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81.
The present paper is aimed at assessing the long term behaviour of 90Sr migration from water to bottom sediments of Lake Uruskul, Southern Urals, Russia. The lake was contaminated following the nuclear accident at the Mayak nuclear complex in 1957 (the Kyshtym accident). Some transfer parameters relevant to the behaviour of 90Sr in the water-sediment system were evaluated: a) the radionuclide migration velocity from the water column to the bottom sediment, b) the radionuclide migration rate from bottom sediment to water, and c) the radionuclide migration rate from bottom sediment to deep sediment. The estimated values of the above parameters were 6.4 x 10(-1) m s(-1), 5.7 x 10(-10) s(-1) and 5.2 x 10(-10) s(-1), respectively. These values were compared with data obtained for some Italian lakes contaminated by 90Sr after the nuclear weapons tests fallout. The relatively low radionuclide migration from water to sediment of these lakes is reflected by the values of the ratio migration velocity/migration rate from sediment to water (4 m and 12 m) that are significantly lower than the corresponding value in the Russian lake (112 m). The peculiar hydrochemical conditions of Lake Uruskul (high pH, high mineralisation, etc.) are considered to be responsible for the high radionuclide migration from water to sediment. 相似文献
82.
83.
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
84.
It has been proposed that blue colouration in eggs has evolved as a signal of female quality that males can use to modulate
their parental investment. This hypothesis is based in the antioxidant properties of biliverdin whose costly deposition in
the eggshell is expected to signal female antioxidant capacity and egg quality. Since maternally derived androgens are costly
to produce and may adaptively affect offspring phenotype, high-quality females may benefit by signalling their androgen investment
through egg colouration. Our aim was to investigate whether egg colour variation in the spotless starling reflected the amount
of pigments on the eggshell and whether egg pigmentation was related to female and egg quality. Chromatography analyses revealed
that spotless starling eggshells contained two different pigments: biliverdin and protoporphyrin IX with no correlation between
them. Biliverdin contents correlated positively with egg colouration indicating that darker eggs with a higher peak in the
blue–green segment of the spectrum contained higher amounts of biliverdin. Eggs containing more biliverdin were laid by high-quality
females and contained higher yolk testosterone levels. However, despite the strong correlation between biliverdin and colorimetric
variables, egg colouration did not reflect accurately female and egg quality. Our results provide evidence that eggshell pigmentation
in the spotless starling is related to female and egg quality as shown by the yolk testosterone levels. However, the lack
of relation between egg colour and female condition and egg quality do not provide evidence to support the signalling function
of egg colouration. 相似文献
85.
Winfried Schröder Cordula Englert Roland Pesch Harald G. Zechmeister Lotti Thöni Ivan Suchara Blanka Maňkovská Zvonka Jeran Harry Harmens Krystyna Grodzinska Renate Alber 《Environmental Sciences Europe》2008,20(2):120-132
Goal and Scope
Several studies show that the concentration of metals in mosses depends not only on metal deposition but also on factors such as moss species, canopy drip, precipitation, altitude, distance to the sea and the analytical technique used. However, contrasting results have been reported and the interpretation of the spatial variability of the metal accumulation in mosses remains difficult. In the presented study existing monitoring data from the European Heavy Metals in Mosses Surveys together with surface data on precipitation, elevation and land use are statistically analysed to assess factors other than emissions that have an influence on the metal accumulation in the mosses.Main Features
Inference statistics and Spearman correlation analysis were applied to examine the association of the metal accumulation and the distance of the monitoring sites to the sea as well as the altitude. Whether or not significant differences of the metal loads in the mosses exist at national borders was examined with help of the U-test after Mann and Whitney. In order to identify and rank the factors that are assumed to have an influence on the metal uptake of the mosses Classification and Regression Trees (CART) were applied.Results
No clear tendency could be derived from the results of the inference statistical calculations and the correlation analyses with regard to the distance of the monitoring site to the sea and the altitude. According to the results of the CART-analyses mainly the moss species, potential emission sources around the monitoring sites, canopy drip and precipitation have an effect on the metal bioaccumulation. Assuming that each participating country followed strictly the manual for sampling and sample preparation the results of the inference statistical calculations furthermore suggest that in most cases different techniques for digestion and analysis bias the measurements significantly.Discussion
For the first time a national monitoring data base consisting of measurement data and metadata as well as surface information on precipitation, land use and elevation was applied to examine influence factors on the metal bioaccumulation in mosses. The respective results mirror existing knowledge from other national studies to a large extend, although further analyses are necessary to affirm the findings. These analyses should include data from other national monitoring programmes and should additionally be carried out with other decision tree algorithms than CART.Conclusions
The local variability in the metal concentration in mosses can be uncovered in terms of predictors or underlying hidden causes by using CART. Ideally, such an approach should be applied across the whole of Europe. This will only be feasible if all participating countries provide additional information about site characteristics as currently is done in for example the German moss surveys.Recommendations
The UNECE Metals in Mosses Survey experimental protocol should be improved in order to reduce the observed influences, to enhance standardisation, and to strengthen the quality control. This implies the integration of sampling site describing metadata into the assessment. Furthermore, basis research is needed to test the hypothesis concerning moss species-specific accumulation of depositions.Perspectives
Provided that the presented results hold true in further analyses correction factors should be applied on the moss data in order to get the depicted spatial patterns and temporal trends of metal bioaccumulation unbiased. Such factors should be calculated for natural landscape units or ecoregions that are homogeneous with regard to climate, vegetation and altitude. 相似文献86.
Guttová A Lackovičová A Pišút I Pišút P 《Environmental monitoring and assessment》2011,182(1-4):361-373
The study illustrates the response of epiphytic lichens to changing atmospheric conditions in Central Europe, where the emission of air pollutants has significantly decreased from 1990, in the area in and around Bratislava City. Variation in concentrations of seven metal elements (Cu, Cd, Cr, Mn, Ni, Pb and Zn) in the thalli of Evernia prunastri, Hypogymnia physodes and Parmelia sulcata is assessed. Samples of these species were exposed in lichen bags in 39 sites throughout the territory of the city (more than 300 km(2)) during the period December 2006-February 2007. The samples were analyzed by AAS for metal element contents prior to and after exposure. The decrease in air pollution (for all studied elements by more than 90%) corresponded to a decrease in the accumulation of elements in lichen thalli, e.g. the contents of Pb decreased by 69% and of Cd by 34% on average. The results show also variations in accumulation between with different lichen species. The background values of metal element contents in thalli of H. physodes growing in situ were measured in semi-natural sites in Slovakia. It is suggested that these can be used as a reference in large-scale monitoring studies in Central Europe. Analysis of compatible data from the current study, and the study performed at the end of 1990s shows a significant decrease of metal elements in the air pollution load. 相似文献
87.
88.
Albert C. F. Lam Daniel H. C. Chan Tony M. F. Tong Mary H. Y. Tang Steven Y. F. Lo Ivan F. M. Lo Stephen T. S. Lam 《黑龙江环境通报》2006,26(11):1018-1020
We present the first confirmed case by molecular analysis of a metaphyseal chondrodysplasia, McKusick type, in a 22-week fetus. Two novel compound heterozygous mutations, 64T> A and 79G > T, were found in the highly conserved regions of the RMRP gene. Twenty-two heterozygous g.1018 T> C mutations, two homozygous g.1018 T> C mutations, two heterozygous insertion mutations g.799_g.800insC and one heterozygous insertion mutation g.849_g.850insT were found among 100 normal controls. Careful radiological examination of the fetus for skeletal dysplasia allowed definitive diagnosis, proper genetic counselling and future prenatal diagnosis. Copyright © 2006 John Wiley & Sons, Ltd. 相似文献
89.
Many Eastern European countries suffer the lack of data on concentrations of persistent organic pollutants in the environmental matrices. This absence of information is preventing the local authorities from taking the adequate actions to protect the people and environment. This is even more alarming in the countries recently affected by the wars where the chemicals released to the environment during the military operations can cause a significant ecological damage and health effects on the population. A potential of passive air sampling technique as a tool capable of providing seasonally and spatially resolved information about the local sources and levels of contamination was explored in this study as a first step to the establishment of a cost-effective long-term monitoring in this area. The passive air samplers proved to be a powerful technique capable of detecting the concentrations ranging over four orders of magnitude providing the information very comparable with the conventional techniques. 相似文献
90.
Caenorhabditis elegans is a free-living soil nematode that is commonly used as a model for toxicity tests. The aim of this study was to investigate the toxicity of seven organic pollutants: four azaarenes (quinoline, acridine, phenazine, and 1,10-phenanthroline), short-chain chlorinated paraffins, and two organochlorinated pesticides (toxaphene and hexachlorobenzene). The exposure to all chemicals was carried out in three test media (soil, agar, and aquatic medium), and adult mortality was evaluated after 24 and 48 h. Toxaphene was the most toxic substance with LC(50) (48 h) of 379 mg/kg in the soil and 0.2 mg/L in the aquatic medium. Quinoline was the most toxic chemical in agar test with LC(50) (48 h) of 10 mg/L. HCB showed a very low toxicity in all tests, maybe due to its very low water solubility. Longer than 24-h test duration was found necessary for getting more correct data on toxicity. In comparison with other studies, C. elegans was less sensitive than other soil invertebrates. Different response might be attributed to different exposure routes and shorter test duration. Equilibrium partitioning theory was used to calculate K(oc) from results of soil and aquatic tests but this approach was found not working. Our results suggest that the tests with nematode C. elegans should be included to the battery of tests for risk assessment of POPs in soil. 相似文献