Food consumption by seabirds in Norwegian waters   总被引：2，自引：1，他引：2  

Barrett  Robert T.; Anker-Nilssen  Tycho; Gabrielsen  Geir W.; Chapdelaine  Gilles 《ICES Journal of Marine Science》2002,59(1):43-57

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The first use of Fulton's K for assessing and comparing the conditions of inter‐tidal fish populations          下载免费PDF全文

Chris J. Barrett  Magnus L. Johnson  Nicola J. Hall  Sue L. Hull 《Marine Ecology》2016,37(1):42-45

Fulton's K condition factor was applied, for the first time, to inter‐tidal specimens of the shanny (Lipophrys pholis) and long‐spined scorpion fish (Taurulus bubalis) from two English rocky shore and two Welsh rocky shore sites during summer 2010 and winter 2011. As both species contribute to the diet of commercial species such as cod (Gadus morhua) and near‐threatened species such as the European otter (Lutra lutra), their condition may affect that of these predators. Fulton's K found that inter‐tidal Welsh fish maintained a ‘good’ condition between seasons, whereas the inter‐tidal English fish were in a poorer condition during winter. Although condition also changed amongst the sites on each coast, further studies are needed into fish morphologies, environmental parameters, prey availabilities and abundances, and fish specimen sex and maturities.  相似文献   

A new specimen of Ichthyosaurus communis from Dorset,UK, and its bearing on the stratigraphical range of the species     

S.P. Bennett  P.M. Barrett  M.E. Collinson  S. Moore-Fay  P.G. Davis  C.P. Palmer 《Proceedings of the Geologists' Association. Geologists' Association》2012,123(1):146-154

This paper describes a new ichthyosaur specimen from the Stonebarrow Marls Member (Charmouth Mudstone Formation) of Charmouth, Dorset. It is substantially complete and various characters of the skull (snout ratios and basioccipital morphology) and appendicular skeleton (the number of digits on the hind paddle, which can be used to infer the number of digits on the front paddle) indicate that the specimen is referable to Ichthyosaurus communis. This provides the first direct evidence for the presence of I. communis in the Pliensbachian, extending the stratigraphic range of the species. The specimen also preserves a probable gullet content, which demonstrates that fish formed part of the diet of this individual.  相似文献   

Reduction of interpolation errors when using local correlation tracking for motion detection     

Potts  H.E.  Barrett  R.K.  Diver  D.A. 《Solar physics》2003,217(1):69-78

Local correlation tracking (LCT) is a commonly used motion tracking technique, particularly in solar physics. When used to track motions smaller than one pixel per time sample, interpolation of the original data is required. We demonstrate that it is possible to introduce large systematic errors by using an inappropriate interpolation method, and describe how to avoid these errors. The effect of these errors on the calculated velocity field is demonstrated on simulated solar granulation data.  相似文献   

Multi-epoch spectroscopy, polarimetry and photometry of the polar UW Pic     

E. Romero-Colmenero  Stephen B. Potter  D. A. H. Buckley  P. E. Barrett  S. Vrielmann † 《Monthly notices of the Royal Astronomical Society》2003,339(3):685-694

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Geological setting of the Rapu Rapu gold-rich volcanogenic massive sulfide deposits,Albay Province,Philippines     

Ross?L.?SherlockEmail author  Timothy?J.?Barrett  Peter?D.?Lewis 《Mineralium Deposita》2003,38(7):813-830

Gold-rich Fe–Cu–Zn volcanogenic massive sulfide deposits occur within strata of probable Jurassic age on Rapu Rapu Island in Albay Province, Philippines. Massive sulfides at the Ungay Malobago and Hixbar deposits are spatially associated with dacitic volcanic rocks within a highly-deformed sequence of mafic volcanic and quartzofeldspathic sedimentary rocks. The massive sulfide deposits formed at the stratigraphic contact between footwall dacites and hangingwall mafic volcanic and quartzofeldspathic rocks. The deposits and their host strata have undergone regional metamorphism with strong penetrative deformation. Metamorphic mineral assemblages and textural evidence suggest that peak metamorphism was upper-greenschist to lower-amphibolite grade and syn-D₁ deformation. Based on the age of regional metamorphism, deformation is inferred to be mid-Tertiary in age. Deformation at Rapu Rapu resulted in reorientation of the strata into a broad antiform with strong shallow-plunging elongation fabrics, overturning of the volcanic sequence that hosts the Ungay Malobago deposit, and complex folding of the mineralized zones. The present highly linear form of the Ungay Malobago deposit is mainly a product of this ductile strain.Immobile element ratios for a given lithology generally remain constant in saprolitic samples, and thus provide an effective identification tool even in strongly weathered rocks. Lithogeochemical data define a bimodal volcanic suite that is comparable to bimodal assemblages that occur in several modern back-arc basins in the southwestern Pacific Ocean, including those behind the Vanuatu and the New Britain arcs. On Rapu Rapu, the dacitic rocks are enriched in light REE and have high Zr/Y ratios, which indicates a calc–alkaline affinity and suggests a mature island-arc setting. The quartzofeldspathic sedimentary rocks are more widespread than the dacites and have notably lower Zr/Y ratios; they may have been derived from erosion of a distant volcanic arc. The mafic volcanic rocks are dominantly low-K arc tholeiites of basaltic to andesitic composition, but with modest enrichment in the light REE; comparable rocks can be found in the Vanuatu and New Britain back-arc basins.Electronic Supplementary Material Supplementary material is available in the online version of this article at http://dx.doi.org/10.1007/s00126-003-0349-0An erratum to this article can be found at Editorial handling: O. Christensen  相似文献   

Temporal variations in the depth-specific hydrochemistry and sewage-related microbiology of an urban sandstone aquifer,Nottingham, United Kingdom     

A.?A.?CroninEmail author  R.?G.?Taylor  K.?L.?Powell  M.?H.?Barrett  S.?A.?Trowsdale  D.?N.?Lerner 《Hydrogeology Journal》2003,11(2):205-216

The temporal and spatial characteristics of groundwater recharge in urban environments remain poorly understood. Depth-specific monitoring of groundwater quality in the Triassic Sandstone underlying the city of Nottingham, UK, indicates that contamination results primarily from sewage and atmospheric sources. The temporal and depth-specific characteristics of microbial and inorganic (e.g. nitrate, chloride, sulphate) contamination over the investigation period differ significantly and reflect the contrasting transport characteristics of surface-loaded solutes and particulate microbial species (bacteria and viruses) in the Triassic Sandstone. Differences result from a variety of factors, which include microbial die-off, dilution, and the contaminant-source characteristics. Observations in this study show that low levels of microbial contamination should be expected at depth in fissured sandstone due to aquifer heterogeneities such as fissuring and the occurrence of mudstone bands, though the magnitude of this contamination will vary over time. Furthermore, urban groundwater-protection measures based on solute-transport estimates may not be applicable to microbial contamination. Electronic Publication  相似文献   

Habitat disturbance and marina development: An assessment of ecological effects. I. Changes in primary production due to dredging and marina construction     

Timothy J. Iannuzzi  Michael P. Weinstein  Kevin G. Sellner  Jeffrey C. Barrett 《Estuaries and Coasts》1996,19(2):257-271

Potential impacts on primary production were estimated for an 800-slip marina previously planned for Davids Island, located in the extreme western portion of Long Island Sound, New York. Macroalgal and microalgal production in the area of the proposed marina was analyzed on the basis of six depth zones ranging from an existing seawall (at about +2.2 m MLW) seaward to a depth of ?2.4 m MLW. Productivity measurements were based on in situ ¹⁴C uptake studies, chlorophyll a determinations, and varying light exposures within the euphotic zone that were the estimate of daily production calculated for eight dominant macroalgae and microalgae, and summed to estimate existing production in the proposed marina. Similarly, post-construction production was estimated by applying the calculated daily production to the appropriate areas of hard substrate (breakwater, pilings, etc.) in the euphotic zone. Pre- and post-construction macroalgal production values were 50,608 and 42,152 g C d^?1, respectively. This represents a 17% reduction in macroalgal production. It should be noted, however, that production on the seafloor of the marina was not accounted for. Consquently, reductions in macroalgal production that might occur are likely overestimated. Microalgal production constituted less than 3% of total primary production in the nearshore areas of Davids Island. The pre- and post-construction microalgal production values were 1,542 and 743 g C d^?1, respectively. This represents a 48% reduction in microalgal production in unconsolidated sediment. However, micoalgal production would likely occur on hard substrates in the marina. Overall, pre- and post-construction estimates of primary production were remarkably similar, suggesting that production on hard substrates in the marina would compensate for lost production from deepening of the nearshore zone during construction. *** DIRECT SUPPORT *** A01BY074 00012  相似文献   

Thinned and subsided continental crust on the rifted margin of Eastern Canada: crustal structure, thermal evolution and subsidence history     

C. E. Keen  D. L. Barrett 《Geophysical Journal International》1981,65(2):443-465

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The abundance and isotopic composition of water in eucrites          下载免费PDF全文

T. J. Barrett  J. J. Barnes  R. Tartèse  M. Anand  I. A. Franchi  R. C. Greenwood  B. L. A. Charlier  M. M. Grady 《Meteoritics & planetary science》2016,51(6):1110-1124

Volatile elements play a key role in the dynamics of planetary evolution. Extensive work has been carried out to determine the abundance, distribution, and source(s) of volatiles in planetary bodies such as the Earth, Moon, and Mars. A recent study showed that the water in apatite from eucrites has similar hydrogen isotopic compositions compared to water in terrestrial rocks and carbonaceous chondrites, suggesting that water accreted very early in the inner solar system given the ancient crystallization ages (~4.5 Ga) of eucrites. Here, the measurements of water (reported as equivalent H₂O abundances) and the hydrogen isotopic composition (δD) of apatite from five basaltic eucrites and one cumulate eucrite are reported. Apatite H₂O abundances range from ~30 to ~3500 ppm and are associated with a weighted average δD value of ?34 ± 67‰. No systematic variations or correlations are observed in H₂O abundance or δD value with eucrite geochemical trend or metamorphic grade. These results extend the range of previously published hydrogen isotope data for eucrites and confirm the striking homogeneity in the H‐isotopic composition of water in eucrites, which is consistent with a common source for water in the inner solar system.  相似文献