Spatial and temporal distribution of heavy metal concentrations in mussels (Mytilus edulis) from the Baie des Chaleurs, New Brunswick, Canada     

Fraser M  Surette C  Vaillancourt C 《Marine pollution bulletin》2011,62(6):1345-1351

Previous studies on heavy metal contamination of the Baie des Chaleurs focus only on industrial centers and overlooked the ecosystem as a whole. To fill this gap, the objective of this study is to establish a baseline of the spatio-temporal distribution of heavy metals in mussels from the Baie des Chaleurs based on the ecosystem approach. Our results show, for the first time, a cadmium contamination in mussels across the south coast of the Baie des Chaleurs and not only in industrial centers. Our results also confirm previous studies showing heavy metal contamination of the Belledune area. This study demonstrates that the use of the ecosystemic approach is essential to obtain a comprehensive picture of environmental contamination in marine ecosystems.  相似文献   

“Global warming” versus “climate change”: A replication on the association between political self-identification,question wording,and environmental beliefs     

Alistair Raymond Bryce Soutter  René Mõttus 《Chemie der Erde / Geochemistry》2011

Climate change is one of the greatest threats to humanity and requires immediate action. Schuldt, Konrath, and Schwarz (2011) suggested that beliefs in environmental phenomena can be influenced by the terminology used to describe it: changing question wording from global warming to climate change resulted in a 6.3 percentage point increase in belief in environmental phenomena. This association was moderated by political self-identification, with Republicans being 16.2 percentage points more likely to believe in climate change than in global warming, with Democrats showing no difference. The potential for connotative meanings to shift over time and the sociopolitical changes since the original study, potential policy and environmental campaign implications, and an expansion of these findings to other countries, motivated an attempt to replicate this important finding. This pre-registered study repeated the original procedures in the United States of America and two other countries (United Kingdom and Australia; total N = 5,717). Although question wording no longer had a significant effect on beliefs in climate change/global warming, the association of political self-identification with beliefs in environmental phenomena replicated in all three countries, with Conservatives consistently believing less in climate change/global warming than Liberals. The potential impacts of temporal and methodological differences on the discrepancies between this study's and the original's findings are discussed.  相似文献   

The initial impact of the tobacco buyout program     

Hart JF 《Geographical review》2011,101(3):447-457

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Structural and stratigraphic problems of the Argylla Formation near Mary Kathleen,Queensland     

R. J. Holcombe  S. J. Fraser 《Australian Journal of Earth Sciences》2013,60(7-8):419-434

Rocks formerly mapped as Lower Proterozoic Argylla Formation near Mary Kathleen in northwest Queensland consist of parallel lenses of very deformed schist, quartzite and various types of metaporphyry. Completely intermingled with these are bands of amphibolite and lenses of the adjacent Wonga Granite. Finite ductile strains of 65–80% maximum shortening have been measured; these have produced transposition on both a mesoscopic and macroscopic scale. It is shown that the major stratigraphic boundaries are much shallower than the steeply dipping, constantly oriented unit boundaries. Intrusive relationships and structural criteria indicate that all the lithologies found within the mapped boundaries of the Argylla Formation are chronologically separate. This is confirmed by mapping in the much less deformed area near Winston Churchill Mine to the north. It is concluded that an original sedimentary pile was intruded first by dolerite dyke swarms and then by acid porphyry sills followed by granitic sill‐like instrusions of the Wonga Granite. Subsequent deformation and macroscopic transposition produced the present parallel‐layered structure.

These conclusions differ from currently accepted relationships of the Argylla Formation. Various possibilities are suggested; we favour the view that none of these rock types is equivalent to the defined Argylla Formation, and that the acid porphyries are younger than at Jeast some of the metasediments of the Mary Kathleen Group and may be a precursor of the Wonga Granite intrusion.  相似文献   

Background simulations for the Large Area Detector onboard LOFT     

Riccardo Campana  Marco Feroci  Ettore Del Monte  Teresa Mineo  Niels Lund  George W. Fraser 《Experimental Astronomy》2013,36(3):451-477

The Large Observatory For X-ray Timing (LOFT), currently in an assessment phase in the framework the ESA M3 Cosmic Vision programme, is an innovative medium-class mission specifically designed to answer fundamental questions about the behaviour of matter, in the very strong gravitational and magnetic fields around compact objects and in supranuclear density conditions. Having an effective area of ～10 m² at 8 keV, LOFT will be able to measure with high sensitivity very fast variability in the X-ray fluxes and spectra. A good knowledge of the in-orbit background environment is essential to assess the scientific performance of the mission and optimize the design of its main instrument, the Large Area Detector (LAD). In this paper the results of an extensive Geant-4 simulation of the instrumentwillbe discussed, showing the main contributions to the background and the design solutions for its reduction and control. Our results show that the current LOFT/LAD design is expected to meet its scientific requirement of a background rate equivalent to 10 mCrab in 2?30 keV, achieving about 5 mCrab in the most important 2–10 keV energy band. Moreover, simulations show an anticipated modulation of the background rate as small as 10 % over the orbital timescale. The intrinsic photonic origin of the largest background component also allows for an efficient modelling, supported by an in-flight active monitoring, allowing to predict systematic residuals significantly better than the requirement of 1 %, and actually meeting the 0.25 % science goal.  相似文献   

An international comparison of governmental disclosure of hydrocarbon spills from offshore oil and gas installations     

Fraser GS  Ellis J  Hussain L 《Marine pollution bulletin》2008,56(1):9-13

The cumulative effect of accidental spills from oil and gas extraction in the marine environment can have significant impacts on marine wildlife. Oil and gas operators are typically required to report spill data as part of a regulatory process. We conducted a survey of the public disclosure of hydrocarbon spill data for four countries, Australia, Canada, United Kingdom and United States. There was significant variation in the spill data statistics that were publicly reported by the regulators. No country provided full disclosure of spill data or follow-up actions taken by the regulator on their website. The lack of disclosure of spill data is of concern because the scale of environmental effects is more difficult to assess, insufficient information is available to assess the accuracy of predictions made in the environmental assessment process, and without consistency of spill reporting there is no method to compare regional differences of spill rates.  相似文献   

Contamination of marine biogenic habitats and effects upon associated epifauna     

Roberts DA  Johnston EL  Poore AG 《Marine pollution bulletin》2008,56(6):1057-1065

Habitat-forming organisms are frequently used as biomonitors in marine environments due to a widespread ability to accumulate toxic contaminants. Few studies, however, have considered the consequences of these accumulated contaminants on the abundant and diverse fauna associated with these habitats. In this review, we summarize research which has investigated the contamination of biogenic habitats (including seagrasses, macroalgae, ascidians, sponges and bivalve reefs) and the impact of this contamination on the habitat use, feeding behaviour and survival of associated epifauna. In many cases, ecological impacts upon epifauna are not simply predicted by levels of contamination in their habitat, but are determined by the foraging, feeding and reproductive behaviours of the inhabiting organisms. Thus, a thorough understanding of these ecological processes is essential in order to understand the effects of contaminants upon epifaunal communities. The scope of biomonitoring studies which assess the contamination of biogenic habitats should be expanded to include an assessment of potential effects upon associated epifauna. When combined with manipulative field experiments such an approach would greatly assist in our understanding of indirect effects of contaminants in these important benthic habitats.  相似文献   

Object-oriented classification of very high resolution airborne imagery for the extraction of hedgerows and field margin cover in agricultural areas     

Kevin Tansey  Ian Chambers  Andrew Anstee  Anthony Denniss  Alistair Lamb 《Applied geography (Sevenoaks, England)》2009,29(2):145-157

The recent advancement in technology for the airborne collection and subsequent processing and analysis of digital remotely sensed data has been significant. An investigation into the contributions that recent developments have made to the assessment and extraction of hedgerow and field margins is presented. Research into the active legislation by which hedgerows and agricultural biodiversity in England are bound is brought together in the concept of an ideal classification. Using Leica Geosystems ADS40 data, collected for Berkshire (UK), the degree to which the ideal classification can be reached is investigated, focusing on the extraction of hedgerows and unploughed field margin protective boundary strips as image objects. Elevation data were derived from the ADS40 imagery data to accompany true-colour and colour-infrared spectral information. By buffering the detected hedgerow objects in a GIS, we facilitated an investigation of the presence of measures that satisfy the minimum hedgerow protection requirements stipulated by the UK Department for Environment, Food and Rural Affairs (DEFRA). In our study area, it was estimated that 68% of areas that need to be classified as ‘grassy hedgerow boundary strip’ to satisfy the minimum requirements of the legislation were established with low-lying grassy cover before the introduction of the legislation in July 2005. The implications of this research for the development of automated classification methods for field scale agricultural mapping are discussed.  相似文献   

极隙区Pc3频段脉动的传播特性   总被引：1，自引：0，他引：1       下载免费PDF全文

刘勇华  刘瑞源  杨少峰  贺龙松  BJ Fraser 《极地研究》2000,12(2):121-128

南极中山站和戴维斯站 (不变磁纬 74.5°S)白天中午位于磁层极隙区 ,夜间位于极盖区或极光带的极向边沿。两站均安装了完全相同的感应式磁力计。选择两站 1 997年 3月和 1 996年 6、9、1 2月的数据 ,运用快速傅立叶变换和波形检查方法选择 Pc3频段脉动事件 ,然后用信号互谱技术进行统计分析 ,结果如下 :在中山站 -戴维斯站 ,Pc3频段脉动主要出现于白天中午 /磁中午和磁午夜附近 ;白天 ,Pc3频段脉动振幅、出现率和出现的时间范围均有一定的季节变化 ,冬季最小 ,但在夜间 ,Pc3频段脉动没有这种变化 ;夜间 ,Pc3频段脉动振幅比在白天大许多 ;Pc3频段脉动传播方向 ,白天主要向西 ,夜间不太规则。这些可能反映了电离层电导率和日侧电离层电流系统对 Pc3频段脉动的影响。  相似文献   

The Falkland Islands’ palaeoecological response to millennial‐scale climate perturbations during the Pleistocene–Holocene transition: Implications for future vegetation stability in the southern ocean islands     

Robert G. Scaife  Antony J. Long  Alistair J. Monteath  Paul D. M. Hughes  Michael J. Bentley  Philip Stone 《第四纪科学杂志》2019,34(8):609-620

Oceanic island flora is vulnerable to future climate warming, which is likely to promote changes in vegetation composition, and invasion of non‐native species. Sub‐Antarctic islands are predicted to experience rapid warming during the next century; therefore, establishing trajectories of change in vegetation communities is essential for developing conservation strategies to preserve biological diversity. We present a Late‐glacial‐early Holocene (16 500–6450 cal a bp ) palaeoecological record from Hooker's Point, Falkland Islands (Islas Malvinas), South Atlantic. This period spans the Pleistocene‐Holocene transition, providing insight into biological responses to abrupt climate change. Pollen and plant macrofossil records appear insensitive to climatic cooling during the Late‐glacial, but undergo rapid turnover in response to regional warming. The absence of trees throughout the Late‐glacial‐early Holocene enables the recognition of far‐travelled pollen from southern South America. The first occurrence of Nothofagus (southern beech) may reflect changes in the strength and/or position of the Southern Westerly Wind Belt during the Late‐glacial period. Peat inception and accumulation at Hooker's Point is likely to be promoted by the recalcitrant litter of wind‐adapted flora. This recalcitrant litter helps to explain widespread peatland development in a comparatively dry environment, and suggests that wind‐adapted peatlands can remain carbon sinks even under low precipitation regimes. © 2019 The Authors. Journal of Quaternary Science Published by John Wiley & Sons Ltd.  相似文献