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21.
Susanne Pihl Baden 《Marine pollution bulletin》1982,13(6):208-210
Palaemon adspersus is a hyper- and hypo-osmoregulating shallow-water shrimp. For a maximum period of 34 days P. adspersus were exposed to 20, 70, 100 and 200 ppb WSF of North Sea crude oil. The osmotic concentration of the haemolymph was measured by freezing point depression once a week. The ability to maintain hyper-osmolality was significantly decreased (p<0.05) after one, two and three weeks exposure to 200, 70 and 100 ppb, respectively. No effect was observed in 20 ppb. After an accidental exposure of shrimps to 24 h acute oil pollution, they were placed in pure sea water. The ability to maintain hyper-osmolality was reduced one week after the accidental oil exposure, but was regained within three weeks. 相似文献
22.
23.
Impact assessments and policy responses to sea-level rise in three US states: An exploration of human-dimension uncertainties 总被引:2,自引:0,他引:2
Uncertainties in the human dimensions of global change deeply affect the assessment and responses to climate change impacts such as sea-level rise (SLR). This paper explores the uncertainties in the assessment process and in state-level policy and management responses of three US states to SLR. The findings reveal important political, economic, managerial, and social factors that enable or constrain SLR responses; question disasters as policy windows; and uncover new policy opportunities in the history of state coastal policies. Results suggest that a more realistic, and maybe more useful picture of climate change impacts will emerge if assessments take more seriously the locally embedded realities and constraints that affect individual decision-makers’ and communal responses to climate change. 相似文献
24.
25.
Coupling of oceanic and continental crust during Eocene eclogite-facies metamorphism: evidence from the Monte Rosa nappe,western Alps 总被引:1,自引:0,他引:1
Thomas J. Lapen Clark M. Johnson Lukas P. Baumgartner Giorgio V. Dal Piaz Susanne Skora Brian L. Beard 《Contributions to Mineralogy and Petrology》2007,153(2):139-157
High precision U–Pb geochronology of rutile from quartz–carbonate–white mica–rutile veins that are hosted within eclogite
and schist of the Monte Rosa nappe, western Alps, Italy, indicate that the Monte Rosa nappe was at eclogite-facies metamorphic
conditions at 42.6 ± 0.6 Ma. The sample area [Indren glacier, Furgg zone; Dal Piaz (2001) Geology of the Monte Rosa massif: historical review and personal comments. SMPM] consists of eclogite boudins that are exposed
inside a south-plunging overturned synform within micaceous schist. Associated with the eclogite and schist are quartz–carbonate–white
mica–rutile veins that formed in tension cracks in the eclogite and along the contact between eclogite and surrounding schist.
Intrusion of the veins at about 42.6 Ma occurred at eclogite-facies metamorphic conditions (480–570°C, >1.3–1.4 GPa) based
on textural relations, oxygen isotope thermometry, and geothermobarometry. The timing of eclogite-facies metamorphism in the
Monte Rosa nappe determined in this study is identical to that of the Gran Paradiso nappe [Meffan-Main et al. (2004) J Metamorphic Geol 22:261–281], confirming that these two units have shared the same Alpine metamorphic history. Furthermore,
the Gran Paradiso and Monte Rosa nappes underwent eclogite-facies metamorphism within the same time interval as the structurally
overlying Zermatt-Saas ophiolite [∼50–40 Ma; e.g., Amato et al. (1999) Earth Planet Sci Lett 171:425–438; Mayer et al. (1999) Eur Union Geosci 10:809 (abstract); Lapen et al. (2003) Earth Planet Sci Lett 215:57–72]. The nearly identical P–T–t histories of the Gran Paradiso, Monte Rosa, and Zermatt-Saas units suggest that these units shared a common Alpine tectonic
and metamorphic history. The close spatial and temporal associations between high pressure (HP) ophiolite and continental
crust during Alpine orogeny indicates that the HP internal basement nappes in the western Alps may have played a key role
in exhumation and preservation of the ophiolitic rocks through buoyancy-driven uplift. Coupling of oceanic and continental
crust may therefore be critical in preventing permanent loss of oceanic crust to the mantle. 相似文献
26.
Reservoirs have to be released when repairing of the dams is necessary. In 1995, two reservoirs in Baden-Württemberg (Germany) of similar age and volume (Lake Herrenbach near Göppingen, 1.0 Mio. m3 and Lake Breitenau near Heilbronn, 2.3 Mio. m3) were emptied. This allowed the singular possibility to investigate the effects of drainage and refilling on the limnochemistry and the phytoplankton biocoenosis of such artificial lakes.Before the drainage of the reservoirs, both lakes showed phosphorus release from the sediment during summer stagnation. Phosphorus values of Lake Herrenbach were regularly higher than those of Lake Breitenau (Lake Herrenbach 88 μg/l, Lake Breitenau 33 μg/l). During release, both lakes indicated higher phosphorus and chlorophyll concentrations as well as rising biomasses. Remarkable differences were observed during refilling of the reservoirs: while Lake Herrenbach showed higher transparency and lower phosphorus concentrations, Lake Breitenau progressed towards eutrophication (total phosphorus during summer 1996: Lake Herrenbach 30 μg/l, Lake Breitenau 55 μg/l). One reason for the reaction of Lake Breitenau was the reduced ground drainage during the refilling, which caused an accumulation of nutrients in the hypolimnion. Another reason was the mineralisation of vegetation which covered great parts of the dry lake sediment. The limnological change of Lake Herrenbach was not as clear but could be caused by the restauration of the pre-reservoir which was drainaged and dredged before the emptying of the main reservoir started as well as many other facts which differed Lake Herrenbach from Lake Breitenau. 相似文献
27.
Susanne J. McDonald Mahlon C. Kennicutt II James M. Brooks 《Marine pollution bulletin》1992,25(9-12):313-317
PAH exposure was assessed in fish from Arthur Harbor, Antarctica and sites remote from human activities by measuring the concentrations of polycyclic aromatic hydrocarbon (PAH) metabolites in bile and PAH in tissues and stomach contents. The highest concentrations of biliary metabolites and tissue PAH were present in fish captured near an Argentine supply ship (Bahia Paraiso) that ran aground in Arthur Harbor in 1989. The presence of biliary PAH metabolites in fish collected near Palmer Station, a small US scientific station in Arthur Harbor, suggests low level exposure to contaminants. However, PAH tissue concentrations in fish from Palmer Station were similar to those from remote sites. Both tissue PAH and metabolite concentrations were low in fish captured at sites remote from human activities. The confirmation of PAH metabolites in the bile of fish from Arthur Harbor is direct evidence that the presence of humans has resulted in Antarctic fish being exposed to petroleum-derived PAH. 相似文献
28.
Lyle H. Horn 《Theoretical and Applied Climatology》1958,9(2):231-237
Summary Wind data collected during the Great Plains Turbulence Field Experiment of 1953 are used to study the relative performances of various types of cup anemometers subjected to air flow of known gustiness. Scatter diagrams which relate differences in the indicated mean speeds of two anemometers to gustiness are prepared. Although the instruments compared represent a wide range of moments of inertia, no relationship between gustiness and anemometer performance is noted. This result is examined in light of Schrenk's parameter which describes anemometer performance.
With 4 Figures 相似文献
Zusammenfassung Windbeobachtungen, welche während des Great Plains Turbulence Field Program im Jahre 1953 gewonnen wurden, werden zu einem Vergleich verschiedener Typen von Schalenkreuzanemometern in einem Windfeld von bekannter Böigkeit verwendet. Die Ergebnisse werden in Form von Streubildern veranschaulicht, in denen die Geschwindigkeits-unterschiede von verschiedenen Anemometern als Funktion des Böigkeitsgrades aufgetragen sind. Obgleich die verglichenen Anemometer erheblich verschiedene Trägheitsmomente besitzen, ergibt sich keine Abhängigkeit der Anzeigedifferenzen von der Böigkeit des Windes. Dieser Befund wird mit Hilfe des Schrenkschen Parameters näher beleuchtet.
Résumé Les observations anémométriques effectuées dans le cadre du Great Plains Turbulence Field Program en 1953 sont utilisées ici dans le but de comparer différents types d'anémomètres à cupules placés dans un champ de mouvement de turbulence connue. Les résultats sont donnés sous forme d'essaims de points dans un système de référence: écarts individuels de l'indication et degré de turbulence. Bien que les instruments comparés présentent des moments d'inertie notablement différents, les écarts observés ne dépendent pas de la turbulence du vent. Ce résultat est encore examiné à l'aide du paramètre de Schrenk.
With 4 Figures 相似文献
29.
It is shown that endogenic lava flow processes can be identified by their characteristic effects on lunar crater size distributions without necessarily being able to recognise individual flows on the photographs studied. The thickness of lava flows or a series of flows can be estimated from these crater size distribution characteristics. The lava flow histories of the Apollo landing sites 11, 12 and 15 are discussed in detail. The thicknesses of the most recent (3–3.4 × 109 years ago) flows there and of the youngest flows in an area in south-west Mare Imbrium (3 × 109 years) are found to range between 30 and 60 m. The subsequent flow episodes at the landing sites showing up in the crater size distributions can be related to differences in the radiometric ages of the respective lunar rocks. 相似文献
30.
Yin QZ Jacobsen SB McDonough WF Horn I Petaev MI Zipfel J 《The Astrophysical journal》2000,536(1):L49-L53
We report new Zr isotope evidence for live (92)Nb (mean life: tau&d1;92Nb=52 Myr) within the early solar system resulting in &parl0;92Nb&solm0;93Nb&parr0;initial approximately 10-3. The meteoritic minerals rutile and zircon have, respectively, very high and very low Nb/Zr ratios and are ideal for exploring the (92)Nb-(92)Zr chronometer. Rutiles exhibit high positive straightepsilon92Zr ( approximately 14-36) while a zircon has a negative straightepsilon92Zr ( approximately -4), as would be expected if (92)Nb was live in the early solar system. The meteoritic rutiles appear to be young, with apparent times of formation of approximately 80-220 Myr subsequent to the origin of the solar system. The initial (92)Nb/(92)Mo for the solar system is broadly compatible with a model of uniform production if the (92)Nb/(92)Mo production ratio for Type II supernova (SNII) sources with neutrino-driven winds is used. Data for all the now extinct p-process nuclides ((92)Nb, (97)Tc, and (146)Sm) are consistent with these isotopes being derived by uniform production from SNII sources and a free decay interval of approximately 10 Myr. Consideration of a range of models indicates that the average p-process production ratio of (92)Nb/(92)Mo needs to be at least in the range of 0.06-0.25. 相似文献