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61.
Conxita Avila Xavier Buuel Francesc Carmona Albert Cotado Oriol Sacristn-Soriano Carlos Angulo-Preckler 《Marine drugs》2022,20(9)
Many Antarctic marine benthic macroinvertebrates are chemically protected against predation by marine natural products of different types. Antarctic potential predators mostly include sea stars (macropredators) and amphipod crustaceans (micropredators) living in the same areas (sympatric). Recently, alien species (allopatric) have been reported to reach the Antarctic coasts, while deep-water crabs are suggested to be more often present in shallower waters. We decided to investigate the effect of the chemical defenses of 29 representative Antarctic marine benthic macroinvertebrates from seven different phyla against predation by using non-native allopatric generalist predators as a proxy for potential alien species. The Antarctic species tested included 14 Porifera, two Cnidaria, two Annelida, one Nemertea, two Bryozooa, three Echinodermata, and five Chordata (Tunicata). Most of these Antarctic marine benthic macroinvertebrates were chemically protected against an allopatric generalist amphipod but not against an allopatric generalist crab from temperate waters. Therefore, both a possible recolonization of large crabs from deep waters or an invasion of non-native generalist crab species could potentially alter the fundamental nature of these communities forever since chemical defenses would not be effective against them. This, together with the increasing temperatures that elevate the probability of alien species surviving, is a huge threat to Antarctic marine benthos. 相似文献
62.
Núria Martínez-Carreras Andreas Krein Thomas Udelhoven Francesc Gallart Jean F. Iffly Lucien Hoffmann Laurent Pfister Desmond E. Walling 《Journal of Soils and Sediments》2010,10(3):400-413
Purpose
This paper reports on the development of a rapid and simple spectra-reflectance-based fingerprinting approach for documenting suspended sediment sources during storm runoff events. The methodology was applied in the rural Wollefsbach catchment (4.4 km2, NW Luxembourg). 相似文献63.
Daniel Oro Antón Pérez-Rodríguez Albert Martínez-Vilalta Francesc Vidal 《Biological conservation》2009,142(8):1830-261
It is often assumed that conservation actions targeting a threatened community (e.g. habitat protection) will result in similar benefits for all species. However, complex interactions between species, such as interference competition, may result in displacement of subordinate, vulnerable species. We analysed here the spatio-temporal population dynamics of a threatened seabird community since the protection in the 1980s of several breeding sites at the Ebro Delta, western Mediterranean, Spain during 1980-2007. Competition for the most suitable patches was governed by body size, with smaller species avoiding associations with larger, dominant species. We tested whether the density increase of the larger species (yellow-legged gull Larus michahellis and Audouin’s gull Larus audouinii) at La Banya (the highest quality patch within the Delta) affected species diversity at the local level. As expected, such diversity decreased, resulting also from the colonisation of other sites by smaller species, some abandoning the former area. The conservation paradox appeared because the interference competition was dominated not only by the largest species of the community, the yellow-legged gull, which is sometimes considered a pest species, but also by the vulnerable Audouin’s gull, a flagship species which has ca. 65% of the total world population at La Banya. Nevertheless, the availability of alternative patches within the Ebro Delta ensured a high biodiversity at regional scale. Results highlight the role of turnover of competing species within a community in ecosystem function and stability, and the importance of alternative sites and dispersal abilities for the conservation of vulnerable communities. 相似文献
64.
Prescribed fire is a technique sometimes used in forest management but the effects on soil are not fully understood. Soil is a complex system and the spatial variability of properties and processes may increase after a disturbance like fire. We modelled three soil cations Ca2+, Mg2+ and K+ with probabilistic methods and geostatistics in order to assess the spatial effects of a prescribed fire within a plot (108 m2). Soil samples were collected during 6 different sampling campaigns (pre fire, post fire, 2 months, 5 months, 1 year, and 3 years after the prescribed fire). The sampling interval was designed to detect the effect of rainfall (1315 mm for the 3 years with 72 mm/h peak intensity) on the spatial soil changes as consequence of processes such as: leaching, soil erosion, etc. We developed an index of response to compare each cation after the prescribed fire with its pre-fire levels. Results showed that calcium and magnesium recover with time to their original concentrations. Potassium increase slightly in half of the plot just after fire; however, three years after fire the concentration was two orders of magnitude lower than the pre-fire state. The divalent cations (Ca2+ and Mg2+) were more homogeneous but the monovalent cation (K+) was more heterogeneous after the fire. Furthermore the maximum rainfall period triggered different spatial processes and the type of process was a function of the valence of the cation. 相似文献
65.
Ibáñez M Portolés T Rúbies A Muñoz E Muñoz G Pineda L Serrahima E Sancho JV Centrich F Hernández F 《Journal of agricultural and food chemistry》2012,60(21):5311-5323
Laboratories devoted to the public health field have to face the analysis of a large number of organic contaminants/residues in many different types of samples. Analytical techniques applied in this field are normally focused on quantification of a limited number of analytes. At present, most of these techniques are based on gas chromatography (GC) or liquid chromatography (LC) coupled to tandem mass spectrometry (MS/MS). Using these techniques only analyte-specific information is acquired, and many other compounds that might be present in the samples would be ignored. In this paper, we explore the potential of time-of-flight (TOF) MS hyphenated to GC or LC to provide additional information, highly useful in this field. Thus, all positives reported by standard reference targeted LC-MS/MS methods were unequivocally confirmed by LC-QTOF MS. Only 61% of positives reported by targeted GC-MS/MS could be confirmed by GC-TOF MS, which was due to its lower sensitivity as nonconfirmations corresponded to analytes that were present at very low concentrations. In addition, the use of TOF MS allowed searching for additional compounds in large-scope screening methodologies. In this way, different contaminants/residues not included in either LC or GC tandem MS analyses were detected. This was the case of the insecticide thiacloprid, the plant growth regulator paclobutrazol, the fungicide prochloraz, or the UV filter benzophenone, among others. Finally, elucidation of unknowns was another of the possibilities offered by TOF MS thanks to the accurate-mass full-acquisition data available when using this technique. 相似文献
66.
Núria Martínez-Carreras Andreas Krein Francesc Gallart Jean-Fran?ois Iffly Christophe Hissler Laurent Pfister Lucien Hoffmann Philip N. Owens 《Water, air, and soil pollution》2012,223(9):5685-5705
Nutrient (C, N and P) and metal (Cr, Cu, Ni, Pb and Zn) content and dynamics of suspended and channel bed sediments were analysed within the rural Attert River basin (Luxembourg). This basin is representative of the main physiographic characteristics of the country, where there is currently little information available on the composition and dynamics of fluvial sediment. Stream bed fine-grained sediment samples (n?=?139) collected during low flow conditions and time-integrated suspended sediment samples (n?=?183) collected during storm runoff events (October 2005 to April 2008) in seven nested basins ranging from 0.45 to 247?km2 were analysed. Nutrient and metal spatial patterns, temporal trends and the relationship between their content and storm runoff characteristics (e.g. maximum discharge and sediment concentration) were assessed. Results showed a high spatial and temporal variability, mainly associated with basin characteristics and local inputs. Higher values of total C were measured in the highly forested basins located in the northern part of the Attert River basin, whereas the highest values of total P were mainly associated with material coming from grassland and with the inflow of wastewater treatment plants (i.e. higher values of total P were measured in the southern part of the basin). The abundance of metals, not only in suspended but also in channel bed sediments, was generally as follows: Zn > Cr > Ni > Pb > Cu. Both nutrient and metal concentrations were at a maximum at the beginning of the wet season, after having been accumulated during the summer. These values tended to decrease during autumn and winter due to sediment mobilisation, and a higher flow capacity to transport coarser particle fractions from the sources. In general, concentrations of nutrients and metals on suspended sediment were negatively correlated with antecedent precipitation, total precipitation, total specific discharge and maximum discharge, which has been previously associated to a ??dilution?? effect during storm runoff events. Results show that both sediment sources and hydrologic events play an important role on the spatial and temporal variability of sediment-associated nutrient and metal contents. 相似文献
67.
Near-infrared spectroscopy (NIRS) is a well-established technique for determining the components of foods. Sample preparation for NIRS is easy, making it suitable for breeding and/or quality evaluation, for which a large number of samples should be analyzed. We aimed to assess the feasibility of NIRS to estimate parameters that seem to influence consumers' perception of the seed coat of common beans: dietary fiber (DF), uronic acids (UA), ashes, calcium, and magnesium. We used reference methods to analyze ground seed coats of 90 common bean samples with a wide range of genetic variability and cultivated at many locations. We registered the NIR spectra on intact beans and ground seed coat samples. We derived partial least-squares (PLS) regression equations from a set of calibration samples and tested their predictive power in an external validation set. For intact beans, only RER values for ashes and calcium are good enough for very rough screening. For ground seed coat samples, the RPD and RER values for ashes (3.49 and 14.09, respectively) and calcium (3.57 and 12.70, respectively) are good enough for screening. RPD and RER values for DF (2.60 and 9.15, respectively) and RER values for magnesium (6.57) also enable rough screening. A poorer correlation was achieved for UA. We conclude that NIRS can help in common bean breeding research and quality evaluation. 相似文献
68.
Angeles Aroca Francesc García-Figueres Lilian Bracamonte Jordi Luque Rosa Raposo 《European journal of plant pathology / European Foundation for Plant Pathology》2006,115(2):195-202
Grapevine trunk disease pathogens, and specifically Petri disease pathogens, can be spread by planting infected plants. Due to the increasing incidence of Petri disease and other young grapevine declines reported lately in Spain, a sampling of plants used before for new vineyards were carried out in 2002 and 2004. A total number of 208 plants (grafted and non grafted) were collected, of which 94 plants (45.2%) were infected with at least one of the following pathogens: Phaeomoniella chlamydospora, and species of Phaeoacremonium, Botryosphaeria, Cylindrocarpon, and Phomopsis. Species of the genera Phaeoacremonium and Botryosphaeria isolated in 2004 were identified using morphological and molecular characters. Species of Phaeoacremonium identified were P. aleophilum and P. parasiticum; and those of Botryosphaeria were B. obtusa, B. dothidea and B. parva. This is the first report of P. parasiticum and B. parva occurring on grapevines in Spain. Distribution of pathogens within the plants was studied in 2004. Phaeomoniella chlamydospora was not detected in the graft union of any plant; however, species of Botryosphaeria and Phomopsis were detected along the plant, but mainly in the graft union; Phaeoacremonium aleophilum was detected along the grafted plants, but not in rooted rootstocks. The results suggest that infected plants used for new plantings in Spain are an important source of primary inoculum of the pathogens associated with grapevine trunk diseases in the field. 相似文献
69.
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