A Gibbs–Pitzer function for high-salinity seawater thermodynamics     

Rainer Feistel  Giles M. Marion   《Progress in Oceanography》2007,74(4):515-539

A high-salinity Gibbs function for seawater is derived from Pitzer equations of the sea salt components, in conjunction with the 2003 Gibbs function of seawater for low salinities. Various properties, computed from both formulations by thermodynamic rules, are compared with each other, and with high-salinity measurements. The new Gibbs–Pitzer function presented in this paper is valid in the range 0–110 g kg⁻¹ in absolute salinity, −7 to +25 °C in temperature, and 0–100 MPa in applied pressure. The formulation is expressed in the International Temperature Scale 1990 (ITS-90), and is consistent with the International Standard for Fluid Water (IAPWS-95), and with the 2005/2006 equations of state of ice Ih.  相似文献   

A comfortable night out? Alcohol, drunkenness and inclusive town centres   总被引：1，自引：0，他引：1  

Adam Eldridge  Marion Roberts 《Area》2008,40(3):365-374

The Licensing Act (2003) was enacted in England and Wales against the backdrop of media concern about 'binge Britain' and violent town centres avoided by 'social drinkers'. This paper responds to these concerns by asking how to create more inclusive urban centres at night. Findings from focus groups found it was not alcohol consumption or a reluctance to partake in urban life that was detracting residents. Using the notion of 'comfort', the paper instead reveals a strong desire for varied late-night experiences ranging from quiet local venues, to active streets and live venues.  相似文献   

Pb–Nd isotopic constraints on sedimentary input into the Lesser Antilles arc system     

Marion Carpentier  Catherine Chauvel  Nadine Mattielli 《Earth and Planetary Science Letters》2008,272(1-2):199-211

The Lesser Antilles arc is a particularly interesting island arc because it is presently very active, it is located perpendicular to the South American continent and its chemical and isotopic compositions display a strong north–south gradient. While the presence in the south of a thick pile of sedimentary material coming from the old South American continent has long been suspected to explain the geochemical gradient, previous studies failed to demonstrate unambiguously a direct link between the arc lava compositions and the subducted sediment compositions.Here, we present new Nd, Sm, Th, U and Pb concentrations and Nd–Pb isotopic data for over 60 sediments from three sites located in the fore arc region of the Lesser Antilles arc. New data for DSDP Site 543 drill core located east of Dominica Island complement the data published by White et al. [White, W.M., Dupré, B. and Vidal, P., 1985. Isotope and trace element geochemistry of sediments from the Barbados Ridge–Demerara Plain region, Atlantic Ocean. Geochimica et Cosmochimica Acta, 49: 1875–1886.] and confirm their relatively uniform isotopic compositions (i.e., ²⁰⁶Pb/²⁰⁴Pb between 19.13 and 19.53). In contrast, data obtained on DSDP Site 144 located further south, on the edge of the South American Rise and on sediments from Barbados Island are much more variable (²⁰⁶Pb/²⁰⁴Pb ranges from 18.81 to 27.69). The very radiogenic Pb isotopic compositions are found in a 60 m thick black shale unit, which has no age equivalent in the Site 543 drill core. We interpret the peculiar composition of the southern sediments as being due to two factors, (a) the proximity of the South American craton, which contributes coarse grain old detrital material that does not travel far from the continental shelf, and (b) the presence of older sediments including the thick black shale unit formed during Oceanic Anoxic events 2 and 3.The north–south isotopic change known along the Lesser Antilles arc can be explained by the observed geographical changes in the composition of the subducted sediments. About 1% contamination of the mantle wedge by Site 543 sediments explains the composition of the northern islands while up to 10% sediments like those of Site 144 is required in the source of the southern island lavas. The presence of black shales in the subducted pile provides a satisfactory explanation for the very low Δ8/4 values that characterize the Lesser Antilles arc.  相似文献   

The added value of participatory modelling in fisheries management – what has been learnt?     

Christine Röckmann  Clara Ulrich  Marion Dreyer  Ewen Bell  Edward Borodzicz  Päivi Haapasaari  Kjellrun Hiis Hauge  Daniel Howell  Samu Mäntyniemi  David Miller  George Tserpes  Martin Pastoors 《Marine Policy》2012

How can uncertain fisheries science be linked with good governance processes, thereby increasing fisheries management legitimacy and effectiveness? Reducing the uncertainties around scientific models has long been perceived as the cure of the fisheries management problem. There is however increasing recognition that uncertainty in the numbers will remain. A lack of transparency with respect to these uncertainties can damage the credibility of science. The EU Commission's proposal for a reformed Common Fisheries Policy calls for more self-management for the fishing industry by increasing fishers' involvement in the planning and execution of policies and boosting the role of fishers' organisations. One way of higher transparency and improved participation is to include stakeholders in the modelling process itself. The JAKFISH project (Judgment And Knowledge in Fisheries Involving StakeHolders) invited fisheries stakeholders to participate in the process of framing the management problem, and to give input and evaluate the scientific models that are used to provide fisheries management advice. JAKFISH investigated various tools to assess and communicate uncertainty around fish stock assessments and fisheries management. Here, a synthesis is presented of the participatory work carried out in four European fishery case studies (Western Baltic herring, North Sea Nephrops, Central Baltic Herring and Mediterranean swordfish), focussing on the uncertainty tools used, the stakeholders' responses to these, and the lessons learnt. It is concluded that participatory modelling has the potential to facilitate and structure discussions between scientists and stakeholders about uncertainties and the quality of the knowledge base. It can also contribute to collective learning, increase legitimacy, and advance scientific understanding. However, when approaching real-life situations, modelling should not be seen as the priority objective. Rather, the crucial step in a science–stakeholder collaboration is the joint problem framing in an open, transparent way.  相似文献   

Negative effects of Phaeocystis globosa on microalgae   总被引：1，自引：0，他引：1  

刘洁生  杨维东  彭喜春  吕颂辉  王艳  陈菊芳  王朝晖  齐雨藻 《中国海洋湖沼学报》2010,28(4):911-916

The potential allelopathic effects of the microalga, Phaeocystis globosa Scherffel, on three harmful bloom algae, Prorocentrum donghaiense Lu, Chattonella marina (Subrahmanyan) Hara et Chihara and Chattonella ovata Hara et Chihara were studied. The growth of C. marina and C. ovata was markedly reduced when the organisms were co-cultured with P. globosa or cultured in cell-free spent medium. Haemolytic extracts from P. globosa cells in the senescence phase had a similar inhibitory effect on the three harmful bloom algae. However, P. globosa had less influence on the brine shrimp, Artemia salina. These results indicate that P. globosa may have an allelopathic effect on microalgae, which would explain the superior competitive abilities of P. globosa. Because the addition of the haemolytic toxins from P. globosa had similar effects on algae as spent media, these compounds may be involved in the allelopathic action of P. globosa.  相似文献   

Morphology and distribution of dolines on ultramafic rocks from airborne LiDAR data: the case of southern Grande Terre in New Caledonia (SW Pacific)   总被引：1，自引：0，他引：1       下载免费PDF全文

Julie Jeanpert  Pierre Genthon  Pierre Maurizot  Jean‐Luc Folio  Myriam Vendé‐Leclerc  Jeremy Sérino  Jean‐Lambert Join  Marion Iseppi 《地球表面变化过程与地形》2016,41(13):1854-1868

Dolines are closed geomorphological depressions which are surface manifestations of karstic systems. Usually developed on limestones, they also typify the morphology of the New Caledonian landscape, particularly on the southern massif of the main island (known as Massif du Sud). The specificity of dolines here lies in their development on ultramafic rocks. They are evidences of subsidence, suffosion and collapse phenomena resulting from dissolution weathering of peridotites. However, extensive underground drainage systems are still not yet recognized. Semi‐automatic mapping of dolines is carried out on a 148 km² area of the Massif du Sud from a high accuracy LiDAR digital elevation model. In this area 8601 dolines ranging from 1 m² to 2 km² are identified and morphologically characterized with precision. Most are small, shallow and round‐shaped, yet more complex shapes are locally observed. Size distribution analysis allows the setting of a threshold of 20 000 m² above which surface processes rather than chemical weathering control doline evolution. Doline density analysis reveals high concentrations on flat areas where ferricrete overlies the complete weathering profile, especially in the case of elevated rainy watersheds. Dolines are aligned and elongated along a north 135° ± 5° major fracture direction, which is inherited from the obduction of the Pacific Plate upper mantle in the Late Eocene. Finally, we propose a pioneering morphometric typology of dolines that provides important clues as to pseudokarstic activity. We define collapse, bowl‐shaped and flat bottom dolines. Collapse and bowl‐shaped dolines are assumed to denote active pseudokarst. They may widen and deepen, or eventually be filled by sediments. They are distinguished from flat bottom dolines that are partially to completely filled, which suggests that they are associated with paleo‐pseudokarsts. However the groundwater flow paths associated with the genesis and evolution of dolines must be clarified, thus collapse and bowl‐shaped dolines should be hydrologically monitored. Copyright © 2016 John Wiley & Sons, Ltd.  相似文献   

Climate, Communications, And Innovative Technologies: Potential Impacts and Sustainability of New Radio and Internet Linkages in Rural African Communities     

Mohammed Boulahya  Macol Stewart Cerda  Marion Pratt  Kelly Sponberg 《Climatic change》2005,70(1-2):299-310

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Rock fragment distributions and regolith evolution in the Ouachita Mountains,Arkansas, USA   总被引：2，自引：0，他引：2  

Jonathan D. Phillips  Ken Luckow  Daniel A. Marion  Kristin R. Adams 《地球表面变化过程与地形》2005,30(4):429-442

Rock fragments in the regolith are a persistent property that reflects the combined influences of geologic controls, erosion, deposition, bioturbation, and weathering. The distribution of rock fragments in regoliths of the Ouachita Mountains, Arkansas, shows that sandstone fragments are common in all layers, even if sandstone is absent in parent material. Shale and sandstone fragments are produced at the bedrock weathering front, but the shale weathers rapidly and intact fragments are rare in the solum. Sandstone is weathered from ridgetop outcrops and transported downslope. Some of these fragments are moved downward, by faunalturbation and by transport into pits associated with rotting tree stumps. Upward movement by treethrow is common, resulting in a net concentration of rocks near the surface. However, the highest fragment concentrations are in the lower regolith, indicating active production at the weathering front. The regolith is a dynamic feature, reflecting the influences of vertical and horizontal processes, of active weathering at the bedrock interface, and of surficial sediment movements. The role of trees in redistributing rock fragments suggests that significant regolith mixing occurs over time scales associated with forest vegetation communities, and that forest soils have likely been extensively mixed within Holocene and historic time. Copyright © 2005 John Wiley & Sons, Ltd.  相似文献   

On the timing and causes of illite formation and remagnetization in the Cretaceous Marias River Shale, Disturbed Belt, Montana     

W. Crawford Elliott  Stephen G. Osborn  Vanessa J. O'Brien  R. Douglas Elmore  Michael H. Engel  J. Marion Wampler   《Journal of Geochemical Exploration》2006,89(1-3):92

In this study, we test a burial model for diagenetic illite and whether illitization is related to the acquisition of a chemical remanent magnetization (CRM). A prefolding, reversed polarity, secondary magnetization is found in carbonate concretions in diagenetically altered Upper Cretaceous rocks in the disturbed belt of Montana. Stratigraphically equivalent unaltered rocks to the east do not contain the magnetization. The magnetization could be a CRM or a thermoviscous remagnetization. The pole position is generally consistent with the Early Tertiary K–Ar ages of diagenetic illite–smectite formed under thrust loading, but it is not constrained well enough for a precise age comparison. If this magnetization is a CRM, it could be related to illitization. Alternatively, if the prefolding CRM had been acquired prior to thrust loading then the magnetization is not related to illitization. Geochemical studies are currently underway to test if the magnetization could be related to fluid alteration.  相似文献   

Absolute calibration of a photoelectric condensation nucleus counter at low values of nucleus concentration     

Marion B. Emmanuel  Patrick Squires 《Pure and Applied Geophysics》1969,72(1):268-283

Summary A new absolute condensation nucleus counter was constructed to investigate the accuracy of the calibration widely used with the Pollak-Nolan photoelectric condensation nucleus counter. An attempt was made to standardize the conditions affecting calibration and, using the new counter, to recalibrate the photoelectric counter at values of extinction less than 16%.Over this extinction range, the present work indicates nucleus concentrations which are higher by about 30% than those given by the calibration ofPollak andMetnieks [8]³). In view of the great natural variability of Aitken nucleus concentrations, this discrepancy, if real, is of little meteorological importance.  相似文献