Cultures of the copepod Acartia tonsa are used both in aquaculture and ecotoxicology studies. However, the cultivation of these crustaceans at high densities results in the proliferation of microorganisms that can affect the organisms of interest, leading to illness or death. Antimicrobials inhibit microbial growth and may favour the cultivated species, aiding the development of ecological studies. This study investigated the potential of antimicrobials (antibiotic + antifungal) to inhibit bacteria and fungi when applied to marine zooplankton cultures, using the copepod A. tonsa as a bioindicator of acute toxicity. Treatment with 0.025?g?L?1 of penicillin G potassium + 0.08?g?L?1 of streptomycin sulphate + 0.04?g?L?1 of neomycin sulphate + 0.005?g?L?1 of nystatin resulted in 95% bacterial inhibition (after 12?h of exposure); however, after this time, the inhibitory effect was lost. The antimicrobial combination tested in this study prevented colonisation by fungi until 168?h after exposure, without causing acute toxicity to A. tonsa. Thus, it has potential for use in marine cultures of less sensitive organisms. 相似文献
As a top-level predator, the brown grouper Epinephelus marginatus can play an important role in maintaining the ecological balance of hard-bottom ecosystems. However, to fulfil this role, the species must have a sufficient population density and a wide size range. The presence of such a "healthy" grouper population is one of the known benefits of the protection measures applied to marine protected areas. The availability, in marine reserves, of areas suitable for settlement and recruitment of early juveniles can contribute to preserving a well-structured population. Thus, knowledge of microhabitats preferred by juvenile groupers is an important step in locating, within protected or not yet protected areas, nursery sites that might need a specific protection regime. The aim of the present work was to evaluate habitat and microhabitat preferences of juvenile E. marginatus, in comparison with two other serranids of comparable size, Serranus cabrilla and S. scriba, in the marine reserve of Ustica Island (SW Mediterranean). At different sites, located along the shallow coastal area of the reserve, 329 individuals of the three serranid species were visually surveyed by means of skin- or SCUBA-diving in June 1999. The location of each encountered fish was characterised by both biotic and abiotic variables evaluated at two spatial scales. In order to assess interspecific differences in the use of the spatial environment, the results were analysed by correspondence analysis. According to observations on a small spatial scale, juvenile groupers showed a preference for cavities and recesses, in clear contrast with both Serranus species. When out of such sheltered places, juvenile groupers avoided visually exposed locations (convex substrates and very large visual fields), preferring flat or sub-horizontal rocky substrates. Conversely, S. scriba, and especially S. cabrilla, chose rather open microhabitats (flat to convex substrates, with large to very large visual fields). On a larger spatial scale, brown groupers and the two other serranids showed no marked differences in their habitat preferences. 相似文献
The paper outlines potential uses for coal washery rejects. It considers in detail the use of fluidized-bed combustion as a means of lessening rejects disposal problems, as a method of recovering energy for drying, steam raising and electricity production and as a source of ash as a substitute for natural aggregate. Considerable technical information is now available on the use of fluidized beds for these purposes and the paper concludes that it is appropriate to consider a more detailed, site-specific, evaluation. 相似文献
Journal of Material Cycles and Waste Management - In this work, food wastes (FWs) and domestic sewage sludge (DSS) were used as raw materials for energy recovery by anaerobic digestion (AD). AD was... 相似文献
The aspirations, motivations and choices of individual European citizens are a major driver of the future of global, European and local land use. However, until now no land use study has explicitly attempted to find out how the general public wants to live in the future. This paper forms a first attempt to survey European citizens to understand their desired future lives in relation to consequences for European land use. We used a crowdsourcing experiment to elicit visions from young Europeans about their lives in 2040. Participants completed a graphic novel around carefully selected questions, allowing them to create a story of their imagined future lives in pictures. The methodology worked well, and the sample seemed reasonably representative albeit skewed towards an educated population. In total, 1131 responses from 29 countries were received. Results show a strong desire for change, and for more sustainable lifestyles. There is desire for local and ecologically friendly food production, to eat less meat, to have access to green infrastructure and the ability to cycle to work. However, international travel remains popular, and the desire for extensive food production and owning detached houses with gardens will likely result in complex land use trade-offs. Future work could focus more specifically on quantifying these trade-offs and inform respondents about the consequences of their lifestyle choices. This was a first attempt to use crowdsourcing to understand citizen visions for their lives in the future, and our lessons learned will help future studies improve representativeness and increase responses.
The use of biodegradable polymers is increasingly attracting interest over the last years, since they can reduce the environmental effects related to disposal of traditional plastics and, in general, the use of fossil, non-renewable resources. One of the most promising applications is represented by fibers production. However, the orientation and the crystallinity degrees can significantly affect the mechanical properties. Therefore, it is of interest to investigate on the optimum processing conditions, in order to improve the mechanical properties. In particular, while crystallinity can be slightly modified by the processing, orientation can be significantly improved. In this work, the effects of hot stretching on the mechanical and structural properties of fibers made from two different families of biodegradable blends were investigated. The orientation proved to significantly change the mechanical properties, and it was shown that factors such as the different relaxation times, the different crystallization temperatures and the cooling rate can give opposite effects in the three investigated polymer systems with significant consequences on the mechanical behaviour of the fibers. In particular, the behaviour during fiber production in hot stretching, and the orientation mechanisms were studied and explained on the basis of rheological and thermal properties of the polymers. 相似文献