Assessing Oregon's twenty-six coastal beach areas for recreational water quality standards     

Benedict RT  Neumann CM 《Marine pollution bulletin》2004,49(7-8):624-629

Water samples from 26 Oregon beaches were analyzed for Escherichia coli (E. coli) and enterococci concentrations by the Oregon Department of Human Services (ODHS) Public Health Laboratory. Nine Oregon beaches exceeded US Environmental Protection Agency's (USEPA) single sample maximum density of 104 enterococci colony forming units (cfu) per 100 mL with levels ranging from 121 to 4325 most probable number (MPN)/100 milliliters (mL). Otter Rock at South Cove had the highest enterococci concentration at 4352 MPN/100 mL. The results from two Oregon beaches exceeded Oregon Department of Environmental Quality's (ODEQ) estuarine E. coli standard of 406 organisms/100 mL. Otter Rock at South Cove had the highest E. coli concentration at 1850 MPN/100 mL while Road's End had an E. coli density of 771 MPN/100 mL. Results of this study suggest that adopting USEPA's marine enterococci standard in lieu of the ODEQ's estuarine standard will lead to increased Oregon beach water standard failures.  相似文献   

Fluid inclusion studies of the Abawso gold prospect,near the Ashanti Belt,Ghana   总被引：1，自引：0，他引：1  

Sven?E.?WilleEmail author  Reiner?Klemd 《Mineralium Deposita》2004,39(1):31-45

The major Ghanaian lode gold deposits are preferentially aligned along the western and eastern contacts of the Kumasi Basin with the Ashanti and Sefwi Belts, respectively. The investigated area of the Abawso small-scale concession, covering the workings of the old Ettadom mine, is situated 3 km west of the lithological contact of the Birimian metavolcanic rocks of the Akropong Belt in the east with the Birimian metasedimentary rocks of the Kumasi Basin in the west. The rocks of the Abawso concession represent a steeply NW-dipping limb of a SE-verging anticline with an axis plunging to the SW. Quartz veining occurs predominantly in the form of en échelon dilatational veins along NNE–SSW-striking shear zones of a few metres width and shows evidence of brittle and ductile deformation. Also stockwork-style quartz veining occurs in the vicinity of the main shaft of the old Ettadom mine. Hydrothermal alteration includes sericitisation, sulphidation and locally carbonatisation. The auriferous quartz veins mainly follow the trend of brittle to ductile deformed quartz veins; however, some occur in stockwork. Fluid inclusion studies reveal a large number of H₂O inclusions along intragranular trails in auriferous quartz vein samples, as well as an overall dominance of H₂O and H₂O-CO₂ inclusions over CO₂ inclusions. Textural observations and physico-chemical fluid inclusion properties indicate post-entrapment modifications for all quartz vein samples due to grain boundary migration recrystallisation. This process is interpreted to be responsible for the generation of the CO₂ inclusions from a H₂O-CO₂ parent fluid. In comparison with mineralisation at the Ashanti and Prestea deposits, which are characterised by CO₂±N₂ inclusions, the observed inclusion assemblage may be due to a shallower crustal level of mineralisation, or different degrees and styles of recrystallisation, or a less pronounced development of laminated quartz veins due to comparably restricted pressure fluctuations. Furthermore, the microthermometric observations allow the reconstruction of a possible retrograde P-T path, depicting near-isothermal decompression in the P-T range of the brittle/ductile transition.Editorial handling: E. Frimmel  相似文献   

Landscape variations in stream water SO₄ and δS_SO4 in a boreal stream network     

Louise Björkvald  Reiner Giesler  Christoph Humborg 《Geochimica et cosmochimica acta》2009,73(16):4648-2683

Despite reduced anthropogenic deposition during the last decades, deposition sulphate may still play an important role in the biogeochemical cycles of S and many catchments may act as net sources of S that may remain for several decades. The aim of this study is to elucidate the temporal and spatial dynamics of both SO₄²⁻ and δ³⁴S_SO4 in stream water from catchments with varying percentage of wetland and forest coverage and to determine their relative importance for catchment losses of S. Stream water samples were collected from 15 subcatchments ranging in size from 3 to 6780 ha, in a boreal stream network, northern Sweden. In forested catchments (<2% wetland cover) S-SO₄²⁻ concentrations in stream water averaged 1.7 mg L⁻¹ whereas in wetland dominated catchments (>30% wetland cover) the concentrations averaged 0.3 mg L⁻¹. A significant negative relationship was observed between S-SO₄²⁻ and percentage wetland coverage (r² = 0.77, p < 0.001) and the annual export of stream water SO₄²⁻ and wetland coverage (r² = 0.76, p < 0.001). The percentage forest coverage was on the other hand positively related to stream water SO₄²⁻ concentrations and the annual export of stream water SO₄²⁻ (r² = 0.77 and r² = 0.79, respectively). The annual average δ³⁴S_SO4 value in wetland dominated streams was +7.6‰ and in streams of forested catchments +6.7‰. At spring flood the δ³⁴S_SO4 values decreased in all streams by 1‰ to 5‰. The δ³⁴S_SO4 values in all streams were higher than the δ³⁴S_SO4 value of +4.7‰ in precipitation (snow). The export of S ranged from 0.5 kg S ha⁻¹ yr⁻¹ (wetland headwater stream) to 3.8 kg S ha⁻¹ yr⁻¹ (forested headwater stream). With an average S deposition in open field of 1.3 kg S ha⁻¹ yr⁻¹ (2002-2006) the mass balance results in a net export of S from all catchments, except in catchments with >30% wetland. The high temporal and spatial resolution of this study demonstrates that the reducing environments of wetlands play a key role for the biogeochemistry of S in boreal landscapes and are net sinks of S. Forested areas, on the other hand were net sources of S.  相似文献   

Seasonality change and the third millennium BP rainforest crisis in southern Cameroon (Central Africa)     

Alfred Ngomanda  Katharina Neumann  Astrid Schweizer  Jean Maley 《Quaternary Research》2009,71(3):307-318

The third millennium BP crisis of the central African rainforest is not sufficiently understood. The low resolution of most pollen profiles and a large plateau of the calibration curve aggravate the exact dating of the event, and its causal climatic parameters are debated. We present a high-resolution pollen profile from the swamp site Nyabessan in the southern Cameroonian rainforest, covering the period 3100-2300 cal yr BP. Between 3100 and 2500 cal yr BP, the climate was favourable for a regional evergreen forest with Caesalpiniaceae and Lophira and a local Raphia swamp forest. Around 2500/2400 cal yr BP, a significant decrease of mature forest and swamp forest taxa and an increase of pioneers indicate that the rain forest was seriously disturbed and replaced by secondary formations. The dominance of Trema orientalis, a pioneer well adapted to seasonal desiccation, points to a much more accentuated seasonality after 2500 cal yr BP, which seems to be linked to a southwards shift of the ITCZ during the northern hemisphere winter months. We propose that the rain forest crisis between 2500 and 2200 cal BP created favourable conditions for farming and paved the way for a major expansion of Bantu speaking populations.  相似文献   

Planning for Sea Level Rise and Shore Protection Under Climate Uncertainty     

Gary Yohe  James Neumann 《Climatic change》1997,37(1):243-270

Attention is focused here on the effect of additional sources of uncertainty derived from climate change on the cost-benefit procedures applied by coastal planners to evaluate shoreline protection projects. The largest effect would be felt if planners were trying to achieve the first best economic optimum. Given the current view that the seas will rise by significantly less than one meter through the year 2100, present procedures should work reasonably well assuming (1) informed vigilance in monitoring the pace of future greenhouse induced sea level rise, (2) careful attention to the time required for market-based adaptation to minimize the economic cost of abandonment, and (3) firm support of the credibility of an announced policy to proceed with plans to retreat from the sea when warranted. Assumptions (1) and (2) might be satisfied in reality, even cursory review of existing policy makes it clear that meeting (3) is a "long shot" at the very best. In any case, planners should periodically revisit potential protection sites, especially in the wake of catastrophic events, to assess the impact of the most recent information on sea level rise trajectories, local development patterns, and protection costs on the decision calculus.  相似文献   

Über die komplexe Natur des Seeganges     

Gerhard Neumann 《Ocean Dynamics》1952,5(5-6):252-277

Zusammenfassung Unter der Annahme, daß der Seegang nacheinander drei Hauptentwicklungsstufen durchläuft, bis er voll ausgereift ist, lassen sich Beziehungen zwischen den charakteristischen Wellengrößen, der Windgeschwindigkeit, der Wellenlaufstrecke und der Zeitdauer der Windeinwirkung ableiten. Diese Beziehungen sind in graphischer Form für die praktische Seegangsvorhersage dargestellt. Sie gestatten u. a. die Vorausbestimmung der mittleren Periode, d. h. des Mittelwertes der Zeitintervalle zwischen aufeinanderfolgenden Wellenkämmen an einem festen Ort, der häufigsten Periode, der Breite des Periodenspektrums sowie der mittleren und maximalen Wellenhöhe.

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On the complexity of wind waves — 2^nd part: The growth of waves under the wind's influence

Summary Proceeding from the supposition that wind generated waves have to pass through three principal stages before they will be fully developed, one may establish relations between wind velocity, fetch, duration of wind action, and the characteristic wave dimensions. Graphical representations of these relations are given for the practice of wave forecasting. Among others, they allow to predict the mean period, i. e. the mean value of the time intervals between the passage of successive wave crests at a given point, the most frequent period and the width of the spectrum of periods as well as the mean and maximum wave heights.

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La nature complexe des vagues de vent- 2^ième partie: Accroissement des vagues sous l'effect du vent

Résumé En supposant que les vagues de vent doivent parcourir trois phases principales pour atteindre les maxima de leurs dimensions et de leur force on peut établir des relations entre la vitesse du vent, le fetsch, la durée de l'action du vent et les dimensions caractéristiques des vagues. Pour les besoins de la prévision pratique des vagues de vent on a établi des représentations graphiques de ces relations qui permettent entre autres de prévoir la période moyenne, c'est à dire de prévoir la moyenne des intervalles de temps entre le passage par un point donné des crêtes des vagues consécutives, la période la plus fréquence, la largeur du spectre de la période et les moyennes et maxima des hauteurs des vagues.

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Aus den Arbeiten des Department of Meteorology and Oceanography an der New York University für das Office of Naval Research, Washington, D. C., unter Contract No. Nonr — 285(05).  相似文献   

On an effect of the integral scale of turbulence on one-dimensional spectra     

J. Neumann 《Meteorology and Atmospheric Physics》1961,12(3):389-395

Summary Assuming that in isotropic and stationary turbulence the Lagrangian correlation functions of the velocity components are of a simple exponential form, it is shown that the greater the integral scale of turbulence, the lower is the one-dimensional wave number to which a minus five-thirds law will appear to hold. It is pointed out, following a paper byGifford, that the apparent extension to low one-dimensional wave numbers of a minus-fivethirds law, does not necessarily mean thatKolmogoroff's inertial subrange of the three-dimensional turbulence extends to low (three-dimensional) wave numbers.

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Zusammenfassung Unter der Annahme, daß die Korrelationsfunktionen vonLagrange für isotrope und stationäre Turbulenz eine einfache exponentielle Form haben, wird bewiesen, daß, je größer das Integralmaß der Turbulenz ist, desto niedriger die eindimensionale Wellenzahl ist, bis zu der ein –5/3-Gesetz zu gelten scheint. Anschließend an eine Arbeit vonGifford wird betont, daß die scheinbare Erweiterung in Richtung auf niedrige eindimensionale Wellenzahlen nicht notwendigerweise bedeutet, daßKolmogoroffs Inertialteilbereich der dreidimensionalen Turbulenz sich bis zu niedrigen (dreidimensionalen) Wellenzahlen erstreckt.

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Résumé En supposant que les fonctions de corrélation lagrangiennes des composantes de vitesse de la turbulence isotropique et stationnaire sont d'une forme exponentielle simple, il est demontré que l'échelle intégrale de turbulence est d'autant plus grande que le nombre de l'onde unidimensionelle est petit, nombre, auquel une loi de –5/3 apparaît convenir. On pourra remarquer que, suivant un ouvrage deGifford, l'étendue apparente des petits nombres de l'onde unidimensionelle, ne signifie pas nécessairement que le rang d'inertie deKolmogoroff à propos de la turbulence en trois dimensions s'étend aux petits nombres de l'onde.

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Электрооптический Дальномер с Кварцевым Модулятором     

Bořivoj Delong  Bohuslav Sokolík  Přemek Neumann 《Studia Geophysica et Geodaetica》1961,5(1):8-20

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Chevron Ridges and Runup Deposits in the Bahamas from Storms Late in Oxygen-Isotope Substage 5e     

Paul J. Hearty  A.Conrad Neumann  Darrell S. Kaufman 《Quaternary Research》1998,50(3):309-322

Landward-pointing V-shaped sand ridges several kilometers long are common along the windward margin of the Bahama Islands. Their axes share a northeast–southwest trend. Internally, the ridges contain low-angle oolitic beds with few erosional truncations. Commonly interbedded are tabular, fenestrae-rich beds such as those formed by the sheet flow of water over dry sand. Defined here as “chevron ridges,” these landforms appear to have originated in the rapid remobilization of bank margin ooid bodies by the action of long-period waves from a northeasterly source. Deposits along adjacent coastlines also preserve evidence of the impact of large waves. Reworked eolian sand bodies preserve beach fenestrae and hydraulic scour traces up to +40 m on older ridges. On cliffed coasts, 1000-ton boulders have been thrown well inland, recording the impact of large waves. Amino acid ratios confirm a correlation of the ridges across the archipelago, while stratigraphy, spacing, and cross-cutting relationships indicate emplacement as sea level fell rapidly from the substage 5e maximum at or above +6 m.  相似文献   

Origin and implications of mafic xenoliths associated with Cenozoic extension-related volcanism in the Válencia Trough, NE Spain     

Prof. E. -R. Neumann  Dr. J. Martí  Dr. J. Mitjavila  E. Wulff-Pedersen 《Mineralogy and Petrology》1999,65(1-2):113-139

Summary The Válencia Trough of northeastern Spain represents a poorly understood region of Cenozoic extension-related magmatism in western Europe. We present chemical data on mafic xenoliths and their host basalt from the Roca Negra cinder cone in the Catalán Volcanic Zone in the Válencia Trough. The xenoliths consist of augite+hornblende+ oxides±plagioclase±apatite±olivine::Lbiotitelorthopyroxene, and range from clinopyroxenites and hornblendites to gabbroic rocks. The major and trace element compositions of the xenoliths are compatible with formation as cumulates from a range of olivine tholeiitic to strongly alkaline magmas, and show a strong affinity to the Middle Miocene to Recent rift-related magmatism in the Cátalan Volcanic Zone. The xenoliths formed at temperatures of 1110–1180 °C, pressures of 2–7 kb (with 10 kb as the upper limit), and oxygen fugacities corresponding to 1–2 log units above the NNO oxygen buffer. The estimated pressure range implies formation in magma chambers within the crust, possibly also near the crust/mantle boundary (underplating). The presence of crustal cumulates indicates that the total volume of magmas emplaced into the crust in the Cátalan Volcanic Zone may be significantly larger than indicated by surface exposures. Isotopic compositions of the xenoliths are⁸⁷Sr/⁸⁶Sr: 0.703537–0.703647,¹⁴³Nd/¹⁴⁴Nd: 0.512732–0.512766,²⁰⁶Pb/²⁰⁴Pb: 18.097–19.106,²⁰⁷Pb/²⁰⁴Pb: 15.522–15.579, and²⁰⁸Pb/²⁰⁴Pb: 37.850–38.794. This range suggests the involvement of two mantle source components. One of these may be the low-velocity component recognized in Cenozoic magmatism in the eastern Atlantic Ocean to central Europe and western Mediterranean. The other component, which differs from those involved in other domains of Cenozoic volcanism in Europe and adjacent areas, may be located in the lithospheric mantle underlying NE Spain, which was metasomatized during late Variscan to early Alpine deformation.

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Herkunft und Bedeutung mafischer Xenolithe aus känozoiscben Extensions-bezogenen Vulkaniten aus dem Valencia Trog, Nordost-Spanien

Zusammenfassung Der Válencia Trog in Nordost-Spanien stellt eine noch wenig verstandene Region mit känozoischen Extensions-bezogenern Magmatismus in Westeuropa dar. Wir geben hier chemische Daten über mafische Xenolithe und ihre basaltischen Muttergesteine aus dem Roca Negra Kegei in der vulkanischen Zone von Catalan im Valencia Trog. Die Xenolithe bestehen aus Augit+Hornblende+Oxiden±Plagioklas±Apatit±Olivin±Biotit±Orthopyroxen und reichen in ihrer Zusammensetzung von Klinopyroxeniten und Homblenditen his zu gabbroischen Gesteinen. Die Haupt- und Spurenelementzusammensetzung der Xenolithe entspricht einer Kumulatbildung aus Olivin-tholéitischen bis stark alkalischen Magmen and zeigt eine deutliche Affinität mit dem mittelmiozanen bis rezenten Rift-bezogenen Magmatismus in der vulkanischen Zone von Catalan. Die Xenolithe bildeten sich bei Temperaturen von 1.110 bis 1.180 °C und bei Drucken von 2–7 kb (mit 10 kb als Obergrenze) und bei Sauerstoff-Fugazitäten, die 1 bis 2 log Einheiten über dem NNO Sauerstoff-Puffer liegen. Die abgeschätzten Drucke weisen auf Bildung in Magmakammern innerhalb der Kruste bin, womölich auch in der Nähe der Kruste-Mantelgrenze (Underplating). Das Vorkommen von krustalen Kumulaten zeigt, daß das gesamte Volumen von Magma, das in die Kruste der vulkanischen Zone von Catalan eingedrungen ist, wesentlich größer ist als das, das man aus Oberflächen-Ausbissen entnehmen k6nnte. Die Isotopen-Zusammensetzung der Xenolithe sind⁸⁷Sr/⁸⁶Sr: 0.703537–0.703647,¹⁴³Nd/¹⁴⁴Nd: 0.512732–0.512766,²⁰⁶Pb/204 Pb: 18.097–19.106,²⁰⁷Pb/²⁰⁴Pb: 15.522–15.579, and²⁰⁸Pb/²⁰⁴Pb: 37.850–38.794. Dies läßt erkennen, daß es sich bier um zwei verschiedene Mantel-Quellen handelt. Eine davon könnte die Niedrig-Geschwindigkeitskomponente sein, die man in känozoiscben Magmatiten des östlichen Atlantischen Ozeans, sowie in Zentraleuropa und im westlichen Mittelmeer erkannt hat. Die andere Komponete unterscheidet sich von jenen, die in anderen Bereichen von känozoischem Vulkanismus in Europa und benachbarten Gebieten vorkommen. Sie könnte im lithosphärischen Mantel unterhalb von Nordost-Spanien liegen, der während der variszischen bis zur frühalpidischen Deformation metasomatisch beeinflußt wurde.

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With 10 Figures  相似文献