排序方式: 共有50条查询结果,搜索用时 31 毫秒
21.
Pierre A. Maron Christophe Mougel David P. H. Lejon Esmeralda Carvalho Karine Bizet Graldine Marck Nadge Cubito Philippe Lemanceau Lionel Ranjard 《Atmospheric environment (Oxford, England : 1994)》2006,40(40):8074-8080
Temporal airborne bacterial genetic community structure and meteorological factors were analysed above an urban area in the northwest of France from December 2003 to April 2004 with a sampling strategy considering different time intervals (from an hour to a month). Principal component analysis (PCA) of B-ARISA (Bacterial-Automated Ribosomal Intergenic Spacer Analysis) profiles revealed a hierarchy in the temporal variability of bacterial community: daily<weekly<seasonal. Co-inertia analysis between B-ARISA data and meteorological factors demonstrated the correlation between the seasonal variability in the bacterial community and climatic conditions such as temperature and relative humidity, whereas daily and weekly variability seemed likely to be managed by other factors such as anthropogenic activities. 相似文献
22.
The EU directives on air quality force member states to inform the public on the status of the ambient air quality. The Internet is commonly used for this purpose and often air quality is being presented as an index ranging from good to bad. A review of existing websites and air quality indices shows that the way air quality is interpreted differs considerably. The paper presents a new air quality index. The index is part of a project to develop a website dedicated to comparing air quality in European cities. The common air quality index (CAQI) is not aimed at replacing existing local indices. The CAQI is a set of two indices: one for roadside monitoring sites and one for average city background conditions. Differentiating between roadside and general city conditions is a first step in assuring consistence in the parameters that are being compared. 相似文献
23.
We studied the adsorption and desorption of two pesticides, namely isoproturon and dimetomorph, onto a model soil sample.
We first show that the adsorption of isoproturon depends on pH, from 1 mg g−1 at pH 4 to 2 mg g−1 at pH 10, contrary to the adsorption of dimetomorph (5.8 mg g−1). We also studied the influence of metallic cations, copper(II), iron(III), manganese(II), and chromium(III), on the sorption
of isoproturon and dimetomorph. We found that in the case of isoproturon, the presence of metallic cations does influence
the retention capacity of the soil sample. The sorption becomes very weak in the presence of copper and chromium, whereas
in the case of iron and manganese the sorption properties are slightly modified. 相似文献
24.
The capacity for long-distance dispersal is an important factor in determining the spread of invasive species. For algae,
positive buoyancy generally is correlated with increased dispersal potential, and the light environment has been previously
identified as a possible determinant of buoyancy in several species. We examined the effect of light intensity on the buoyancy
of fragments of the invasive green alga Codium fragile ssp. fragile. Under natural and controlled conditions, the buoyancy of samples taken from the thallus tip was higher than those from near
the holdfast. Both laboratory and field experiments also showed that buoyancy was dynamic and switched from positive to negative
under reduced light intensity, but this change required several days. We also observed seasonal changes in buoyancy, presumably
due to natural variations in light intensity, with the buoyancy of fragments washed up on the shore highest in mid-summer.
These results show that buoyancy is a dynamic property of the C. fragile ssp. fragile thallus and suggest that buoyant fragments contribute to long-range dispersal and accelerated regional spread of this invader.
This finding suggests that dispersal is more likely during conditions of high light intensity and illustrates the need to
understand how variations in the natural environment can affect the dispersal potential of invasive species. 相似文献
25.
26.
Effects of pesticides on soil enzymes: a review 总被引:4,自引:0,他引:4
Wassila Riah Karine Laval Emilie Laroche-Ajzenberg Christian Mougin Xavier Latour Isabelle Trinsoutrot-Gattin 《Environmental Chemistry Letters》2014,12(2):257-273
The use of pesticides in agriculture has highly increased during the last 40 years to increase crop yields. However, today most pesticides are polluting water, soil, atmosphere and food. Pesticides are also impact soil enzymes, which are essential catalysts ruling the quality of soil life. In particular, the activity of soil enzymes control nutrient cycles, and, in turn, fertilization. Here, we review the effects of pesticides on the activity of soil enzymes in terrestrial ecosystems. Enzymes include dehydrogenase, fluorescein diacetate hydrolase, acid phosphatase, alkaline phosphatase, phosphatase, β-glucosidase, cellulase, urease and aryl-sulfatase. Those enzymes are involved in the cycles of carbon, nitrogen, sulfur and phosphorus. The main points of our analysis are (1) the common inhibition of dehydrogenase in 61 % of studies, stimulation of cellulase in 56 % of studies and no response of aryl-sulfatase in 67 % of studies. (2) Fungicides have mainly negative effects on enzymatic activities. (3) Insecticides can be classified into two groups, the first group represented by endosulfan having an overall positive impact while the second group having a negative effect. (4) Herbicides can be classified into two groups, one group with few positive effect and another group with negative effect. 相似文献
27.
Karine Vallée-Rehel Valérie Langlois Philippe Guérin Alain Le Borgne 《Journal of Polymers and the Environment》1999,7(1):27-34
Environmental concerns result in a progressive withdrawal of antifouling paints containing organotin derivatives. The nature of the binders is critical with regard to the erosion of the protecting film through factors such as bond cleavage, dissolution, and diffusion of the degradation products. The versatility of acrylic polymers, due to the possibility of varying their chemical structure had conducted, in the first stage, to combine different types of repeating units in the macromolecular backbone. Formulation and evaluation, in natural sites, of these binders, with a well-defined hydrophobic/hydrophilic balance and with hydrolyzable pendant groups, have shown the possibility to prepare new organotin free resins which can be formulated and which are erodible in seawater over a long period (more than 2 years). A further step has been engaged with the development of graft copolymers containing biocompatible and hydrolyzable oligomers of -hydroxyacids. Their preparation requires the synthesis of -methacryloyloxyoligo--hydroxyacid macromonomers. Copolymers prepared from a mixture of the macromonomer and of an alkyl ester of acrylic acid were formulated with a biocide and deposited on a plate. Their ability to release cuprous oxide, as a model molecule, has been checked and quantified by the inductively coupled plasma analytical method. The uptake of water in the paint, which is enhanced by the hydrolysis of -hydroxyacid oligomers, as determined by the enzymatic measurement of liberated L-lactic acid, conducts to the polymer erosion and to a protecting bioactive surface. 相似文献
28.
Lebaron Karine Mechiri Lilia Richard Simone Austruy Annabelle Boudenne Jean-Luc Coupé Stéphane 《Environmental science and pollution research international》2019,26(20):20573-20580
Environmental Science and Pollution Research - Water chlorination is the most widely used technique to avoid microbial contamination and biofouling. Adding chlorine to bromide-rich waters leads to... 相似文献
29.
Elba Calesso Teixeira Camila Dalla Porta Mattiuzi Dayana Milena Agudelo-Castañeda Karine de Oliveira Garcia Flavio Wiegand 《Environmental monitoring and assessment》2013,185(11):9587-9602
Atmospheric fine and coarse particles were collected in Teflon filters in three cities of the region of the Lower Sinos River Basin of Rio Grande do Sul in the year 2010. The filters were Soxhlet extracted, and 14 priority PAHs were analyzed using a gas chromatograph coupled to a mass spectrometer (GC/MS). The principal emission sources of these compounds were assessed by using diagnostic ratios and receptor model: positive matrix factorization (PMF 3.0) of the US Environmental Protection Agency. The results of PAHs concentration for the studied year showed significant levels of high molecular weight (HMW) PAH, Ind, and BghiP, in PM2.5 in the winter season, showing the influence of mobile sources. The application of receptor model PMF 3.0 revealed that the main sources of PAHs were vehicle fleet (both diesel and gasoline), followed by coal combustion, wood combustion, and resuspension of dust. The results of the receptor modeling are in agreement with the data obtained by the ratio diagnostic. 相似文献
30.
Lebrun JD Demont-Caulet N Cheviron N Laval K Trinsoutrot-Gattin I Mougin C 《Chemosphere》2011,82(3):340-345
The relationship between the expression of extracellular enzymatic system and a metal stress is scarce in fungi, hence limiting the possible use of secretion profiles as tools for metal ecotoxicity assessment. In the present study, we investigated the effect of Zn, Cu, Pb and Cd, tested alone or in equimolar cocktail, on the secretion profiles at enzymatic and protein levels in Trametesversicolor. For that purpose, extracellular hydrolases (acid phosphatase, β-glucosidase, β-galactosidase and N-acetyl-β-glucosaminidase) and ligninolytic oxidases (laccase, Mn-peroxidase) were monitored in liquid cultures. Fungal secretome was analyzed by electrophoresis and laccase secretion was characterized by western-blot and mass spectrometry analyses. Our results showed that all hydrolase activities were inhibited by the metals tested alone or in cocktail, whereas oxidase activities were specifically stimulated by Cu, Cd and metal cocktail. At protein level, metal exposure modified the electrophoretic profiles of fungal secretome and affected the diversity of secreted proteins. Two laccase isoenzymes, LacA and LacB, identified by mass spectrometry were differentially glycosylated according to the metal exposure. The amount of secreted LacA and LacB was strongly correlated with the stimulation of laccase activity by Cu, Cd and metal cocktail. These modifications of extracellular enzymatic system suggest that fungal oxidases could be used as biomarkers of metal exposure. 相似文献