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1.
The little auk is the most numerous seabird in the North Atlantic and its most important breeding area is the eastern shores of the North Water polynya. Here, a population of an estimated 33 million pairs breeds in huge colonies and significantly shapes the ecosystem. Archaeological remains in the colonies document that the little auk has been harvested over millennia. Anthropological research discloses how the little auk has a role both as social engineer and as a significant resource for the Inughuit today. The hunting can be practiced without costly equipment, and has no gender and age discrimination in contrast to the dominant hunt for marine mammals. Little auks are ecological engineers in the sense that they transport vast amounts of nutrients from sea to land, where the nutrients are deposited as guano. Here, the fertilized vegetation provides important foraging opportunities for hares, geese, fox, reindeer, and the introduced muskox. We estimate that the relative muskox density is ten times higher within 1 km of little auk fertilized vegetation hotspots.  相似文献   
2.
Introduced and cryptogenic species in Port Phillip Bay, Victoria, Australia   总被引:4,自引:0,他引:4  
Port Phillip Bay (PPB) is a large (1,930 km2), temperate embayment in southern Victoria, Australia. Extensive bay-wide surveys of PPB have occurred since 1840. In 1995/1996 the Commonwealth Scientific and Industrial Research Organization (CSIRO) Centre for Research on Introduced Marine Pests (CRIMP) undertook an intensive evaluation of the region with the aims of developing a comprehensive species list of native and introduced biota and contrasting previous bay-wide assessments with a current field survey in order to detect new incursions and discern alterations to native communities. Two methods were used to meet these aims: a re-evaluation of regional museum collections and published research in PPB to identify and determine the timing of introductions; and field surveys for benthic (infauna, epifauna and encrusting) organisms between September 1995 to March 1996. One hundred and sixty introduced (99) and cryptogenic (61) species were identified representing over 13% of the recorded species of PPB. As expected, the majority of these are concentrated around the shipping ports of Geelong and Melbourne. Invasions within PPB appear to be increasing, possibly due to an increase in modern shipping traffic and an increase in aquaculture (historically associated with incidental introductions); however the records of extensive biological surveys suggest that this may, in part, be an artefact of sampling effort. In contrast to Northern Hemisphere studies, PPB (and Southern Hemisphere introductions in general) have significantly different suites of successfully invading taxa. PPB is presented as one of the most invaded marine ecosystems in the Southern Hemisphere.Communicated by M.S. Johnson, Crawley  相似文献   
3.
An evaluation of lateral landfill gas migration was carried out at the Saint-Michel Environmental Complex in Montreal, City of Montreal Landfill Site, Canada, between 2003 and 2005. Biogas concentration measurements and gas-pumping tests were conducted in multilevel wells installed in the backfilled overburden beside the landfill site. A migration event recorded in autumn 2004 during the maintenance shutdown of the extraction system was simulated using TOUGH-LGM software. Eleven high-density instantaneous surface monitoring (ISM) surveys of methane were conducted on the test site. Gas fluxes were calculated by geostatistical analyses of ISM data correlated to dynamic flux chamber measurements. Variograms using normal transformed data showed good structure, and kriged estimates were much better than inverse distance weighting, due to highly skewed data. Measurement-based estimates of yearly off-site surface emissions were two orders of magnitude higher than modelled advective lateral methane flux. Nucleodensimeter measurements of the porosity were abnormally high, indicating that the backfill was poorly compacted. Kriged porosity maps correlated well with emission maps and areas with vegetation damage. Pumping tests analysis revealed that vertical permeability was higher than radial permeability. All results suggest that most of the lateral migration and consequent emissions to the atmosphere were due to the existence of preferential flow paths through macropores. In December 2006, two passively vented trenches were constructed on the test site. They were successful in countering lateral migration.  相似文献   
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On-going population growth and resulting domestic demand for water require rapid and effective decision-making as regards groundwater management and control of the various sources of salinization and pollution in Coastal aquifers. Sustainability of water resources for utilization by future generations must therefore be a high priority, not only for the purpose of fulfilling needs for water usage but also for bringing people into harmony with their ambient natural environment.The objective of this paper is to propose an empirical approach for prioritization of the needs involved for sustainable aquifer management. The approach involves a schematic format to:(1) develop a global understanding of an aquifer's hydrological and environmental properties in order to delineate appropriate eco-hydrological scenarios and recommend corresponding operational management activities; and(2) emphasize the importance of educating and increasing the awareness of the population involved as to the need for and viability of socially acceptable measures for sustainable management of groundwater and other resources.The psychologist Abraham Maslow utilized a pyramid to illustrate that until people's most basic needs were fulfilled, higher levels of needs would remain irrelevant. This paper postulates a comparable pyramid prioritizing hydrological needs required for progressing towards sustainable groundwater resources. Two sub-regions of Israel's Coastal aquifer in the Sharon region have been presented as representative areas, each characterized by different stress of exploitation. In assessing these sub-regions situation, specific measures have been recommended for achieving and/or maintaining sustainable groundwater resources in light of the ambient environment, and the level of the population on the pyramidal hierarchy of groundwater needs.  相似文献   
6.
We have earlier shown that radio frequency electromagnetic fields can cause significant leakage of albumin through the blood–brain barrier of exposed rats as compared to non-exposed rats, and also significant neuronal damage in rat brains several weeks after a 2 h exposure to a mobile phone, at 915 MHz with a global system for mobile communications (GSM) frequency modulation, at whole-body specific absorption rate values (SAR) of 200, 20, 2, and 0.2 mW/kg. We have now studied whether 6 h of exposure to the radiation from a GSM mobile test phone at 1,800 MHz (at a whole-body SAR-value of 13 mW/kg, corresponding to a brain SAR-value of 30 mW/kg) has an effect upon the gene expression pattern in rat brain cortex and hippocampus—areas where we have observed albumin leakage from capillaries into neurons and neuronal damage. Microarray analysis of 31,099 rat genes, including splicing variants, was performed in cortex and hippocampus of 8 Fischer 344 rats, 4 animals exposed to global system for mobile communications electromagnetic fields for 6 h in an anechoic chamber, one rat at a time, and 4 controls kept as long in the same anechoic chamber without exposure, also in this case one rat at a time. Gene ontology analysis (using the gene ontology categories biological processes, molecular functions, and cell components) of the differentially expressed genes of the exposed animals versus the control group revealed the following highly significant altered gene categories in both cortex and hippocampus: extracellular region, signal transducer activity, intrinsic to membrane, and integral to membrane. The fact that most of these categories are connected with membrane functions may have a relation to our earlier observation of albumin transport through brain capillaries.  相似文献   
7.
This paper summarizes developments made in the field of waste-to-energy technology between the 1980s and the present. In the USA, many waste-to-energy systems were developed in the 1980s and early 1990s. These plants generated power relatively efficiently (typically 23%) in 60 bar/ 443 degrees C boilers. Unfortunately, the development came to a stop when the US Supreme Court rejected the practice of waste flow control in 1994. Consequently, waste was directed to mega-landfills, associated with very negative environmental impacts. However, given landfill taxes and increased fuel prices, new waste-to-energy projects have recently been developed. Attractive premiums for renewable power production from municipal waste have been introduced in several European countries. This triggered important innovations in the field of improved energy recovery. Examples of modern waste-to-energy plants are Brescia and Amsterdam with net efficiencies of 24 and 30%, respectively. Incineration is traditionally preferred in Japan due to space constraints. New legislation promoted ash melting or gasification to obtain improved ash quality. However, these processes reduce the efficiency in terms of energy, cost and availability. A new oxygen-enriched waste-to-energy system is under development in order to better achieve the required inert ash quality.  相似文献   
8.
Avermectins are widely used to treat livestock for parasite infections. Ivermectin, which belongs to the group of avermectins, is particularly hazardous to the environment, especially to crustaceans and to soil-dwelling organisms. Sorption is one of the key factors controlling transport and bioavailability. Therefore, batch studies have been conducted to characterize the sorption and desorption behavior of ivermectin in three European soils (Madrid, York, and artificial soil). The solid-water distribution coefficient (K(d)) for ivermectin sorption to the tested soils were between 57 and 396 L kg(-1) (determined at 0.1 microg g(-1)), while the organic carbon-normalized sorption coefficients (K(oc)) ranged from 4.00 x 10(3) to 2.58 x 10(4) L kg(-1). The Freundlich sorption coefficient (K(F)) was 396 (after 48 h) for the artificial soil over a concentration range of 0.1 to 50 microg g(-1), with regression constants indicating a concentration-dependent sorption. The obtained data and data in the literature are inconclusive with regard to whether hydrophobic partitioning or more specific interactions are involved in sorption of avermectins. For abamectin, hydrophobic partitioning seems to be one of the dominant types of binding, while hydrophobicity is less important for ivermectin, which is probably due to the lower lipophilicity of the molecule. Furthermore, the presence of cations such as Ca(2+) leads to decreasing sorption. Thus, it is presumed that ivermectin binds to soil by formation of complexes with immobile, inorganic soil matter. In contrast to abamectin, hysteresis could be excluded for ivermectin in the studied soils for the evaluation of sorption and desorption. The sorption mechanism is highly dependent on physicochemical properties of the avermectin.  相似文献   
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10.
A diffusive sampling method for the determination of methyl isocyanate (MIC) in air is introduced. MIC is collected using a glass fiber filter impregnated with 4-nitro-7-piperazinobenzo-2-oxa-1,3-diazole (NBDPZ). The urea derivative formed is desorbed from the filter with acetonitrile and analyzed by means of high-performance liquid chromatography (HPLC) using fluorescence detection (FLD) with lambdaex = 471 nm and lambdaex = 540 nm. Additionally, a method was developed using tandem mass spectrometric (MS-MS) detection, which was performed as selected reaction monitoring (SRM) on the transition [MIC-NBDPZ + H]+ (m/z 307) to [NBDPZ + H]+ (m/z 250). The diffusive sampler was tested with MIC concentrations between 1 and 35 microg m(-3). The sampling periods varied from 15 min to 8 h, and the relative humidity (RH) was set from 20% up to 80%. The sampling rate for all 15 min experiments was determined to be 15.0 mL min(-1) (using HPLC-FLD) with a relative standard deviation of 9.9% for 56 experiments. At 80% RH, only 15 min sampling gave acceptable results. Further experiments revealed that humidity did not affect the MIC derivative but the reagent on the filter prior to and during sampling. The sampling rate for all experiments (including long term sampling) performed at 20% RH was found to be 15.0 mL min(-1) with a relative standard deviation of 6.3% (N = 42). The limit of quantification was 3 microg m(-3) (LC-MS-MS: 1.3 microg m(-3)) for 15 min sampling periods and 0.2 microg m(-3) (LC-MS-MS: 0.15 microg m(-3)) for 8 h sampling runs applying fluorescence detection.  相似文献   
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