Vitellogenin in the blood plasma of male cod (Gadus morhua): a sign of oestrogenic endocrine disruption in the open sea?     

Scott AP  Katsiadaki I  Witthames PR  Hylland K  Davies IM  McIntosh AD  Thain J 《Marine environmental research》2006,61(2):149-170

An ELISA for cod vitellogenin (VTG) has been set up using cod lipovitellin for plate coating and standardisation. The assay has been applied to plasma samples collected from male and female cod caught in three distinct areas around the UK, three areas off the Norwegian coast and also to cod reared initially at an aquaculture site and subsequently maintained at a research station. The aim of the study was to determine whether there were any signs of oestrogenic endocrine disruption in a fish species living offshore. VTG induction was found in male cod caught in the North Sea, the Shetland Box area, in Oslofjord and also in cultivated fish. There was a strong relationship between concentrations of VTG and fish size. There was no evidence that the presence of VTG in the plasma of males is a natural part of their life cycle. On the other hand, the size of fish at which these elevated VTG concentrations appear (ca. 5 kg) is about the size that cod change from feeding primarily on benthic invertebrates to mainly other fish, both benthic and pelagic. The possibility is suggested that large cod pick up oestrogenic endocrine disrupters through the food chain.  相似文献   

An assessment of the fine-scale eddies in a high-resolution model of the shelf seas west of Great Britain   总被引：1，自引：0，他引：1  

Jason T. Holt  Ian D. James 《Ocean Modelling》2006,13(3-4):271-291

High-resolution (1.8 km) simulations of the shelf seas west of Great Britain with the Proudman Oceanographic Laboratory Coastal Ocean Modelling System (POLCOMS) demonstrate the formation of an intense field of baroclinic eddies in open stratified waters such as the Celtic Sea. These eddies are most likely to be the result of an inverse energy cascade resulting from tidal flow over rough topography, as demonstrated by a series of idealised model experiments. They are shown to possess many of the properties of eddies identified in idealised laboratory and numerical simulations. Namely, they are predominantly anticyclonic and they merge to increase their size up to a limit set by the internal Rossby radius. An investigation of satellite sea surface temperature observations provides indirect evidence that these model eddies are too energetic, long-lived and frequent. The inclusion of a horizontal diffusion term with a shear dependent diffusivity is shown to significantly reduce the eddy kinetic energy and improve the simulation, without significantly affecting the results in other regions. An optimal parameter value is suggested for this resolution, but the need to put the treatment of horizontal turbulence in such models on a sounder theoretical or empirical footing is identified.  相似文献   

Distribution of DDT and other persistent organic contaminants in Canyons and on the continental shelf off the central California coast     

Hartwell SI 《Marine environmental research》2008,65(3):199-217

Sediment samples were collected to delineate the distribution of contaminants along the central California coast. Sampling included a variety of Canyons and shelf/slope areas to evaluate contaminant transport patterns and potential delivery to Canyons and the continental slope to a depth of 1200 m. Sediments were collected and analyzed for organic contaminants using standard techniques of the NOAA National Status and Trends Program (NS&T). DDT is distributed on the shelf within a zone of fine-grained sediments between Half Moon and Monterey Bays. DDT was found at higher concentrations in Ascension, A?o Nuevo, and Monterey/Soquel Canyons than in Pioneer and Carmel Canyons, the Gulf of the Farallones, or the continental slope. The Monterey Bay watershed appears to be the primary source of DDT. In contrast, PAHs and PCBs on the shelf appear to be derived primarily from San Francisco Bay. DDT appears to be delivered to the deep ocean via the Canyons more than from cross-shelf sediment transport. Sediment budget estimates for the continental shelf north of Monterey Bay need further refinement and more data to account for the movement of material from Monterey Bay onto the shelf.  相似文献   

The effect of habitat and environmental history on otolith chemistry of barramundi Lates calcarifer in estuarine populations of a regulated tropical river     

David Milton  Ian Halliday  Michelle Sellin  Richard Marsh  Jonathan Staunton-Smith  Jon Woodhead 《Estuarine, Coastal and Shelf Science》2008

We examine the microchemistry of otoliths of cohorts of a fished population of the large catadromous fish, barramundi Lates calcarifer from the estuary of a large tropical river. Barramundi from the estuary of the large, heavily regulated Fitzroy River, north-eastern Australia were analysed by making transects of ⁸⁷Sr/⁸⁶Sr isotope and trace metal/Ca ratios from the core to the outer edge. Firstly, we examined the Sr/Ca, Ba/Ca, Mg/Ca and Mn/Ca and ⁸⁷Sr/⁸⁶Sr isotope ratios in otoliths of barramundi tagged in either freshwater or estuarine habitats that were caught by the commercial fishery in the estuary. We used ⁸⁷Sr/⁸⁶Sr isotope ratios to identify periods of freshwater residency and assess whether trace metal/Ca ratios varied between habitats. Only Sr/Ca consistently varied between known periods of estuarine or freshwater residency. The relationships between trace metal/Ca and river flow, salinity, temperature were examined in fish tagged and recaptured in the estuary. We found weak and inconsistent patterns in relationships between these variables in the majority of fish. These results suggest that both individual movement history within the estuary and the scale of environmental monitoring were reducing our ability to detect any patterns. Finally, we examined fish in the estuary from two dominant age cohorts (4 and 7 year old) before and after a large flood in 2003 to ascertain if the flood had enabled fish from freshwater habitats to migrate to the estuary. There was no difference in the proportion of fish in the estuary that had accessed freshwater after the flood. Instead, we found that larger individuals with of each age cohort were more likely to have spent a period in freshwater. This highlights the need to maintain freshwater flows in rivers. About half the fish examined had accessed freshwater habitats before capture. Of these, all had spent at least their first two months in marine salinity waters before entering freshwater and some did not enter freshwater until four years of age. This contrasts with the results of several previous studies in other parts of the range that found that access to freshwater swamps by larval barramundi was important for enhanced population productivity and recruitment.  相似文献   

Flow resistance in the Great Belt,the biggest strait between the North Sea and the Baltic Sea     

Flemming Jakobsen  Ian Sehested Hansen  Niels-Erik Ottesen Hansen  Frank Østrup-Rasmussen 《Estuarine, Coastal and Shelf Science》2010

The Danish Straits are part of the transition area between the North Sea and the central Baltic Sea. More precisely, the Danish Straits connect Kattegat to the Arkona Basin and includes the relatively narrow and shallow sub-areas: Great Belt, Little Belt, Fehmarn Belt and Sound. The flow resistances in the straits are hydraulically determined by among other factors, the contractions, sills and stratification found in the straits. Close to the entrance to the Arkona Basin the Darss and Drogden Sills are located that trap inflowing dense water partially before it enters the central Baltic Sea. Hence, the resistances in the Danish Straits are of crucial importance for the stratification and ecosystems in the central Baltic Sea. The present work comprises calculations of flow resistance in the Great Belt based on measurements collected as part of the Great Belt Fixed Link investigations. The specific resistance in the Great Belt is determined to be an average of 41.2 × 10⁻¹² s² m⁻⁵, but it depends heavily on the interface position. When calculating long-term discharge time-series on the basis of the momentum equation it is advised to apply a seasonal varying resistance.  相似文献   

The hydrodynamics and salinity regime of a coastal lagoon – The Coorong,Australia – Seasonal to multi-decadal timescales     

Ian T. Webster 《Estuarine, Coastal and Shelf Science》2010

The Coorong is a choked coastal lagoon in South Australia that forms part of the terminal lake system at the end of the River Murray, Australia’s major river. It is an inverse estuary with a constricted channel connection to the sea at one end and extends parallel to the coast for more than 100 km away from this inlet. The present paper considers the physical dynamics of the Coorong, particularly its ecologically important salinity and water level regimes, and how these respond to connectedness with the ocean, barrage flows and meteorological conditions. The approach combines hydrodynamic modelling with measurements and considers temporal variation in the system ranging from seasonal to multi-decadal timescales.  相似文献   

Modelling tidal stream power potential     

Ian Walkington  Richard Burrows 《Applied Ocean Research》2009,31(4):239-245

In recent years, there has been an increase in interest in renewable energy sources for a number of reasons. A particular interest in tidal energy has developed within the UK due to its numerous sites of high current velocity. In this article a development, based upon previous work, of an existing hydrodynamic computational model is shown which is used to study the potential generation and the physical impacts of tidal stream farms. An idealised geometry is used to study the impacts of installed capacity and general layout of tidal stream farms and a realistic UK west coast model is used to examine the potential of presently proposed in-stream farms.  相似文献   

The formation of farm mounds on the Island of Sanday,Orkney     

Donald A. Davidson  Douglas D. Harkness  Ian A. Simpson 《Geoarchaeology》1986,1(1):45-59

A recent archaeological site survey of the island of Sanday on Orkney has identified a distinct concentration of 15 farm mounds. An immediate need is to determine the nature, age, and processes of formation of these very distinctive landform features. This paper reports a geoarchaeological investigation of three mounds at Westbrough, Langskaill, and Skelbrae. For the island as a whole, the mounds vary in diameter from 50 to 205 m, with deposits up to a thickness of 4.3 m. The mounds vary in their morphology, reflecting complex processes of accumulation, often intense disturbance, and in some cases, erosion by the sea. Sections at the three sites are described with analytical data also being given for particle size, percent loss-on-ignition, total phosphate, δ¹³C, and radiocarbon dating. The Westbrough and Skelbrae mounds were formed post-7th century A.D.; more detailed dating was possible for the Langskaill site, which was initiated in the early to mid 13th century. A steady and relatively rapid sedimentation rate (ca. 1.9 cm year⁻¹) took place over the 200 years following the initiation of the mound. The lower part of the Westbrough mound is distinguished by the presence of peat, interpreted as discarded bedding material, but the remainder of the investigated sections are composed dominantly of mineral sediments containing organic matter of terrestrial origin. It is suggested that these materials accumulated from the ash of domestic hearths as well as from the residues of bedding material from the byres (cattle sheds). Turves (vegetation plus some underlying soil) would have been cut, dried, and then used in the byres and such turves would have retained a significant mineral content. The implication is that the inherent fertility of the island made it unnecessary for the farmers to spread the dung over the fields. This may explain why there is the distinct concentration of these mounds on the island of Sanday, an island noted in earlier times for its fertile soils developed on calcareous sands.  相似文献   

Isotopic fractionation of oxygen and carbon in decomposed lower-mantle inclusions in diamond     

Felix Kaminsky  Jennifer Matzel  Ben Jacobsen  Ian Hutcheon  Richard Wirth 《Mineralogy and Petrology》2016,110(2-3):379-385

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The 2dF Galaxy Redshift Survey: Wiener reconstruction of the cosmic web     

Pirin Erdo&#;du  Ofer Lahav  Saleem Zaroubi  George Efstathiou  Steve Moody  John A. Peacock  Matthew Colless  Ivan K. Baldry  Carlton M. Baugh  Joss Bland-Hawthorn  Terry Bridges  Russell Cannon  Shaun Cole  Chris Collins  Warrick Couch  Gavin Dalton  Roberto De Propris  Simon P. Driver  Richard S. Ellis  Carlos S. Frenk  Karl Glazebrook  Carole Jackson  Ian Lewis  Stuart Lumsden  Steve Maddox  Darren Madgwick  Peder Norberg  Bruce A. Peterson  Will Sutherland  Keith Taylor 《Monthly notices of the Royal Astronomical Society》2004,352(3):939-960

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