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601.
区域开发生态影响评价方法及应用 总被引:7,自引:0,他引:7
建立一套系统的区域生态影响评价方法,对于区域环评和环境的可持续发展具有重要的意义。以济南舜湖社区区域开发为例,建立和应用由生态指标法、图形叠图法、景观生态学方法构成的方法体系,对舜湖社区区域开发生态环境影响进行了评价,并提出生态保护和建设的具体措施。结果表明,3者构成的方法体系,能较全面的反映生态环境质量现状,预测生态环境影响,有较为广泛的应用前景。 相似文献
602.
Effect of Fe0 quantity on the efficiency of integrated microbial-Fe0 treatment processes 总被引:4,自引:0,他引:4
Batch experiments were conducted with different reaction systems to investigate how the treatment efficiency of integrated microbial-Fe0 processes is affected by the amount of Fe0 added. Abiotic experiments with hexavalent chromium and carbon tetrachloride mixtures corroborated that different pollutants could compete for reactive sites on the iron surface, which would hinder specific degradation rates when the available Fe0 surface area is relatively small (e.g., 11 m(2) l(-1)). In such cases, reductive precipitation of chromium could occlude reactive sites and significantly inhibit removal efficiency. Microbial participation in the cleanup process was also influenced by the amount of Fe0 added. Increasing the Fe0 dose (and thus the available surface area) had a stimulatory effect possibly due to a higher production of cathodic H2, which can be used as electron donor for reductive biotransformation of many pollutants. However, high Fe0 doses had an inhibitory effect due to a corrosion-induced increase in pH beyond the optimum range of the bacteria. This suggest that there may be a system-specific, optimum quantity of Fe0 that satisfies availability requirements to preclude contaminant competition for reactive sites and biological requirements for H2 production while minimizing inhibitory increases in pH. Results also confirmed extensive RDX mineralization in bioaugmented (but not in abiotic) Fe0 systems, and support the notion that permeable reactive iron barriers performance might be enhanced by the participation of some microorganisms. 相似文献
603.
604.
Polycyclic aromatic hydrocarbons (PAHs) and dioxins are lipophilic organic pollutants occurring widely in the terrestrial environment. In order to study the PAHs and 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) transfer in the food chain, pigs have been fed with milk mixed either with 14C-phenanthrene, with 14C-benzo[a]pyrene or with 14C-TCDD. The analysis of portal and arterial blood radioactivity showed that both PAHs and TCDD were absorbed with a maximum concentration at 4-6 h after milk ingestion. Then, the blood radioactivity decreased to reach background levels 24 h after milk ingestion. Furthermore, the portal and arterial blood radioactivities were higher for phenanthrene (even if the injected load was the lowest) than these of benzo[a]pyrene or these of TCDD, in agreement with their lipophilicity and water solubility difference. Main 14C absorption occurred during the 1-3 h time period after ingestion for 14C-phenanthrene and during the 3-6 h time period for 14C-benzo[a]pyrene and for 14C-TCDD. 14C portal absorption rate was high for 14C-phenanthrene (95%), it was close to 33% for 14C-benzo[a]pyrene and very low for 14C-TCDD (9%). These results indicate that the three studied molecules have a quite different behaviour during digestion and absorption. Phenanthrene is greatly absorbed and its absorption occurs via the blood system, whereas benzo[a]pyrene and TCDD are partly and weakly absorbed respectively. However these two molecules are mainly absorbed via the portal vein. 相似文献
605.
Eric Lichtfouse Michel Lichtfouse Michaele Kashgarian Roland Bol 《Environmental Chemistry Letters》2005,3(2):78-81
Measuring the amount of fossil fuel carbon stored in the vegetation is now crucial to understand the mechanisms ruling climate
changes. In this respect, highly polluted areas such as major towns represent “natural” laboratories because fossil fuel CO2 (14C-free) is isotopically distinct from mean atmospheric CO2 (14C-labeled). Here, a14C study of urban grasses near a major highway in Paris, France, shows that plants store up to 13% of fossil fuel carbon. The
14C composition of urban grasses is thus a novel parameter to assess the fossil fuel CO2 pollution. 相似文献
606.
607.
Patrice Lucchetta Emmanuel Desouhant Eric Wajnberg Carlos Bernstein 《Behavioral ecology and sociobiology》2007,61(9):1409-1418
The reproductive success of insect parasitoids depends on two activities, searching for hosts to obtain immediate fitness
rewards (offspring) and searching for food to extend life span and enhance future reproductive opportunities. Models suggest
that to deal with this trade-off and to cope with the variability of the resources they depend on, parasitoids should simultaneously
integrate information originating from three distinct sources: host and food availabilities in the environment (environmental
information) and the metabolic reserves of the parasitoid (internal information). We tested whether, in the parasitic wasp
Venturia canescens, these three types of information are perceived simultaneously and interact during host-patch exploitation. Experiments were
performed with strains originating from two different geographical locations and with individuals of the two reproductive
modes, arrhenotoky and thelytoky. We hypothesised that there would be differences between modes of reproduction as they thrive
in different ecological conditions. Our results show that metabolic state, food availability and the number of ovipositions
performed simultaneously modulate patch residence time in V. canescens of both populations and reproductive modes. Unfed wasps left their host patch earlier than fed ones. The tendency to leave
the patch increased with an increasing probability of finding food. Our study confirms that globally, each oviposition increases
the patch-leaving tendency (decremental mechanism). This effect was modulated by both the metabolic reserves and food availability,
and the relationship depended on the geographic origin of populations. Individuals of one of the populations switched from
a decremental to an incremental patch-leaving mechanism depending on the presence or absence of food in the vicinity. Differences
between reproductive modes in the responses to environmental cues can be explained by the different ecological conditions
they live in. 相似文献
608.
Eric J Bergman Robert A Garrott Scott Creel John J Borkowski Rosemary Jaffe E G R Watson 《Ecological applications》2006,16(1):273-284
Within predator-prey systems behavior can heavily influence spatial dynamics, and accordingly, the theoretical study of how spatial dynamics relate to stability within these systems has a rich history. However, our understanding of these behaviors in large mammalian systems is poorly developed. To address the relationship between predator selection patterns, prey density, and prey vulnerability, we quantified selection patterns for two fine-scale behaviors of a recovering wolf (Canis lupus) population in Yellowstone National Park, Wyoming, USA. Wolf spatial data were collected between November and May from 1998-1999 until 2001-2002. Over four winters, 244 aerial locations, 522 ground-based telemetry locations, 1287 km of movement data from snow tracking, and the locations of 279 wolf kill sites were recorded. There was evidence that elk (Cervus elaphus) and bison (Bison bison) densities had a weak effect on the sites where wolves traveled and made kills. Wolf movements showed a strong selection for geothermal areas, meadows, and areas near various types of habitat edges. Proximity to edge and habitat class also had a strong influence on the locations where elk were most vulnerable to predation. There was little evidence that wolf kill sites differed from the places where wolves traveled, indicating that elk vulnerability influenced where wolves selected to travel. Our results indicate that elk are more vulnerable to wolves under certain conditions and that wolves are capable of selecting for these conditions. As such, vulnerability plays a central role in predator-prey behavioral games and can potentially impact the systems to which they relate. 相似文献
609.
610.
This study aims to screen plant species native to Taiwan that could be used to eliminate (137)Cs radionuclides from contaminated soil. Four kinds of vegetables and two kinds of plants known as green manures were used for the screening. The test plants were cultivated in (137)Cs-contaminated soil and amended soil which is a mixture of the contaminated one with a horticultural soil. The plant with the highest (137)Cs transfer factor was used for further examination on the effects of K addition on the transfer of (137)Cs from the soils to the plant. Experimental results revealed that plants cultivated in the amended soil produced more biomass than those in the contaminated soil. Rape exhibited the highest production of aboveground parts, and had the highest (137)Cs transfer factor among all the tested plants. The transfer of (137)Cs to the rape grown in the soil to which 100 ppm KCl commonly used in local fertilizers had been added, were restrained. Results of this study indicated that rape, a popular green manure in Taiwan, could remedy (137)Cs-contaminated soil. 相似文献