presented as a tool to explore the behaviour of global ocean-ice models under forcing from a common atmospheric dataset. We highlight issues arising when designing coupled global ocean and sea ice experiments, such as difficulties formulating a consistent forcing methodology and experimental protocol. Particular focus is given to the hydrological forcing, the details of which are key to realizing simulations with stable meridional overturning circulations.The atmospheric forcing from [Large, W., Yeager, S., 2004. Diurnal to decadal global forcing for ocean and sea-ice models: the data sets and flux climatologies. NCAR Technical Note: NCAR/TN-460+STR. CGD Division of the National Center for Atmospheric Research] was developed for coupled-ocean and sea ice models. We found it to be suitable for our purposes, even though its evaluation originally focussed more on the ocean than on the sea-ice. Simulations with this atmospheric forcing are presented from seven global ocean-ice models using the CORE-I design (repeating annual cycle of atmospheric forcing for 500 years). These simulations test the hypothesis that global ocean-ice models run under the same atmospheric state produce qualitatively similar simulations. The validity of this hypothesis is shown to depend on the chosen diagnostic. The CORE simulations provide feedback to the fidelity of the atmospheric forcing and model configuration, with identification of biases promoting avenues for forcing dataset and/or model development.  相似文献   

Assessment of susceptibility to landslides through geographic information systems and the logistic regression model     

Riegel  Roberta Plangg  Alves  Darlan Daniel  Schmidt  Bruna Caroline  de Oliveira  Guilherme Garcia  Haetinger  Claus  Osório  Daniela Montanari Migliavacca  Rodrigues  Marco Antônio Siqueira  de Quevedo  Daniela Muller 《Natural Hazards》2020,103(1):497-511

Natural Hazards - The increase in the frequency of natural disasters in recent years and its consequent social, economic and environmental impacts make it possible to prioritize areas of risk as an...  相似文献   

Large microplastic particles in sediments of tributaries of the River Thames,UK – Abundance,sources and methods for effective quantification     

Alice A. Horton  Claus Svendsen  Richard J. Williams  David J. Spurgeon  Elma Lahive 《Marine pollution bulletin》2017,114(1):218-226

Sewage effluent input and population were chosen as predictors of microplastic presence in sediments at four sites in the River Thames basin (UK). Large microplastic particles (1 mm–4 mm) were extracted using a stepwise approach to include visual extraction, flotation and identification using Raman spectroscopy. Microplastics were found at all four sites. One site had significantly higher numbers of microplastics than other sites, average 66 particles 100 g^? 1, 91% of which were fragments. This site was downstream of a storm drain outfall receiving urban runoff; many of the fragments at this site were determined to be derived of thermoplastic road-surface marking paints. At the remaining three sites, fibres were the dominant particle type. The most common polymers identified included polypropylene, polyester and polyarylsulphone. This study describes two major new findings: presence of microplastic particles in a UK freshwater system and identification of road marking paints as a source of microplastics.

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This study is the first to quantify microplastics of any size in river sediments in the UK and links their presence to terrestrial sources including sewage and road marking paints.  相似文献   

The emergence of equatorial deep jets in an idealised primitive equation model: an interpretation in terms of basin modes     

Jan-Dirk Matthießen  Richard John Greatbatch  Martin Claus  François Ascani  Peter Brandt 《Ocean Dynamics》2017,67(12):1511-1522

Ocean circulation models do not generally exhibit equatorial deep jets (EDJs), even though EDJs are a recognised feature of the observed ocean circulation along the equator and they are thought to be important for tracer transport along the equator and even equatorial climate. EDJs are nevertheless found in nonlinear primitive equation models with idealised box geometry. Here we analyse several such model runs. We note that the variability of the zonal velocity in the model is dominated by the gravest linear equatorial basin mode for a wide range of baroclinic vertical normal modes and that the EDJs in the model are dominated by energy contained in vertical modes between 10 and 20. The emergence of the EDJs is shown to involve the linear superposition of several such neighbouring basin modes. Furthermore, the phase of these basin modes is set at the start of the model run and, in the case of the reference experiment, the same basin modes can be found in a companion experiment in which the amplitude of the forcing has been reduced by a factor of 1000. We also argue that following the spin-up, energy must be transferred between different vertical modes. This is because the model simulations are dominated by downward phase propagation following the spin-up whereas our reconstructions imply episodes of upward and downward propagation. The transfer of energy between the vertical modes is associated with a decadal modulation of the EDJs.  相似文献   

Volcanic stratigraphy of a high-altitude Mammuthus columbi (Tlacotenco,Sierra Chichinautzin), Central México     

Marie-Noelle Guilbaud  Lilia Arana-Salinas  Claus Siebe  Luis Alberto Barba-Pingarrón  Agustín Ortiz 《Bulletin of Volcanology》2015,77(3):1-16

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Cryptogam covers on sepulchral monuments and re-colonization of a marble surface after cleaning     

Christine Hallmann  Wanja Wedekind  Dorothea Hause-Reitner  Michael Hoppert 《Environmental Earth Sciences》2013,69(4):1149-1160

Re-colonization of freshly cleaned surfaces by aeroterrestrial microbial communities is up to now poorly understood. Here, we present a comparative study addressing the composition of algal and fungal communities on a marble sculpture, based upon the analysis of 18S rRNA gene clone libraries from environmental samples. The samples were taken from a blackish and greenish biofilm cover before surface cleaning and 1 year after cleaning treatment, when traces of re-colonization became visible to the naked eye. The composition of the fungal community indicated clear differences between the old grown biofilm and the treated surface. While the former was dominated by the ascomycetes Rhinocladiella, Glyphium and Capnodiales, the black yeast Sarcinomyces was clearly dominant 1 year after cleaning, but could not be retrieved from the old grown black biofilm. The green algal community was dominated by different phylotypes of the lichen algae Trebouxia, as well as the cosmopolitan green algae Apatococcus and Stichococcus. No essential differences in the green algal community before and after cleaning could be observed.  相似文献   

Moisture expansion associated to secondary porosity: an example of the Loseros Tuff of Guanajuato, Mexico   总被引：2，自引：2，他引：0  

Rubén López-Doncel  Wanja Wedekind  Reiner Dohrmann  Siegfried Siegesmund 《Environmental Earth Sciences》2013,69(4):1189-1201

The old mining city of Guanajuato in middle Mexico preserves one of the most important historical legacies in colonial buildings, the UNESCO declared the city World Heritage Site in 1988. Practically all the colonial constructions were built with natural stones from the neighbourhood, of which stands a greenish to reddish vulcanite, called Loseros Tuff. Although the Loseros Tuff is widely used in historical buildings in the city. It shows significant deterioration and weathering effects, principally in the parts where the tuff shows a coarse grain size. The petrographic, petrophysical, mineralogical and geochemical properties of the Loseros Tuff were analysed in order to determine the causes, effects, behaviour and response to deterioration of this volcanic rock. The results of the investigations suggest that in addition to the parameters like the grain size and the porosity properties, the pore radii distribution is decisive for the effectiveness of porosity and the water transport into the rock. It is recognized that once the liquid water invades the rock the dissolution of the matrix occurs, which is accompanied by a sudden moisture expansion favoured by the newly formed secondary porosity and the high content of expandable clay minerals.  相似文献   

A high-resolution stellar library for evolutionary population synthesis     

Lucimara P. Martins  Rosa M. González Delgado  Claus Leitherer  Miguel Cerviño  Peter Hauschildt 《Monthly notices of the Royal Astronomical Society》2005,358(1):49-65

We present a library of 1654 high-resolution stellar spectra, with a sampling of 0.3 Å and covering the wavelength range from 3000 to 7000 Å. The library was computed with the latest improvements in stellar atmospheres, incorporating non-local thermodynamic equilibrium (non-LTE) line-blanketed models for hot, massive  ( T _eff≥ 27 500 K)  and line-blanketed models for cool  (3000 ≤ T _eff≤ 4500 K)  stars. The total coverage of the grid is  3000 K ≤ T _eff≤ 55 000 K  and  −0.5 ≤ log g ≤ 5.5  , for four chemical abundance values: twice solar, solar, half solar and 1/10 solar. Evolutionary synthesis models using this library are presented in a companion paper. We tested the general behaviour of the library by calculating and comparing equivalent widths of numerous H and He  i lines, and some of the commonly used metallic indices. We also compared the library with the empirical libraries STELIB and Indo-US. The full set of the synthetic stellar spectra is available from our websites ( http://www.iaa.csic.es/~rosa and http://www.astro.iag.usp.br/~lucimara/library.htm ).  相似文献   

Thermal expansion on volcanic tuff rocks used as building stones: examples from Mexico     

Rubén López-Doncel  Wanja Wedekind  Alfredo Aguillón-Robles  Reiner Dohrmann  Sergio Molina-Maldonado  Theresa Leiser  Anna Wittenborn  Siegfried Siegesmund 《Environmental Earth Sciences》2018,77(9):338

Three cities in the center of Mexico, declared as cultural heritage, were erected mainly of volcanic tuffs as main construction element. Many of the historic buildings of these cities show significant damage and deterioration. One of the causes of these damages can be attributed to a phenomenon poorly studied in volcanic tuffs, the thermal expansion. To understand the response of volcanic tuffs to thermal expansion, as well as to know their thermal expansion coefficient, thermal expansion test was performed on 12 representative tuffs of these localities. In the same way and to know which of their petrographic, petrophysical, mineralogical, and geochemical properties influence this phenomenon, several laboratory studies were carried out to determine which of these plays an important role in the expansion. The results of our tests showed that volcanic tuffs rocks have very varied thermal expansion values, ranging from 0.7 mm/m at their maximum expansion to even contraction in the order of ??0.5 mm/m. Equally varied were the thermal expansion coefficient values ranging from 10.1 to ??7.2 10^?6/K. The most dominant behavior type is the “anisotropic no residual strain behavior”. In general, the behavior of the tuffs in practically all the tests carried out showed a very important heterogeneity in the rocks; however, in spite of the non-homogeneous behavior of the tuffs, three main factors could be identified that play an important role in the thermal expansion of the studied rocks, the chemical composition, e.g., acid volcanic tuff rocks (rhyolitic composition) had greater expansions, while the more basic rocks (basaltic composition) expanded less, the textural and fabrics homogeneity, e.g., the most homogeneous rocks texturally have higher expansion values and the degree of crystallinity, and, e.g., the tuff rocks with the largest amount of glass showed smaller thermal expansions than the tuffs composed of microcrystals.  相似文献