Using AMOEBAs to display multispecies, multifleet fisheries advice     

Collie  Jeremy S.; Gislason  Henrik; Vinther  Morten 《ICES Journal of Marine Science》2003,60(4):709-720

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From single-species advice to mixed-species management: taking the next step     

Vinther  Morten; Reeves  Stuart A.; Patterson  Kenneth R. 《ICES Journal of Marine Science》2004,61(8):1398-1409

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Food consumption of the NE Atlantic minke whale (Balaenoptera acutorostrata) population estimated with a simulation model     

Markussen  Nina Hedlund; Ryg  Morten; Lydersen  Christian 《ICES Journal of Marine Science》1992,49(3):317-323

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Suspended Matter,Chl-a,CDOM, Grain Sizes,and Optical Properties in the Arctic Fjord-Type Estuary,Kangerlussuaq, West Greenland During Summer     

Lars Chresten Lund-Hansen  Thorbjørn Joest Andersen  Morten Holtegaard Nielsen  Morten Pejrup 《Estuaries and Coasts》2010,33(6):1442-1451

Optical constituents as suspended particulate matter (SPM), chlorophyll (Chl-a), colored dissolved organic matter (CDOM), and grain sizes were obtained on a transect in the arctic fjord-type estuary Kangerlussuaq (66°) in August 2007 along with optical properties. These comprised diffuse attenuation coefficient of downwelling PAR (K _d(PAR)), upwelling PAR (K _u(PAR)), particle beam attenuation coefficient (c _p), and irradiance reflectance R(−0, PAR). PAR is white light between 400 and 700 nm. The estuary receives melt water from the Greenland Inland Ice and stations covered a transect from the very high turbid melt water outlet to clear marine waters. Results showed a strong spatial variation with high values as for suspended matter concentrations, CDOM, diffuse attenuation coefficient K _d(PAR), particle beam attenuation coefficients (c _p), and reflectance R(−0, PAR) at the melt water outlet. Values of optical constituents and properties decreased with distance from the melt water outlet to a more or less constant level in central and outer part of the estuary. There was a strong correlation between inorganic suspended matter (SPMI) and diffuse attenuation coefficient K _d(PAR) (r ² = 0.92) and also for particle beam attenuation coefficient (c _p; r ² = 0.93). The obtained SPMI specific attenuation—K _d^*(PAR) = 0.13 m² g⁻¹ SPMI—and the SPMI specific particle beam attenuation—c _p^* = 0.72 m² g⁻¹—coefficients were about two times higher than average literature values. Irradiance reflectance R(−0, PAR) was comparatively high (0.09−0.20) and showed a high (r ² = 0.80) correlation with K _u(PAR). Scattering dominated relative to absorption—b(PAR)/a(PAR) = 12.3. Results strongly indicated that the high values in the optical properties were related to the very fine particle sizes (mean = 2–6 μm) of the suspended sediment. Data and results are discussed and compared to similar studies from both temperate and tropical estuaries.  相似文献   

High resolution profiles of vertical particulate organic matter export off Cape Blanc,Mauritania: Degradation processes and ballasting effects     

Morten Hvitfeldt Iversen  Nicolas Nowald  Helle Ploug  George A. Jackson  Gerhard Fischer 《Deep Sea Research Part I: Oceanographic Research Papers》2010,57(6):771-784

Vertical carbon fluxes between the surface and 2500 m depth were estimated from in situ profiles of particle size distributions and abundances me/asured off Cape Blanc (Mauritania) related to deep ocean sediment traps. Vertical mass fluxes off Cape Blanc were significantly higher than recent global estimates in the open ocean. The aggregates off Cape Blanc contained high amounts of ballast material due to the presence of coccoliths and fine-grained dust from the Sahara desert, leading to a dominance of small and fast-settling aggregates. The largest changes in vertical fluxes were observed in the surface waters (<250 m), and, thus, showing this site to be the most important zone for aggregate formation and degradation. The degradation length scale (L), i.e. the fractional degradation of aggregates per meter settled, was estimated from vertical fluxes derived from the particle size distribution through the water column. This was compared with fractional remineralization rate of aggregates per meter settled derived from direct ship-board measurements of sinking velocity and small-scale O₂ fluxes to aggregates measured by micro-sensors. Microbial respiration by attached bacteria alone could not explain the degradation of organic matter in the upper ocean. Instead, flux feeding from zooplankton organisms was indicated as the dominant degradation process of aggregated carbon in the surface ocean. Below the surface ocean, microbes became more important for the degradation as zooplankton was rare at these depths.  相似文献   

Homotopy scattering series for seismic forward modelling with variable density and velocity     

Kui Xiang  Kjersti Solberg Eikrem  Morten Jakobsen  Geir Nvdal 《Geophysical Prospecting》2022,70(1):3-18

We have derived a convergent scattering series solution for the frequency-domain wave equation in acoustic media with variable density and velocity. The convergent scattering series solution is based on the homotopy analysis of a vectorial integral equation of the Lippmann–Schwinger type. By using the Green's function and partial integration, we have derived the vectorial integral equation of the Lippmann–Schwinger type that involves the pressure gradient field as well as the pressure field from the wave equation. The vectorial Lippmann–Schwinger equation can in principle be solved via matrix inversion, but the computational cost of matrix inversion scales like $N^3$, where $N$ is the number of grid blocks. The computational cost can be significantly reduced if one solves the vectorial Lippmann–Schwinger equation iteratively. A simple iterative solution is the Born series, but it is only convergent when the scattering potential is sufficiently small. In this study, we have used the so-called homotopy analysis method to derive an iterative solution for the vectorial Lippmann–Schwinger equation which can be made convergent even in strongly scattering media. The computational cost of our convergent scattering series scales as $N^2$. Our algorithm, which is based on the homotopy analysis method, involves a convergence control operator that we select using hierarchical matrices. We use a three-layer model and a resampled version of the SEG/EAGE salt model to show the performance of the developed convergent scattering series.  相似文献   

An example of flow differentiation: clinopyroxenite of the Predazzo igneous complex (north Italy)     

Federico Lucchini  Lauro Morten 《Lithos》1977,10(1):39-47

Chemical, modal and mineralogic data and textural observations suggest that the small mafic-ultramafic body at Predazzo, consisting of olivine-bearing gabbro, clinopyroxenite and quartz-bearing gabbro, is the result of a flow differentiation mechanism acting on a mush formed of 60% solid plus 40% liquid. Such a mechanism was capable of producing the concentration of the early formed crystals ($\text{cpx}\text{+}\text{mt}$) towards the center of the body (clinopyroxenite) with segregation of two portions enriched in liquid toward the margins (olivine- and quartz-bearing gabbros).  相似文献   

The Mesozoic–Cenozoic structural framework of the Bay of Kiel area, western Baltic Sea     

Martin Bak Hansen  Holger Lykke-Andersen  Ali Dehghani  Dirk Gajewski  Christian Hübscher  Morten Olesen  Klaus Reicherter 《International Journal of Earth Sciences》2005,94(5-6):1070-1082

A dense grid of multichannel high-resolution seismic sections from the Bay of Kiel in the western Baltic Sea has been interpreted in order to reveal the Mesozoic and Cenozoic geological evolution of the northern part of the North German Basin. The overall geological evolution of the study area can be separated into four distinct periods. During the Triassic and the Early Jurassic, E–W extension and the deposition of clastic sediments initiated the movement of the underlying Zechstein evaporites. The deposition ceased during the Middle Jurassic, when the entire area was uplifted as a result of the Mid North Sea Doming. The uplift resulted in a pronounced erosion of Upper Triassic and Lower Jurassic strata. This event is marked by a clear angular unconformity on all the seismic sections. The region remained an area of non-deposition until the end of the Early Cretaceous, when the sedimentation resumed in the area. Throughout the Late Cretaceous the sedimentation took place under tectonic quiescence. Reactivated salt movement is observed at the Cretaceous Cenozoic transition as a result of the change from an extensional to compressional regional stress field. The vertical salt movement influenced the Cenozoic sedimentation and resulted in thin-skinned faulting.  相似文献   

Spinels in Harzburgite and Lherzolite inclusions from the San Giovanni Ilarione Quarry,Lessini Mountains,Veneto Region,Italy     

Prof. L. Morten  Prof. L. A. Taylor  Prof. A. Durazzo 《Mineralogy and Petrology》1989,40(1):73-89

Summary Chrome-bearing spinels in 21 ultramafic nodules contained in a basanite from San Giovanni Ilarione (SGI), Veneto Region, Italy, have been grouped from a textural and chemical standpoint into five types: (1) Interstitial, surrounded by silicates, homogeneous, with a Cr/(Cr + Al) ratio averaging 0.11; (2) Within alteration pods and veinlets, in contact with either silicates or alteration products, showing zonation with Mg/(Mg + Fe²⁺), Cr, and Ti increasing and Al decreasing from core to rim; (3) In contact with the basalt or surrounded by basalt but distinct from ground-mass grains. The former are strongly zoned while the latter, referred to as xenocrysts, are relatively homogeneous. Both belong to a trend distinct from that of (2); (4) Symplectic, intergrown with pyroxenes and homogeneous, or in contact with plagioclase and/or reaction products and showing more variable composition than the former. Both are generally richer in Cr than all other spinet types and define a trend parallel to and with higher Cr/(Cr + Al) and Cr values than that of (3); and (5) groundmass grains within the host basalt, showing lower Mg/(Mg + Fe²⁺) and Cr/(Cr + Al), and higher Fe values than for all other, types.Group 1 spinels and the cores of group 2 and group 3 spinets display very similar compositions, suggesting a common origin, modified by later events such as partial melting, solid-liquid reactions, and subsolidus reactions which occurred prior to, during, and subsequent to interaction with the host basalt. Group 2 and 3 spinels define trends diverging from a common composition—i.e., the same origin. Group 4 spinels are probably due to exsolution which occurred after formation of the original spinels, while group 5 spinels are not directly related to types 1–4.

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Spinelle in Harzbugit- und Lherzolitheinschlüssen vom Steinbruch San Giovanni Ilarione, Lessini-Berge, Region Veneto, Italien

Zusammenfassung Chromhaltige Spinelle 21 ultramafischer Knollen aus einem Basanit von San Giovanni Ilarione (SGI), Region Veneto, Italien, wurden nach texturellen und chemischen Gesichtspunkten in fünf Gruppen eingeteilt: 1. Interstitiell, von Silikaten umgeben, mit einem durchschnittlichen Cr/(Cr + Al)-Verhältnis von 0,11.2. In Umwandlungstaschen und -gängchen, in Kontakt entweder mit Silikaten oder mit Umwandlungsprodukten, zoniert mit Mg/(Mg + Fe²⁺), Cr und Ti vom Kern zum Rand zunehmend, Al aber abnehmend. 3. Im Kontakt zum Basalt oder vom Basalt umgeben, aber von den Körnern der Grundmasse verschieden. Die ersteren sind stark zonar, während die Letzteren, die als Xenokrysten angesehen werden, relativ homogen sind. Beide gehören zu einem Trend, welcher von jenem der Gruppe 2 verschieden ist. 4. Simplektitisch, mit Pyroxenen verwachen und homogen, oder im Kontakt zu Plagioklas und/oder Reaktionsprodukten und von variablerer Zusammensetzung ab die ersteren. Beide sind allgemein reicher an Cr als alle anderen Spinelltypen und sie definieren einen Trend parallel zu und mit höheren Cr/(Cr + Al)- und Cr- Werten als jene von Gruppe 3. 5. Körner der Grundmasse des Wirtsbasaltes, die niedrigere Mg/(Mg + Fe²⁺)- und Cr/(Cr + Al)- Werte und höhere Fe-Werte zeigen als alle anderen Typen.Die Spinelle der Gruppe 1 und die Kerne der Spinelle der Gruppen 2 und 3 zeigen sehr ähnliche Zusammensetzungen, die auf einen gemeinsamen Ursprung hinweisen, der später modifiziert wurde durch Ereignisse wie partielles Schmelzen, fest-flüssig-Reaktionen und subsolidus-Reaktionen, die vor, wärend und nach der Wechselwirkung mit dem Wirtsbasalt stattfanden. Die Spinelle der Gruppen 2 und 3 definieren Trends, die von einer gemeinsamen Zusammensetzung und damit von einem gemeinsamen Ursprung her auseinanderlaufen Spinelle der Gruppe 4 entstanden wahrscheinlich durch Entmischung, die nach Bildung der Ursprungsspinele eintrat, während die Spinelle der Gruppe 5 zu denen der Gruppen 1 bis 4 in keiner direkten Beziehung stehen.

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Tectono-magmatic evolution of sheeted plutonic bodies along the north Giudicarie line (northern Italy)     

S. Martin  G. Prosser  L. Morten 《International Journal of Earth Sciences》1993,82(1):51-66

Tectonized slices of foliated quartz-diorite/ quartz-gabbro rocks are exposed along the north Giudicarie line between Dimaro and Rumo (Western Trentino region, north-east Italy). They show geochemical and mineralogical similarities with the north-east corner of the Adamello batholith (Presanella pluton) and may be regarded as a northern apophysis lamella of Adamello. The intrusive bodies were emplaced within the Adria crust at a relatively shallow depth (approximately equal to 3 kbar) along a proto-Giudicarie line under transtensive conditions during late Oligocene. Only near Rumo has contact metamorphism on the Austroalpine basement been observed, whereas in other outcrops it has been tectonically removed by later movements along the Giudicarie line. In the Samoclevolamella a magmatic flow texture, which developed during the emplacement of a crystal mush at shallow depth, is recorded by the preferred alignment of plagioclase and hornblende. A solid state foliation, outlined by quartz crystal aggregates, green hornblende and biotite, has been observed mostly in the Rumolamella. This indicates that a later ductile deformation, which developed under decreasing temperatures, overprinted the intrusive rocks. This deformation probably reflects late Oligocene strike-slip movements along the Tonale and Giudicarie lines. Finally semi-brittle to brittle deformation overprints the foliated igneouslamellae producing cataclasites and pseudotachylites. Sometimes these structures are subsequently cut by prehnite and epidote bearing veins. During this event, the intrusivelamellae were decoupled from their contact aureole and carried over the Insubric Flysch of the southern Alps. This last tectonic phase may be correlated to the Upper Miocene neo-Alpine transpressive event along the Giudicarie Line. Correspondence to: S. Martin  相似文献