Sea

Distribution by Scientific Domains
Distribution within Earth and Environmental Science

Kinds of Sea

  • Barent sea
  • adriatic sea
  • andaman sea
  • arabian sea
  • baltic sea
  • bering sea
  • black sea
  • bohai sea
  • caspian sea
  • central baltic sea
  • central north sea
  • china sea
  • dead sea
  • deep sea
  • dutch wadden sea
  • east china sea
  • east sea
  • eastern mediterranean sea
  • high sea
  • ionian sea
  • irish sea
  • japan sea
  • labrador sea
  • laptev sea
  • ligurian sea
  • mediterranean sea
  • north aegean sea
  • north sea
  • north-eastern mediterranean sea
  • northern adriatic sea
  • northern baltic sea
  • northern north sea
  • norwegian sea
  • open sea
  • red sea
  • ross sea
  • south china sea
  • southern north sea
  • tasman sea
  • temperate sea
  • wadden sea
  • western black sea
  • western mediterranean sea
  • white sea
  • yellow sea

  • Terms modified by Sea

  • sea area
  • sea basin
  • sea bass
  • sea bass Dicentrarchu labrax
  • sea bass fillet
  • sea bass larva
  • sea bottom
  • sea bream
  • sea breeze circulation
  • sea cage
  • sea change
  • sea coast
  • sea condition
  • sea cucumber
  • sea duck
  • sea floor
  • sea grass bed
  • sea ice
  • sea interaction
  • sea level
  • sea level change
  • sea level pressure
  • sea level rise
  • sea lion
  • sea louse
  • sea otter
  • sea plate
  • sea population
  • sea region
  • sea regions
  • sea sediment
  • sea shelf
  • sea side
  • sea snake
  • sea spider
  • sea star
  • sea state
  • sea surface
  • sea surface temperature
  • sea surface temperature anomaly
  • sea temperature
  • sea trout
  • sea turtle
  • sea urchin
  • sea urchin development
  • sea urchin egg
  • sea urchin embryo
  • sea water
  • sea water intrusion

  • Selected Abstracts


    Formation processes at the Ohalo II submerged prehistoric campsite, Israel, inferred from soil micromorphology and magnetic susceptibility studies

    GEOARCHAEOLOGY: AN INTERNATIONAL JOURNAL, Issue 4 2003
    Alexander Tsatskin
    Soil-geomorphic analysis coupled with micromorphology, SEM/EDS, magnetic susceptibility, and conventional sedimentological studies allowed us to reconstruct the site formation history and validate the archaeologically observed variability of human activities in the prehistoric camp of Ohalo II (19.5 ka B.P.), Sea of Galilee, Israel. The cultural layers rest upon the Late Pleistocene Lake Lisan deposits that accumulated under conditions of changing water supply and increasing rate of sedimentation from deep-water varvelike deposits to basalt-derived, near-shore sandy lacustrine deposits. Intermittent occupation is recorded in some localities, indicating short-term inundation episodes, which led to partial truncation and deformation of the sediments, primarily in the eastern lakeward part of the site. On the elevated, landward positions, incipient soils with strongly bioturbated profiles formed. Micromorphology demonstrates that intentional flooring was applied within the remains of brush huts, where millimeter-sized, horizontally organized burnt and unheated vegetal tissues were likely to have been placed upon the compacted ground. In fireplaces, the cultural deposits in thin sections are composed of strongly mixed, abundant wood charcoal, ashes, and fishbone remains. Post-depositional alterations were controlled by intermittent inundation of the site and salinization, which induced gypsum and pyrite deposition, primarily along decayed roots, and eventual pyrite oxidation. Accumulation of sodium and chlorine in the post-occupation deposits is likely to have occurred because of discharge of saline groundwater. Although only suggestive at this stage of research, the conclusions drawn from magnetic susceptibility parameters of archaeologically related deposits at Ohalo II fit well with the micromorphological reconstructions and provide new information on the Late Pleistocene evolution of the Lake Lisan/Sea of Galilee fluctuating system. 2003 Wiley Periodicals, Inc. [source]


    Implementing the strategic environmental assessment (SEA) Directive in the South West of England

    ENVIRONMENTAL POLICY AND GOVERNANCE, Issue 3 2004
    Clare Brooke
    The South West of England is famous as being an area rich in environmental features and heritage. The tools available to local authorities and other organizations to protect this valued environment are being expanded to include strategic environmental assessment (SEA). SEA is being introduced under a European Community directive, which will be incorporated into UK law in 2004. The directive will require national, regional and local authorities to carry out environmental assessment on certain plans and programmes that they promote. To ensure that the effectiveness of SEA in the South West is maximized, the South West Regional Assembly is working with local authorities and regional partners to consider the implications of the directive, and help the region prepare for its implementation. The aim of the project is to more clearly define the potential for SEA within the South West, examine the barriers that organizations may face when implementing the directive and establish good practice within the region. Work has been carried out to examine specific requirements of the SEA Directive, including the baseline data requirements for undertaking SEAs, and methodological differences between SEA and sustainability appraisals. Existing practice was examined to consider how current planning processes can be adapted to fulfil the requirements of the directive. Case studies were also undertaken to examine the issues around implementing the directive for non-land-use plans, including transport, economic development, waste management, renewable energy and flood management. Copyright 2004 John Wiley & Sons, Ltd and ERP Environment. [source]


    ,Objective-led' SEA in a Scottish local authority

    ENVIRONMENTAL POLICY AND GOVERNANCE, Issue 3 2004
    Graham Esson
    Scottish planners have expanded environmental effect assessment of development plans into the policy appraisal of their sustainability impacts. The application of this methodology is demonstrated in our review of the appraisal of the Perth and Kinross structure plan, which demonstrates the strengths and limitations of this objective-led approach to strategic environmental assessment when compared with a baseline-led one. Scottish Executive interim planning guidance for the European Union directive on strategic environmental assessment integrates the two approaches. This requires the local baseline to be clearly established and plan-induced movements in it to be predicted, monitored and evaluated. It also requires the use of techniques capable of assessing all forms of impact, and better engagement with the public and environmental authorities. Implementation of the directive will tax the capacity of Scottish planning authorities to meet these requirements whilst retaining their preference for an objective-led policy-based approach to assessment. Copyright 2004 John Wiley & Sons, Ltd and ERP Environment. [source]


    Swedish Guidelines for Strategic Environmental Assessment for EU Structural Funds

    ENVIRONMENTAL POLICY AND GOVERNANCE, Issue 1 2002
    Berit Balfors
    This paper examines the Swedish Strategic Environmental Assessment (SEA) guidelines as developed by the Swedish Environmental Protection Agency for applications made to the EU Structural Funds for financial assistance for regional development plans and programmes. These guidelines aim to increase the integration of environmental concerns in the programming process by promoting the application of environmental-objective-led SEA. The issues of screening for sustainability and environmental integration through objective-led SEA are addressed. The guidelines are considered as a positive development, which has potential for furthering the application of SEA in regional planning in Sweden. Copyright 2002 John Wiley & Sons, Ltd. and ERP Environment [source]


    Neonatal exposure to staphylococcal superantigen improves induction of oral tolerance in a mouse model of airway allergy

    EUROPEAN JOURNAL OF IMMUNOLOGY, Issue 2 2009
    Anna Lnnqvist
    Abstract The hygiene hypothesis suggests that lack of microbial stimulation in early infancy may lead to allergy, but it has been difficult to identify particular protective microbial exposures. We have observed that infants colonised in the first week(s) of life with Staphylococcus aureus have lower risk of developing food allergy. As many S. aureus strains produce superantigens with T-cell stimulating properties, we here investigate whether neonatal mucosal exposure to superantigen could influence the capacity to develop oral tolerance and reduce sensitisation and allergy. BALB/c mice were exposed to staphylococcal enterotoxin A (SEA) as neonates and fed with OVA as adults, prior to sensitisation and i.n. OVA challenge. Our results show that SEA pre-treated mice are more efficiently tolerised by OVA feeding, as shown by lower lung-cell infiltration and antigen-specific IgE response in the SEA pre-treated mice, compared with sham-treated mice. This was not due to deletion or anergy of lymphocytes by SEA treatment, because the SEA pre-treated mice that were fed with PBS showed similar inflammatory response as the sham-treated PBS-fed mice. Our results suggest that strong T-cell activation in infancy conditions the mucosal immune system and promotes development of oral tolerance. [source]


    Novel TRIP-Steel/Mg-PSZ Composite,Open Cell Foam Structures for Energy Absorption

    ADVANCED ENGINEERING MATERIALS, Issue 3 2010
    Christos G. Aneziris
    Porous materials have received extensive attention for energy absorption in the last years. In terms of this study austenitic TRIP-steel/Mg-PSZ composite,open cell foam structures are formed based on replicas using open-celled polyurethane foam as a skeleton with and without a supporting dense face (jacket) coating. Their compression strength as well as their specific energy absorption SEA has been registered as a function of the compressive strain. The zirconia addition has reinforced the composite material with the face coating up to a compressive strain of 50%. The stress-induced martensitic transformation of partially stabilized zirconia phases has been investigated as a function of the compressive strain by EBSD. The zirconia phase transformation is triggered already at low compressive strains below 2%. [source]


    ISOLATION BY DISTANCE IN EQUILIBRIUM AND NONEQUILIBRIUM POPULATIONS OF FOUR TALITRID SPECIES IN THE MEDITERRANEAN SEA

    EVOLUTION, Issue 5 2000
    Elvira De Matthaeis
    Abstract Allozymic variation at 21,23 loci was studied in 28 populations of Talitrus saltator, 23 populations of Orchestia montagui, 13 populations of O. stephenseni, and five populations of Platorchestia platensis from the Mediterranean Basin. Different levels of gene flow (Nm,) were detected within each species at the scale of the whole Mediterranean: O. montagui and P. platensis had low population structure, with levels of Nm, 1, whereas the T. saltator and O. stephenseni populations have values of Nm, < 1. The relationship between Nm, and geographic distance was analyzed to test for the presence of an isolation by distance pattern in the spatial genetic variation within each species. A model of isolation by distance is useful to describe the pattern of genetic structuring of study species at the scale of the whole Mediterranean: geographic distance explained from 28% to 70% of the variation in gene flow. In the Aegean area all species showed an island model of genetic structuring regardless of the levels of gene flow. [source]


    PIPD, a new high-modulus and high-strength polymer fibre with exceptional fire protection properties

    FIRE AND MATERIALS, Issue 4-5 2002
    M.G. Northolt
    The development of the new high-modulus and high-strength fibre M5, made of poly{2,6-diimidazo[4,5-b:4,,5, -e]-pyridinylene-1,4(2,5-dihydroxy)phenylene} or PIPD, has resulted in an organic polymer fibre with exceptional fire protection properties when compared with PBO, Twaron, Kevlar and Nomex fibres. The PIPD as-spun fibre with a modulus of 150 GPa and a tensile strength of 2.5 GPa is a crystal hydrate containing 21 wt% water. Cone calorimeter measurements yielded a fire performance index (FPI) 20 times higher than Nomex, with extremely low value for the specific extinction area (SEA) characterizing the smoke formation. The PIPD-HT fibre (recrystallized in an after treatment into the anhydrous crystalline structure) with a modulus >300 GPa and a strength >5 GPa has a FPI value similar to PBO but shows much less smoke formation than this fibre. Copyright 2002 John Wiley & Sons, Ltd. [source]


    Increased serum anandamide level at ruptured plaque site in patients with acute myocardial infarction

    FUNDAMENTAL & CLINICAL PHARMACOLOGY, Issue 3 2009
    Naotaka Maeda
    Abstract Inflammation caused by activated macrophages and T lymphocytes may trigger plaque rapture in acute coronary syndrome (ACS). Anandamide and 2-arachidonylglycerol (2-AG) are macrophage-derived signal lipids and may be involved in the pathogenesis of ACS, but no clinical relevant data have been reported. In 43 acute myocardial infarction (AMI) patients (66 2 years), blood samples were obtained from the aortic root and the infarct-related coronary artery (IRA) using a PercuSurge system during primary percutaneous coronary intervention (PCI). In six patients with stable effort angina (SEA) (56 6 years), blood samples were obtained from the site of stenosis during elective PCI. In 25 of the 43 AMI patients, anandamide was detected in the serum. Serum anandamide level was 35 20 pmol/mL in the aorta and was significantly increased to 401 134 pmol/mL in the IRA (P < 0.01). 2-AG was undetectable in most of the patients. In patients with SEA, neither anandamide nor 2-AG was detected in the serum at the plaque site. In AMI patients with anandamide detected, left ventricular ejection fraction at 2 weeks after PCI was increased by 3.7 2.1% compared with that at the acute phase, while it was decreased by 3.0 1.8% in those without anandamide detected (P < 0.05). The serum anandamide level at the culprit lesion was elevated compared with the systemic level in a significant number of AMI patients, indicating the synthesis of anandamide at the IRA. Anandamide was suggested to be derived from ruptured plaque and may exert beneficial effects in humans. [source]


    Women's rights in Peru: insights from two organizations

    GLOBAL NETWORKS, Issue 4 2009
    ROSA ALAYZA MUJICA
    Abstract In this article we explore the appropriation of ideas about women's rights in Lima, Peru through an ethnographic study of two non-governmental organizations. SEA is a local NGO grounded in the Catholic Church's liberation theology movement, which seeks to promote integrated human development, and is linked to the worldwide Catholic Church. DEMUS, the second NGO, with feminist roots, actively fights gender discrimination and belongs to networks of international women's human rights movements and UN organizations. We argue that the struggle for women's rights is part of a broader struggle for recognition and equality for the poor, shaped by changing notions of national identity, citizenship and diversity. Our research revealed clear examples of vernacularization, whereby local context, values and culture played a decisive role in the adoption of women rights ideas. Encounters with other concepts and movements, including social justice, family violence and women's mobilization, intimately shaped the vernacularization of women's rights. Ultimately, the adoption of rights ideas involved changes in women's individual and collective empowerment. [source]


    Simple efficient algorithm (SEA) for shallow flows with shock wave on dry and irregular beds

    INTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN FLUIDS, Issue 11 2008
    Alireza Zia
    Abstract An explicit Godunov-type solution algorithm called SEA (simple efficient algorithm) has been introduced for the shallow water equations. The algorithm is based on finite volume conservative discretisation method. It can deal with wet/dry and irregular beds. Second-order accuracy, in both time and space, is achieved using prediction and correction steps. A very simple and efficient flux limiting technique is used to equip the algorithm with total variation dimensioning property for shock capturing purposes. In order to make sure about the balance between the flux gradient and the bed slope, treatment of the source term has been done using a new procedure inspired mainly by the physical rather than mathematical consideration. SEA has been applied to one-dimensional problems, although it can equally be applied to multi-dimensional problems. In order to assess the capability of proposed algorithm in dealing with practical applications, several test cases have been examined. Copyright 2007 John Wiley & Sons, Ltd. [source]


    A review of recent climate variability and climate change in southeastern Australia

    INTERNATIONAL JOURNAL OF CLIMATOLOGY, Issue 7 2008
    Bradley F. Murphy
    Abstract Southeastern Australia (SEA) has suffered from 10 years of low rainfall from 1997 to 2006. A protracted dry spell of this severity has been recorded once before during the 20th century, but current drought conditions are exacerbated by increasing temperatures. Impacts of this dry decade are wide-ranging, so a major research effort is being directed to better understand the region's recent climate, its variability and climate change. This review summarizes the conditions of these 10 years and the main mechanisms that affect the climate. Most of the rainfall decline (61%) has occurred in autumn (March,May). Daily maximum temperatures are rising, as are minimum temperatures, except for cooler nights in autumn in the southwest of SEA closely related to lower rainfall. A similar rainfall decline occurred in the southwest of western Australia around 1970 that has many common features with the SEA decline. SEA rainfall is produced by mid-latitude storms and fronts, interactions with the tropics through continental-scale cloudbands and cut-off lows. El Nio-Southern Oscillation impacts on SEA rainfall, as does the Indian Ocean, but neither has a direct influence in autumn. Trends have been found in both hemispheric (the southern annular mode) and local (sub-tropical ridge) circulation features that may have played a role in reducing the number and impact of mid-latitude systems around SEA, and thus reducing rainfall. The role of many of these mechanisms needs to be clarified, but there is likely to be an influence of enhanced greenhouse gas concentrations on SEA climate, at least on temperature. Copyright 2007 Royal Meteorological Society [source]


    Haemoglobin H disease due to (,,,SEA) ,-globin gene deletion and ,2-codon 30 (,GAG) mutation: a family study

    INTERNATIONAL JOURNAL OF LABORATORY HEMATOLOGY, Issue 5 2001
    S.K. Ma
    A Chinese family in which two siblings suffer from haemogloblin (Hb) H disease due to (,,,SEA) ,-globin gene deletion and ,2-codon 30 (,GAG) mutation is described. Both siblings are transfusion-independent and have survived to adulthood. In contrast to previous report of hydrops fetalis associated with ,-,-thal-1 and ,2-codon 30 (,GAG) mutation, the ,-globin genes are intact in the two siblings, which most probably alleviates the ,-chain excess and protects the fetus from severe anaemia. Correlation of genotype with phenotype in Hb H disease is important for genetic counselling, especially in the antenatal setting. [source]


    Evaluation of Common Bean for Drought Tolerance in Juana Diaz, Puerto Rico

    JOURNAL OF AGRONOMY AND CROP SCIENCE, Issue 5 2009
    T. G. Porch
    Abstract Drought tolerance is an increasingly important trait in common bean (Phaseolus vulgaris L.) due to the reduction in water resources, a shift in production areas and increasing input costs. The objective of this study was to evaluate 29 genotypes for drought tolerance under drought stress (DS) and reduced stress treatments in Juana Diaz, Puerto Rico. The use of DS and reduced stress treatments facilitated the identification of drought tolerant germplasm that also had good yield potential under more optimal conditions. Based on the results of seed yield under DS and reduced stress conditions, and DS indices, including the geometric mean (GM), stress tolerance index (STI) and percent yield reduction (YR), genotypes were identified with greater yield potential under the tested environment. Based on average GM over the 2 years, the superior common bean genotypes identified were SEA 5, G 21212, A 686, SEN 21 and SER 21. These genotypes performed well in both years and under both treatment conditions and thus may serve as parents for DS improvement and genetic analysis. [source]


    An Application of Score Equity Assessment: Invariance of Linkage of New SAT to Old SAT Across Gender Groups

    JOURNAL OF EDUCATIONAL MEASUREMENT, Issue 2 2006
    Jinghua Liu
    The College Board's SAT data are used to illustrate how the score equity assessment (SEA) can help inform the program about equatability. SEA is used to examine whether the content change(s) to the revised new SAT result in differential linking functions across gender groups. Results of population sensitivity analyses are reported on the linkage of the new SAT critical reading (CR) prototype to an old SAT verbal (OV). Based on the criteria used in this study, population invariance was achieved with respect to gender groups. [source]


    LIPID, CHOLESTEROL AND FATTY ACID PROFILE OF SOME COMMERCIALLY IMPORTANT FISH SPECIES FROM SOUTH CASPIAN SEA

    JOURNAL OF FOOD BIOCHEMISTRY, Issue 4 2010
    S. PIRESTANI
    ABSTRACT The fatty acid, lipid, cholesterol and energy contents in five commercially important fish species from South Caspian Sea (common kilka, Caspian kutum, golden gray mullet, common carp and pike perch) were evaluated. The fatty acid compositions of these five fish species ranged from 28.99 to 41.05% saturated fatty acids, 40.99,56.25% monounsaturated fatty acids and 14.22,23.03% polyunsaturated fatty acids. Among these, those occurring in the highest proportions were palmitic acid (20.42,27.9%), palmitoleic acid (11.09,26.26%), oleic acid (16.1,36.94%), eicosapentaenoic acid (3.22,7.53%) and docosahexaenoic acid (3.86,11.36%). The lipid, cholesterol and energy contents ranged from 1.97% to 10.23%, 57,302 mg/100 g and 4365.4,5544.2 cal g/dm, respectively. The obtained Statistical results showed that in these fishes, many of the above mentioned indices had significant differences (P , 0.01) and the cluster analysis results of fatty acid compositions showed that common carp and pike perch had good similarity, followed by the Caspian kutum and golden gray mullet. However, common kilka did not show any similarity to others. PRACTICAL APPLICATIONS Fish consumption has been linked to health benefits such as reduced risk of coronary heart disease. This is largely attributed to the lipid, cholesterol, energy contents, fatty acid compositions and the polyunsaturated fatty acids present in fish oils. The ,-3 : ,-6, polyunsaturated fatty acid/saturated fatty acid and eicosapentaenoic acid + docosahexaenoic acid/C16 ratios are considered to be useful criteria for comparing relative nutritional and oxidation values of fish oils. [source]


    OIL-PRONE LOWER CARBONIFEROUS COALS IN THE NORWEGIAN BARENTS SEA: IMPLICATIONS FOR A PALAEOZOIC PETROLEUM SYSTEM

    JOURNAL OF PETROLEUM GEOLOGY, Issue 2 2010
    J.H. Van Koeverden
    In this study, we assess the oil generation potential of Lower Carboniferous, liptinite-rich coals in the Tettegras Formation on the Finnmark Platform, southern Norwegian Barents Sea. Oil from these coals has been expelled into intercalated sandstones. The coals may have contributed to petroleum recorded in well 7128/4,1 on the Finnmark Platform and may constitute a new Palaeozoic source rock in the Barents Sea. The Tettegras Formation coals contain up to 80 vol.% liptinite (mineral matter free base) and have low oxygen indices. Hydrogen indices up to 367 mg HC/g TOC indicate liquid hydrocarbon potential. In wells 7128/4,1 and 7128/6,1, the coals have vitrinite reflectance Ro= 0.75,0.85 %. Compared to shale and carbonate source rocks, expulsion from coal in general begins at higher maturities (Ro= 0.8,0.9% and Tmax= 444,453C). Thus, the coals in the wells are mostly immature with regard to oil expulsion. The oil in well 7128/4,1 most likely originates from a more mature part of the Tettegras Formation in the deeper northern part of the Finnmark Platform. Wide variations in biomarker facies parameters and ,13C isotope values indicate a heterogeneous paralic depositional setting. The preferential retention by coal strata of naphthenes (e.g. terpanes and steranes) and aromatic compounds, compared to n-alkanes and acyclic isoprenoids, results in a terrigenous and waxy oil. This oil however contains marine biomarkers derived from the intercalated shales and siltstones. It is therefore important to consider the entire coal-bearing sequence, including the intercalated shales, in terms of source rock potential. Coals of similar age occur on Svalbard and Bjrnya. The results of this study therefore suggest that a Lower Carboniferous coaly source rock may extend over large areas of the Norwegian Barents Sea. This source rock is mature in areas where the otherwise prolific Upper Jurassic marine shales are either immature or missing and may constitute a new Palaeozoic coal-sourced petroleum system in the Barents Sea. [source]


    PETROPHYSICAL CHARACTERISTICS OF SOURCE AND RESERVOIR ROCKS IN THE HISTRIA BASIN, WESTERN BLACK SEA

    JOURNAL OF PETROLEUM GEOLOGY, Issue 4 2009
    C. Cranganu
    The petroleum system in the Histria Basin, Western Black Sea, includes Oligocene source rocks and Upper Cretaceous , Eocene reservoir rocks. Here we report on the petrophysical characteristics of these source and reservoir rocks using mercury intrusion porosimetry data from 14 core samples collected from five wells drilled on the East Lebada, West Lebada and Pescarus structures. Samples were in general dominated by carbonate lithologies with minor shales. Petrophysical parameters analyzed were: median pore-throat radius, average pore-throat radius, apparent porosity, pore-throat size distribution, pore-throat type, pore-throat sorting, maximum threshold entry radius, pore-throat radius at 35% mercury saturation (R35), and air permeability. Reservoir rock quality was estimated using a permeability / porosity / pore-throat type plot. The Oligocene samples showed little petrophysical variation. Samples were relatively homogenous and had the same pore-throat type (nano), were well sorted, had unimodal pore-throat distribution (suggesting the existence of a single fluid phase), had similar values for median and average pore-throat radius, and similar values for R35 and maximum threshold entry radius. Upper Cretaceous , Eocene samples were more heterogeneous in terms of petrophysical properties, and reservoir quality was in general higher than in the Oligocene interval. Average porosity and calculated air-permeability values were 18.4% and 0.37 mD, respectively for Upper Cretaceous samples; and 11.8% and 27.11 mD, respectively for Eocene samples. A case study of Oligocene and Cretaceous , Eocene samples from well West Lebada 817 is presented. This paper represents the first petrophysical study of source and reservoir rocks in the Histria Basin, Western Black Sea. The results will help to establish the links between petrophysical characteristics, age and depositional environment for source and reservoir rocks in other basins bordering the Black Sea. [source]


    THE STRUCTURAL STYLE OF SEDIMENTARY BASINS ON THE SHELVES OF THE LAPTEV SEA AND WESTERN EAST SIBERIAN SEA, SIBERIAN ARCTIC

    JOURNAL OF PETROLEUM GEOLOGY, Issue 3 2005
    D. Franke
    A total of 11,700 km of multichannel seismic reflection data were acquired during three recent reconnaissance surveys of the wide, shallow shelves of the Laptev and western East Siberian Seas in the Siberian Arctic Ocean. Three seismic marker horizons were defined and mapped in both shelf areas. Their nature and age were predicted on the basis of regional tectonic and palaeoenvironmental events and corroborated using onshore geology. To the north of the Laptev Sea, the Gakkel Ridge, an active mid-ocean ridge which separates the North American and Eurasian Plates, abruptly meets the steep slope of the continental shelf which is curvilinear in plan view. Extension has affected the Laptev Shelf since at least the Early Tertiary and has resulted in the formation of three major, generally north-south trending rift basins: the Ust'Lena Rift, the Anisin Basin and the New Siberian Basin. The Ust'Lena Rift has a minimum east-west width of 300km at latitude 75N and a Cenozoic infill up to 6 s (twt) in thickness. Further to the NW of the Laptev Shelf, the downthrown and faulted basement is overlain by a sub-parallel layered sedimentary succession with a thickness of 4 s (twt) that thins towards the west. Although this area was affected by extension as shown by the presence of numerous faults, it is not clear whether this depression on the NW Laptev Shelf is continuous with the Ust'Lena Rift. The Anisin Basin is located in the northern part of the Laptev Shelf and has a Cenozoic sedimentary fill up to 5 s (twt) thick. The deepest part of the basin trends north-south. To the west is a secondary, NW-SE trending depression which is slightly shallower than the main depocentre. The overall structure of the basin is a half-graben with the major bounding fault in the east. The New Siberian Basin is up to 70 km wide and has a minimum NW-SE extent of 300 km. The sedimentary fill is up to 4.5 s (twt) thick. Structurally, the basin is a half-graben with the bounding fault in the east. Our data indicate that the rift basins on the Laptev Shelf are not continuous with those on the East Siberian Shelf. The latter shelf can best be described as an epicontinental platform which has undergone continuous subsidence since the Late Cretaceous. The greatest subsidence occurred in the NE, as manifested by a major depocentre filled with inferred (?)Late Cretaceous to Tertiary sediments up to 5 s (twt) thick. [source]


    THE APPLICATION OF ELECTRON SPIN RESONANCE AS A GUIDE TO THE MATURATION AND TYPING OF ORGANIC MATTER IN THE NORTH SEA

    JOURNAL OF PETROLEUM GEOLOGY, Issue 1 2003
    R. A. McTavish
    In early electron spin resonance (ESR) analysis of North Sea wells, maturation of organic matter (OM) was expressed in terms of maximum palaeotemperature (MPT) based on North American calibrations that did not consider the influences of kerogen composition or overpressure. In the North Sea, the MPTs were anomalous in overpressured sequences and relative to other indices of OM maturation such as vitrinite reflectance, so the ESR method was abandoned there in geochemical studies. However, early empirical study of North Sea ESR data indicated that, in relation to functions that linked temperature and pore pressure, some ESR parameters were predictable without reference to MPTs. In order to re-evaluate ESR parameters as indices of OM maturation, the physical factors (temperature and pressure) which affect OM maturation are related in the present paper to the ESR parameters "g" (spectral position) and Ng (spin density) at six well locations in the northern North Sea. A third ESR parameter, W (line width), is not an effective guide to maturation levels due to its complex relationship to the physical factors and kerogen types. However, cross-plots of W versus "g" and Ng appear to be as effective as pyrolysis for kerogen typing. Levels of maturation investigated in the North Sea wells range through the equivalent vitrinite reflectance values of about 0.50,1.50%. The values of "g" and Ng have been differentiated for kerogen type, but undifferentiated values of "g" have also been studied. Regression analysis has shown that there are linear relationships between the ESR parameters "g" and Ng, and the physical factors present-day temperature (To), "effective" temperature (Te), and differential pressure (Pd). Correlation coefficients for both "g" (undifferentiated and differentiated) and Ng (differentiated) relative to the physical factors are high; the highest values are for "g" and Ng relative to Te and Pd (r =,0.950 for "g" differentiated or undifferentiated, r = 0.944,0.976 for Ng differentiated, respectively). However, correlation coefficients were lower for "g" and Ng relative to To. More frequent high correlation coefficients and larger sample populations suggest that "g" (undifferentiated) is a more reliable index of OM maturation than Ng(differentiated). However, the estimation of levels of OM maturation is improved if both indices are used together. The ESR method appears to be effective both for estimating levels of OM maturation and for kerogen typing. It has a number of potential advantages over other geochemical methods: firstly, it is more sensitive for estimating OM maturation than most other methods; secondly, it can be used to analyze organic matter which is as old as Proterozoic; thirdly, it does not destroy the samples analyzed. [source]


    PHOTOSYNTHETIC UTILIZATION OF INORGANIC CARBON IN THE ECONOMIC BROWN ALGA, HIZIKIA FUSIFORME (SARGASSACEAE) FROM THE SOUTH CHINA SEA,

    JOURNAL OF PHYCOLOGY, Issue 6 2003
    Dinghui Zou
    The mechanism of inorganic carbon (Ci) acquisition by the economic brown macroalga, Hizikia fusiforme (Harv.) Okamura (Sargassaceae), was investigated to characterize its photosynthetic physiology. Both intracellular and extracellular carbonic anhydrase (CA) were detected, with the external CA activity accounting for about 5% of the total. Hizikia fusiforme showed higher rates of photosynthetic oxygen evolution at alkaline pH than those theoretically derived from the rates of uncatalyzed CO2 production from bicarbonate and exhibited a high pH compensation point (pH 9.66). The external CA inhibitor, acetazolamide, significantly depressed the photosynthetic oxygen evolution, whereas the anion-exchanger inhibitor 4,4,-diisothiocyano-stilbene-2,2,-disulfonate had no inhibitory effect on it, implying the alga was capable of using HCO3, as a source of Ci for its photosynthesis via the mediation of the external CA. CO2 concentrations in the culture media affected its photosynthetic properties. A high level of CO2 (10,000 ppmv) resulted in a decrease in the external CA activity; however, a low CO2 level (20 ppmv) led to no changes in the external CA activity but raised the intracellular CA activity. Parallel to the reduction in the external CA activity at the high CO2 was a reduction in the photosynthetic CO2 affinity. Decreased activity of the external CA in the high CO2 grown samples led to reduced sensitiveness of photosynthesis to the addition of acetazolamide at alkaline pH. It was clearly indicated that H. fusiforme, which showed CO2 -limited photosynthesis with the half-saturating concentration of Ci exceeding that of seawater, did not operate active HCO3, uptake but used it via the extracellular CA for its photosynthetic carbon fixation. [source]


    ARE SPERM LIMITING IN THE SEA?

    JOURNAL OF PHYCOLOGY, Issue 2000
    M. L. Berndt
    The reproductive success of marine species with external fertilization depends on environmental conditions during gamete release. There is special interest presently in whether water motion causes sperm limitation under natural conditions. We investigated gamete release of Fucus vesiculosus from an exposed shore to ascertain: 1) when gametes are released during the tidal cycle, 2) when fertilization occurs, and 3) what the natural sperm:egg ratios are. Water samples were collected and concentrated over five minutes every half hour off Pemaquid Point, ME from three replicate sites within each of two locations using a pump-filter device. Immunofluorescence microscopy revealed that gamete release occurred only on the two calmest spring tides. Sperm became present in the water column at the same time as oogonia (30 min,1 h prior to high tide [HT]) and reached peak concentration at exactly HT. The sperm:egg ratio was 76:1 on 8 Oct 1999 and 21:1 on 8 Nov 1999 at exactly 30 min prior to HT and dropped sharply after HT. Gametes continued to be collected for several hours after HT but analysis of pronuclear position in aceto-iron-hematoxylin stained eggs revealed that all fertilization occurred at approximately HT. We modelled the total number of days when reproduction was possible using these results and wind and wave data from the National Data Buoy Center. Our research provides evidence that gamete release by F. vesiculosus occurs at slack HT on calm days and that sperm are not a limiting factor in fertilization for this species. [source]


    EFFECTS OF AN OFFSHORE OIL DEVELOPMENT ON LOCAL ABUNDANCE AND DISTRIBUTION OF RINGED SEALS (PHOCA HISPIDA) OF THE ALASKAN BEAUFORT SEA,

    MARINE MAMMAL SCIENCE, Issue 2 2005
    Valerie D. Moulton
    Abstract This study investigates how densities of ringed seals were affected by construction and oil production activities at Northstar, an artificial island built in the nearshore Alaskan Beaufort Sea. Intensive and replicated aerial surveys of seals on landfast ice were conducted during six spring seasons: for three seasons before island construction began (1997,1999); after a winter of intensive island construction (2000); and after more limited construction plus drilling (2001) and drilling plus oil production (2002). A Poisson regression model was used to examine seal densities relative to distance from Northstar after allowance for environmental covariates. Post hoc power analysis indicated that the study design and Poisson regression approach had high power to detect small-scale changes in seal densities near Northstar if such changes had occurred. However, seal densities during spring were not significantly affected by proximity to Northstar in 2000,2002. Habitat, temporal, and weather factors did have significant effects on seal densities. This study shows that effects of the Northstar oil development on local distribution of basking ringed seals are no more than slight, and are small relative to the effects of natural environmental factors. An understanding of environmental effects is essential when assessing potential impacts of industrial activity on ringed seals. [source]


    KILLER WHALE (ORCINUS ORCA) DISTRIBUTION AND ABUNDANCE IN THE CENTRAL AND SOUTHEASTERN BERING SEA, JULY 1999 AND JUNE 2000

    MARINE MAMMAL SCIENCE, Issue 3 2002
    Janice M. Waite
    [source]


    GEOGRAPHICAL VARIATION OF THE PARASITE, PHYLLOBOTHRIUM DELPHINI (CESTODA), IN BALL'S PORPOISE, PHOCOENOIDES DALLI, IN THE NORTHERN NORTH PACIFIC, BERING SEA, AND SEA OF OKHOTSK

    MARINE MAMMAL SCIENCE, Issue 2 2001
    William A. Walker
    Abstract Prevalence of the larval cestode, Phyllobothrium delphini, was estimated from 2,445 Dall's porpoise, Phocoenoides dalli, from the incidental take of the Japanese high seas salmon drift-net fishery in the northwestern North Pacific Ocean, Bering Sea, and a local hand harpoon fishery in the southern Sea of Okhotsk. Prevalence of P. delphini was 22.7% in the northwestern North Pacific Ocean and 1.4% in the Bering Sea. This parasite was not found in the southern Sea of Okhotsk. Geographical differences in the prevalence of P. delphini may be due, at least in part, to regional differences in abundance of elasmobranchs known to feed on marine mammals and suspected as hosts of the parasite. Estimated intensity of infection of individual porpoises by P. delphini was low (estimated mean intensity of 3.5 plerocercoids per animal). This is a low intensity of infection compared to other species of small cetaceans studied and may be due to both differences in regional abundance of elasmobranchs and the comparatively short life span of P. dalli. [source]


    A MODEL FOR THE BIOECONOMIC EVALUATION OF MARINE PROTECTED AREA SIZE AND PLACEMENT IN THE NORTH SEA

    NATURAL RESOURCE MODELING, Issue 4 2002
    ALASDAIR BEATTIE
    ABSTRACT. The use of marine protected areas (MPAs) as a basic management tool to limit exploitation rates in marine fisheries has been widely suggested. Models are important in predicting the consequences of management decisions and the design of monitoring programs in terms of policy goals. However, few tools are available that consider both multiple fleets and ecosystem scale dynamics. We use a new applied game theory tool, Ecoseed, that operates within a temporally and spatially explicit biomass dynamics model, Ecopath with Ecosim, to evaluate the efficacy of marine protected areas in the North Sea in both ecological and economic terms. The Ecoseed model builds MPAs based on the change in values of predicted economic rents of fisheries and the existence value of biomass pools in the ecosystem. We consider the market values of four fisheries operating in the North Sea: a trawl fishery, a gill net fishery, a seine fishery, and an industrial (reduction) fishery. We apply existence values, scaled such that their aggregate is similar to the total fishery value, to six biomass pools of concern: juvenile cod, haddock, whiting, saithe, seals, and the collective pool ,Other predators' that include marine mammals. Four policy options were considered: to maximize the rent only; to maximize the existence values only; to maximize the sum of the rent and existence values; and, finally, to maximize the sum of the rent and the existence values, but excluding only the trawl fleet from the MPA. The Ecoseed model suggests that policy goals that do not include ecological considerations can negatively impact the rents obtained by the different fishing sectors. The existence values will also be negatively impacted unless the MPA is very large. The Ecoseed model also suggests that policy goals based solely on existence values will negatively impact most fisheries. Under policy options that included ecological considerations, maximum benefits were derived from an MPA that covered 25,40% of the North Sea, placed along the southern and eastern coasts. Finally, the Ecoseed model suggests that an exclusion of the trawl fishery only from the MPA can provide small-to-substantial positive impacts to most species and fleets; this relative impact depends on level of interaction between the trawl fleet and the other fleets target species (e.g., through bycatch). [source]


    Cytokine responses to mitogen and Schistosoma haematobium antigens are different in children with distinct infection histories

    PARASITE IMMUNOLOGY, Issue 10 2001
    Janet T. Scott
    Prevalence of Schistosoma haematobium infection in children from two neighbouring villages in Zimbabwe was 771% and 403%, respectively. The age-intensity data indicated peak intensities of infection at a lower age in the high prevalence village. This study investigated whether the difference in infection histories was reflected in a difference in cytokine profiles between children resident in these two villages. Blood samples were taken to assay for cytokine secretion 1 year after treatment for schistosomiasis. They were cultured with phytohaemagglutinin (PHA), schistosome egg antigens (SEA) or cultured without stimulant and tested for the presence of interleukin (IL)-4, IL-5, IL-10, granulocyte-macrophage colony-stimulating factor (GM-CSF) and IFN-,. Blood samples from children from the low prevalence village were more likely to produce IL-4 (P < 00001) and produced higher levels of IFN-, (P < 002) and GM-CSF (P < 003) when cultured with PHA for 24 h. Residence in the high prevalence village was associated with production of IL-10 (P < 0006) and GM-CSF (P < 004) in response to culture with SEA and IL-5 (P < 002) with PHA for 48 h. The interaction between age and village was not significant for these results; however, there was a significant interaction between age and village for IL-5 detected in blood samples cultured with PHA for 24 h (P < 001). These results concur with previous observations that major patterns of cytokine production can be related to immunosuppression, but also indicate an underlying pattern which reflects the importance of history of infection to the immune response. [source]


    Apoptosis: a mechanism of immunoregulation during human schistosomiasis mansoni

    PARASITE IMMUNOLOGY, Issue 6 2000
    Patricia Carneiro-Santos
    People infected with schistosomes may present with a variety of clinical manifestations ranging from the relatively asymptomatic intestinal (INT) form to the hepatointestinal (HI) or hepatosplenic (HS) forms characterized by hepatomegaly and hepatosplenomegaly with severe portal hypertension, respectively. Flow cytometry analyses were used to evaluate the contribution of apoptosis in specific cell populations from schistosomiasis patients to the development of the different clinical forms of the disease. The results showed that cell death induced by combinations of specific antigen and cytokines corresponds with specific clinical presentations. It was shown that soluble egg antigen (SEA) increased the level of apoptosis only in T cells from INT patients. Stimulation with soluble lung worm antigen preparation (SLAP) did not induce significant differences in the levels of apoptosis in T cells from the patients with the different clinical forms of schistosomiasis. These results suggest for the first time that apoptosis plays an important role in the modulation of the anti-SEA response in INT patients. [source]


    Alignment of protein sequences by their profiles

    PROTEIN SCIENCE, Issue 4 2004
    Marc A. Marti-Renom
    Abstract The accuracy of an alignment between two protein sequences can be improved by including other detectably related sequences in the comparison. We optimize and benchmark such an approach that relies on aligning two multiple sequence alignments, each one including one of the two protein sequences. Thirteen different protocols for creating and comparing profiles corresponding to the multiple sequence alignments are implemented in the SALIGN command of MODELLER. A test set of 200 pairwise, structure-based alignments with sequence identities below 40% is used to benchmark the 13 protocols as well as a number of previously described sequence alignment methods, including heuristic pairwise sequence alignment by BLAST, pairwise sequence alignment by global dynamic programming with an affine gap penalty function by the ALIGN command of MODELLER, sequence-profile alignment by PSI-BLAST, Hidden Markov Model methods implemented in SAM and LOBSTER, pairwise sequence alignment relying on predicted local structure by SEA, and multiple sequence alignment by CLUSTALW and COMPASS. The alignment accuracies of the best new protocols were significantly better than those of the other tested methods. For example, the fraction of the correctly aligned residues relative to the structure-based alignment by the best protocol is 56%, which can be compared with the accuracies of 26%, 42%, 43%, 48%, 50%, 49%, 43%, and 43% for the other methods, respectively. The new method is currently applied to large-scale comparative protein structure modeling of all known sequences. [source]


    Decreased activity of the smooth muscle Na+/Ca2+ exchanger impairs arteriolar myogenic reactivity

    THE JOURNAL OF PHYSIOLOGY, Issue 6 2008
    Hema Raina
    Arteriolar myogenic vasoconstriction occurs when stretch or increased membrane tension leads to smooth muscle cell (SMC) depolarization and opening of voltage-gated Ca2+ channels. While the mechanism underlying the depolarization is uncertain a role for non-selective cation channels has been demonstrated. As such channels may be expected to pass Na+, we hypothesized that reverse mode Na+/Ca2+ exchange (NCX) may act to remove Na+ and in addition play a role in myogenic signalling through coupled Ca2+ entry. Further, reverse (Ca2+ entry) mode function of the NCX is favoured by the membrane potential found in myogenically active arterioles. All experiments were performed on isolated rat cremaster muscle first order arterioles (passive diameter ,150 ,m) which were pressurized in the absence of intraluminal flow. Reduction of extracellular Na+ to promote reverse-mode NCX activity caused significant, concentration-dependent vasoconstriction and increased intracellular Ca2+. This vasoconstriction was attenuated by the NCX inhibitors KB-R7943 and SEA 04000. Western blotting confirmed the existence of NCX protein while real-time PCR studies demonstrated that the major isoform expressed in the arteriolar wall was NCX1. Oligonucleotide knockdown (24 and 36 h) of NCX inhibited the vasoconstrictor response to reduced extracellular Na+ while also impairing both steady-state myogenic responses (as shown by pressure,diameter relationships) and acute reactivity to a 50 to 120 mmHg pressure step. The data are consistent with reverse mode activity of the NCX in arterioles and a contribution of this exchanger to myogenic vasoconstriction. [source]