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  • Other Sources  (89)
  • Springer  (50)
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  • 1986  (38)
  • 1
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    Elsevier
    In:  Amsterdam, Elsevier, vol. 3, pp. 6322, (ISBN 0-521-79203-7)
    Publication Date: 1989
    Keywords: Textbook of physics ; Textbook of geophysics ; Stress ; Boundary Element Method
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  • 2
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    Elsevier
    In:  Amsterdam, 652 pp., Elsevier, vol. 39, no. XVI:, pp. 227-235, (0-444-51955-6)
    Publication Date: 1989
    Keywords: Borehole geophys. ; Textbook of geophysics ; Dual Induction Latero log
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  • 3
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    Elsevier
    In:  Amsterdam, Elsevier, vol. Developments in Petroleum Science vol. 15B, no. Publ. No. 12, pp. 9, (ISBN: 0-12-636380-3)
    Publication Date: 1986
    Keywords: Borehole geophys. ; Textbook of geophysics ; Tectonics ; Geol. aspects ; GFZ ; RUB ; GMG ; 3.45.8 ; UniL ; IfGuG ; in ; Französisch
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  • 4
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    Springer
    In:  Bull., Polar Proj. OP-O3A4, Wavelets: Time-Frequency Methods and Phase, Berlin, Springer, vol. 22, no. 4, pp. 21-37, (ISBN 0080419208)
    Publication Date: 1989
    Keywords: Wavelet processing ; Textbook of geophysics ; Spectrum ; Data analysis / ~ processing ; noksp
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  • 5
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    Elsevier
    In:  Bull., Open-File Rept., The Origin of Arcs, Amsterdam, Elsevier, vol. 65, no. 1, pp. 63-78, (ISBN 0080419208)
    Publication Date: 1986
    Keywords: Tectonics ; Geol. aspects ; Fault zone ; Plate tectonics
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  • 6
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    Springer
    In:  Berlin, Springer, vol. 17, pp. 225, (ISBN 1-4020-1408-2)
    Publication Date: 1986
    Keywords: Statistical investigations ; Textbook of physics
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  • 7
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    Elsevier
    In:  Amsterdam, Elsevier, vol. 6, no. 16, pp. 220, (ISBN: 3540148477)
    Publication Date: 1989
    Keywords: Fracture ; Rock mechanics ; Elasticity
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  • 8
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    Springer
    In:  Berlin, Springer, vol. 7, no. 1, pp. 443-487, (ISBN 0-89871-560-1)
    Publication Date: 1989
    Keywords: Geodesy ; Muller
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  • 9
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    Elsevier
    In:  Amsterdam, 566+XIII pp., Elsevier, vol. 65, no. ALEX(01)-FR-77-01, AFTAC Contract F08606-76-C-0025, pp. 95-104, (ISBN: 0-08-044051-7)
    Publication Date: 1986
    Keywords: Elasticity theory of dislocations ; Textbook of geophysics ; Dislocation
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  • 10
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    Elsevier
    In:  Amsterdam, Elsevier, vol. 65, no. ALEX(01)-FR-77-01, AFTAC Contract F08606-76-C-0025, pp. 95-104, (ISBN: 0-08-044051-7)
    Publication Date: 1989
    Keywords: Textbook of geophysics ; Gravimetry, Gravitation ; Crustal deformation (cf. Earthquake precursor: deformation or strain)
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  • 11
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    Springer
    In:  Professional Paper, The German Continental Deep Drilling Program (KTB), Site-Section Studies in the Oberpfalz and Schwarzwald, Berlin, Springer, vol. 120, no. 231, pp. 37-54, (ISBN: 3-540-23712-7)
    Publication Date: 1989
    Keywords: KTB ; Geol. aspects ; Tectonics
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  • 12
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    Springer
    In:  Bull., Open-File Rept., Lecture Notes in Earth Sciences, Berlin, Springer, vol. 89, no. 1, pp. Paper A 25 - A 34, (ISBN 1-86239-165-3, vi + 330 pp.)
    Publication Date: 1989
    Keywords: Seismics (controlled source seismology) ; Textbook of geophysics ; Acoustics
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  • 13
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    Springer
    In:  Berlin, Springer, vol. 138, no. 2, pp. 527-553, (ISBN 0-7923-5034-0)
    Publication Date: 1989
    Keywords: Borehole geophys. ; Tectonics ; Textbook of geophysics ; Geol. aspects ; BO, ; RUB, ; GMG: ; MB ; 4129 ; 3.45.19
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  • 14
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    Springer
    In:  Berlin, Springer, vol. 20, no. 1, pp. 662-664, (ISBN 1-58488-320-0)
    Publication Date: 1989
    Keywords: Handbook of mathematics ; Finite Element Method ; Finite difference method ; DGL
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  • 15
    Publication Date: 1989
    Keywords: Proceedings of a conference ; Geodesy ; Plate tectonics ; Muller
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  • 16
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    Springer
    In:  Berlin, Springer, vol. 15, no. Publ. No. 12, pp. 585, (ISBN 1-85233-708-7)
    Publication Date: 1989
    Keywords: Textbook of informatics ; Textbook of mathematics ; Chaotic behaviour
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  • 17
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    Elsevier
    In:  Amsterdam, Elsevier, vol. 20, no. Publ. No. 12, pp. 23-40, (ISBN 3935922167)
    Publication Date: 1986
    Keywords: Textbook of geophysics ; Data analysis / ~ processing ; Elasticity
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  • 18
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    Elsevier
    In:  Amsterdam, Elsevier, vol. 2, no. 1, pp. 1-40, (ISBN 3-7643-6675-3)
    Publication Date: 1989
    Keywords: Textbook of geophysics ; Seismics (controlled source seismology) ; Applied geophysics ; Data analysis / ~ processing
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  • 19
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    Springer
    In:  Professional Paper, The German Continental Deep Drilling Program (KTB), Site-Selection Studies in the Oberpfalz and Schwarzwald, Berlin, Springer, vol. 9, no. 16, pp. 527-553, (ISBN 1-4020-1729-4)
    Publication Date: 1989
    Keywords: Borehole geophys. ; KTB ; Tectonics ; Review article ; Geol. aspects
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  • 20
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    Elsevier
    In:  Bull., Polar Proj. OP-O3A4, Fractals in Physics, Amsterdam, Elsevier, vol. 24, no. 4, pp. 177-180, (ISBN 0080419208)
    Publication Date: 1986
    Keywords: Fracture ; FractureT
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  • 21
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    Elsevier
    In:  Bull., Polar Proj. OP-O3A4, The Origin of Arcs, Amsterdam, Elsevier, vol. 13, no. Subvol. a, pp. 93-113, (ISBN 0080419208)
    Publication Date: 1986
    Keywords: CRUST ; earth mantle ; Plate tectonics ; Muller
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  • 22
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    Springer
    In:  Berlin, Springer, vol. 96, pp. 225, (ISBN 0-471-95596-5)
    Publication Date: 1986
    Keywords: COS ; gra ; Textbook of informatics
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  • 23
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    Springer
    In:  New York, Springer, vol. 6, no. XVI:, pp. 65-70, (ISBN 0521824893, 280 pp.)
    Publication Date: 1986
    Keywords: Borehole geophys. ; KTB ; Textbook of geophysics
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  • 24
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    Elsevier
    In:  Bull., Open-File Rept., Continuum Theories in Solid Earth Physics, Amsterdam, 566+XIII pp., Elsevier, vol. 186, no. 16, pp. 18-186, (ISBN 0080419208)
    Publication Date: 1986
    Keywords: Elasticity theory of dislocations ; Dislocation ; Review article
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  • 25
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    Elsevier
    In:  Professional Paper, Open-File Rept., Thermodynamics of Point Defects and the Relation with Bulk Properties, New York, Elsevier, vol. 1, no. 16, pp. 410-412, 417-420, (ISBN 0080419208)
    Publication Date: 1986
    Keywords: Geomagnetics ; Earthquake precursor: prediction research ; Earthquake precursor: magnetic ; Geoelectrics ; Physical properties of rocks
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  • 26
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    Springer
    In:  Bull., Open-File Rept., The German Continental Deep Drilling Program (KTB), Site-Section Studies in the Oberpfalz and Schwarzwald, Berlin, Springer, vol. 65, no. 16, pp. 99-150, (ISBN 1-86239-165-3, vi + 330 pp.)
    Publication Date: 1989
    Keywords: KTB ; Deep seismic sounding (espec. cont. crust) ; Tectonics ; Reflection seismics ; Duerbaum ; Durbaum ; Ruehl ; Ruhl ; Meissner
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  • 27
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    Elsevier
    In:  Fisheries Research, 8 (1). pp. 35-44.
    Publication Date: 2017-01-10
    Description: In Moreton Bay, Queensland, the catch obtained using monofilament polyamide (PA) otter trawl-nets with multifilament polyethylene (PE) cod ends was compared with that obtained using multifilament PE trawl-nets of identical mesh opening (38 mm). Monofilament PA otter trawl-nets retained fewer small prawns ( 〈 24 mm carapace length) than conventional multifilament PE nets, but both nets caught similar quantities of larger prawns ( 〉 24 mm carapace length). The higher retention rate of small prawns by multifilament PE gear was reflected in the greater catch weights of Peraeus plebejus, Metapenaeus bennettae and Metapenaeopsis novaeguineae in those nets. Catch weights of larger prawn species such as Penaeus esculentus and Metapenaeus endeavouri did not differ between nets. Winter whiting (Sillago maculata) and squid (Loligo spp.) were trawled in similar abundance in both nets, although the monofilament retained fewer squid 〈 50 mm mantle length. More marketable ( 〉 15 cm carapace width) sand crabs (Portunus pelagicus) were caught in the monofilament net. There was not significant difference in the trash (noncommercial component) weight caught in both nets. Over the range of towing speeds tested (1.7–2.3 kn), use of monofilament nets significantly reduced total gear drag.
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  • 28
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    Springer
    In:  Polar Biology, 9 (3). pp. 137-145.
    Publication Date: 2020-06-10
    Description: The diets of five breeding seabird species were investigated on Adélie Land in January–February 1982. Stomach contents of Adélie penguins, Pygoscelis adeliae, were sampled by a water off-loading method and of Procellariiformes by spontaneous regurgitation. Diet compositions by mass were: Adélie penguin (79% euphausiid, 18% fish, 3% squid); Cape pigeon, Daption capense, (64% euphausiid, 29% fish, 7% carrion); Antarctic fulmar, Fulmarus glacialoides, (64% euphausiid, 20% carrion, 16% fish); snow petrel, Pagodroma nivea, (95% fish, 2% euphausiid, 1% carrion) and Wilson's stormpetrel, Oceanites oceanicus, (39% fish, 37% euphausiid, 13% carrion, 12% various crustaceans). The present Adélie penguin diet is consistent with those reported in other studies, given our knowledge of geographical variation in food availability. Differences in the diets of fulmarine petrels appear to relate to differences in foraging areas. The snow petrel is a fish-eating bird associated with pack-ice. Cape pigeon and Antarctic fulmar are mainly krill-eaters and we infer segregation along a neritic/oceanic gradient because of the importance of the neritic Euphausia crystallorophias in the former and the oceanic E. superba in the latter.
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  • 29
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    Springer
    In:  Polar Biology, 6 (1). pp. 43-45.
    Publication Date: 2020-06-10
    Description: Faecal material of leopard, crabeater and elephant seals was collected from the vicinity of Davis station, Antarctica. Very few identifiable remains were found in elephant seal droppings. Fish remains, mainly of Pleuragramma antarcticum, were found in both leopard and crabeater seal droppings. The mysid Antarctomysis maxima was also found in crabeater seal droppings and amphipods and decapod crustaceans in leopard seal droppings.
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  • 30
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    Springer
    In:  Polar Biology, 6 (3). pp. 187-188.
    Publication Date: 2020-06-10
    Description: The food of emperor penguins Aptenodytes forsteri at the edge of the sea ice off the Vestfold Hills was studied by faecal analysis. Fish, crustacean, cephalopod and gastropod remains were found in 151 droppings collected between August and October 1984. The main fish identified from otoliths was Pleurogramma antarcticum with an average standard length of 129.5 mm. Amphipods increased in frequency from August to October with gammarids predominating.
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  • 31
    Publication Date: 2020-06-10
    Description: The foraging behaviour of fur seals and two species of surface feeding seabirds was observed over swarms of vertically migrating krill along the Antarctic Peninsula in July 1987. Fur Seal haul out patterns were correlated with krill in the upper 30 m of the water column. Krill moved to the surface at night; seals subsequently foraged from 1400-0700 hours before returning to floes. Foraging was continuous through the night. Dive duration decreased as krill moved up to the surface; shorter dives may have been more successful than longer ones. It is possible that very deep dives, which occur early in a foraging bout, represent more of an attempt to assess krill depth and distribution rather than being a genuine foraging effort. Seabirds responded to the presence of a surface krill swarm by circling over it and foraging; krill at depths greater than 30 m elicited directional flight and low frequencies of prey capture attempts. Both Snow Petrels and Antarctic Terns preyed on krill, but each species approached the swarms from different habitats. Snow Petrels primarily overflew areas covered by ice; terns preferred open water. This suggested that prey encounters are essentially opportunistic, although the search for prey is limited to rather specific marine habitats. This feature may be important to our understanding of the factors that determine the pelagic distribution of seabirds.
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  • 32
    Publication Date: 2018-03-02
    Description: Sediments on high Arctic shelves result from modern processes and the effect of former glaciations. Based on data from the northern Barents Sea, an area with input from large and numerous surging glaciers, we define two principal zones with different environmental regimes and corresponding sedimentary facies: (1) a glacier-proximal zone influenced by grounding-line processes and the immediately adjacent areas affected by glacial sediment input, and (2) a glacier-distal, sea-ice and current-controlled zone, which also includes a wide sediment-starved region dominated by biogenic carbonate accumulation. Characteristic of the glacier-proximal zone are glacial surges which affect sedimentation rates and leave a diagnostic pattern of sea-floor morphologies. Extensive ice gouging causes a homogeneous sediment texture. In the glacier-distal zone, fine-grained mud supplied from sea ice and infrequent coarser material deposited from icebergs is reworked by modern oceanographic processes. On shallow banks, in 30–50 m of water, carbonates accumulate from a prolific bottom fauna formed in response to extensive reworking and nutrient supply.
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  • 33
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    Springer
    In:  Contributions to Mineralogy and Petrology, 102 (1). pp. 93-101.
    Publication Date: 2018-03-02
    Description: Five major alteration zones in the Extrusive Series and the Sheeted Dike Complex of the Troodos Ophiolite are each characterized by (a) distinct elemental changes compared to the original composition and (b) secondary mineralogy. The upper ca. 300 m of the extrusive crust, the highly oxidatedcold seawater alteration zone (CSA), is strongly enriched in K2O and depleted in Na2O. It is followed downwards by alow temperature alteration zone (〈170° C) which is most widespread in the Troodos extrusives and where Na2O and K2O are enriched, the latter less strongly than in the CSA zone. Three types ofhigh temperature alteration zones (〈440° C; HTA I–III) are found in the Sheeted Dike Complex. All are marked by thorough leaching of K2O, while the behavior of Na2O (e.g. unchanged in type III) and CaO (depleted in type I, enriched in types II, III) is variable. Mass budgets of elemental changes are quantified by calibration of whole rock analyses via systematic stable element variations of fresh glasses found throughout the extrusive section. The Troodos extrusive crust and upper Sheeted Dike Complex are a major sink for MgO, K2O, and Na2O, and a source for CaO; the overall scale of fluxes drastically exceeds estimates based on fresh basalt compositions from present ocean crust.
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  • 34
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    Springer
    In:  Bulletin of Volcanology, 48 (4). pp. 195-207.
    Publication Date: 2018-05-29
    Description: Many of the world's flood basalt provinces form elevated plateaux at the margins of continents, although in most cases their present large elevation is not the result of mountain building processes. Several explanations have recently been put forward to explain such occurrences of epeirogeny. The Deccan Trap basalt province forms one such elevated plateau, and results are presented here showing how the epeirogenic uplift in this region, combined with crustal subsidence probably associated with the rifting of the Indian continental margin, has affected the structure of the basalt sequence. Trace element analytical data are used for samples from numerous vertical sections through the Deccan Traps lava series along and around the Western Ghats ridge in India. The results reinforce the previously defined stratigraphy of the Mahabaleshwar area, and extend it over a region covering some 36 000 km2, reaching as far south as Belgaum and the Trap/basement contact. These results show that the lava pile is not flat lying, but forms a very low amplitude anticlinal fold structure plunging southwards by up to 0.3 ° over most of the area, although in the south there is evidence of a reversal of this plunge. The fold is interpreted as being the result of two tilting processes: (1) westward tilting near the coast, due to the foundering of the passive continental margin, and (2) epeirogenic uplift along the whole west coast of India producing the observed topography and the peninsula-wide drainage patterns, and also the easterly component of dip. Variations in the magnitude of the latter effect along the western continental margin may also be important in generating the plunge of the fold, although the possibility of some component of depositional dip may also be important. This latter possibility can be modelled using a simple computer program. The results of this modelling show that a migrating linear volcanic edifice fits the observations best.
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  • 35
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    Springer
    In:  Paläontologische Zeitschrift, 63 (3). pp. 207-214.
    Publication Date: 2016-02-23
    Description: Growth line analysis of diagenetically altered scleractinians is only possible if carbonate diagenesis has followed the pathway of aragonite leaching and coeval formation of low magnesium calcite. All other possibilities of aragonite transformation into calcite exclude the preservation of this growth line banding. Examples of these diagenetic patterns are found in the Pleistocene of Barbados.
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  • 36
    Publication Date: 2016-04-08
    Description: Clay- and silt-size mineral assemblages are described from eight piston cores from the fiords and shelf on the western margin of Baffin Bay, Arctic Canada. Radiocarbon dates indicate that all the cores extend back in time to the last local glacial/interglacial transition (i.e. 8–10 ka); four extend back to between 10 and 12 ka, and HU77-021-156, located on the Southeast Baffin Island shelf, includes the entire late Foxe glacial stage. Silt- and clay-size particles constitute ca 40 and 55%, respectively, by weight of the bulk sediment. The clay-size fraction is dominated by mica; feldspars and quartz are the main constituents of the silt fraction. The fiord sediments are mainly composed of local mineralogies, but on the shelf, and at times in the fiords, exotic mineral species occur. The most important of these are detrital carbonates, derived from erosion of the Paleozoic basins in Arctic Canada and/or northwest Greenland. Both calcite and dolomite occur; calcite is the major carbonate mineral in the “southern” cores, whereas dolomite is the most abundant in cores north of 66°N. Higher inputs of carbonate species occur during regional deglaciation, 7–10 ka, and during the last 5 ka (probably reflecting increased iceberg production from northwest Greenland). Thus variations in the precentages of the carbonate minerals indicate significant shifts in Late Quaternary glacial-sediment source areas and oceanographic regimes.
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  • 37
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    Elsevier
    In:  Marine Geology, 87 (2-4). pp. 323-328.
    Publication Date: 2016-04-11
    Description: Changes in composition of modern benthic ostracod faunas across the continental margin of southwestern Africa occur at boundaries between and within major water masses: a Mixed Layer-Antarctic Intermediate Water (AAIW) boundary at 200 m, an AAIW salinity minimum zone at 650 m, an AAIW bathyal thermocline at 1000 m, and the AAIW/North Atlantic Deep Water (NADW) boundary at 1500 m. In addition, two population changes occur within the NADW at 1.8–2.0 km and 2.0–3.0 km. The Antarctic Bottom Water assemblage is sparse and poorly preserved.
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  • 38
    Publication Date: 2020-07-14
    Description: Microheterotrophic dissolved free amino acid (DFAA) utilization, and microbial community and bacterial community carbon production and growth were studied using 3H-labeled organics as tracers in marine surface-film and subsurface (10 cm) waters off Baja California in November 1983. DFAA utilization was generally more rapid during the day (0.14 to 0.38 nM h-1) than at night (0.04 to 0.14 nM h-1) in surface-film and subsurface waters, but the percent of utilized amino acid which was respired was always greater during the night (22 to 57%) compared to the day (14 to 18%). Utilization of DFAA-carbon was estimated to range from 0.3 to 5.3 μg C l-1 d-1 for all stations studied. In six of the 8 samples examined, the percentage of microbial carbon accounted for by the bacterial component of the population (1.4 to 5.9%) was strikingly similar to the percentage of microbial carbon production accounted for by bacterial carbon production (1.9 to 5.1%). In all of these six samples, total microbial specific-growth rates and bacterial specific-growth rates were approximately equivalent (0.9 to 2.2 d-1 for the microbial community; 0.7 to 1.9 d-1 for bacteria). The two exceptions were samples apparently influenced by transient flagellate populations migrating into the surface or subsurface waters at night. These observations support the conclusion that surface films contain unique and highly active microbial populations.
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  • 39
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    In:  Bulletin of Volcanology, 48 . pp. 39-59.
    Publication Date: 2018-05-29
    Description: We distinguish three eruptive units of pyroclastic flows (T1, T2, and T3; T for trass) within the late Quaternary Laacher See tephra sequence. These units differ in the chemical/mineralogical composition of the essential pyroclasts ranging from highly differentiated phonolite in T1 to mafic phonolite in T3. T1 and T2 flows were generated during Plinian phases, and T3 flows during a late Vulcanian phase. The volume of the pyroclastic flow deposits is about 0.6 km3. The lateral extent of the flows from the source vent decreases from 〉 10 km (T1) to 〈 4.5 km (T3). In the narrow valleys north of Laacher See, the total thickness of the deposits exceeds 60 m. At least 19 flow units in T1, 6 in T2, and 4 in T3 can be recognized at individual localities. Depositional cycles of 2 to 5 flow units are distinguished in the eruptive units. Thickness and internal structure of the flow units are strongly controlled by topography. Subfacies within flow units such as strongly enriched pumice and lithic concentration zones, dust layers, lapilli pipes, ground layers, and lithic breccias are all compositionally related to each other by enrichment or depletion of clasts depending on their size and density in a fluidized flow. While critical diameters of coarse-tail grading were found to mark the boundary between the coarse nonfluidized and the finer fluidized grain-size subpopulations, we document the second boundary between the fluidized and the very fine entrained subpopulations by histograms and Rosin-Rammler graphs. Grain-size distribution and composition of the fluidized middle-size subpopulations remained largely unchanged during transport. Rheological properties of the pyroclastic flows are deduced from the variations in flow-unit structure within the valleys. T1 flows are thought to have decelerated from 25 m/s at 4 km to 〈 15 m/s at 7 km from the vent; flow density was probably 600–900 kg/m3, and viscosity 5–50 P. The estimated yield strength of the flows of 200– 〉 1000 N/m2 is consistent with the divergence of lithic size/distance curves from purely Newtonian models; the transport of lithics must be treated as in a Bingham fluid. The flow temperature probably decreased from T1 (300°–500°C) to T3 (〈200°C). A large-scale longitudinal variation in the flow units from proximal through medial to distal facies dominantly reflects temporal changes during the progressive collapse of an eruption column. Only a small amount of fallout tephra was generated in the T1 phase of eruption. The pyroclastic flows probably formed from relatively low ash fountains rather than from high Plinian eruption columns.
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  • 40
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    Springer
    In:  In: Sea-Level Research : a manual for the collection and evaluation of data. , ed. by Plassche, O. Springer, Dordrecht, pp. 435-456.
    Publication Date: 2016-01-11
    Description: There are over 1000 foraminiferal species presently living in marine environments, but relatively few of these can be used as direct indicators of sea level. We detail here certain assemblages occupying marsh environments that can be used for that purpose. Marsh foraminiferal assemblages have been shown to occur worldwide within narrowly defined vertical zones some of which extend less than 10 cm in total vertical range. These assemblage zones, once known, can be relocated in paleo-marsh deposits and accurately related to paleo-sea level. The key to success of these organisms as sea-level indicators is that their primary controlling factor appears to be elevation above mean sea level. Other foraminiferal assemblages are controlled by a series of parameters (eg. salinity, temperature, dissolved O2, etc.) which often have no direct relationship with actual water depth. Under appropriate circumstances, some information concerning sea level can be derived from other foraminiferal assemblages using indirect means. For instance areas which have undergone substantial emergence often contain small basins which, prior to emergence, were marine. The marine sediments at the bottom can be identified using foraminifera and the sill elevation of the basin can then be related to some prior sea-level stand. Both these methods have imperfections, but in areas where both emergence and submergence have taken place they can be combined to obtain a relatively complete sea-level history.
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  • 41
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    In:  Geo-Marine Letters, 6 (3). pp. 165-172.
    Publication Date: 2016-02-15
    Description: In a core from the outer Skagerrak, the content of biogenic opal is higher in Late Pleistocene (Younger Dryas) than in Holocene deposits. In terms of opal accumulation, rates are 1 g/cm2/1,000 y during the Holocene and five to ten times larger during the Younger Dryas. Intensive dissolution has greatly reduced the Holocene opal content and does not allow calculation of paleoproductivity. The intensity of opal dissolution is reflected by dissolution stages of both the diatomParalia sulcata and sponge spicules. The intensity of dissolution is negatively correlated to the sedimentation rate and appears to be controlled by silica-undersaturated environment on the sea floor and the uppermost sediment layer.
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  • 42
    Publication Date: 2020-07-30
    Description: At ODP Site 661 from the continental margin of Northwest Africa, authigenic clinoptilolites were investigated in detail. Based on chemical data, crystal size and shape and their intergrowth with associated mineral phases, two types of clinoptilolite (type A and B) occur representing different diagenetic conditions under which the formation of zeolites took place. Clinoptilolite type A was found in a sediment section comprises numerous hiatuses and stratigraphically condensed sediments and could have been formed during early diagenesis. In contrast, clinoptilolite type B was precipitated in Campanian sediments during later diagenesis, after the transformation from opal-A to opal-CT had taken place. At Site 661, the silica source for the authigenesis of both clinoptilolite types is biogenic opal. Volcanic ash material occurs, but in low amounts and thus is not a prerequisite for the formation of clinoptilolite at Site 661.
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  • 43
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    Elsevier
    In:  Aquatic Toxicology, 8 . pp. 129-137.
    Publication Date: 2015-06-24
    Description: The primary purpose of this study was to determine the toxicity of nitrite to several species of freshwater fishes and to investigate the underlying physiological mechanisms which account for differential toxicity among species. Green sunfish (Lepornis cyanellus) was the most resistant species studied while the channel catfish (Ictaluruspunctatus) was the least resistant. Ninety-six hour median lethal concentrations correlated significantly with both the percentage of hemoglobin in the methemoglobin form and plasma nitrite concentrations among species. Plasma nitrite levels also correlated significantly with percent methemoglobin. Environmental chloride did not increase the tolerance of largemouth bass (Micropterus salmoides) to nitrite toxicity as it did for channel catfish. These results indicate that plasma nitrite concentrations are the primary determinant of the toxicity of nitrite to fishes. Further, plasma nitrite concentrations in various species depend on the discriminatory ability of the active transport system in fish gills which ordinarily transports chloride ions.
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  • 44
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    Springer
    In:  Bulletin of Volcanology, 48 . pp. 325-339.
    Publication Date: 2018-05-29
    Description: We report experiments on the flow of two fluids of contrasting viscosity through a pipe in which low-viscosity fluid occupies the center of the pipe. The volume flux of the low-viscosity fluid in the pipe increased during an experiment but did not reach 100% in most cases. The transition from high- to low-viscosity-dominated outflow involved a drop in pressure gradient and an increase in flow rate due to reduced viscous resistance in the pipe. Initially, the central flow was thin and parallel-sided, but as its diameter increased the flow became unstable. A sequence of instabilities was observed during the course of each experiment, both in time and as a function of height in the pipe. In the most commonly observed instability the central flow adopted a helical geometry. The transition from parallel-sided to unstable flow first appeared at the top of the pipe and propagated downwards against the flow. Axisymmetric instabilities originating at the pipe entrance were also observed. All forms of instability exhibited entrainment of viscous fluid into the faster moving central flow. Entrainment was extensive early in the existence of the central flow, but later on the volume flux of lower-viscosity fluid in the central flow rose more rapidly than the rate of entrainment and the proportion of lower-viscosity fluid increased with time. These compositional changes determined the viscosity of the central flow which was found to control its diameter and velocity. In banded pumice deposits, silicic pumice without mafic component is commonly erupted alongside banded pumice blocks. We infer that banded pumice may correspond to the central flow in our experiments, i. e., that viscous magma has been incorporated into less viscous melt, and that pure acid pumice is derived from the outer flow. Changes in eruption style may be caused by variations in pressure gradient and flow rate due to changes in the viscosity of the melt in the conduit. Varied mafic/silicic proportions and degree of mixing in magmatic associations are controlled by the bulk volume erupted, discharge rate, initial temperature difference and aspect ratio of the conduit.
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  • 45
    Publication Date: 2017-06-22
    Description: The Teahitia-Mehetia hot spot region located in the southeastern extension of the Society Islands chain, near 18° S–148° W consists of several active volcanoes. The distribution of recent volcanic activity correlates with seismic epicenters, and covers an area of more than 1000 km2. Intermittent volcanic activity has given rise to large (〉1000 m high) and small (〈500 m high) edifices composed of various types of flows. Several recent volcanic events have produced a suite of alkalic rocks ranging from ankaramites, through alkali basalts to trachy-phonolites. The presence of altered MORB-like tholeiites on one small seamount suggests that a different mantle source material was involved in forming some of the crust in this hot spot region.
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  • 46
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    In:  In: LANDOLT-BÖRNSTEIN, Numerical Data and Functional Relationships in Science and Technology, New Series, Oceanography. , ed. by Sündermann, J. Springer, Berlin, Germany, pp. 233-264.
    Publication Date: 2013-01-15
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  • 47
    Publication Date: 2020-07-14
    Description: During R.R.S. "Discovery" Cruise 100 in the Southern Ocean (1979), 620 specimens of the Antarctic cranchiid squid Galiteuthis glacialis (Chun) were caught in the RMT8 opening-closing net, to the south of the Antarctic Polar Front (APF). The catch was dominated by individuals 〈 20 mm dorsal mantle length (DML) and, apart from two specimens, the rest of the catch was 〈 60 mm DML. Two larger squid (255 mm DML) were both immature and apparently female. The species is concentrated at a depth of 300 to 400 m; there is evidence of ontogenetic spreading and a shift in the modal depth of the population from the 300 to 400 m horizon in daylight to the 200 to 300 m horizon in darkness. The collection confirms the circumpolar distribution of the species and supports previous evidence that it rarely, if ever, occurs to the north of the APF. As in Mesonychoteuthis hamiltoni, the only other species of cranchiid squid known to occur south of the APF, the early-life phase of G. glacialis is concentrated in the upper zone of the "warm deep water" beneath the Antarctic surface layer where, putatively, there is a zone of enhanced biological activity.
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  • 48
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    In:  AMBIO, 18 (1). pp. 55-59.
    Publication Date: 2020-09-18
    Description: In the Antarctic there are large unexploited stocks of cephalopods with high potential commercial value and there are two important fisheries for squid in the cool temperate waters of the Southern Ocean, adjacent to the Antarctic, in the Atlantic and Pacific sectors. Squid fisheries can develop very rapidly, and if this were to happen in the Antarctic before adequate management plans could be established, there would be serious consequences for the squid stocks, and also for the vertebrate predator populations which depend on them. It is especially important to increase our knowledge of the Antarctic cephalopod species, their distribution and role in the food chain, and to understand their life cycles
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  • 49
    Publication Date: 2018-03-21
    Description: Phytoplankton production, standing crop, and loss processes (respiration, sedimentation, grazing by zooplankton, and excretion) were measured on a daily basis during the growth, dormancy and decline of a winter-spring diatom bloom in a large-scale (13 m3) marine mesocosm in 1987. Carbonspecific rates of production and biomass change were highly correlated whereas production and loss rates were unrelated over the experimental period when the significant changes in algal biomass characteristic of phytoplankton blooms were occurring. The observed decline in diatom growth rates was caused by nutrient limitation. Daily phytoplankton production rates calculated from the phytoplankton continuity equation were in excellent agreement with rates independently determined using standard 14C techniques. A carbon budget for the winter bloom indicated that 82.4% of the net daytime primary production was accounted for by measured loss processes, 1.3% was present as standing crop at the end of the experiment, and 16.3% was unexplained. Losses via sedimentation (44.8%) and nighttime phytoplankton respiration (24.1%) predominated, while losses due to zooplankton grazing (10.7%) and nighttime phytoplankton excretion (2.8%) were of lesser importance. A model simulating daily phytoplankton biomass was developed to demonstrate the relative importance of the individual loss processes.
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  • 50
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    Elsevier
    In:  Advances in Space Research, 6 (12). pp. 299-306.
    Publication Date: 2016-01-22
    Description: Halophilic representatives are found in all main lines of evolutionary descendence of microbes: in archaebacteria, Gram-negative and Gram-positive eubacteria, and also in eucaryotes. In principe all halophilic microorganisms have to adapt their surface and membrane structures to their highly ionic environments. Concerning their intracellular compartment two different strategies have been developed: Inorganic ions are largely excluded in some microorganisms while such ions are actively accumulated in others. In particular the second group of organisms has to adapt the whole metabolic machinery to the highly ionic conditions of several molar salts, whereas in the first group only the outer surface of the cytoplasmic membrane and the extracytoplasmic structures are in contact with high concentrations of inorganic ions. In this latter group, a variety of organic solutes is accumulated in response to increases of the salinity of the environment.
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  • 51
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    Elsevier
    In:  Estuarine, Coastal and Shelf Science, 28 (6). pp. 615-638.
    Publication Date: 2017-01-04
    Description: Measurements in the mixing zone of the Elbe estuary were performed during three consecutive tidal cycles with three types of instruments—a moored tripod with velocity and temperature/conductivity/light attenuation sensors, a profiling sonde with similar sensors lowered from an anchored vessel, and instrumented moorings. Acoustic-travel-time sensors were used for velocity measurements. Spectral analysis of 12·8 min pieces of the obtained time series gives results that are consistent with isotropic turbulence for part of the frequency space. Temporal changes of turbulent kinetic energy are correlated with tidal current velocity. A retardation is found between changes in tidal current and turbulent energy. Not all shear stress terms are in similar phase with tidal flow. Mean gradients, Reynolds stress terms, and turbulent salt flux terms are combined to determine eddy viscosity and eddy diffusion coefficients.
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  • 52
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    In:  In: Plankton ecology: succession in plankton communities. , ed. by Sommer, U. Springer, Berlin, Germany, pp. 57-106. ISBN 3-540-51373-6
    Publication Date: 2012-03-22
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  • 53
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    In:  , ed. by Sommer, U. Springer, Berlin, Germany, 369 pp. ISBN 3-540-51373-6
    Publication Date: 2012-02-28
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  • 54
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    Elsevier
    In:  Quaternary Research, 26 (1). pp. 121-134.
    Publication Date: 2016-06-16
    Description: Published oxygen isotope results from benthic and planktonic foraminifera are used to constrain the extent to which surface ocean temperatures in the tropics changed between glacial and interglacial time. The possible impacts of bioturbation and of the redistribution of 18O16O ratios within the sea, putting aside the oxygen isotope results, are consistent with the CLIMAP project conclusion that tropical ocean temperatures remained within ±2°C of their present value.
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  • 55
    Publication Date: 2016-09-02
    Description: Marine molluscan shells from para-type and other loclities of the Holsteinian interglaciation were dated by ThU and the electron spin resonance (ESR) method to more than 350,000 and 370,000 yr B.P., beyond the limit of ThU dating. The high age estimate is corroborated by a KAr age of 420,000 yr B.P. determined from volcanic ash near the base of the Ariendorf paleosol in the Middle Rhine valley believed to be a pedostratigraphic equivalent of the Holsteinian. Shells from the Herzeele marine unit III, an equivalent of the Wacken (Dömnitz) warm stage in northern France and subsequent to the Holsteinian, revealed ages between 300,000 and 350,000 yr B.P. A correlation of these two warm stages with marine oxygen-isotope stages 11 and 9 on the SPECMAP and CARTUNE time scales is suggested. From the benthic oxygen-isotope record one may infer that no exceptionally high global sea-level rise corresponds to the large transgressions of the Holstein Sea in northern Germany. Therefore, a significant proportion of the transgression was probably the result of an unusually large local glacial-isostatic depression caused by the extreme buildup of ice during the preceding Elster glaciation (stage 12). According to the deep-sea record, it lasted approximately 50% longer than the subsequent cold stage 10. The outstanding soil formation with Braunlehm and the well-developed thermal optimum of the Holsteinian are tentatively related to a phase of minimum sea-ice cover in the Norwegian-Greenland Sea, as deduced from long benthic carbon-isotope records from the central Atlantic.
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  • 56
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    Elsevier
    In:  Marine Geology, 71 (3-4). pp. 341-362.
    Publication Date: 2016-06-23
    Description: Dissolution of biogenic shallow-water carbonates exposed on deep-sea moorings indicates that skeletal structure is important for the rate of disintegration of biogenic carbonates, besides mineralogy and grain size of particles. The aragonites and high Mg-calcites used represent a wide spectrum of mineralogies and types of skeletal framework. The particles were deployed at different water depths on a mooring in the Drake Passage for 52 days. Weight loss curves for the various types of particles show the relative importance of the different structural factors for the disintegration of these biogenic carbonates. Organic coatings, intraskeletal pore spaces, and sizes and shapes of individual crystallites in the skeletons may be more important than carbonate mineralogy and particle size in cases. The presence of internal sediments, cement aggregates and natural contaminations and of diatoms incorporated during growth into carbonate skeletons, strongly influence the disintegration of the skeletal materials. The first step of particle disintegration is the selective removal of impurities. This step is analogous to a “cleaning” of specimens. It is succeeded by initial dissolution, by strong dissolution and finally by disintegration.
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  • 57
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    In:  In: Reef Diagenesis. , ed. by Schroeder, J. H. and Purser, B. H. Springer , Berlin, Heidelberg, pp. 245-268. ISBN 978-3-642-82814-0
    Publication Date: 2016-06-30
    Description: Earlier studies of the Wetterstein series were concerned mainly with sedimentation (Sander 1936, Sarnthein 1965, 1966), or specific aspects of diagenesis (German 1968, 1969, Bechstädt 1975, 1979, Bechstädt and Dohler-Hirner 1983). The first modern facies concept, including ecological zonation, for a specific reef complex near Innsbruck, e.g., Hafelekar reef, was made by Brandner and Resch (1981).
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  • 58
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    In:  In: The role of freshwater outflow in coastal marine ecosystems. , ed. by Skreslet, S. NATO ASI Series, G7 . Springer, Berlin, Heidelberg, pp. 85-106.
    Publication Date: 2018-01-19
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  • 59
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    Elsevier
    In:  Earth and Planetary Science Letters, 94 (3-4). pp. 291-300.
    Publication Date: 2016-08-02
    Description: Compressional-wave (P-wave) velocities and magnetic susceptibilities were measured on gravity (GGC) and piston cores (PC) and Ocean Drilling Program (ODP) Leg 108 advanced piston cores (APC) from the equatorial Atlantic to test our hypothesis that climatically driven changes in terrigenous and biogenic fluxes, and in carbonate dissolution control the interrelationships between the two signals. In Pleistocene sediments deposited above the calcium compensation depth (CCD) we observed changes in P-wave velocity and magnetic susceptibility that are (1) inversely correlated, and (2) coherent to changes in glacial-interglacial climate. Glacials show low P-wave velocities and relatively high magnetic susceptibilities. In contrast, interglacials show high P-wave velocities and relatively low magnetic susceptibilities. These temporal changes in P-wave velocity and magnetic susceptibility reflect the climatic history recorded in the sediments and are related to: (1) the production of biogenic carbonate, mainly planktonic foraminifera, and (2) the terrigenous sediment supply that contains magnetic minerals. Below the CCD this pattern disappears and consistently low P-wave velocities and distinctly higher magnetic susceptibilities prevail. The distinct decrease of large P-wave velocity fluctuations is due to the dissolution of carbonate sediments which cause a distinct decrease in sand grain sizes and a consistently low carbonate content (〈 10%). Dilution of magnetic material by the carbonate fraction is minor and the high magnetic susceptibility values and the relatively high amplitude variations in magnetic susceptibility are due to changes in the magnetic mineral concentration of the terrigenous (non-carbonate) fraction. In early Pliocene sediments we also observed covarying velocity and magnetic susceptibility signals that may reflect a predominatly terrigenous control on sedimentation. Our preliminary results demonstrate that a combined use of non-destructive measurements of acoustic and rock-magnetic signals provides a potential paleoceanographic tool for characterizing: (1) glacial-interglacial pelagic sedimentation, (2) pelagic sedimentation above the CCD, (3) increases in carbonate dissolution, and (4) areas below the CCD. Furthermore, rock magnetic fluctuations in sediments below the CCD may provide an important stratigraphic tool for the deep carbonate-free basins of the world's oceans.
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  • 60
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    In:  Polar Biology, 6 (2). pp. 97-102.
    Publication Date: 2020-06-10
    Description: Stomach and intestine samples from 21 adult Weddell seals were used to study the diet of these seals from the eastern and southern Weddell Sea coast from January to February 1983 and 1985. Fish occurred in all seals, squid in five, octopods in three and Euphausia crystallorophias in one seal. Pleuragramma antarcticum was the predominant fish in the diet, constituting 61.1% of otoliths in 1983 samples and 93.8% in 1985. Aethotaxis mitopteryx, Dissostichus mawsoni, unidentified Trematomus spp. and channichthyids were also recorded. Size and wet weight of P. antarcticum were calculated from uneroded otoliths, found in 6 seal stomachs with liquid food pulp, collected during early morning hours in 1985. Size distribution of P. antarcticum from individual seals was reasonably constant, ranging between 5.0 and 22.0 cm SL; adult fish from about 14.0 to 19.0 cm SL predominated. P. antarcticum in seals from the southern area had a larger median size (16.5 cm SL), than those from further east (15.5 cm SL). Calculated wet weights of all P. antarcticum from individual seal stomachs ranged between 4.7 and 16.9 kg the mean was 12.8 kg. Comparisons with net-hauls from the southern Gould Bay suggest that Weddell seals feed mainly in deeper water layers (〉400 m) where adult P. antarcticum occur at higher densities.
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  • 61
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    Elsevier
    In:  Aquacultural Engineering, 8 (1). pp. 47-65.
    Publication Date: 2020-06-11
    Description: The life cycle of loliginid squids has been completed in recirculating seawater systems. Two systems were required: a 2 m diameter circular culture tank (CT) with adjoining 2 m circular filter tank (3000 liters total volume of natural seawater) for culture of hatchlings, 1–60 days old; and a 6 × 2·6 × 1 m raceway culture tank (RW) with a smaller adjoining rectangular filter tank (14 850 liters total volume of artificial seawater) for the grow-out of adults. Both systems were equipped with temperature control apparatus, modular filter units (particle filters and activated carbon), foam fractionators, biological filters (crushed oyster shell) and UV sterilizers. The systems carried low bioloads, 〈 1·0 g/m3 and as high as 0·8 kg/m3, respectively. Water quality was excellent: NH4N was below 0·01 mg/liter in the CT and 0·10 mg/liter in the RW: NO2N was below 0·01 mg/liter in the CT and 0·03 mg/liter in the RW; NO3N was below 12 mg/liter in the CT and below 50 mg/liter in the RW; and pH was above 8·0 in both systems. The design of the systems proved to be behaviorally and physiologically suitable for squids and two species grew to adult size and produced viable young. These systems are compared to other squid maintenance and rearing systems and marine recirculating seawater systems.
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  • 62
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    In:  Oecologia, 68 (4). pp. 503-506.
    Publication Date: 2017-10-10
    Description: Natural phytoplankton from Lake Constance was used for chemostat competition experiments performed at a variety of dilution rates. In the first series at high Si:P ratios and under uniform phosphorus limitation for all species, Synedra acus outcompeted all other species at all dilution rates up to 1.6 d-1, only at the highest dilution rate (2.0 d-1) Achnanthes minutissima was successful. In the second series in the absence of any Si a green algal replacement series was found, with Mougeotia thylespora dominant at the lowest dilution rates, Scenedesmus acutus at the intermediate ones, and Chlorella minutissima at the highest ones. The outcome of interspecific competition was not in contradiction with the Monod kinetics of P-limited growth of the five species, but no satisfactorily precise prediction of competitive performance can be derived from the Monod kinetics because of insufficient precision in the estimate of k s .
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  • 63
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    In:  Marine Biology, 91 (3). pp. 345-351.
    Publication Date: 2018-06-06
    Description: Natural phytoplankton from antarctic waters in the Drake Passage were used for competition experiments in semicontinuous cultures. The outcome of interspecific competition for silicate and nitrate was studied at a range of Si:N ratios (from 2.6:1 to 425:1) and at three different dilution rates. For five species Monod kinetics of silicate-and nitrate-limited growth has been established. Comparison between theoretical predictions derived from Monod kinetics and the outcome of competition experiments showed only minor deviations. Contrary to literature data, considerable depletion of nitrate was found in antarctic seawater. Both the concentrations of soluble silicate and of nitrate were too low to support maximum growth rates of some of the diatom species under investigation.
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  • 64
    Publication Date: 2018-06-29
    Description: Phytoplankton periodicity has been fairly regular during the years 1979 to 1982 in Lake Constance. Algal mass growth starts with the vernal onset of stratification; Cryptophyceae and small centric diatoms are the dominant algae of the spring bloom. In June grazing by zooplankton leads to a lsquoclear-water phasersquo dominated by Cryptophyceae. Algal summer growth starts under nutrient-saturated conditions with a dominance of Cryptomonas spp. and Pandorina morum. Depletion of soluble reactive phosphorus is followed by a dominance of pennate and filamentous centric diatoms, which are replaced by Ceratium hirundinella when dissolved silicate becomes depleted. Under calm conditions there is a diverse late-summer plankton dominated by Cyanophyceae and Dinobryon spp.; more turbulent conditions and silicon resupply enable a second summer diatom growth phase in August. The autumnal development leads from a Mougeotia — desmid assemblage to a diatom plankton in late autumn and winter. Inter-lake comparison of algal seasonality includes in ascending order of P-richness Königsee, Attersee, Walensee, Lake Lucerne, Lago Maggiore, Ammersee, Lake Zürich, Lake Geneva, Lake Constance. The oligotrophic lakes have one or two annual maxima of biomass; after the vernal maximum there is a slowly developing summer depression and sometimes a second maximum in autumn. The more eutrophic lakes have an additional maximum in summer. The number of floristically determined successional stages increases with increasing eutrophy, from three in Königsee and Attersee to eight in Lake Geneva and Lake Constance.
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  • 65
    Publication Date: 2016-11-14
    Description: Nutrient concentrations and phytoplankton species composition in near surface samples were studied along a S-N gradient in the Drake Passage, in early December 1984. Nitrate concentrations were much lower than usually previously reported from circum-Antarctic waters. Comparison of dissolved nutrient concentrations with growth requirements of Antarctic plankton algae suggests potential limitation of at least some species by nitrate or silicate. The taxonomic composition of the phytoplankton in our samples seemed to be partially controlled by competition for limiting nutrients.
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  • 66
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    Elsevier
    In:  Dynamics of Atmospheres and Oceans, 10 (1). pp. 63-92.
    Publication Date: 2018-01-24
    Description: In a series of numerical experiments the wind-driven ocean circulation is studied in an idealized, rectangular model ocean, which is forced by steady zonal winds and damped by lateral and/or bottom friction. The problem as described by the barotropic vorticity equation is characterized by a Rossby number (R) and horizontal and/or vertical Ekman numbers (EL, EB) only. With free-slip conditions at the boundaries steady solutions for all chosen values of R are obtained, provided the diffusivity is sufficiently large. For both the forms of frictional parameterization a northern boundary current emerges with an eastward penetration scale depending on R. The recirculation pattern in the oceanically relevant ‘intermediate’ range of R is strongly affected by the type of friction. If lateral diffusion dominates bottom friction, a strong recirculating sub-gyre emerges in the northwestern corner of the basin. Its shape resembles the vertically integrated transport fields in recent eddy resolving model (EGCM) studies. The maximum transport is increased to values several times larger than the Sverdrup transport. The increase in transport is coupled with a development of closed contours of potential vorticity, enabling a nearly free inertial flow. This behaviour provides a sharp contrast to the bottom friction case (Veronis) where inertial recirculation only takes place with values of R so large that the eastward jet reaches the eastern boundary. It is shown that the linear friction law puts a strong constraint on the flow by preventing an intense recirculation in a small part of the basin. A reduction of the diffusivity (EL) in the lateral friction case leads to quasi-steady solutions. The interaction with eddies becomes an integral part of the time mean energetics but does not influence the recirculation character of the flow. The main conclusion of the study is that the horizontal structure of the EGCM-transport fields can be explained in terms of a steady barotropic model where lateral friction represents the dominant dissipation mechanism
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  • 67
    Publication Date: 2020-05-13
    Description: A comparative study of isodideimnine-1 and didemnin B is presented using spcctroecopic methods, partial degradation and partial synthesis. This leads to the conclusion of the presence of a single depsipeptide, namely didemnin B, with (3S,4R,5S) isostatine instead of the previous statine residue. An attempt to determine the whole conformation in solution of didemnin B by using 2D-NMR is also described.
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  • 68
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    Springer
    In:  In: Volcanic hazards. , ed. by Latter, J. H. IAVCEI Proceedings in Volcanology, 1 . Springer , Berlin, pp. 210-229.
    Publication Date: 2014-02-10
    Type: Book chapter , NonPeerReviewed
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  • 69
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    Elsevier
    In:  Tectonophysics, 162 (1-2). pp. 51-85.
    Publication Date: 2019-05-06
    Description: Seismic refraction investigations along a 440-km long profije on the northern Baltic Shield have resolved the crustal structure in this area of Archaean to Early Proterozoic lithosphere formation. The profile, called the POLAR Profile, extends approximately along a SW-NE-oriented line from the Karelian Province in northern Finland across the Lapland Granulite Belt and the Kola Peninsula Province to the Varanger Peninsula in northeastern Norway. At six shotpoints, large explosions (200–1680 kg), and at three shotpoints, small explosions (80 kg) were detonated and recorded at an average station spacing of 2 km, providing high-quality record sections. A two-dimensional cross section of the crust was obtained by forward modelling using ray-tracing techniques. High-velocity bodies are found in the upper crust related to the Karasjok-Kittilä Greenstone Belt and the Lapland Granulite Belt. They extend to a depth of 6–13 km. In the Karelian Province in the southwest, a low-velocity zone was found between the depths of 8 and 14 km. The middle crust shows a slight increase in the average velocities from the southwest to the northeast, and a small velocity jump is found along a mid-crustal boundary between 18 and 21 km. The thickness of the middle crust varies between 16 and 18 km. The lower crust and the crust-mantle boundary (Moho) show considerable lateral variation. The top of the lower crust lies between 26 and 33 km, while its thickness decreases from 21 km in the southwest to 10–14 km beneath the Lapland Granulite Belt and the Inari Terrain, reaching 20 km again in the extreme northeast. The velocities also change laterally. The thin lower crust is characterized by rather low velocities (6.8–6.9 km/s), whereas in the southwest and northeast the velocities (6.9–7.3 km/s) resemble more typical shield structures. The Moho is found at 47 km in the Karelian Province, rises to 40 km beneath the Lapland Granulite Belt and descends to 46 km in the northeastern part of the Kola Peninsula Province. The upper mantle velocities at the Moho range from 8.1 km/s in the region of the thin crust, to 8.5 km/s and more beneath the Karelian Province. It is tempting to suggest that the anomalous lower crust underlying the Lapland Granulite Belt and the Inari Terrain may represent the remnants of an Early Proterozoic back-arc basin that was active prior to the 2.0 to 1.9 Ga plate convergence event, during which the Lapland Granulite Belt was thrust onto the Archaean basement of the Karelian Province. Another explanation is to assume that the velocity reduction in the anomalous lower crust was caused by a rather pronounced uplift of this region following the 1.9-Ga collision event.
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  • 70
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    Elsevier
    In:  Palaeogeography, Palaeoclimatology, Palaeoecology, 71 (1-2). pp. 97-118.
    Publication Date: 2019-05-06
    Description: Pore fluid venting associated with subduction-induced sediment deformation causes precipitation of calcium carbonate as prominent carbonate chimneys or cement in the accreted sediments across the active continental margin off Oregon and Washington. A depletion of interstitial Ca2+ with a maximum decrease of 50% relative to seawater Ca2+ over only 1.5m depth and reduction in porosity in the deformed sediments suggest that interstitial Ca2+ is removed to form calcium carbonate cement. In contrast, the pore waters of the undeformed abyssal plain sediments show no depletion in dissolved Ca2+. They are either enriched to a maximum of 5% or show no change in dissolved Ca2+. Here the background level of CaCO3 content in the sediment is only 0.1 to 1%. Calcium carbonate precipitation in the deformed sediments probably occurs as the result of upward migration and oxidation of biogenic methane and of the increase in carbonate saturation due to release of excess pore pressure during fluid venting. Upward advection of fluids at rates of 1–28 cm y−1 is predicted from diffusion-advection-reaction models applied to the downcore concentration profiles of dissolved Ca2+ and NH4+ in the tectonically-deformed sediments. The range of predicted flow rates is related to the type of calcium carbonate lithification; i.e. slow rates generate cement and fast rates generate chimneys. Carbonate mineral precipitation associated with pore fluid venting requires direct transfer of Ca2+ from the oceanic basement to the accretionary complex. Such a mechanism leads us to propose that the accretionary complexes of the global plate subduction zones are a major sink for crustal Ca2+. A global flux of crustal Ca2+ that is removed by carbonate mineral precipitation may be as muc3 as the hydrothermal Ca-input. This significant Ca-flux, not previously considered in the global geochemical budget, implies that pore fluid venting in subduction zones may also act as a global sink or source for other elements.
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  • 71
    Publication Date: 2019-05-10
    Description: Ocean crustal carbon uptake during seafloor alteration at DSDP Sites 417A, 417D, and 418A exceeds the estimated loss of carbon during magmatic ridge outgassing. If these sites are representative for oceanic crust in general, 2.2–2.9 × 1012 moles of carbon are removed from the oceans per year as a net flux of carbon between the oceanic crust and seawater. Although most of this carbon occurs as calcium carbonate, this ocean crustal carbonate probably cannot be considered part of the marine calcium carbonate sink since much of the Ca in these carbonates must be derived from basalt alteration that is not balanced by a concomitant uptake of seawater Mg. Our present estimate cannot be satisfactorily applied to global carbon budgets, because of uncertainties in the bulk budget of ocean floor alteration and because of the uniqueness of our estimate. Yet, our data document that the formation of ocean crust provides a significant sink for carbon that should be included in models of the global cycling of carbon. Furthermore, magmatic outgassing during ocean crust emplacement and seafloor basalt alteration may provide a buffering mechanism for atmospheric carbon.
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  • 72
    Publication Date: 2019-02-01
    Description: Manganese nodules from the Kane Gap (a deep sea channel connecting the Sierra Leone and Gambia Basins off West Africa) were investigated chemically and dated by10Be along cross-sections. Comparing the nodule structure with the stratigraphy of the related sediments, the following conclusions are drawn concerning the sedimentation processes during the last 4 to 6×106 years: The growth of the nodules started about 4 to 4.5 Ma before present during or near to the end of a period of erosion on a fossil-free, probably Miocene sediment. During the first phase of only a few hundred thousandyears, the nodules grew very quickly (7 to 〉18 mm/Ma). Fe-rich hydrogenetic material formed the internal sections of the nodules during this time. Slowing down of the bottom currents, resulting in deposition of thin sediment covers for short intervals, caused the character of the nodules to change to a more diagenetic composition. The growth rates were reduced to about 1 to 2 mm/Ma. The time of slowing is roughly 3 to 4 Ma BP. Probable uncertainties of the dating and growth rates resulting from supposed changes of the10Be supply to the nodules due to variations of the near bottom environment are discussed.
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  • 73
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    Springer
    In:  Contributions to Mineralogy and Petrology, 102 (1). pp. 112-126.
    Publication Date: 2019-05-13
    Description: A global compositional dichotomy for N-MORB magma (N1/N2) is recognized on the basis of Na2O, TiO2, CaO, and Al2O3 contents, and their respective ratios. We have characterized the two magma sub-types by means of their trace element patterns, and attempted to explain the differences in major and trace element contents in terms of a partial melting model, using data from DSDP/IPOD Leg 82. Mass balance calculations for N-MORB glass and rock compositions indicate that differences between N1-and N2-MORB are consistent with simple differences (5%–10%) in the degree of partial melting of a plagioclase-(±spinel) lherzolite, at pressures 〈10 kbar, rather than their respective derivation from plagioclase- and spinel-lher-zolite sources. Based on published and calculated partition coefficients, and calculated source magmaphile trace element compositions, the calculations indicate that the overall range of N-MORB compositions may be derived by between approximately 8% and 20% partial melting of a fertile lherzolite source. Fluid dynamic and melt kinematic considerations will probably necessitate refinement of the model, but should also take account of its qualitative precepts.
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  • 74
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    Elsevier
    In:  Tectonophysics, 160 (1-4). pp. 75-90.
    Publication Date: 2019-05-13
    Description: The imaging of a multichannel seismic record was improved by reprocessing using pre-stack techniques. The reprocessed record shows structures that indicate tectonic erosion and gravity collapse at the front of the Japan Trench margin. Much of the lower slope appears to be underlain by a detached, coherent block of continental crust. The lower slope has failed by mass wasting and the resulting apron of slump debris at the base of the slope has become involved in thrust faulting at the front of the subduction zone. Slumping continues as long as debris is removed from the front of the margin by subduction, and the apron cannot build up sufficiently to stabilize the failing lower slope. Truncated beds at the base of the upper plate indicate subcrustal erosion as well, this probably being the main cause of massive subsidence of the margin. Subsidence was the cause of oversteepening, destabilization and subsequent gravity collapse of the leading edge of the upper plate.
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  • 75
    Publication Date: 2019-05-06
    Description: The ice-proximal environment of the Nordaustlandet tidewater ice cap, Svalbard Archipelago, is one of the best analogues for understanding glacial geologic processes of northern continental shelves during initial Pleistocene deglaciation. Investigations of the proglacial region in 1980–1983 showed that the sedimentary environment is dominated by numerous meltwater outflows which discharge sediment-laden water from subglacial meltwater streams during the summer. Two large, stable meltwater outflows were observed in embayments along the southern part of the ice front. Landsat images show that both outflows have been in approximately the same position since at least 1976. They are located at the intersection of glacial drainage basins and centered over depressions in the underlying bedrock. An “outflow valley” extending away from the ice front was observed in front of the western meltwater outflow. Sidescan sonar profiling along the glacier front showed a 200 m wide gap in acoustic reflection at the base of the western meltwater outflow, probably caused by meltwater effluence. Enhanced sediment accumulations in this region, observed as a ≈ 3 ms sediment drape in front of the outflow, and large arcuate ridges in the outflow valley, testify to the transport efficiency of the subglacial meltwater stream. Several mounds, up to about 25 m high and 200 m wide, are observed on sidescan and 3.5 kHz profiles directly in front of the outflow. Although samples from these structures are absent, they are most likely composed of sediment and are similar to beaded eskers observed in Pleistocene glacimarine sequences indicating locally very high sedimentation rates. Fine-grained components of the subglacial discharge incorporated in the buoyant meltwater plume are usually entrained in a westerly coastal current. Elevated suspended particulate material concentrations are observed within the coastal waters in a region extending about 15 km perpendicular to the glacier front and at least 60 km along the ice front extending into the northwestern Barents Sea.
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  • 76
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    Springer
    In:  In: Landolt-Börnstein Zahlenwerte und Funktionen aus Naturwissenschaften und Technik: Neue Serie = Numerical data and functional relationships in science and technology: new series / Ed.-in-chief: O. Madelung Gruppe 5, Geophysik und Weltraumforschung = Geophysics and space research Bd. 3, Ozeanographie = Oceanography, Teilband a. Springer, Berlin, Germany, pp. 233-264. ISBN 3-540-15092-7
    Publication Date: 2020-03-05
    Type: Book chapter , NonPeerReviewed
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  • 77
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    Elsevier
    In:  Advances in Marine Biology, 25 . pp. 85-115.
    Publication Date: 2019-02-19
    Description: Cephalopods are exclusively marine molluscs and should be included among the organisms that are of general interest to marine biologists. As to experimental embryology, Naef has already stressed the suitability of cephalopod embryos for experimental work. The whole body of information accumulated in this field during the past half century since Naef published his monograph was reviewed by Marthy. This field of research is clearly underrated by many developmental biologists who could profit by the topological simplicity of the blastulation pattern in cephalopods, which contrasts with the spiralian mode of other molluscs. Questions raised by comparative/evolutionary embryology, following the tradition of descriptive developmental morphology, are truly stimulating to the field of experimental embryology, and vice versa. However, experimental studies are generally possible with only a limited number of models, which, in the case of cephalopods, appear to be embryos of medium to small size. On the other hand, some of the most intriguing questions in cephalopod biology are related to those forms that produce eggs of extremely large size. This chapter gives a brief overview of these recent studies placing them in the chronological sequence of embryogenesis. Studies covering early stages of embryonic development as well as later ones will be cited at least once in the section dealing with the earliest stage considered. Most of these investigations ultimately rest on the basic work by Naef.
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  • 78
    Publication Date: 2016-11-25
    Description: Indirect evidence suggests that Stenoteuthis oualaniensis is a multiple spawner, a reproductive strategy not reported previously for squid. After spawning once, S. oualaniensis apparently continues to feed, grow, and mature additional oocytes before spawning again. Squid were caught by jigging at night in waters around the main Hawaiian Islands during four cruises from 1981 to 1987. All females from 200 mm mantle length (ML) to at least 318 mm ML were sexually mature, indicating that considerable growth takes place after reaching sexual maturity. Size-frequency analyses of ovarian oocytes revealed continuous egg production throughout adult life. Mature ova are stored in the oviducts, but oviduct fullness is unrelated to body size, indicating repeat spawning.
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  • 79
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    Springer
    In:  Polar Biology, 9 (6). pp. 385-390.
    Publication Date: 2020-06-10
    Description: The diet of the emperor penguin Aptenodytes forsteri in the eastern Weddell Sea, Antarctica was studied during October and November 1986 by stomach content analysis. Emperor penguins fed mainly on Antarctic krill Euphausia superba, Antarctic silverfish Pleuragramma antarcticum and squid Psychroteuthis glacialis. Benthic prey was not found. The prey composition suggests two different feeding strategies, shallow dives exploring the rugged underside of sea ice where krill is taken, and deep dives when mesopelagic fish and squid are consumed. Chicks were fed on average every 1.44 days.
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  • 80
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    Elsevier
    In:  Journal of Experimental Marine Biology and Ecology, 104 . pp. 23-30.
    Publication Date: 2021-01-19
    Description: The octopus Eledone cirrhosa (Lamarck 1798), enclosed in a small chamber of flowing sea water, was tested for responses to water-borne chemicals. Incidence of body movements and change in ventilation rate were recorded by a non-invasive technique- At concentrations no more than 1x10 -4M at the animal, the octopuses responded to betaine, proline, alanine, lactic acid, and serine (order of decreasing sensitivity)- Glutamic acid and trimethylamine oxide were considerably less stimulatory, arginine and taurine were hardly more effective than sea-water controls.
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  • 81
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    Elsevier
    In:  Organic Geochemistry, 10 (4-6). pp. 759-768.
    Publication Date: 2018-09-04
    Description: Microbial anaerobic oxidation of methane in sediments is a kinetic process associated with a carbon isotope effect which enriches the remaining methane in 13C. Three, models: % residual methane, higher hydrocarbon enrichment, and CO2-CH4 coexisting pairs are used to independently calculate fractionation factors (αc) in the range of 1.002–1.014, which overlap the range determined by culture studies, αc is smaller than that associated with methanogenesis by CO2 reduction or by acetate-type fermentation, and comparison of the coexisting CO2-CH4 pairs can distinguish between the formation and consumption processes. Methane oxidation in sediments continues to a threshold concentration of ca. 0.2 mM; the residual methane is either unavailable or unattractive to consumption. Minor amounts of methane may also be produced simultaneously in the methane consumption zone, influencing the apparent fractionation factor in this zone.
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  • 82
    Publication Date: 2020-11-06
    Description: The fur seal, Arctocephalus gazella, population at Mossman Peninsula (Laurie Island) was studied from 1985 to 1987. Weekly counts were carried out at a 4 km bachelor haul-out beach from December through June. Maxima of 2 240, 2 787 and 5 196 juvenile and adult males were counted during March of the respective years. Census data indicate an increase in the non-breeding population of 13.5% between 1985–1986 and 46.5% between 1986–1987.
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  • 83
    Publication Date: 2019-05-06
    Description: Sediment fluxes were highest in the Norwegian Sea during late glacial/early deglacial periods, i.e., at oxygen isotope transition 43, below transition 65, at various levels within stage 6, and below stage 9. Dark diamictons deposited at these times reflect intense iceberg rafting in surface waters fed by surges along the front of the marine-based parts of the continental ice sheets in the southeastern sector of the Norwegian Sea. The high organic carbon content (0.5–1.3%) in these layers reflects input from erosion of terrigenious matter-rich sediments outcropping on the shelves. Partial oxidation of organic matter and decreased deep-water renewal may explain the strong carbonate dissolution observed during these periods. Interglacial environments were strongly variable throughout the last 350 ka. Circulation patterns of stage 5e best resemble modern conditions, while stage 7 and 9 sediments record a much weaker Norwegian Current.
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  • 84
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    Elsevier
    In:  Journal of Experimental Marine Biology and Ecology, 126 (3). pp. 231-241.
    Publication Date: 2016-11-29
    Description: 19 samples (1189 individuals) of the commercially fished Patagonian squid Loligo gahi d'Orbigny were collected from Falkland waters between March 1987 and April 1988 and subjected to starch gel electrophoresis. 41 enzyme-coding loci were screened for polymorphism. Clearly resolved enzyme phenotypes were obtained at 21 loci of which six exhibited polymorphism (glutamate oxaloacetate transaminase, GOT-II, E.C. 2.6.1.1.; α-glycerophosphate dehydrogenase, α-GPDH, E.G. 1.1.1.8; isocitrate dehydrogenase, ICD, E.C. 1.1.1.42; malate dehydrogenase, MDH-II, E.G. 1.1.1.37; phosphogluconate dehydrogenase, PGD, E.C. 1.1.1.44; and phosphoglucose mutase, PGM, E.G. 2.7.5.1). Routine scoring at the 21 loci revealed moderate levels of genetic variability, with the proportion of polymorphic loci, P = 0.273, mean heterozygosities per locus = 0.0693, and the effective number of alleles, Ne, with values of 1.13–1.83.
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  • 85
    Publication Date: 2016-11-29
    Description: Genetic population structure of the commercially fished Patagonian squid Loligo gahi d'Orbigny was examined by collecting 19 samples (1189 individuals) from Falkland waters between March 1987 and April 1988 and subjecting individuals to electrophoretic and morphometric analysis. Morphological features (dorsal mantle length, fin length oblique, fin width, interorbital width, tentacle length, length of arms I and II, and mid-mantle circumference), sex and stage of reproductive maturity (Lipinski's universal scale) were recorded prior to electrophoresis. Analyses of allele frequencies at six polymorphic loci provided no evidence of stock separation, and the frequency distribution of genotypic classes almost exclusively fitted Hardy-Weinberg expectations for a randomly interbreeding population. Nei's mean genetic distances and identities between samples ranged from 0.000–0.002 and 0.997–1.00, respectively, supporting the contention of a genetically homogeneous breeding unit. Multivariate analyses revealed significant differences in the morphometrics among certain samples collected at approximately the same time, especially of interorbital width, first arm length and fin width. This morphological differentiation was not correlated with differences at the genetic level. The frequency distribution of dorsal mantle length and stages of reproductive maturity through the year were compatible with two alternative interpretations of population structure: (i) the existence of two temporally distinct separate spawning populations, one autumn- and the other spring-spawning, or, (ii) that slow-growing or late spawned individuals spawn at 18 months old while most squid spawn at 1 yr old in the austral spring and summer. Although it is not possible to discount either interpretation unequivocally, the latter hypothesis of population structure is more congruent with existing genetic evidence.
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  • 86
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    Springer
    In:  Marine Biology, 103 (3). pp. 333-338.
    Publication Date: 2020-07-14
    Description: Respiration and nitrogen excretion rates of mature adult Loligo forbesi were investigated at the Roscoff Laboratory (North Brittany, France) during individual short-term incubation experiments in January 1986. The squids were in post-digestive condition and not actively swimming. Both oxygen uptake and nitrogen excretion are continuous processes. The metabolic rates of this active nektonic species (145 ml kg-1 h-1 oxygen uptake, 18.56 μg g-1 h-1 ammonia excretion) are distinctly higher than those of benthic cephalopods. Proteins constitute the main metabolic substrate for energetic needs. Besides ammonia, urea is also continuously released, in amounts ranging from 5 to 16% of ammonia-excretion values.
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  • 87
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    Springer
    In:  In: Plankton ecology - success in plankton communities. , ed. by Sommer, U. Springer, Berlin, Germany, pp. 1-8.
    Publication Date: 2019-08-07
    Type: Book chapter , NonPeerReviewed
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  • 88
    Publication Date: 2017-10-10
    Description: The influence of periodic disturbances of various frequency on the maintenance of the phytoplankton diversity was studied by semicontinuous competition experiments. Disturbances consisted of dilution events, which meant both addition of fresh nutrients and elimination of organisms. The intervals between dilution events varied from 1 to 14 days. Diversity was found to increase with increasing intervals between disturbances. coexisting species belonged to different strategy types: (a) species with rapid growth under enriched conditions, (b) species with good competitive abilities under impoverished conditions, (c) species with the ability to build up storage pools of the limiting nutrient. An increase of the number of coexisting species over the number that would have coexisted in steady state was only found when the interval exceeded one generation time.
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  • 89
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    Elsevier
    In:  Palaeogeography, Palaeoclimatology, Palaeoecology, 71 (1-2). pp. 119-136.
    Publication Date: 2020-08-07
    Description: Pore fluids extracted from near-surface sediments of the deformation front along the Oregon subduction zone have, in general, the dissolved nutrient pattern characteristic of bacterial sulfate reduction. However, in certain locations there are peculiar ammonium distributions and anomalously 13C-depleted dissolved ΣCO2. These carbon isotope and nutrient patterns are attributed to the concurrent microbially-mediated oxidation of sedimentary organic matter (POC) and methane (CH4) originating from depth. In contrast to the oxidation of sedimentary organic matter in the sulfate zone, utilization of methane as the carbon source by sulfate-reducing bacteria would generate only half as much total carbon dioxide for each mole of sulfate consumed and would not generate any dissolved ammonium. The isotopically light ΣCO2 released from methane oxidation depletes the total metabolic carbon dioxide pool. Therefore, NH4+, ΣCO2 and δ13C of interstitial carbon dioxide in these pore fluids distintcly reflect the combined contributions of each of the two carbon substrates undergoing mineralization; i.e. methane and sedimentary organic matter. By appropriately partitioning the nutrient and substrate relationships, we calculate that in the area of the marginal ridge of the Oregon subduction zone as much as 30% of the ΣCO2 in pore fluids may result from methane oxidation. The calculation also predicts that the carbon isotope signature of the carbon dioxide derived from methane is between −35‰ and −63‰ PDB. Such an isotopically light gas generated from within the accretionary complex could be the residue of a biogenic methane pool. Fluid advection is required to carry such methane from depth to the present near-surface sediments. This mechanism is consistent with large-scale, tectonically-induced fluid transport envisioned for accreted sediments of the world's convergent plate boundaries.
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