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941.
Pueyo M Rauret G Bacon JR Gomez A Muntau H Quevauviller P López-Sánchez JF 《Journal of environmental monitoring : JEM》2001,3(2):238-242
There is an increasing requirement for assessment of the bioavailable metal fraction and the mobility of trace elements in soils upon disposal. One of the approaches is the use of leaching procedures, but the results obtained are operationally defined; therefore, their significance is highly dependent on the extraction protocol performed. So, for this type of study, there is a need for reference materials that allow the quality of measurements to be controlled. This paper describes the steps involved in the certification of an organic-rich soil reference material, BCR-700, for the EDTA- and acetic acid-extractable contents of some trace elements, following collaboratively tested and harmonised extraction procedures. Details are given for the preparation of the soil, homogeneity and stability testing, analytical procedures and the statistical selection of data to be included in the certification. 相似文献
942.
A laboratory experiment was conducted to investigate the longterm effects of amending sulfide-rich lignite mine spoil with fly ash (originating from a coal-fired power station and largely comprised of aluminosilicates) and/or agricultural limestone. The experiment was carried out with soil moisture maintained at field capacity or alternate cycles of wetting and drying. Results obtained suggest that the principal acidification processes were oxidation of sulfide and formation of hydroxysulfate (FeOHSO4), whereas the main neutralization processes were weathering of aluminosilicates in fly ash-treated samples and dissolution of calcium carbonate in limestone-treated samples. The highest dose of limestone rapidly raised the pH of the spoil, but this increase was not maintained throughout the one-year experiment. In contrast, fly ash-treated samples showed a more sustained increase in pH, attributable to the gradual weathering of aluminosilicates. The best results (i.e., good short- and long-term neutralization) were obtained in samples treated with both fly ash and limestone. The low liming capacity of the fly ash (47.85 cmol kg(-1)) means that it must be used in large quantities, an advantage in achieving the further aim of disposing of the fly ash. 相似文献
943.
Unique components of tropical habitats, such as abundant vascular epiphytes, influence the distribution of species and can contribute to the high diversity of many animal groups in the tropics. However, the role of such features in habitat selection and demography of individual species has not been established. Understanding the mechanisms of habitat selection requires both experimental manipulation of habitat structure and detailed estimation of the behavioral and demographic response of animals, e.g., changes in movement patterns and survival probabilities. Such studies have not been conducted in natural tropical forest, perhaps because of high habitat heterogeneity, high species diversity, and low abundances of potential target species. Agroforestry systems support a less diverse flora, with greater spatial homogeneity which, in turn, harbors lower overall species diversity with greater numerical dominance of common species, than natural forests. Furthermore, agroforestry systems are already extensively managed and lend themselves easily to larger scale habitat manipulations than protected natural forest. Thus, agroforestry systems provide a good model environment for beginning to understand processes underlying habitat selection in tropical forest animals. Here, we use multistate, capture-recapture models to investigate how the experimental removal of epiphytes affected monthly movement and survival probabilities of two resident bird species (Common Bush-Tanager [Chlorospingus ophthalmicus] and Golden-crowned Warbler [Basileuterus culicivorus]) in a Mexican shade coffee plantation. We established two paired plots of epiphyte removal and control. We found that Bush-Tanagers were at least five times more likely to emigrate from plots where epiphytes were removed compared to control plots. Habitat-specific movement patterns were not detected in the warbler. However, unlike the Golden-crowned Warbler, Common Bush-Tanagers depend upon epiphytes for nest sites and (seasonally) for foraging. These dispersal patterns imply that active habitat selection based on the presence or absence of epiphytes occurs in C. ophthalmicus on our study area. Survival rates did not vary with habitat in either species. Interestingly, in both species, survival was higher in the nonbreeding season, when birds were in mixed-species flocks. Movement by Common Bush-Tanagers into areas with epiphytes occurred mostly during the breeding season, when mortality-driven opportunity was greatest. 相似文献
944.
Sergio Rossi Georgios Tsounis Covadonga Orejas Tirma Padrón Josep-Maria Gili Lorenzo Bramanti Núria Teixidó Julian Gutt 《Marine Biology》2008,154(3):533-545
The distribution and population structure of the eurybathic gorgonian Corallium rubrum were studied off Cap de Creus (Costa Brava, Northwestern Mediterranean Sea). Red coral is endemic to the Mediterranean Sea
and the adjacent NE Atlantic coast, where it has been over exploited for centuries. This study presents, the first quantitative
data on the spatial distribution and structure of a population extending between 50 (common SCUBA limits) and 230 m depth,
and compared it with shallow populations previously studied in the same area. Different remotely operated vehicles (ROV) and
two methodological approaches were employed during four cruises between 2002 and 2006: 1-Extensive surveys: sea to coast transects
in which red coral density and patch frequency were recorded; 2-Intensive surveys, in which parameters describing colony morphology
were recorded. Most of the hard substrate between 50 and 85 m depth was inhabited by red coral colonies, showing a patch frequency
of 8.3 ± 7.9 SD patches per 100 m-transect (total transect area: 34 m2), and within-patch colony densities of 16–376 colonies m−2 (mean of 43 ± 53 colonies m−2). Below 120 m depth red coral was less abundant, and rather than forming dense patches as in shallow water, isolated colonies
were more common. The population structure differed between sites that are easily accessible to red coral fishermen, and remote
ones (both at similar depth, 60–80 m), as colonies in easily accessible locations were smaller in height and diameter, and
showed a less developed branching pattern. At shallower locations (10–50 m depth) the population structure was significantly
different from those at deeper locations, due to the heavy harvesting pressure they are exposed to in the shallows. Twenty-five
to forty-six percentage of the deeper colonies were taller than 6 cm, while only 7–16% of the shallow water colonies exceeded
6 cm colony height. Forty-six to seventy-nine percentage of the colonies in deeper waters were large enough to be legally
harvested, while only 9–20% of the shallow water colonies met the 7 mm legal basal diameter to be collected. The branching
pattern was also better developed in deeper colonies, as up to 16% of the colonies showed fourth order branches, compared
to less than 1% of the shallow water colonies (of which 96% consisted of only one single branch). The results thus confirm
that C. rubrum populations above 50 m depth are exposed to a higher harvesting intensity than deeper populations in the same area. 相似文献
945.
946.
Christian Pansch Ivan Gómez Eva Rothäusler Karina Veliz Martin Thiel 《Marine Biology》2008,155(1):51-62
Chemical defense is assumed to be costly and therefore algae should allocate defense investments in a way to reduce costs
and optimize their overall fitness. Thus, lifetime expectation of particular tissues and their contribution to the fitness
of the alga may affect defense allocation. Two brown algae common to the SE Pacific coasts, Lessonia nigrescens Bory and Macrocystis integrifolia Bory, feature important ontogenetic differences in the development of reproductive structures; in L. nigrescens blade tissues pass from a vegetative stage to a reproductive stage, while in M. integrifolia reproductive and vegetative functions are spatially separated on different blades. We hypothesized that vegetative blades
of L. nigrescens with important future functions are more (or equally) defended than reproductive blades, whereas in M. integrifolia defense should be mainly allocated to reproductive blades (sporophylls), which are considered to make a higher contribution
to fitness. Herein, within-plant variation in susceptibility of reproductive and vegetative tissues to herbivory and in allocation
of phlorotannins (phenolics) and N-compounds was compared. The results show that phlorotannin and N-concentrations were higher
in reproductive blade tissues for both investigated algae. However, preferences by amphipod grazers (Parhyalella penai) for either tissue type differed between the two algal species. Fresh reproductive tissue of L. nigrescens was more consumed than vegetative tissue, while the reverse was found in M. integrifolia, thus confirming the original hypothesis. This suggests that future fitness function might indeed be a useful predictor of
anti-herbivore defense in large, perennial kelps. Results from feeding assays with artificial pellets that were made with
air-dried material and extract-treated Ulva powder indicated that defenses in live algae are probably not based on chemicals that can be extracted or remain intact after
air-drying and grinding up algal tissues. Instead, anti-herbivore defense against amphipod mesograzers seems to depend on
structural traits of living algae. 相似文献
947.
Virginia E. Villafañe Paul J. Janknegt Marco de Graaff Ronald J. W. Visser Willem H. van de Poll Anita G. J. Buma E. Walter Helbling 《Marine Biology》2008,154(6):1021-1029
During austral summer 2006, experiments were carried out to evaluate the effects of ultraviolet radiation (UVR, 280–400 nm)
on carbon fixation of natural phytoplankton assemblages from Patagonia (Argentina). Surface water samples were collected (ca.
100 m offshore) at mid morning using an acid-cleaned (1 N HCl) dark container. The short-term impact of UVR (measured as radiocarbon
incorporation) was immediately assessed by exposing samples to three artificial illumination treatments: PAR (400–700 nm),
PAR + UV-A (320–700 nm), and PAR + UV-A + UV-B (280–700 nm). Pico-nanoplankton characterized the assemblages, and taxon-specific
pigment fingerprinting combined with CHEMTAX and supplemented with microscopic observations showed varied proportions of diatoms,
chlorophytes, and cyanobacteria throughout January–February 2006. Photosynthetic efficiency, as assessed through assimilation
numbers, was high [between 4.4 and 10.4 μg C (μg chl-a)−1 h−1], and it was probably favored by the supply of inorganic nutrients from the Chubut River. UVR-induced photoinhibition appeared
to be related to the taxonomic composition: in general, higher photoinhibition was observed when diatoms dominated, whereas
this was lower when samples were dominated by chlorophytes. Our data suggest that xanthophyll pigments might have provided
only limited protection in these already highlighted acclimated assemblages. 相似文献
948.
White lupin is an annual crop that has been used for phytostabilization of acidified multicontaminated (heavy metals and As)
soils from the Aznalcóllar spill-affected area, Southern Spain. One of the most important factors for successful phytostabilization
is monitoring the pollutant bioavailability in the soil. The aim of this work was to determine the best-suited method for
assessing the bioavailability of heavy metals together with As in the Aznalcóllar spill-affected area, by means of a systematic
comparison between different extraction methods (Ammonium bicarbonate-diethylenetriamine pentaacetic acid (AB-DTPA), CaCl2, NaNO3, BCR, (NH4)2SO4 and rhizo). Both AB-DTPA and the first step of the BCR method were found to be unsuitable for assessing the bioavailability of heavy
metals and As to plants growing in acidic soils. However, CaCl2-extractable As, Cu, and Zn and NaNO3-extractable As and Zn were well correlated with their concentrations in plant organs. Rhizo and (NH4)2SO4, with the highest determination coefficients, were the most recommended simple extraction methods to assess the bioavailability
of As, Cu, Fe, Mn, and Zn in acidified multicontaminated soils using white lupin as an excluder model plant. 相似文献
949.
Csaba Moskát Jesús M. Avilés Miklós Bán Rita Hargitai Anikó Zölei 《Behavioral ecology and sociobiology》2008,62(12):1885-1890
Common cuckoo (Cuculus canorus) parasitism drastically reduces the reproductive success of their hosts and selects for host discrimination of cuckoo eggs.
In a second stage of anti-parasite adaptation, once cuckoos can lay eggs that mimic those of their hosts, a high uniformity
of host egg appearance within a clutch may favour cuckoo egg discrimination. Comparative evidence provides indirect support
for this hypothesis although experimental support is currently lacking. Here, we studied the effect of experimentally decreased
uniformity of host egg appearance on cuckoo egg discrimination by great reed warbler (Acrocephalus arundinaceus) hosts in a population in which long-term cuckoo parasitism has led to high levels of cuckoo–host egg mimesis. We manipulated
host clutch uniformity by adding extra spots to fresh host eggs just after they were laid. Rejection of non-mimetic experimental
eggs added to these nests was compared with those in control nests in which uniformity was not altered. Previously, by over-painting
real spots in a control group of nests, we showed a negligible effect of our paints on hosts’ perception of their eggs. We
show that for the great reed warbler, non-mimetic experimental eggs were relatively more tolerated in experimental nests,
i.e. with lower uniformity (40%) than in control nests (5%). This is the first experimental study, to our knowledge, which
demonstrates a reduced discrimination of foreign eggs as a consequence of an increase of egg phenotypes variation perception
in a cuckoo host. 相似文献
950.
Veronika Bókony László Zsolt Garamszegi Katharina Hirschenhauser András Liker 《Behavioral ecology and sociobiology》2008,62(8):1229-1238
Despite the functional significance of melanin-based plumage coloration in social and sexual signaling, the mechanisms controlling
its information content are poorly understood. The T-regulation hypothesis proposes that melanin ornaments signal competitive
abilities via the effects of testosterone (T) mediating both melanization and sexual/aggressive behaviors. Using the phylogenetic
comparative approach, we tested whether frontal black melanization is associated with elevated T around the time of breeding
plumage development across all bird species with available T-data. We found a context-dependent relationship between melanization
and T, varying with the type of ornamentation (patchy or full-black) and with the presumed taxonomic distribution of the hormonal
control of plumage dichromatism. Within two taxa in which male plumage development is assumed androgen-dependent (Charadriiformes,
Corvida), evolutionary increases in male melanization, and melanin dichromatism correlated with increases in T in most analyses
but not within the basal lineage (ratites, Galloanseriformes) with androgen-independent male plumage. Among Passeroidea with
presumably genetically or luteinizing-hormone-based male plumage, melanization and its dichromatism correlated with T only
in species with <100% frontal melanization. These results were robust as we controlled for several confounding variables such
as mating and parental behaviors. This study is the first to test and support the T-regulation hypothesis interspecifically,
suggesting that among-species differences in melanization may have evolved in response to differences in circulating T in
certain avian taxa. Our results imply that the extent of black ornamentation may serve as an honest indicator of male competitiveness
in those species that evolved an appropriate hormonal basis (T dependence) for color production.
Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users. 相似文献