Ecological consequences of dredged material disposal in the marine environment: a holistic assessment of activities around the England and Wales coastline   总被引：2，自引：0，他引：2  

Bolam SG  Rees HL  Somerfield P  Smith R  Clarke KR  Warwick RM  Atkins M  Garnacho E 《Marine pollution bulletin》2006,52(4):415-426

This study provides a holistic perspective on the ecological effects of dredged material disposal, both intertidally and subtidally. A number of numerical techniques (univariate, distributional, multivariate and meta-analysis) were used to assess impacts at 18 different disposal sites. The analyses revealed that ecological effects associated with dredged material disposal were dependent on the numerical techniques used, and that impacts were disposal-site specific. Disposal-site communities were generally faunistically impoverished to varying degrees, and impacts following intertidal placement were comparable to those of subtidal placement. We conclude that any assessment of the consequences of dredged material disposal to the coastal environment must take account of site-specific variation in prevailing hydrographic regimes and in ecological status, along with information on the disposal activity itself (mode, timing, quantity, frequency and type of material). As would be expected, variability in the latter presents a significant challenge in attempts to generalise about environmental and ecological impacts.  相似文献   

Midge-inferred temperature reconstructions and vegetation change over the last ~15,000?years from Trout Lake, northern Yukon Territory, eastern Beringia     

Fonya Irvine  Les C. Cwynar  Jesse C. Vermaire  Andrew B. H. Rees 《Journal of Paleolimnology》2012,48(1):133-146

Two cores from Trout Lake, northern Yukon, yielded quantitative estimates of summer air temperatures using fossil midge larvae. Warming began around 14,400?cal?yr BP, with inferred mean July air temperatures reaching values warmer than present by 12,800?cal?yr BP. A 1?°C cooling from 12,200 to 11,200?cal?yr BP closely corresponds with the Younger Dryas chronozone. A broad temperature maximum occurred between 10,800 and 9,800?cal?yr BP, with mean July air temperature about 2.2?°C warmer than present. This represents an early Holocene thermal maximum and coincides with increased organic content of the sediment. Both the shallow- and deep-water cores show similar temperature trends for their overlapping periods. The inferred rise in mean July air temperature at 14,200?cal?yr BP coincides with a shift in vegetation from an herb- to shrub-dominated landscape. In contrast, the increase in Alnus pollen at 6,400?cal?yr BP does not coincide with a change in temperature, but may be a response to a rise in precipitation.  相似文献   

Potential impact of climate change and reindeer density on tundra indicator species in the Barents Sea region     

Christoph Zöckler  Lera Miles  Lucy Fish  Annett Wolf  Gareth Rees  Fiona Danks 《Climatic change》2008,87(1-2):119-130

Climate change is expected to alter the distribution of habitats and thus the distribution of species connected with these habitats in the terrestrial Barents Sea region. It was hypothesised that wild species connected with the tundra and open-land biome may be particularly at risk as forest area expands. Fourteen species of birds were identified as useful indicators for the biodiversity dependent upon this biome. By bringing together species distribution information with the LPJ-GUESS vegetation model, and with estimates of future wild and domestic reindeer density, potential impacts on these species between the present time and 2080 were assessed. Over this period there was a net loss of open land within the current breeding range of most bird species. Grazing reindeer were modelled as increasing the amount of open land retained for nine of the tundra bird species.  相似文献   

Vulnerability of European reindeer husbandry to global change     

W. G. Rees  F. M. Stammler  F. S. Danks  P. Vitebsky 《Climatic change》2008,87(1-2):199-217

Reindeer husbandry represents a major land use in the Barents region, and has been predicted to be adversely affected by climate change. This paper considers the likely response of reindeer husbandry to changes both in climate and in socio-economic circumstances in the four countries of the Barents region from 1990 to 2080. Key natural factors include vegetation distribution, and a range of meteorological variables including temperature, wind, snow cover and freezing of rivers. The potential impact of these factors is evaluated quantitatively using the tolerable windows method, the results of which indicate a general but spatially non-uniform decline in the suitability of the region for reindeer husbandry. Relevant socio-economic factors include regional patterns of politics, management and knowledge. A focus on herders’ own perceptions of environmental change and flexibility of response, derived particularly from study sites in Russia, suggests that models of vulnerability to climate change should be tempered by paying greater attention to changes in socio-economic factors. When compared with the potential effect of changing these socioeconomic factors, the vulnerability of reindeer husbandry to projected climate change appears to be comparatively small.  相似文献   

北秦岭西段冥古宙锆石(4.1～3.9Ga)年代学新进展   总被引：15，自引：13，他引：2  

第五春荣  孙勇  董增产  王洪亮  陈丹玲  陈亮  张红 《岩石学报》2010,26(4):1171-1174

2007年王洪亮等报道在北秦岭西段火山岩中获得一粒年龄为4079±5Ma的冥古宙捕虏锆石。之后,对这一发现开展了深入的调查研究,我们除利用SHIMP技术方法对原4079Ma的锆石进行验证外,新获得了两粒~(207)Pb/~(206)Pb年龄为4007±29Ma和3908±45Ma捕获的变质成因锆石,表明早在4.0Ga已经有变质作用的发生,这或许说明在冥古宙时期地球已经具有相当规模和厚度的地壳。同时开展的岩石学研究表明,蕴含古老锆石的母岩属于火山碎屑熔岩类而不是火山熔岩。  相似文献   

火山岩风化壳储层发育模式——以三塘湖盆地马朗凹陷石炭系火山岩为例   总被引：4，自引：1，他引：3  

王君  朱如凯  郭宏莉  李文科  毛治国  王志勇 《岩石学报》2010,26(1):217-226

中国的火山岩油气勘探近年来进展非常快,并不断在许多盆地发现了优质火山岩储层,其中风化壳型储层作为非常重要的火山岩储集体类型而倍受重视。三塘湖盆地马朗凹陷石炭系风化壳型储层储集空间以溶蚀孔洞缝为主,储层物性非常好。通过火山岩油气勘探中的野外露头观察、钻井取心、镜下薄片鉴定,及主量元素、微量元素等分析化验资料,并结合火山岩岩石学特征和物性特点,初步建立了该区的风化壳储层的发育模式,将火山岩风化壳储层在垂向上自上而下划分为五个带: ①最终分解产物带; ②水解带; ③淋滤带; ④崩解带; ⑤未风化带(母岩)。淋滤带储集物性最好,该区风化淋滤是改善储层的关键。  相似文献   

Is there a win–win scenario for marine nature conservation? A case study of Lyme Bay,England     

Siân E. Rees  Martin J. Attrill  Melanie C. Austen  Steven C. Mangi  Jo P. Richards  Lynda D. Rodwell 《Ocean & Coastal Management》2010,53(3):135-145

A statutory two hundred and six square kilometre ‘closed area’ in Lyme Bay, South West England entered into force on the 11 July 2008 to protect the reef substrate and the associated biodiversity from the impacts of trawling and dredging with heavy demersal fishing gear. This case study provides an example of how the ecosystem approach has been incorporated into decision making for marine nature conservation and shows that despite sound ecological knowledge of a marine area, the current reliance on traditional neo-classical economic valuations for marine spatial planning can obscure other issues pertinent to the ecosystem approach. With the Government seeking win–win scenarios for stakeholders in the designation of Marine Conservation Zones under the Marine and Coastal Access Act, experience of marine spatial planning in Lyme Bay has revealed that a win–win must be a long-term goal based on a thorough evaluation of the environmental, social and economic values of marine biodiversity.  相似文献   

Incidence of imposex in thais orbita from Port Phillip Bay (Victoria, Australia), following 10 years of regulation on use of TBT.     

C M Rees  B A Brady  G J Fabris 《Marine pollution bulletin》2001,42(10):873-878

Imposex, the phenomenon in which induced male sex characteristics are superimposed on normal females, still occurs widely in the gastropod Thais orbita from Port Philip Bay, and its incidence is greatest in areas that have high boating and shipping activities. Compared to 1992, both the extent and severity of imposex has reduced. By inference, this means that pollution by tributyltin (TBT) in Port Phillip Bay has decreased and that the bans limiting its use to vessels greater than 25 m in length, in place since 1989, have been effective. However, TBT pollution is still an issue at locations that are adjacent to major ports, such as the Port of Melbourne, where TBT from large ships and ship maintenance activities continues to pollute fish habitats. It is anticipated that the incidence of imposex, and therefore TBT pollution, will continue to decrease in Port Phillip Bay as long as the bans currently in place continue to be observed. If the trends observed in the present study continue, then it is unlikely, with the notable exception of commercial ports, that TBT will pose a threat to the health of fish habitats in Port Phillip Bay.  相似文献   

The orientation of grains in a sheared dispersion     

A. I. Rees 《Tectonophysics》1979,55(3-4)

Two mechanisms have been suggested whereby preferred orientation of long and short axes might be produced in a small number of marker grains dispersed in a granular matrix under shear. One relies on the varying angular velocity of non equidimensional grains as they rotate in a sheared fluid, the other on grains tending to take up attitudes such that minimum angular momentum is transferred during collisions as they are sheared past each other. The two mechanisms are not necessarily mutually exclusive: experiments have been performed to test their relative effectiveness in producing preferred orientation.The style of orientation varies. When the marker and matrix grains are the same size and geometrically similar the orientation appears dominated by the effects of intergranular collisions. In particular, there is an angle, which maybe almost 30°, between the preferred direction of long axis orientation and the direction of flow. When the marker grains are much larger than the matrix their orientation is like that of grains in a viscous fluid, the preferred direction of long axes orientation being in or near to the flow direction. The results are relevant to the understanding of grain orientation in sedimentary and igneous rocks.  相似文献   

Mussel mortality in the Gulf of La Spezia,Italy     

R.I Collinson  C.P Rees 《Marine pollution bulletin》1978,9(4):99-101

High mortality of mussels on culture-ropes observed during dredging operations in the Gulf of La Spezia, Italy, was due primarily to reduced levels of dissolved oxygen. Mud particles blocking the mantle cavity produced suffocation, and their presence on the valves and in the vicinity of the mussels produced a high BOD which markedly reduced the oxygen concentration in the water. The effect of soluble and insoluble phases of copper released from the perturbed mud and re-suspended in the water column is difficult to ascertain, but under certain conditions it may have introduced additional mechanical and physiological stress.  相似文献