The marine 14C age of the Vedde Ash Bed along the west coast of Norway     

Stein Bondevik  Jan Mangerud  Steinar Gulliksen 《第四纪科学杂志》2001,16(1):3-7

Articulated molluscs, sea urchins and barnacle fragments close to the Vedde Ash Bed in a shallow marine deposit on the west coast of Norway have been ¹⁴C dated. The weighted mean of four dates from a sediment slice 8 cm thick centred on the Vedde Ash Bed is 10920 ± 24 ¹⁴C yr BP. The most accurate ¹⁴C age of the Vedde Ash from terrestrial plant macrofossils is 10310 ± 50 yr BP. The difference is the ¹⁴C reservoir age for coastal water at the west coast of Norway during the mid‐Younger Dryas and equals 610 ± 55 yr. This is 230 yr older than the reservoir age for the Bølling/Allerød and for the present day in this area. The result supports earlier conclusions of a higher reservoir age for the Younger Dryas in the North Atlantic and Nordic Seas, although our reservoir age of 610 ± 55 yr is a few hundred years younger. This suggests that the ¹⁴C reservoir age at Vedde Ash time may increase from coastal water towards the open North Atlantic and Nordic Seas. Copyright © 2001 John Wiley & Sons, Ltd.  相似文献   

Water column monitoring near oil installations in the North Sea 2001-2004     

Hylland K  Tollefsen KE  Ruus A  Jonsson G  Sundt RC  Sanni S  Røe Utvik TI  Johnsen S  Nilssen I  Pinturier L  Balk L  Barsiene J  Marigòmez I  Feist SW  Børseth JF 《Marine pollution bulletin》2008,56(3):414-429

Fisheries have been vital to coastal communities around the North Sea for centuries, but this semi-enclosed sea also receives large amounts of waste. It is therefore important to monitor and control inputs of contaminants into the North Sea. Inputs of effluents from offshore oil and gas production platforms (produced water) in the Norwegian sector have been monitored through an integrated chemical and biological effects programme since 2001. The programme has used caged Atlantic cod and blue mussels. PAH tissue residues in blue mussels and PAH bile metabolites in cod have confirmed exposure to effluents, but there was variation between years. Results for a range of biological effects methods reflected exposure gradients and indicated that exposure levels were low and caused minor environmental impact at the deployment locations. There is a need to develop methods that are sufficiently sensitive to components in produced water at levels found in marine ecosystems.  相似文献   

Dynamic instability of clays: an energy approach   总被引：1，自引：0，他引：1  

Eugene A. Voznesensky  Steinar Nordal 《Soil Dynamics and Earthquake Engineering》1999,18(2):601

The dynamic instability of any soil is based on the ability to accumulate from cycle to cycle a part of the energy to be dissipated. Using the general thermodynamic approach in combination with high resolution experiments it is possible to analyze the transformations of energy in soil under dynamic loading. Undisturbed specimens of two Norwegian clays, sufficiently different in their engineering properties, were used in a number of undrained cyclic triaxial tests to study the influence of confining stress, coefficient of earth pressure at rest (K₀), dynamic stress amplitude and frequency of loading in the development of instability in the clays. This paper discusses the unit dissipated energy and the unit activation energy as possible energy criteria for evaluation of dynamic instability in soils.  相似文献   

Assessing and monitoring local and long-range-transported hydrocarbons as potential stressors to fish stocks     

Arnfinn Skadsheim  Steinar Sanni  Laurence Pinturier  Ulf-Einar Moltu  Melania Buffagni  Laura Bracco   《Deep Sea Research Part II: Topical Studies in Oceanography》2009,56(21-22):2037

The Arctic is poorly described and understood compared to the North Sea and other boreal areas. We need to learn how knowledge obtained at boreal conditions may be applied at Arctic conditions. Increasing activity of the hydrocarbon industry may cause exposure stress from discharges. Within a joint industry research programme (Biosea) we studied how responses in fish from oil exposure may differ at North Sea boreal and Barents Sea Arctic conditions. Hydrocarbon uptake, metabolites, and enzymatic and genotoxic biomarker type of effect responses were measured in cod (Gadus morhua L.). Hydrocarbon metabolites remain longer in fish bile than original hydrocarbons, which are eliminated fast from tissues. The metabolites may be measured to background concentrations. They describe exposure and they constitute a link to other effects. Body burden, biliary polyaromatic hydrocarbon (PAH) metabolite concentration, and quantities of Cytochrome P-450 1A (CYP1A) and DNA adducts increased with oil in water concentration. The extent of biomarker expression was lower for some biomarkers and elimination was slower at the lowest temperature. The results show that several factors have to be accounted for if warm-water biomarker data are to be applied in cold water.  相似文献   

Modeling creep and rate effects in structured anisotropic soft clays   总被引：3，自引：2，他引：1  

Gustav Grimstad  Samson Abate Degago  Steinar Nordal  Minna Karstunen 《Acta Geotechnica》2010,5(1):69-81

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Effects of chronic exposure to dispersed oil on selected reproductive processes in adult blue mussels (Mytilus edulis) and the consequences for the early life stages of their larvae     

Baussant T  Ortiz-Zarragoitia M  Cajaraville MP  Bechmann RK  Taban IC  Sanni S 《Marine pollution bulletin》2011,62(7):1437-1445

Mussels (Mytilus edulis) were continuously exposed to dispersed crude oil (0.015-0.25 mg/l) for 7 months covering the whole gamete development cycle. After 1 month exposure to 0.25 mg oil/l, the level of alkali-labile phosphates (ALP) and the volume density of atretic oocytes in female gonads were higher than those in the gonads of control females, indicating that oil affected the level of vitellogenin-like proteins and gamete development. Spawning of mussels was induced after 7 months oil exposure. Parental oil exposure did not affect subsequent fertilization success in clean seawater but this was reduced in 0.25 mg oil/l. Parental exposure to 0.25 mg oil/l caused both slow development and a higher percentage of abnormalities in D-shell larvae 2 days post-fertilization; reduced growth 7 days post-fertilization. These effects were greatly enhanced when larval stages were maintained at 0.25 mg oil/l. Similar studies are warranted for risk assessment prognosis.  相似文献   

Practical aspects of frequency-domain identification of dynamic models of marine structures from hydrodynamic data     

Tristan Perez  Thor I. Fossen 《Ocean Engineering》2011,38(2-3):426-435

The motion response of marine structures in waves can be studied using finite-dimensional linear-time-invariant approximating models. These models, obtained using system identification with data computed by hydrodynamic codes, find application in offshore training simulators, hardware-in-the-loop simulators for positioning control testing, and also in initial designs of wave-energy conversion devices. Different proposals have appeared in the literature to address the identification problem in both time and frequency domains, and recent work has highlighted the superiority of the frequency-domain methods. This paper summarises practical frequency-domain estimation algorithms that use constraints on model structure and parameters to refine the search of approximating parametric models. Practical issues associated with the identification are discussed, including the influence of radiation model accuracy in force-to-motion models, which are usually the ultimate modelling objective. The illustration examples in the paper are obtained using a freely available MATLAB toolbox developed by the authors, which implements the estimation algorithms described.  相似文献   

Evolution of parental magmas of Miocene shield basalts of Gran Canaria (Canary Islands): constraints from crystal,melt and fluid inclusions in minerals   总被引：7，自引：0，他引：7  

A. A. Gurenko  Thor H. Hansteen  Hans-Ulrich Schmincke 《Contributions to Mineralogy and Petrology》1996,124(3-4):422-435

 Picritic units of the Miocene shield volcanics on Gran Canaria, Canary Islands, contain olivine and clinopyroxene phenocrysts with abundant primary melt, crystal and fluid inclusions. Composition and crystallization conditions of primary magmas in equilibrium with olivine Fo_90-92 were inferred from high-temperature microthermometric quench experiments, low-temperature microthermometry of fluid inclusions and simulation of the reverse path of olivine fractional crystallization based on major element composition of melt inclusions. Primary magmas parental for the Miocene shield basalts range from transitional to alkaline picrites (14.7–19.3 wt% MgO, 43.2–45.7 wt% SiO₂). Crystallization of these primary magmas is believed to have occurred over the temperature range 1490–1150° C at pressures ≈5 kbar producing olivine of Fo_80.6-90.2, high-Ti chrome spinel [Mg/ (Mg+Fe²⁺)=0.32–0.56, Cr/(Cr+Al)=0.50–0.78, 2.52–8.58 wt% TiO₂], and clinopyroxene [Mg/(Mg+Fe)=0.79–0.88, Wo_44.1-45.3, En_43.9-48.0, Fs_6.8-11.0] which appeared on the liquidus together with olivine≈Fo₈₆. Redox conditions evolved from intermediate between the QFM and WM buffers to late-stage conditions of NNO+1 to NNO+2. The primary magmas crystallized in the presence of an essentially pure CO₂ fluid. The primary magmas originated at pressures >30 kbar and temperatures of 1500–1600° C, assuming equilibrium with mantle peridotite. This implies melting of the mantle source at a depth of ≈100 km within the garnet stability field followed by migration of melts into magma reservoirs located at the boundary between the upper mantle and lower crust. The temperatures and pressures of primary magma generation suggest that the Canarian plume originated in the lower mantle at depth ≈900 km that supports the plume concept of origin of the Canary Islands. Received: 23 October 1995/Accepted: 21 February 1996  相似文献   

Application of Soft Data in Nodule Resource Estimation     

Ellefmo  Steinar Løve  Kuhn  Thomas 《Natural Resources Research》2021,30(2):1069-1091

Natural Resources Research - Minerals and metals are of uttermost importance in our society, and mineral resources on and beneath the deep ocean floor represent a huge potential. Deciding whether...  相似文献   

Challenges in financing public sector low-carbon initiatives: lessons from private finance for a school district in British Columbia,Canada     

Thor Jensen  Hadi Dowlatabadi 《Climate Policy》2018,18(7):878-888

Governments are major investors in climate change mitigation, but aversion to public indebtedness has led to reliance on private finance to deliver public assets. Compounding this challenge, financing through Energy Service Contracts is ruled out by accounting rules. With public and traditional private funding avenues closed, government departments have sought contracts that do not disclose the full cost of borrowing, such as the Public–Private Partnership (PPP) described in this case study. We unpack the utility contract filed with the provincial regulator to show that circumventing budgetary constraints cost the Delta School Board (DSB) 8.75% per annum on borrowed private funds while public finance would have cost 4%pa. All levels of the public sector are keen to play their role in climate mitigation. Climate policy is about not passing our burden of unbridled fossil fuel use and greenhouse gas emissions to future generations. If we do not exempt public sector capital investments for decarbonization from deficit regulations, we risk passing an unnecessary economic burden to future generations.

Key policy insights

• Transition to a low-carbon economy requires public sector investments that exceed budget deficit regulations and political aversion in many jurisdictions;

• Private–Public Partnerships are currently viewed as the solution to this self-imposed fiscal constraint;

• PPPs without clear performance targets or contractual templates will expose less experienced public sector investors to high costs and emissions above expectations.

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