Cumulative impacts of aggregate extraction on seabed macro-invertebrate communities in an area off the east coast of the United Kingdom     

Keith Cooper  Sin Boyd  John Aldridge  Hubert Rees 《Journal of Sea Research》2007,57(4):288-302

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Stable Atmospheric Boundary-Layer Experiment in Spain (SABLES 98): A Report   总被引：1，自引：1，他引：0  

J. Cuxart  C. Yagüe  G. Morales  E. Terradellas  J. Orbe  J. Calvo  A. Fernández  M. R. Soler  C. Infante  P. Buenestado  A. Espinalt  H. E. Joergensen  J. M. Rees  J. Vilá  J. M. Redondo  I. R. Cantalapiedra  L. Conangla 《Boundary-Layer Meteorology》2000,96(3):337-370

This paper describes the Stable AtmosphericBoundary Layer Experiment in Spain (SABLES 98),which took place over the northern Spanish plateaucomprising relatively flat grassland,in September 1998. The main objectives of the campaign were to study the properties of themid-latitude stable boundary layer (SBL).Instrumentation deployed on two meteorologicalmasts (of heights 10 m and 100 m)included five sonic anemometers, 15 thermocouples,five cup anemometers and three propeller anemometers,humidity sensors and radiometers.A Sensitron mini-sodar and a tetheredballoon were also operated continuously. Atriangular array of cup anemometers wasinstalled to allow the detection ofwave events. Two nocturnal periods analysedon 14–15 and 20–21 September are used toillustrate the wide-ranging characteristics of the SBL.  相似文献   

Hypoxic blackwater events suppress the emergence of zooplankton from wetland sediments     

Nathan S. P. Ning  Rochelle Petrie  Ben Gawne  Daryl L. Nielsen  Gavin N. Rees 《Aquatic Sciences - Research Across Boundaries》2015,77(2):221-230

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The distribution of supermassive black holes in the nuclei of nearby galaxies     

Andrea Cattaneo  Martin G. Haehnelt  Martin J. Rees 《Monthly notices of the Royal Astronomical Society》1999,308(1):77-81

The growth of supermassive black holes by merging and accretion in hierarchical models of galaxy formation is studied by means of Monte Carlo simulations. A tight linear relation between masses of black holes and masses of bulges arises if the mass accreted by supermassive black holes scales linearly with the mass-forming stars and if the redshift evolution of mass accretion tracks closely that of star formation. Differences in redshift evolution between black hole accretion and star formation introduce a considerable scatter in this relation. A non-linear relation between black hole accretion and star formation results in a non-linear relation between masses of remnant black holes and masses of bulges. The relation of black hole mass to bulge luminosity observed in nearby galaxies and its scatter are reproduced reasonably well by models in which black hole accretion and star formation are linearly related but do not track each other in redshift. This suggests that a common mechanism determines the efficiency for black hole accretion and the efficiency for star formation, especially for bright bulges.  相似文献   

The Doppler Imaging System: Initial observations of the auroral thermosphere     

D. Rees  A.H. Greenaway  R. Gordon  I. McWhirter  P.J. Charleton  Åke Steen 《Planetary and Space Science》1984,32(3):273-285

During December 1982, a novel Fabry-Perot interferometer—a Doppler Imaging System (DIS)— was used at Kiruna Geophysical Institute (KGI), Sweden (67.8°N, 21.2°E) to complement a series of coordinated observations of global thermospheric dynamics utilizing a number of conventional ground-based Fabry-Perot interferometers and the NASA Dynamics Explorer satellite. The DIS is an interferometer with two unique attributes : it has a luminosity or étendue more than one hundred times that of the conventional Fabry-Perot interferometer, and it is also capable of deducing a two-dimensional velocity field of a suitable line-emitting areal source by independently measuring the Doppler shift at a large number of points within the field of view. On 17 December 1982, a very large geomagnetic Storm Sudden Commencement (08.05 U.T.) preceded a major geomagnetic disturbance. During this disturbance, Northern Scandinavia was influenced by a strong eastward auroral electrojet for an extended period (10–19 U.T.). The DIS was able to observe the dynamical response of the upper thermosphere to this event in conjunction with a second Fabry-Perot interferometer (FPI) at KGI. Westward thermospheric winds of about 900 m s^?1 occurred during the disturbance and, at the peak of the disturbance, the combined DIS and FPI observations indicate that the thermospheric flow was quite chaotic. Fluctuations of the order of ± 150 ms^?1, associated with spatial scales of the order of 100 or 200 km occurred within the mean westward flow inside the 800 km diameter region observed from Kiruna.  相似文献   

Interpretation of an anticipated long-lived vortex in the lower thermosphere following simulation of an isolated substorm     

T.J. Fuller-Rowell  D. Rees 《Planetary and Space Science》1984,32(1):69-85

Using a three-dimensional, time-dependent, global model, we have simulated the response of the thermosphere to an isolated substorm. The substorm is characterized by a time variance of the high latitude convective electric field with an associated enhancement of auroral E region electron density, from an initially quiet thermosphere. We have simulated such an impulsive energy input with both separated and co-incident geographic and geomagnetic poles and have found that, in both cases, in the lower thermosphere ( ～ 120 km), a long-lived vortex phenomenon is generated. Initially, two contra-rotating vortices are generated by the effects of ion drag during the period of enhanced high latitude energy input centred on the polar cap/auroral oval boundary, one at dusk (18.00 L.T.) and the other at dawn (06.00 L.T.). After the end of the substorm, the cyclonic vortex (dawn) dissipates rapidly while the dusk anti-cyclonic vortex appears virtually self-sustaining and survives many hours after the substorm input has ceased. A theory is derived to explain and interpret the results and it appears that the effect is analogous to a meteorological weather system. In this case, however, the dusk anti-cyclonic vortex has, instead of pressure, the centrifugal acceleration balancing the Coriolis force. The equivalent anti-clockwise dawn vortex, unlike a low pressure system, has no balancing force, since Coriolis and the centrifugal term assist and this vortex rapidly disappears.  相似文献   

Spatial and temporal trends in the benthos and sediments in relation to sewage sludge disposal off the northeast coast of England     

Rees  H. L.; Rowlatt  S. M.; Lambert  M. A.; Lees  R. G.; Limpenny  D. S. 《ICES Journal of Marine Science》1992,49(1):55-64

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Flexural interaction and the dynamics of neogene extensional Basin formation in the Alboran-Betic region     

S. Cloetingh  P. A. van der Beek  D. van Rees  T. B. Roep  C. Biermann  R. A. Stephenson 《Geo-Marine Letters》1992,12(2-3):66-75

Quantitative tectonic modelling demonstrates an interaction of flexure of the lithosphere underlying the western Betics with crustal thinning in the Alboran Basin and flank uplift in the Internal Zone. In the eastern Betics the flexural response is overprinted by post-thrusting extensional events. Lateral variations in thermal structure and rheology of the lithosphere along strike of the Betics shed light on changes in tectonic configuration and are consistent with evidence for lateral variations in the mode of extension in the Alboran Basin. Flexural modelling and subsidence analysis of Neogene basins in the Internal Zone of the Betics, with spatial development controlled by contrasts in lithosphere rheology, demonstrate that at least two extensional events have affected the orogenic evolution of the Betics. The first event appears to reflect Oligocene-Early Miocene rifting observed throughout the Western Mediterranean. The second phase, which caused the present configuration of the Betics, corresponds to Tortonian-Recent extension centered in the Alboran Basin.  相似文献   

Pollution investigations off the north-east coast of England: Community structure,growth and production of Benthic Macrofauna     

H.L. Rees 《Marine environmental research》1983,9(2):61-110

The growth of major polychaete and bivalve species inhabiting sandy sediments off the north-east coast of England was examined over a 1-year period in a comparative study of community production in relation to contaminant sources. Background information on site locations, sampling methods and benthic community structure is provided.The polychaetes Spiophanes bombyx, Magelona spp. and Nephtys spp. were major contributors to community biomass at most sites, either individually or collectively. Tellina fabula, Nucula turgida, Venus striatula and other bivalves were only sparsely represented at most sites and growth rates were generally lower than elsewhere. Reduced bivalve populations, together with the presence in high numbers of short-lived polychaete species, may be connected with the vulnerability of bottom sediments to disturbance by water movements in this coastal region.Recruitment patterns were generally similar between sites but showed marked annual variation, with a substantially greater bivalve settlement occurring at the end of the sampling period.Estimates of community production ranged from 3.4 to 7.4 g ash-free dry weight per square metre a year, and showed relatively high turnover rates compared with other regions, which, again, may be related to a greater degree of fluctuation in the physical environment. Production was highest at a site near to the Tees estuary and was accounted for mainly by the polychaetes Nephtys hombergi and Spiophanes bombyx. The concentration of biomass into one or two species may have consequences for the stability of the fauna. However, the results do not appear to indicate any serious effects of pollution, which may suggest that the coastal waters have sufficient capacity to effectively dilute and disperse any harmful constituents of present estuarine efflux.Limitations to the interpretation of field data using conventional methods of sampling and analysis are discussed, and the application of growth studies to investigations of water pollution is advocated.  相似文献   

Recovery of the seabed following marine aggregate dredging on the Hastings Shingle Bank off the southeast coast of England     

Keith Cooper  Sian Boyd  Jacqueline Eggleton  David Limpenny  Hubert Rees  Koen Vanstaen 《Estuarine, Coastal and Shelf Science》2007,75(4):547-558

The aim of this study was to investigate the effect of dredging intensity on the physical and biological recovery times of the seabed following marine aggregate dredging. Two areas of seabed, previously subject to, respectively, relatively high and lower levels of dredging intensity, were identified on the Hastings Shingle Bank. Two reference areas were also selected for comparative purposes. All four sites were monitored annually over the period 2001–2004, using a combination of acoustic, video and grab sampling techniques. Since the site was last dredged in 1996, this was intended to provide a sequence of data 5–8 years after cessation of dredging. However, an unexpected resumption of dredging within the high intensity site, during 2002 and 2003, allowed an additional assessment of the immediate effects and aftermath of renewed dredging at the seabed. The early stages of recovery could then be assessed after dredging ceased in 2003. Results from both dredged sites provide a useful insight into the early and latter stages of physical and biological recovery. A comparison of recent and historic dredge track features provided evidence of track erosion. However, tracks were still visible 8 years after the cessation of dredging. Within the high dredging intensity site, recolonisation was relatively rapid after the cessation of dredging in 2003. Rather than indicating a full recovery, we suggest that this initial ‘colonization community’ may enter a transition phase before eventually reaching equilibrium. This hypothesis is supported by results from the low intensity site, where biological recovery was judged to have taken 7 years. Further monitoring is needed in order to test this. An alternative explanation is that the rapid recovery may be explained by the settlement of large numbers of Sabellaria spinulosa. As the resumption of dredging within the high intensity site limited our assessment of longer-term recovery it is not yet possible to assume that a 7-year biological recovery period will be applicable to other, more intensively dredged areas at this or more distant locations.  相似文献