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891.
Hauke Reuter Ulrike Middelhoff Frieder Graef Richard Verhoeven Thomas Batz Martin Weis Gunther Schmidt Winfried Schröder Broder Breckling 《Environmental science and pollution research international》2010,17(8):1479-1490
Background, aim and scope
European legislation stipulates that genetically modified organisms (GMO) have to be monitored to identify potential adverse environmental effects. A wealth of different types of monitoring data from various sources including existing environmental monitoring programmes is expected to accumulate. This requires an information system to efficiently structure, process and evaluate the monitoring data. 相似文献892.
Niels M. Schmidt Bess Hardwick Olivier Gilg Toke T. Høye Paul Henning Krogh Hans Meltofte Anders Michelsen Jesper B. Mosbacher Katrine Raundrup Jeroen Reneerkens Lærke Stewart Helena Wirta Tomas Roslin 《Ambio》2017,46(1):12-25
How species interact modulate their dynamics, their response to environmental change, and ultimately the functioning and stability of entire communities. Work conducted at Zackenberg, Northeast Greenland, has changed our view on how networks of arctic biotic interactions are structured, how they vary in time, and how they are changing with current environmental change: firstly, the high arctic interaction webs are much more complex than previously envisaged, and with a structure mainly dictated by its arthropod component. Secondly, the dynamics of species within these webs reflect changes in environmental conditions. Thirdly, biotic interactions within a trophic level may affect other trophic levels, in some cases ultimately affecting land–atmosphere feedbacks. Finally, differential responses to environmental change may decouple interacting species. These insights form Zackenberg emphasize that the combination of long-term, ecosystem-based monitoring, and targeted research projects offers the most fruitful basis for understanding and predicting the future of arctic ecosystems. 相似文献
893.
Ana S. Vaz Christoph Kueffer Christian A. Kull David M. Richardson Stefan Schindler A. Jesús Muñoz-Pajares Joana R. Vicente João Martins Cang Hui Ingolf Kühn João P. Honrado 《Ambio》2017,46(4):428-442
Interdisciplinarity is needed to gain knowledge of the ecology of invasive species and invaded ecosystems, and of the human dimensions of biological invasions. We combine a quantitative literature review with a qualitative historical narrative to document the progress of interdisciplinarity in invasion science since 1950. Our review shows that 92.4% of interdisciplinary publications (out of 9192) focus on ecological questions, 4.4% on social ones, and 3.2% on social–ecological ones. The emergence of invasion science out of ecology might explain why interdisciplinarity has remained mostly within the natural sciences. Nevertheless, invasion science is attracting social–ecological collaborations to understand ecological challenges, and to develop novel approaches to address new ideas, concepts, and invasion-related questions between scholars and stakeholders. We discuss ways to reframe invasion science as a field centred on interlinked social–ecological dynamics to bring science, governance and society together in a common effort to deal with invasions. 相似文献
894.
895.
A Method for Ensemble Wildland Fire Simulation 总被引:1,自引:0,他引:1
Mark A. Finney Isaac C. Grenfell Charles W. McHugh Robert C. Seli Diane Trethewey Richard D. Stratton Stuart Brittain 《Environmental Modeling and Assessment》2011,16(2):153-167
An ensemble simulation system that accounts for uncertainty in long-range weather conditions and two-dimensional wildland
fire spread is described. Fuel moisture is expressed based on the energy release component, a US fire danger rating index,
and its variation throughout the fire season is modeled using time series analysis of historical weather data. This analysis
is used to characterize the seasonal trend in ERC, autocorrelation of residuals, and daily standard deviation and stochastically
generate artificial time series of afternoon fuel moisture. Daily wind speed and direction are sampled stochastically from
joint probabilities of historical wind speed and direction for the date range of the fire simulation period. Hundreds or thousands
of fire growth simulations are then performed using the synthetic fire weather sequences. The performance of these methods
is evaluated in terms of the number of ensemble member simulations, one- versus two-dimensional fire spread simulations, and
comparison with results from 91 fires occurring from 2007 to 2009. Simulations were found to be in consistent agreement with
observations, but trends indicate that the ensemble average of simulated fire sizes were consistently larger than actual fires
whereas the farthest extent burned by fires was underestimated. 相似文献
896.
Chlorinated paraffins (CPs) are straight chain hydrocarbons that are produced as complex mixtures and are used as flame retardants
and paint additives. These mixtures are extremely difficult to characterize using conventional chromatographic methods, as
conventional gas chromatography results in unresolved complex chromatograms that preclude the identification and quantification
of individual congeners or any reasonable assessment of the average carbon chain length. Carbon chain length is an important
parameter for assessing physical properties and the toxicity of these materials. We have modified and improved a previously
published gas chromatography–flame ionization detector method that uses Pd catalyst held in the gas chromatograph injector
to simultaneously dechlorinate the CPs and separate the resulting alkanes. In addition, we have adapted this method to gas
chromatography–mass spectrometry. Dehalogenation of other compounds was also studied with this system to investigate potential
application to other complex halogenated mixtures. 相似文献
897.
Adjoint method is applied to various oil spill problems. A three-dimensional model for describing the dispersion of a quasi-passive substance (a pollutant or a nutrient) and its adjoint model are considered in a limited sea region. Direct and adjoint estimates are used to get dual (equivalent) estimates of the mean concentration of the substance in important zones of the region. The role of dual estimates is illustrated with a few examples. They include such oil spill problems as the search of the most dangerous point of the oil tanker route, the oil dispersion with a climatic velocity, and the dependence of the oil concentration estimates on the oil spill rate. One more example is the application of optimal bioremediation strategy for cleaning a few zones polluted by oil. In this case, instead of oil, the model describes the dispersion of a nutrient released to marine environment. Balanced, unconditionally stable second-order finite-difference schemes based on the splitting method for the solution of the dispersion model and its adjoint are suggested. The main and adjoint difference schemes are compatible in the sense that at every fractional step of the splitting algorithm, the one-dimensional split operators of both schemes satisfy a discrete form of Lagrange identity. In the special unforced and non-dissipative case, each scheme has two conservation laws. Every split one-dimensional problem is solved by Thomas’ factorization method. 相似文献
898.
Cassava starch waste hydrolysates (CSWHs) with different degrees of polymerisation, i.e., CSWHs-1, CSWHs-2 and CSWHs-3, were prepared through the hydrolysis of cassava starch waste with thermostable a-amylase from Thermococcus sp. HJ21. The prepared CSWHs were then used as a carbon source for curdlan production with Alcaligenes faecalis ATCC 31749. The amount of curdlan produced and the glucosyltransferase activity during curdlan synthesis increased more obviously when CSWHs-2 was used as the carbon source than when glucose was used. Using both carbon sources, the maximum curdlan production was observed at day 5, and the maximum glucosyltransferase activity was observed at day 4. Glucosyltransferase activity decreased thereafter, and biomass continued to increase until the end of the experiment (day 6). Results indicated that the enhanced curdlan production with CSWHs as the carbon source was highly correlated with glucosyltransferase activity. 相似文献
899.
Ernesto Azzurro Antonio Pais Pierpaolo Consoli Franco Andaloro 《Marine Biology》2007,151(6):2245-2253
Ecological information on coastal fish distribution patterns and habitat use can be greatly improved by nocturnal samplings
and observations. To this purpose, the structure of a Mediterranean fish assemblage inhabiting the shallow rocky littoral
of Linosa Island (Sicily Strait, Italy) was examined by using visual census to detect possible diel variations in species
composition and abundance. Day–night fish distribution patterns were investigated by multivariate and univariate analyses.
Overall, 42 fish taxa belonging to 19 families were recorded: 35 during the day and 24 during the night. Seventeen species
were common to both diurnal and nocturnal assemblages. Within the diurnal assemblage, Chromis chromis was the most represented species (37.2%), followed by Thalassoma pavo (23.2%) and Sparisoma cretense (10.8%). Within the nocturnal assemblage, the most abundant taxon was Atherina spp. (33.9%), followed by Apogon imberbis (26.4%) and Boops boops (11.5%). Our results indicated wide variation in the abundance and species composition during the day and during the night.
Multi Dimensional Scaling plot showed a clear-cut separation between the two assemblages and analysis of similarities found
significant differences as well. SIMPER analysis revealed that ten species individually contributed by more than 2.5% to the
dissimilarity between diurnal and nocturnal assemblages, T. pavo, C. chromis and S. cretense being the first three species in order of decreasing percentage. ANOVA performed on species richness and fish abundance detected
significant differences between diurnal and nocturnal assemblages, the latter showing far lower average values for both variables. 相似文献
900.
The effect of salinity on survival, bioenergetics and predation risk was studied in two common mud crabs in the Gulf of Mexico,
Eurypanopeus depressus and Panopeus simpsoni. Eurypanopeus survived better at low salinities (the 28-day LC50 of E. depressus was 0.19 PSU compared with 6.97 PSU for P. simpsoni). While low salinity increased energy expenditure and reduced food consumption and absorption, resulting in lower scope for
growth, identical responses to salinity occurred in both species. Both species also had similar salinity-dependent patterns
of hyper-osmoregulation. Because these physiological mechanisms could not explain differences between the two species in salinity
tolerance, we explored the effect of salinity on competition for refugia. Eurypanopeus had higher resource holding potential for refugia, especially at low salinity. As a consequence it had lower predation risk
to blue crabs in laboratory experiments. The higher tolerance by E. depressus for low salinities, and greater resource holding potential for refugia may explain why it has a more euryhaline distribution
than P. simpsoni. 相似文献