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111.
Galloway TS Brown RJ Browne MA Dissanayake A Lowe D Jones MB Depledge MH 《Marine environmental research》2004,58(2-5):233-237
The ECOMAN project was initiated from an awareness of the complexity of the functioning of coastal marine systems and the clear need for more pragmatic environmental assessment techniques linking environmental degradation with its causes. The aim of the project is to develop a suite of easy to use, cost effective and environmentally valid biological responses (biomarkers) to assess the general health of coastal systems, including estuaries. To achieve this aim, various sublethal endpoints are being measured and evaluated from a range of common coastal organisms showing different feeding types (filter feeding, grazing and predation) and habitat requirements (estuary and rocky shore) and at different levels of biological response (cellular, physiological and behavioural). This holistic integrated approach is essential to identify the full impact of chemical contamination on organisms, and enables the sensitivity of organisms to be ranked and key sentinel species for specific habitats to be identified. 相似文献
112.
In the present study, a Fourier analysis is used to develop expressions for phase and group speeds for both continuous and discretized, linearized two-dimensional shallow water equations, in Cartesian coordinates. The phase and group speeds of the discrete equations, discretized using a three-point scheme of second order, five-point scheme of fourth order and a three-point compact scheme of fourth order in an Arakawa C grid, are calculated and compared with the corresponding values obtained for the continuous system. The three-point second-order scheme is found to be non-dispersive with grid resolutions greater than 30 grids per wavelength, while both the fourth-order schemes are non-dispersive with grid resolutions greater than six grids per wavelength. A von Neumann stability analysis of the two- and three-time-level temporal schemes showed that both schemes are stable. A wave deformation analysis of the two-time-level Crank–Nicolson scheme for one-dimensional and two-dimensional systems of shallow water equations shows that the scheme is non- dispersive, independent of the Courant number and grid resolution used. The phase error or the dispersion of the scheme decreases with a decrease in the time step or an increase in grid resolution. 相似文献
113.
A comprehensive oilspill fates model, developed by Cornillon and Spaulding at the University of Rhode Island, has been employed to hindcast the well-studied Argo Merchant spill. Using data collected during the spill to define the environmental conditions and the oil composition, properties and release rates, the oil spill fates model was used to predict the spatial and temporal distribution of spilled oil from December 16 to 31, 1976. Comparison of model predictions to observations for spilled oil mass balance, surface trajectories and oiled surface area was in general quite good. Improved predictions require a better definition of the wind and tidally-forced circulation in the vicinity of the wreck site, a more soundly based theory for oil entrainment or dispersion into the water column and an oil spreading theory which more accurately addresses the complex behaviour of a weathering multicomponent petroleum hydrocarbon. 相似文献
114.
The past 50 years in the Gulf of Maine and Georges Bank is marked by a growing divide between fishermen, scientists, and managers. This paper tracks the scientific, regulatory, social and political evolution of fisheries management in the Northwest Atlantic, culminating in a distrustful and adversarial climate, a convergence of diverse policy needs, and the emergence of a multi-stakeholder cooperative research program—the Northeast Consortium. The institutional structure and activities of the Northeast Consortium are presented and we conclude with a discussion of the role of cooperative research in building mutual understanding and respect, trust and scientific legitimacy. 相似文献
115.
When a steep bottom slope exists, it is well known that conventional methods for calculating horizontal diffusion in sigma-coordinate coastal ocean models causes spurious transport (e.g. salinity, temperature, and sediments) and currents. In this study, a second-order accurate finite-difference algorithm and program have been developed to reduce the spurious numerical diffusion errors. In the proposed algorithm, the finite differencing is performed in the x-z coordinate system to approximate the horizontal gradient. Each variable in the finite differential formation is calculated in the sigma-coordinate grid cells using a second-order Lagrangian interpolation polynomial. In conjunction with a stepwise bottom boundary condition, numerical experiments show that the proposed finite-difference scheme considerably reduces numerical errors compared to conventional approaches when dealing with horizontal diffusion over steep topography, which often occurs in coastal oceans and navigation channels. 相似文献
116.
Tamara S. Galloway Rebecca J. Brown Mark A. Browne Awantha Dissanayake David Lowe Malcolm B. Jones Michael H. Depledge 《Marine environmental research》2004,58(2-5):233
The ECOMAN project was initiated from an awareness of the complexity of the functioning of coastal marine systems and the clear need for more pragmatic environmental assessment techniques linking environmental degradation with its causes. The aim of the project is to develop a suite of easy to use, cost effective and environmentally valid biological responses (biomarkers) to assess the general health of coastal systems, including estuaries. To achieve this aim, various sublethal endpoints are being measured and evaluated from a range of common coastal organisms showing different feeding types (filter feeding, grazing and predation) and habitat requirements (estuary and rocky shore) and at different levels of biological response (cellular, physiological and behavioural). This holistic integrated approach is essential to identify the full impact of chemical contamination on organisms, and enables the sensitivity of organisms to be ranked and key sentinel species for specific habitats to be identified. 相似文献
117.
Danielle Schreve Andy Howard Andrew Currant Stephen Brooks Simon Buteux Russell Coope Barnaby Crocker Michael Field Malcolm Greenwood James Greig Phillip Toms 《第四纪科学杂志》2013,28(2):118-130
This paper reports the discovery of a rare partial skeleton of a woolly rhinoceros (Coelodonta antiquitatis Blumenbach, 1799) and associated fauna from a low Pleistocene terrace of the River Tame at Whitemoor Haye, Staffordshire, UK. A study of the sedimentary deposits around the rhino skeleton and associated organic‐rich clasts containing pollen, plant and arthropod remains suggests that the animal was rapidly buried on a braided river floodplain surrounded by a predominantly treeless, herb‐rich grassland. Highlights of the study include the oldest British chironomid record published to date and novel analysis of the palaeoflow regime using caddisfly remains. For the first time, comparative calculations of coleopteran and chironomid palaeotemperatures have been made on the same samples, suggesting a mean July temperature of 8–11 °C and a mean December temperature of between ?22 and ?16 °C. Radiocarbon age estimates on skeletal material, supported by optically stimulated luminescence ages from surrounding sediments, indicate that the rhino lived around 41–43 k cal a BP. The combined geochronological, stratigraphic and palaeoenvironmental evidence places the assemblage firmly within the Middle Devensian (Marine Oxygen Isotope Stage 3). This would agree with other regional evidence for the timing of aggradation for the lowest terrace of the Trent and its tributary systems. Copyright © 2012 John Wiley & Sons, Ltd. 相似文献
118.
Malcolm B. Hart 《Geology Today》2019,35(3):115-118
Statoliths, in modern cephalopods, are the paired calcareous ‘stones’ that lie in two adjacent cavities (or statocysts) within the cartilage of the head. The stones are generally 0.5–2.0 mm in length and appear to be formed of aragonite. Statoliths often co‐occur with fish otoliths, and being of similar appearance, size, colour, etc., this has caused confusion in the past. It was only towards the latter part of the twentieth century that it was recognized that statoliths could occur as fossils. 相似文献
119.
Dean A. Shaw Garth Vanderkamp F. Malcolm Conly Al Pietroniro Lawrence Martz 《水文研究》2012,26(20):3147-3156
The fill–spill of surface depressions (wetlands) results in intermittent surface water connectivity between wetlands in the prairie wetland region of North America. Dynamic connectivity between wetlands results in dynamic contributing areas for runoff. However, the effect of fill–spill and the resultant variable or dynamic basin contributing area has largely been disregarded in the hydrological community. Long‐term field observations recorded at the St. Denis National Wildlife Area, Saskatchewan, allow fill–spill in the basin to be identified and quantified. Along with historical water‐level observations dating back to 1968, recent data collected for the basin include snow surveys, surface water survey and production of a light detection and ranging–derived digital elevation model. Data collection for the basin includes both wet and dry antecedent basin conditions during spring runoff events. A surface water survey at St. Denis in 2006 reveals a disconnected channel network during the spring freshet runoff event. Rather than 100% of the basin contributing runoff to the outlet, which most hydrological models assume, only approximately 39% of the basin contributes to the outlet. Anthropogenic features, such as culverts and roads, were found to influence the extent and spatial distribution of contributing areas in the basin. Historical pond depth records illustrate the effect of antecedent basin conditions on fill–spill and basin contributing area. A large pond at the outlet of the St. Denis basin, which only receives local runoff during dry years when upstream surface storage has not been satisfied, has pond runoff volumes that increase by a factor of 20 or more during wet years when upstream antecedent basin surface storage is satisfied and basin‐wide runoff contributes to the pond. Copyright © 2011 John Wiley & Sons, Ltd. 相似文献
120.
Nicholas E. Graham Malcolm K. Hughes Caspar M. Ammann Kim M. Cobb Martin P. Hoerling Douglas J. Kennett James P. Kennett Bert Rein Lowell Stott Peter E. Wigand Taiyi Xu 《Climatic change》2007,83(1-2):241-285
Terrestrial and marine late Holocene proxy records from the western and central US suggest that climate between approximately 500 and 1350 a.d. was marked by generally arid conditions with episodes of severe centennial-scale drought, elevated incidence of wild fire, cool sea surface temperatures (SSTs) along the California coast, and dune mobilization in the western plains. This Medieval Climate Anomaly (MCA) was followed by wetter conditions and warming coastal SSTs during the transition into the “Little Ice Age” (LIA). Proxy records from the tropical Pacific Ocean show contemporaneous changes indicating cool central and eastern tropical Pacific SSTs during the MCA, with warmer than modern temperatures in the western equatorial Pacific. This pattern of mid-latitude and tropical climate conditions is consistent with the hypothesis that the dry MCA in the western US resulted (at least in part) from tropically forced changes in winter NH circulation patterns like those associated with modern La Niña episodes. We examine this hypothesis, and present other analyses showing that the imprint of MCA climate change appears in proxy records from widely distributed regions around the planet, and in many cases is consistent with a cool medieval tropical Pacific. One example, explored with numerical model results, is the suggestion of increased westerlies and warmer winter temperatures over northern Europe during medieval times. An analog technique for the combined use of proxy records and model results, Proxy Surrogate Reconstruction (PSR), is introduced. 相似文献