Effects of chronic oil pollution from refinery effluent on sediment microflora in a Danish coastal area     

Henrik Grüttner  Kurt Jensen   《Marine pollution bulletin》1983,14(12):456-459

Kalundborg Fjord is a Danish marine area which has been heavily oil polluted by refinery effluent, leading to accumulation of petroleum hydrocarbons in the surface sediments. A study of the occurrence in the sediment of heterotrophic bacteria, yeasts and filamentous fungi has been carried out, and the physiological composition of the microbial community has been recorded. Though the abundance of oil-degrading microorganisms was significant, a correlation between the number of these and the oil content of the sediment could not be demonstrated.  相似文献   

U–Pb dating of plutonic rocks involved in the nappe tectonic in southern Cameroon: consequence for the Pan-African orogenic evolution of the central African fold belt     

Sadrack Felix Toteu  Rose Yongue Fouateu  Joseph Penaye  Jacqueline Tchakounte  Aubin Ciriaque Seme Mouangue  William Randall Van Schmus  Etienne Deloule  Henrik Stendal 《Journal of African Earth Sciences》2006,44(4-5):479

TIMS-ID and SIMS U–Pb dating on zircons from metaplutonic rocks involved in the Pan-African nappe of southern Cameroon allow definition of three groups of subduction-related intrusions: group-I intrusions represented by the Masins metagabbro in the Lomie region yielded 666 ± 26 Ma; group-II intrusions represented by the Mamb metasyenogabbro and the Yaoundé pyriclasite yielded ca. 620 Ma and are broadly coeval with the deposition of the Yaoundé metasediments; group-III intrusions represented by the Elon augen metagranite and the Ngaa Mbappe metamonzodiorite yielded ca. 600 Ma. The onset of the nappe tectonics occurred under high-grade conditions in the range 616 to 610 Ma and continued around 600 Ma with the emplacement of the shallowest nappes. Finally, the construction of southern Cameroon proceeded by a multi-stage evolution characterized by a long-lived development of magmatic arcs associated with rapid opening and closure of sedimentary marginal basins in relation to a northward subduction.  相似文献   

Ecological Cost-Benefit Modelling of Herbivore Habitat Quality Degradation due to Range Fragmentation     

Henrik Lundqvist 《Transactions in GIS》2007,11(5):745-763

Fragmentation of grazing ranges and ensuing rise in edge effects decrease forage range quality for large herbivores. A method is proposed to quantify, in ecological cost‐benefit terms, the negative impact of fragmentation by linear structures with special emphasis on summer ranges of semi‐domesticated reindeer (Rangifer t. tarandus). The method is also applicable to other terrestrial species and on different scales. The term ‘reachability’ is introduced for this measurement, which integrates forage quality, quantity and availability, as well as the costs of the animal's movement in a variable landscape and across fragmenting linear structures. The method uses a cost‐distance algorithm, commonly available in GIS software. Effective distances and reachability over large areas are calculated from evenly distributed sample points. Effects of varying sample point distance, fragmenting structure friction weight and density, and edge effect depth were analysed for model calibration. In an example the model was used for estimation of reachability alteration due to linear structures in the summer ranges of the Handölsdalen reindeer herding district in Sweden, where hourly GPS positions of 10 free‐ranging female reindeer were available. In these data the reindeer population density appeared to decrease up to 1 km away from roads, but no effect from hiking trails was detected. The reachability model quantified a loss of 2.2–2.7% in range quality due to range fragmentation.  相似文献   

The distribution and relative toxic potential of organic chemicals in a PCB contaminated bay     

Sundberg H  Tjärnlund U  Kerman G  Blomberg M  Ishaq R  Grunder K  Hammar T  Broman D  Balk L 《Marine pollution bulletin》2005,50(2):195-207

For reliable monitoring of environmental improvement, the PCB contaminated bay Orserumsviken on Sweden's Baltic coast was investigated prior to remediation. We examined PCB congener patterns and the relative toxic potential of PCBs in extracts of three matrices: bottom sediment, settling particulate matter and the dissolved phase (obtained from semi-permeable membrane devices). Congener patterns were similar in all matrices. Three fractions were isolated from the extracts: (1) aliphatic and monocyclic aromatic compounds (MAC-fraction), (2) dicyclic aromatic compounds (DAC-fraction), including PCBs, and (3) polycyclic aromatic compounds (PAC-fraction), including PAHs. Total extracts and fractions were injected into newly fertilised rainbow trout eggs. At larval stage, hepatic EROD activities were quantified. Though high, the PCB contamination could explain only an estimated 1-5% of the total EROD induction. The order of EROD induction potential was: total extract > PAC-fraction > DAC-fraction > MAC-fraction in all matrices, suggesting that in Orserumsviken PACs made a larger contribution to the EROD induction potential than PCBs and other DACs.  相似文献   

Hydrogen incorporation in orthopyroxene: interaction of different trivalent cations     

Roland?StalderEmail author  Stephan?Klemme  Thomas?Ludwig  Henrik?Skogby 《Contributions to Mineralogy and Petrology》2005,150(5):473-485

The incorporation of hydrogen into ferrosilite, Fe-bearing enstatite and orthopyroxene containing different trivalent cations (Cr³⁺ and Al³⁺, Cr³⁺ and Fe³⁺) was investigated experimentally at 25 kbar. Hydrogen concentration was determined by FTIR-spectroscopy on oriented crystal sections and by secondary ion mass spectroscopy, whereas Mößbauer spectroscopy and optical spectroscopy were used to characterise the valence state of Fe in orthopyroxene. Results suggest that hydrogen incorporation in ferrosilite is achieved by a similar mechanism as in pure enstatite. In Cr-bearing samples, however, hydrogen incorporation is reduced by the presence of other trivalent cations by an increased tendency to form Tschermaks substitutions, e.g. Si _T ⁴⁺ + Mg _M1 ²⁺ ? Al _T ³⁺ + Cr _M1 ³⁺ . Thus, hydrogen solubility in natural orthopyroxenes from the Earth’s mantle, containing significant amounts of Cr³⁺, Al³⁺, and Fe³⁺, may be much more limited than expected from their trivalent cation content, as a large fraction of the trivalent cations does not participate in H-incorporating reactions as 2 Mg _M1 ²⁺ ? M _M1 ³⁺ + V_M1 + H _i ⁺ .  相似文献   

Improved estimates of the natural mortality rates of nine commercially important fish species included in the North Sea Multispecies VPA model   总被引：1，自引：2，他引：1  

Sparholt  Henrik 《ICES Journal of Marine Science》1990,46(2):211-223

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Changes in the North Sea fish community: evidence of indirect effects of fishing?   总被引：7，自引：4，他引：7  

Daan  Niels; Gislason  Henrik; G. Pope  John; C. Rice  Jake 《ICES Journal of Marine Science》2005,62(2):177-188

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The biomass of starry ray (Raja radiata) in the North Sea     

Sparholt  Henrik; Vinther  Morten 《ICES Journal of Marine Science》1991,47(3):295-302

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Non-predation natural mortality of Norway pout (Trisopterus esmarkii) in the North Sea     

Sparholt  Henrik; Larsen  Lena I.; Nielsen  J. Rasmus 《ICES Journal of Marine Science》2002,59(6):1276-1284

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Seep carbonate formation controlled by hydrothermal vent complexes: a case study from the Vøring Basin, the Norwegian Sea     

Henrik Svensen  Sverre Planke  Bjørn Jamtveit  Tom Pedersen 《Geo-Marine Letters》2003,23(3-4):351-358

Several hundred hydrothermal vent complexes were formed in the Vøring Basin as a consequence of magmatic sill emplacement in the late Palaeocene. The 6607/12-1 exploration well was drilled through a 220-m-thick sequence of Eocene–Miocene diatomites with carbonate nodules above the apex of one of these vent complexes. Analysed calcites and dolomites from this interval have isotopic signatures typical for methane seep carbonates, with low ¹³C signatures of –28 to –54 PDB. The data suggest that the vent complex acted as a fluid migration pathway for about 50×10⁶ years after its formation, leading to near-surface microbial activity and seep carbonate formation.  相似文献