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61.
The umbric epipedon is a diagnostic surface horizon recognized by both the World Reference Base for Soil Resources and the U.S. Soil Taxonomy. It is mainly characterized by a dark color, a moderate to high content of OM, and a base saturation of less than 50%. In the N Apennines, Central Italy, forest soils over 600–700 m a.s.l. often have this epipedon. This paper stresses the morphological, chemical, and biological properties of the epipedon, specifically in the Vallombrosa Forest, where considerable work has been done in the last decade. Here, the umbric epipedon forms on sandstone, in high forests of Abies alba, Fagus sylvatica, and Castanea sativa. It does not have homogeneous properties throughout its thickness and often is divided into two distinct genetic horizons, A1 and A2. The A1 horizon is thinner, darker, and richer in OM, more base‐saturated, and biologically more active than the underlying A2 horizon. The mean residence time of the bulk OM amounts to about a century in the A1 horizon, versus half a millennium in the A2. In both A1 and A2 horizons, the non‐humic fraction prevails in the OM; this could account for the high susceptibility of the umbric epipedon to degrade when the forest is clear‐cut or undergoes extensive uprooting due to windstorms or heavy snow loads. Significant discrepancies between the two A horizons have been found in regard to the microbial community. Umbric epipedons which developed under different tree species show minor differences, mainly concerning the microbial community. 相似文献
62.
J. Staehelin A. Waldvogel J. L. Collett Jr. R. Dixon R. Heimgartner W. Henrich C. Hsu L. Li L. Mosimann B. Oberholzer A. S. H. Prevot W. Schmid T. Schumann M. Steiner M. Volken B. Zinder 《Water, air, and soil pollution》1993,68(1-2):1-14
Wet deposition plays an important role as a mechanism for cleansing of the polluted troposphere. Fluxes of pollutants from the atmosphere to earth's surface can affect soil and aquatic ecosystems. The investigation of the pollutant incorporation into wet deposition is therefore of considerable interest for environmental research. The project “Winter precipitation at Mount Rigi” addresses the processes determining the chemical composition of wet deposition through an integrated approach considering atmospheric physical and chemical processes and their complex interactions. The investigated topics include: aerosol and gas scavenging, atmospheric chemistry (cloud water chemistry), cloud physics and dynamics. The design of the experiment, using three ground based measuring stations at the northwestern slope of the mountain, and the conceptual ideas using case study investigations are discussed. 相似文献
63.
Relationships between Acid Ions and Carbonaceous Fly-Ash Particles in Deposition at European Mountain Lakes 总被引:1,自引:0,他引:1
N.L. Rose E. Shilland T. Berg K. Hanselmann R. Harriman K. Koinig U. Nickus B. Steiner Trad E. Stuchlík H. Thies M. Ventura 《Water, air, and soil pollution》2001,130(1-4):1703-1708
The concentrations of major ions and spheroidal carbonaceous fly-ash particles (SCPs) in bulk deposition were determined in weekly samples from six European mountain lakes during 1997/98. SCPs are produced only from high temperature combustion of fossil-fuels and therefore provide an unambiguous indicator of atmospheric deposition from this source. Positive correlations were observed between SCPs and SO4 2?, NO3 ? and NH4 + at all sites except for some determinands at Jorisee (Switzerland) and Starolesnienske (Slovakia). Correlations between SCPs and SO4 2? + NO3 ? were always more positive than for SCPs with 'total acid ions' (SO4 2? + NO3 ? + NH4 +). This is in agreement with the expectation that the contribution to NH4 + deposition made by fossil-fuels is negligible. Good positive correlations between SCPs and all acid anions were observed at Estany Redo (Pyrenees); lower but still positive correlations were observed for all acid ions with SCPs at Gossenköllesee (Austria), Lochnagar and Kårvatn (central Norway), whilst little trend in correlation was observed for Jorisee and Starolesnienske. It is suggested that this gradient reflects the influence of fossil-fuels on acid deposition in these areas. A high positive correlation was observed between SCP and Cl? at Gossenkollesee possibly as a result of HCl from coal combustion. 相似文献
64.
The volatiles produced by leaves and fruits of Olea europaea cv. Olivastra Seggianese have been analyzed in two different phenological stages. Furthermore, the volatiles of the virgin olive oil obtained from ripe fruits has been characterized. The volatiles were sampled by means of two different techniques: hydrodistillation and SPME. Differences were observed between the two different collection times, the different organs, and sampling techniques. The major constituents were often aldehydes, particularly (E)-2-hexenal (9.8-48.0%); however, also many terpenoids have been identified, mainly (E,E)-alpha-farnesene (0.2-27.0%), linalool (0-3.6%), beta-caryophyllene (0-8.1%), and valencene (0-2.5%). This is the first investigation on this cultivar. 相似文献
65.
Grova N Feidt C Crépineau C Laurent C Lafargue PE Hachimi A Rychen G 《Journal of agricultural and food chemistry》2002,50(16):4640-4642
Polycyclic aromatic hydrocarbons (PAHs), mainly formed by incomplete anthropogenic organic matter combustion, are ubiquitous in the environment. To assess milk PAH contamination sources, milk samples were collected from the tank milk at farms located near potential contaminating emission sources such as cementworks, steelworks, and motorways. PAH analyses were carried out by gas chromatography coupled to mass spectrometry. Eight PAHs were identified in milk: naphthalene, acenaphthylene, acenaphthene, fluorene, anthracene, fluoranthene, pyrene, and benzo[a]anthracene. For all potential contaminating sources, these eight PAHs were detected with similar profiles and at low concentrations except for fluorene and naphthalene, for which source-molecule interaction is pointed out. 相似文献
66.
K. M. Hart St. R. McDow W. Giger D. Steiner H. Burtscher 《Water, air, and soil pollution》1993,68(1-2):75-90
Aerosol photoemission (APE) has been found to be an excellent surrogate measure of particulate PAH concentration in combustion aerosols under a variety of laboratory and field conditions. Samples of oil stove, automobile exhaust, and urban air particulate matter were concurrently analyzed for aerosol photoemission intensity and particulate PAH concentration. In-situ, real-time analysis of the particulate matter was performed by UV-induced electron photoemission. Two photon energies, 4.9 and 6.7 eV, were chosen for irradiation. The latter energy was more sensitive and less selective. Particulate PAH concentrations were determined by collecting the particulate matter on a filter, solvent extracting the filter, and analyses of the extracts by gas chromatography / mass spectroscopy. Linear correlations (0.84≤r2≤1.00) were observed between aerosol photoemission intensities and the sum of particulate PAH concentrations for laboratory and field studies under a wide variety of conditions. The studies performed to date cover a dynamic range of three orders of magnitude (1 to 1000 ng / m3). The time resolution is in the order of a few seconds. 相似文献
67.
Anthrax is a serious disease caused by Bacillus anthracis. Humans can become infected by handling products from infected animals, by breathing spores and rarely by eating undercooked meat from infected animals. The genome of B. anthracis is highly monomorphic and thus shows very low DNA sequence variation. We analysed the molecular characteristics of 12 B. anthracis isolates from outbreaks in Croatia and Bosnia and Herzegovina, which have occurred during the past 10 years along with two vaccine strains. Genotyping system based on variable‐number tandem repeat analysis at six loci revealed that six isolates belong to genotype from the A1.a cluster whilst six isolates relate to the B2 cluster, compared to 89 previously described genotypes. The distribution of two evolutionarily distant clusters suggests an introduction of B. anthracis to this area in at least two separate events. 相似文献
68.
69.
70.
Guido Cipriani Francesco Pinosa Maura Bonoli Walter Faedi 《The Journal of Horticultural Science and Biotechnology》2013,88(4):668-675
SummaryThis study reports the development of 68 new microsatellite markers. Of these, 45 were obtained, together with 20 others already published, from an AC-enriched genomic library of the wild strawberry Fragaria vesca. The 68 markers were tested for transportability to the cultivated strawberry F. ananassa ‘Miss’ and 83% gave positive amplifications. Twenty pairs of primers were selected and tested for their transportability to 16 Fragaria taxa and eight species of Rosaceae (peach, almond, apricot, European and Sino-Japanese plums, sweet and sour cherry, apple). The average proportion of primers amplifying loci in Fragaria was 69%, while the transportability to Rosaceae was very low and resulted in null amplification for 80% of the primer pairs. In addition, 23 microsatellite markers were developed from F. ananassa ‘expressed sequence tags’ databases. A total of 141 primer pairs from these and published primers, were tested for polymorphism in the two parents (91.333.2 and ‘Snovit’; both belonging to F. vesca) of a full sib population of 46 individuals. Fifty-eight percent of the primers were discarded because they were monomorphic, or were difficult to interpret, or their allelic conformation was not useful for mapping. The segregation of 73 primers was tested in the progeny and a partial map of the female parent was constructed, based on the segregation of 66 useful markers that were ordered into eight linkage groups of which four had from seven to 14 markers. 相似文献