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  • Other Sources  (72)
  • Springer  (61)
  • GEOMAR Forschungszentrum für marine Geowissenschaften  (11)
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  • 1995-1999  (42)
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  • 1996  (42)
  • 1993  (30)
  • 1
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    Springer
    In:  Springer
    Publication Date: 1996
    Keywords: Textbook of mathematics ; Data analysis / ~ processing ; Textbook of geophysics ; Chaotic behaviour
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  • 2
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    In:  Berlin, Springer, vol. 20, no. Publ. No. 12, pp. 23-40, (ISBN 1-4020-3326-5, VIII + 343 pp.)
    Publication Date: 1996
    Keywords: Volcanology ; Review article ; Earthquake hazard ; PAG
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  • 3
    Publication Date: 2020-07-14
    Description: Horizontal starch gel electrophoresis was used to investigate levels of genetic differentiation between four samples of the nominate squid species Martialia hyadesi Rochbrune and Mabille, 1889, obtained from regions of the Patagonian Shelf and Antarctic Polar Fron-tal Zone over 1000 km apart. M. hyadesi is an ecologically important South Atlantic ommastrephid squid and it is probable that, in the future, fishing effort will be increasingly directed towards this species. Details regarding the population structure of the species are therefore required. In comparison with the other three samples of M. hyadesi, one of the samples from the Patagonian Shelf (PAT 89II) exhibited fixed allelic differences at 16 of the 39 enzyme loci which were resolved (genetic identity, I=0.51). This high level of genetic differentiation contradicts the apparent morphological similarity between samples, indicating the presence of a cryptic or sibling congeneric species. Deviations from Hardy-Weinberg equilibrium and significant differences in allele distribution were also detected within and between the other three putative M. hyadesi samples, suggesting that the species fails to maintain effective panmixia across its geographical range. The occurrence of both temporal (1986 cf. 1989) and geographic structuring within the species complex is consequently indicated, caused possibly by an overlap of reproductively isolated stocks (stock mixing) outside their respective breeding areas. Low levels of genetic variability were detected throughout the samples examined, estimates of average heterozygosity per locus within the two species detected being in the order of 0.01 and 0.002. These values are discussed in relation to levels of genetic variability reported for other squid species, and in comparison with values typically expected for marine invertebrates.
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  • 4
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    Springer
    In:  Marine Biology, 115 (1). pp. 143-150.
    Publication Date: 2018-03-21
    Description: Lower and upper survival temperatures of microthalli of 25 species of South American Phaeophyceae isolated from central Peru (14°S) to the Canal Beagle (55°S) were determined using 2-wk exposure for the upper and 4-wk exposure for the lower limit. All species survive 4 wks at -2°C. With respect to the upper limit, species reported only from southernmost South America tolerate 19.9 to 24.5°C (n=8), and species occurring from Cape Horn to central Chile 24.6 to 27.4°C (n=7). Three species that occurred as far north as northern Chile and Peru before the 1982–1983 El Niño event, and whose northern limit was dramatically shifted southwards in 1983, tolerate 20.8 to 25.3°C, whereas five species that have survived in Peru tolerate 25.6 to 28.5°C. Tinocladia falklandica which tolerates 27.8 to 28.1°C but lives only in southernmost South America and Striaria attenuata, which tolerates 31.6 to 31.9°C but occurs at ca. 42°S, are exceptional. Their high temperature tolerance may have no adaptive value in South America. They are restricted to the cold-temperate region due to low temperature requirements for reproduction or for reasons yet unknown. In general, the northern distributional limits of the Phaeophyceae studied along the temperate Pacific coast of South America are reproduction boundaries, except in El Niño years when they are redefined according to the species' upper suvival limits. Temperature tolerance of isolates from northern Chile and Peru agrees well with maximum temperatures reached during the 1983 El Niño.
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  • 5
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    In:  Fresenius' Journal of Analytical Chemistry, 345 (12). pp. 773-779.
    Publication Date: 2018-03-23
    Description: During a cruise in the Baltic Sea in March/April 1991, dissolved lipids were concentrated from acidified sea water by adsorption on reversed phase material; the free fatty acids in the lipids were isolated. Titration of the acids with 0.01 mol/l methanolic KOH resulted in a very poor titration curve; assessing total concentration of organic acids in sea water by base titration appears to be impractical. After derivatization with p-phenylphenacyl bromide under crown ether catalysis the fatty acids were analyzed by micro-bore HPLC with UV-detection and comparison with standard reference substances. Some unknown fatty acids were characterized by GC/MS. Total concentrations were in the range from 1 to 4.5 nmol/l. They were the same in parallel samples liquid/liquid extracted with dichloromethane. The HPLC spectra of the fatty acids in both kinds of samples were also quite similar. This confirms earlier observations that adsorptive concentration of dissolved fatty acids and non-polar lipids from sea water is as effective as liquid/liquid extraction. Higher amounts of fatty acids can be concentrated by adsorption from large water volumes, thus lowering detection limits. Palmitic acid had by far the highest concentration in every sample followed by myristic acid, lauric acid, and stearic acid. Palmitoleic acid and oleic acid were the most abundant unsaturated acids. The other saturated and unsaturated acids had medium to low concentrations.
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  • 6
    Publication Date: 2018-03-21
    Description: Crossing studies revealed an intraspecifìc sterility barrier on the level of zygote formation between Japanese Sphaerotrichia divaricata and isolates of the same species from the Northeast Pacific and the North Atlantic. Because no consistent morphological differences exist between sporophytes from Japan and other areas, we propose not to distinguish the intersterile populations as different species. Japanese Sphaerotrichia and isolates from a recently detected population in the Étang de Thau, French Mediterranean coast, are interfertile. The crossing studies support the assumption that this Mediterranean population is a recent introduction from Japan.
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  • 7
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    In:  Polar Biology, 13 (5). pp. 355-357.
    Publication Date: 2020-06-10
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  • 8
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    In:  Polar Biology, 13 (6). pp. 373-376.
    Publication Date: 2020-06-10
    Description: Regurgitations were collected from 41 black-browed albatross adults feeding chicks at Bird Island (54°S 38°W), South Georgia in February 1986. The samples were sorted into recognisable food categories and weighed. Cephalopods were identified by means of the lower beak, or in some cases the gladius, and allometric equations were used to calculate mantle length and wet body weight represented by beaks. The samples contained 35.5%Euphausia superba, 30.9% cephalopods and 27.1% fish, by weight. A total of 21 samples contained recognisable cephalopod remains and 20 contained specimens that could be identified. In all, 50 cephalopod specimens, representing an estimated 6,866 g wet weight, were identified. The diet was dominated in terms of numbers, weight and percent occurrence by the ommastrephid squidMartialia hyadesi, and in most cases the entire squid was present with only partial digestion of the skin and arm armature. The cranchiid squidGaliteuthis glacialis was the only other cephalopod of numerical importance but no soft parts were present suggesting that, although significant in the diet of the adults, this species was not being fed to chicks. One specimen each ofGonatus antarcticus, Chiroteuthis sp.,Histioteuthis sp. B. and the octopodidPareledone polymorpha were also present. The cephalopod composition of the diet corresponded closely with a collection made 10 years earlier. The commonest species in the bird's diet,M. hyadesi, has not been found in net and jig samples at South Georgia although it has been taken from the Antarctic Polar Frontal Zone to the west of the Island. The presence of almost complete, undigested, specimens ofM. hyadesi in the bird's diet indicates that it occurs relatively close to South Georgia.M. hyadesi preys largely on myctophid fishes, which themselves prey on small zooplankters, so a significant component of the black-browed albatross diet depends on a food chain which largely by-passesE. superba.
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  • 9
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    In:  Marine Biology, 117 . pp. 495-500.
    Publication Date: 2017-04-28
    Description: The accumulation of parasites in a fish host is modelled as a function of the total amount of prey consumed. The accumulated parasite load is then expressed as a function of fish length so that the asymptotic growth, L∞, of any population of commonly infected fish can be estimated. Estimates of L∞ are obtained for orange roughy (Hoplostethus atlanticus), albacore tuna (Thunnus alalunga) and the New Zealand southern arrow squid (Nototodarus sloanii).
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  • 10
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    In:  In: Applied Micropalaeontology. , ed. by Jenkins, D. G. Springer, Dordrecht, pp. 69-91.
    Publication Date: 2017-08-03
    Description: This chapter records the benthonic foraminifera associated with a biogenic gas seep in the North Sea. A sample from an actively seeping site contains a benthonic foraminiferal assemblage statistically distinct from that of a control site. The distinctions are in terms of, firstly, abundance, diversity and dominance, secondly, taxonomic composition, and thirdly, proportions of epifaunal (surface-dwelling) and infaunal (sediment-dwelling) morphotypes.
    Type: Book chapter , NonPeerReviewed
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  • 11
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    In:  Boundary-Layer Meteorology, 65 (3). pp. 249-254.
    Publication Date: 2018-03-07
    Description: Turbulence in the Planetary Boundary Layer has been a topic of research for a long time. Its theory, however, is hampered by the fact that we have fewer fundamental equations than unknowns when dealing with turbulent motions. The search for additional “laws” to match the number of equations with the number of unknowns in turbulence theory is commonly labelled the turbulent closure problem. Despite considerable effort, this problem has not been solved. There is a variety of approaches available. However, these have not converged towards a commonly accepted PBL theory, like the Monin-Obukhov similarity for the surface layer. The Working Group on Boundary Layer Dynamics and Air-Sea interaction of ICDM/IAMAP therefore invites the scientific community to discuss these problems and possible solutions. The present paper intends to stimulate such a discussion.
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  • 12
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    In:  Hydrobiologia, 260/261 . pp. 263-267.
    Publication Date: 2018-03-07
    Description: The objective of the study was to produce a size-based matrix model of a Laminaria digitata (L.) Lamour. population. ‘Hard’ data for insertion in the matrix were collected in a 9 year cohort analysis of size and age specific survival and fertility for a stand in south west Nova Scotia, Canada. The product of the square matrix containing these values and a column vector containing the densities of size classes was used to project the size class structure one year later. The projected estimates were found to fit empirical estimates with some confidence. In contrast, an age-based fertility life table wrongly predicted a population declining in density by 45% per year. The study supports, in theory, the use of size-based matrix models for management of harvested stands. In reality, the amount of work required to obtain ‘hard’ data and the site specific nature of the projections may preclude the use of such an approach to broad scale management.
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  • 13
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    In:  Umweltwissenschaften und Schadstoff-Forschung, 5 (1). pp. 27-44.
    Publication Date: 2018-03-02
    Description: Die häufigsten vulkanischen Volatilen sind H2O, CO2, SO3 und Halogene. Zusammensetzung, Menge und Injektionsraten von vulkanischen Gasen und Partikeln in die Troposphäre und Stratosphäre hängen ab von der chemischen Zusammensetzung eines Magmas, dem plattentektonischen Milieu sowie Eruptionsmechanismen und Eruptionsraten. Über 90% der eruptierten Magmen sind basaltischer Zusammensetzung mit niedriger Viskosität, relativ geringen Volatilengehalten und meist niedrigen Eruptionsraten sowie wenig explosiven Eruptionen überwiegend entlang der mittelozeanischen Rücken in großen Wassertiefen. Magmen in Inselbögen und Subduktionszonen an Kontinenträndern sind H2O-reich, in anderen plattentektonischen Milieus überwiegt in basaltischen Magmen CO2. In mafischen Magmen ist CO2 schlecht löslich und kann daher schon mehrere Kilometer unter der Erdoberfläche als Gasphase aus einem Magma entweichen. Felsische (hochdifferenzierte) Magmen, H2O-reich und CO2-arm, eruptieren oft hochexplosiv, insbesondere an Subduktionszonen, und mit hohen Eruptionsraten, z.B. El Chichón (Mexiko, 1982) und Pinatubo (Philippinen, 1991). Ihre Eruptionssäulen (Gas-/Partikelgemische) können bis ca. 40 km Höhe erreichen und sind Hauptlieferant der in die Stratosphäre injizierten Gasmengen.
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  • 14
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    In:  Facies, 29 (1). pp. 133-148.
    Publication Date: 2016-04-15
    Description: In the subtropical belt highly productive ecosystems are formed by coral reefs in oligotrophic seas. Towards more eutrophic conditions, coral reefs diminish and are subsequently replaced by highly productive kelp forests. In high latitudes framework constructing carbonate production is enhanced by the growth of branching coralline algae which predominantly generate maerl-type deposits. On a global view, these coralline algal ecosystems show an island-like distribution pattern within the phaeophytic kelp belt. Compared to kelp ecosystems, coralline-algaldominated ecosystems have low rates of productivity. Therefore, it is reasonable to seek the pronounced competitive value of the extremely slow-growing corallines. Due to their low annual growth increment, the coralline algae studied are very endangered by abiotic physical disturbances and by overgrowth of rapidly growing filamentous algae or sessile invertebrates. To overcome fouling pressure and storm-triggered physical disturbances, coralline algae thrive well in wave-sheltered headlands or skerry areas and generate characteristic ‘denuded areas’ by intense herbivory. This general distributional pattern is also true for high-boreal to subarctic coralline algal bioherms in northern Norway. Such a complex biological feedback maintains a high potential of self-regulation or self-organization in the algal reef bioherms. The different proponents involved in feedback processes include bacterial colonization, diatom microfouling and selective induction of larval metamorphosis. The negative impact of diatom microfouling and the important role of herbivores are relevant activities in the feedback system on a microscopic scale. Macroscopically, intense herbivory on coralline algae create denuded conditions, which are a widespread phenomenon in coralline algal ecosystems.
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  • 15
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    In:  In: The South Atlantic: Present and Past Circulation. , ed. by Wefer, G., Berger, W. H., Siedler, G. and Webb, D. J. Springer, Berlin, Heidelberg, pp. 125-162.
    Publication Date: 2020-01-10
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  • 16
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    GEOMAR Forschungszentrum für marine Geowissenschaften
    In:  (PhD/ Doctoral thesis), Christian-Albrechts-Universität, Kiel, 127 pp . GEOMAR-Report, 019 . DOI 10.3289/GEOMAR_REP_19_1993 〈http://dx.doi.org/10.3289/GEOMAR_REP_19_1993〉.
    Publication Date: 2020-05-08
    Description: Based on the vector character the treatment of the three-dimensional seismic wavefield becomes complex. With the exploitation of converted wave-modes the acquisition of vectorwavefield data is effective, especially in the wide-angle range. Consequently shear waveacquisition with conventional sources, including marine sources, is possible and only multicomponent seismometers are required. Using this method wide-angle recordings of high quality were obtained within the BABEL-project (Baltic and Bothnian Echoes from the Lithosphere). However the processing of such vector-wavefield data raises the question of how to decompose the wavefield in its single modes. This thesis classifies the separation techniques, which have been presented in the literature, and shows a strong connection between polarization and separation of the seismic wavefield. Taking wide-angle data into particular consideration a discussion of these methods demonstrates the general applicability provided that equidistant traces are available. It is found out with the Controlled Orientation - a further developed method for the automatic reorientation of three-component recordings - that the alignment of refraction seismic data to the direction of the P-wave first arrival is not reliable because of the nearly vertical incidence. However it turns out, that the correction of the apparent angle of incidence need not be considered. With the processive realization of equidistant traces it is demonstrated that the amplitude character for the analysis of polarization is preserved. Therefore a multi-trace procedure can be implemented, which is in a position to process effectively long offset three-component data based on a two-dimensional operator window. This two-dimensional polarization-filter works data-adaptively for the determination of polarization parameters and is superior to the conventional method of Montalbetti and Kanasewich (1970). Three-component wide-angle data are used to illustrate the improvements obtained in noise reduction and in wave-mode separation using this technique .
    Type: Thesis , NonPeerReviewed
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  • 17
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    GEOMAR Forschungszentrum für marine Geowissenschaften
    In:  (PhD/ Doctoral thesis), Christian-Albrechts-Universität, Kiel, 111 pp . GEOMAR-Report, 022 . DOI 10.3289/GEOMAR_REP_22_1993 〈http://dx.doi.org/10.3289/GEOMAR_REP_22_1993〉.
    Publication Date: 2015-07-20
    Type: Thesis , NonPeerReviewed
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  • 18
    Publication Date: 2015-09-30
    Description: Paragenetic mineral assemblages have been established based on mineralogical, chemical, and isotope (S, Pb) studies, and the sequence of deposition has been defined in hydrothennal sulfide structures in a typical back-arc basin. The ores in the Manus basin have a prominent Zn specialization (sphalerite, würtzite, and fe-sphalerite). An association of Fe-spbalerite and galena with Ag sulfosalts is noted that is not characteristic of typical midocean ridge hydrothennal systems. The average 34S in the sulfide minerals is 3.5%o, which corresponds to the medium-temperature sphalerite stage in hydrothermal mineral fonnation. It is suggested that the metal source is located in the relatively acid rocks of the island-arc tholeiitic series and possibly in sediments.
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  • 19
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    GEOMAR Forschungszentrum für marine Geowissenschaften
    In:  GEOMAR-Report, 017 . GEOMAR Forschungszentrum für marine Geowissenschaften, Kiel, 111 pp.
    Publication Date: 2017-11-13
    Type: Report , NonPeerReviewed
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  • 20
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    GEOMAR Forschungszentrum für marine Geowissenschaften
    In:  (PhD/ Doctoral thesis), Christian-Albrechts-Universität, Kiel, 81 pp . GEOMAR-Report, 052 . DOI 10.3289/GEOMAR_REP_52_1996 〈http://dx.doi.org/10.3289/GEOMAR_REP_52_1996〉.
    Publication Date: 2017-06-27
    Type: Thesis , NonPeerReviewed
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  • 21
    Publication Date: 2019-01-22
    Description: Sediment samples from the Mid-Atlantic Reykjanes Ridge (59°N) were taken to get information about sediment genesis and to identify different sources during the late Quaternary. Samples were investigated by X-ray diffraction and grain-size analyses. The clay mineral assemblages in sediments of the Reykjanes Ridge reflect paleoceanographic changes during the late Quaternary. Holocene sediments are characterized by high contents of smectite, mainly of less developed crystallinity. In the spatial distribution of clay minerals high smectite concentrations on the eastern flank and slightly decreasing concentrations on the western flank of the Reykjanes Ridge indicate the action of bottom-water transport. The smectite originates mainly from the volcanogenous Icelandic shelf and reflects the influence of Iceland-Scotland Overflow Water (ISOW). Stratigraphic variability in the clay mineral composition reflects predominantly the influence of different sources, resulting from oceanographic and glacial transport processes. During glacial time sediment transport is due mainly to input by icebergs. Increasing amounts of illite, chlorite, and kaolinite characterize ice-rafted sediments of the “Heinrich layers”. In these sediments smectite crystallinity is well developed. In contrast, several other ice-rafted layers contain smectite with low crystallographic order, similar to smectites of Holocene age. The icelandic source was proved by distinct amounts of basaltic glass in the coarse-grained sediment. At approximately 55 ka increasing amounts of chlorite and kaolinite suggest an enhanced influx of warm North Atlantic surface waters. This hypothesis is supported by a high carbonate shell production at this time. Relative low concentrations and the well-developed crystallinity of smectite minerals characterize the Last Glacial Maximum (LGM; 18–16 ka), indicating a reduced supply of fine icelandic material. Shortly after the LGM, at the beginning of termination IA, a distinct increase in fine-grained quartz (〈2µm) and smectite are visible, which are proposed to reflect a supply of fine-grained ice-rafted material. At 13 ka linear increasing smectite concentrations of lower crystallographic order indicate increasing supply of fine-grained material from Iceland, linked to reinitiation of bottom currents of the ISOW. Full reinitiation is indicated at around 10 ka, where a strong increase in smectite of low crystallographic order is detected.
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  • 22
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    GEOMAR Forschungszentrum für marine Geowissenschaften
    In:  (PhD/ Doctoral thesis), Christian-Albrechts-Universität, Kiel, 112 pp . GEOMAR-Report, 021 . DOI 10.3289/GEOMAR_REP_21_1993 〈http://dx.doi.org/10.3289/GEOMAR_REP_21_1993〉.
    Publication Date: 2015-07-20
    Type: Thesis , NonPeerReviewed
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  • 23
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    GEOMAR Forschungszentrum für marine Geowissenschaften
    In:  (PhD/ Doctoral thesis), Christian-Albrechts-Universität, Kiel, 148 pp . GEOMAR-Report, 053 . DOI 10.3289/GEOMAR_REP_53_1996 〈http://dx.doi.org/10.3289/GEOMAR_REP_53_1996〉.
    Publication Date: 2015-07-20
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  • 24
    Publication Date: 2016-01-28
    Description: The Platanar volcanic center is dominated by a calc-alkaline, basalt-andesite-dacite-rhyolite magma series with unusual LREE enrichment. Adjacent and overlapping the calc-alkaline rocks are the most alkaline basalts found along the volcanic front of Central America. These basalts are mafic, LIL- and LREE-enriched transitional to alkaline basalts. Several are found on the north flank of Platanar in the Aguas Zarcas region, where there are nine cinder cones and a few isolated flows. However, they are also found in isolated lava outcrops at least as far south as Porvenir volcano along the volcanic front. The addition of mafic alkaline magmas with high La/Yb and low Ba/La into the Platanar magma chamber or chambers may contribute to the LREE-enriched character of the Platanar basaltic andesites and andesites. At Platanar the field and geochemical evidence suggest mixing between calc-alkaline and alkaline magmas, a process that has probably occurred throughout the development of the Cordillera Central of Costa Rica. The presence of negative Ce anomalies in several of the calc-alkaline lavas also make the Platanar complex very unusual compared to the rest of the Central American volcanic front. In the center of the Platanar complex is the Chocosuela caldera, an apparent remnant of an avalanche caldera created by the collapse in the Middle Pleistocene of an ancestral stratovolcano toward the NNW in a directed blast-type eruption. Rhyolite is present as pumice lapilli in pyroclastic flow deposits outside the caldera rim. Whole lapilli analyses span the daciterhyolite range. The previous eruption of high silica tephra as pyroclastic flows, the current long dormant period and the repeated occurrence of earthquake swarms on the flanks of the Platanar complex make it a candidate for volcanic hazard mapping, detailed geological mapping and emergency planning.
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  • 25
    Publication Date: 2017-05-22
    Description: Seismic profiles from a venting area on the western margin of Paramushir Island (Sea of Okhotsk) reveal a local complex structure and an interesting, unusual pattern of the bottom simulating reflector (BSR). The BSR is gradual rising towards the venting area. The geothermal gradient and the bottom temperature confirmed the methane hydrate. The temperature appears to be the most important factor controlling the hydrate stability. A locally higher heat flow caused the upward migration of the hydrate stability field and the subsequent degradation of the hydrated sediments, causing gas vent formation and the flux of methane gas into the water column.
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  • 26
    Publication Date: 2016-09-21
    Description: Picritic units of the Miocene shield volcanics on Gran Canaria, Canary Islands, contain olivine and clinopyroxene phenocrysts with abundant primary melt, crystal and fluid inclusions. Composition and crystallization conditions of primary magmas in equilibrium with olivine Fo90-92 were inferred from high-temperature microthermometric quench experiments, low-temperature microthermometry of fluid inclusions and simulation of the reverse path of olivine fractional crystallization based on major element composition of melt inclusions. Primary magmas parental for the Miocene shield basalts range from transitional to alkaline picrites (14.7–19.3 wt% MgO, 43.2–45.7 wt% SiO2). Crystallization of these primary magmas is believed to have occurred over the temperature range 1490–1150° C at pressures ≈5 kbar producing olivine of Fo80.6-90.2, high-Ti chrome spinel [Mg/ (Mg+Fe2+)=0.32–0.56, Cr/(Cr+Al)=0.50–0.78, 2.52–8.58 wt% TiO2], and clinopyroxene [Mg/(Mg+Fe)=0.79–0.88, Wo44.1-45.3, En43.9-48.0, Fs6.8-11.0] which appeared on the liquidus together with olivine≈Fo86. Redox conditions evolved from intermediate between the QFM and WM buffers to late-stage conditions of NNO+1 to NNO+2. The primary magmas crystallized in the presence of an essentially pure CO2 fluid. The primary magmas originated at pressures 〉30 kbar and temperatures of 1500–1600° C, assuming equilibrium with mantle peridotite. This implies melting of the mantle source at a depth of ≈100 km within the garnet stability field followed by migration of melts into magma reservoirs located at the boundary between the upper mantle and lower crust. The temperatures and pressures of primary magma generation suggest that the Canarian plume originated in the lower mantle at depth ≈900 km that supports the plume concept of origin of the Canary Islands.
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  • 27
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    In:  Geologische Rundschau, 85 (3). pp. 409-437.
    Publication Date: 2019-01-22
    Description: Tectonics and climate are both directly and indirectly related. The direct connection is between uplift, atmospheric circulation, and the hydrologic cycle. The indirect links are via subduction, volcanism, the introduction of gasses into the atmosphere, and through erosion and consumption of atmospheric gases by chemical weathering. Rifting of continental blocks involves broad upwarping followed by subsidence of a central valley and uplift of marginal shoulders. The result is an evolving regional climate which has been repeated many times in the Phanerozoic: first a vapor-trapping arch, followed by a rift valley with fresh-water lakes, culminating in an arid rift bordered by mountains intercepting incoming precipitation. Convergence tectonics affects climate on a larger scale. A mountain range is a barrier to atmospheric circulation, especially if perpendicular to the circulation. It also traps water vapor converting latent to sensible heat. Broad uplift results in a shorter path for both incoming and outgoing radiation resulting in seasonal climate extremes with reversals of atmospheric pressure and enhanced monsoonal circulation. Volcanism affects climate by introducing ash and aerosols into the atmosphere, but unless these are injected into the stratosphere, they have little effect. Stratospheric injection is most likely to occur at high latitudes, where the thickness of the troposphere is minimal. Volcanoes introduce CO2, a greenhouse gas, into the atmosphere. Geochemical effects of tectonic uplift and unroofing relate to the weathering of silicate rocks, the means by which CO2 is removed from the atmosphere-ocean system on long-term time scales.
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  • 28
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    In:  In: The South Atlantic: Present and Past Circulation. , ed. by Wefer, G., Berger, W. H., Siedler, G. and Webb, D. J. Springer, Berlin, Heidelberg, pp. 261-271. ISBN 3-540-62079-6
    Publication Date: 2020-04-02
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  • 29
    Publication Date: 2020-07-30
    Description: High-resolution records of the natural radionuclide230Th were measured in sediments from the eastern Atlantic sector of the Antarctic circumpolar current to obtain a detailed reconstruction of the sedimentation history of this key area for global climate change during the late Quaternary. High-resolution dating rests on the assumption that the230Thex flux to the sediments is constant. Short periods of drastically increased sediment accumulation rates (up to a factor of 8) were determined in the sediments of the Antarctic zone during the climate optima at the beginning of the Holocene and the isotope stage 5e. By comparing expected and measured accumulation rate of230Thex, lateral sediment redistribution was quantified and vertical particle rain rates originating from the surface water above were calculated. We show that lateral contributions locally were up to 6.5 times higher than the vertical particle rain rates. At other locations only 15% of the expected vertical particle rain rate were deposited.
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  • 30
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    In:  In: The South Atlantic: Present and Past Circulation. , ed. by Wefer, G., Berger, W. H., Siedler, G. and Webb, D. J. Springer, Berlin, Heidelberg, pp. 105-120. ISBN 3-540-62079-6
    Publication Date: 2020-04-03
    Description: Hydrographic data along 11°S occupied in 1983 by the R.V. OCEANUS are used together with various wind climatologies to estimate the annual average transport of heat at this latitude. Some motivation for expecting fairly well-defined estimates at this latitude compared to others comes from the absence of a strong western boundary current. Results include flow in four layers representing the thermocline, Antarctic Intermediate Water, North Atlantic Deep Water, and Antarctic Bottom Water, using zero velocity reference level choices based on property distributions. The annual average heat transport is estimated to be 0.6 ± 0.17 x 1015 W. Previous estimates of the transport at 8–16°S range from 0.2 PW to greater than 1 PW. Interannual variability from the wind field alone leads to interannual heat transport variability of about 0.05 PW. Comparisons with other recent studies at 45–30°S and 11°N are made.
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  • 31
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    In:  In: The South Atlantic: Present and Past Circulation. , ed. by Wefer, G., Berger, W. H., Siedler, G. and Webb, D. J. Springer, Berlin, Germany, pp. 83-104. ISBN 3-540-62079-6
    Publication Date: 2019-09-03
    Description: The data from six zonal sections in the World Ocean Circulation Experiment (WOCE) in the tropical and southem Atlantic are used to describe the distribution of water masses. Due to the high spatial resolution, the structure oftemperature, salinity, oxygen, silicate and nitrate displays details related to transport and mixing in this region. Temperature-salinity diagrams are also presented which indicate the effects ofbranching and recirculation loops in the water mass flow.
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  • 32
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    In:  Boundary-Layer Meteorology, 78 . pp. 247-290.
    Publication Date: 2016-09-06
    Description: During the past quarter century the study of air-sea interaction has evolved from a small branch of marine climatology to play a key role in the modelling of the coupled system of ocean and atmosphere. Knowledge of air- sea fluxes has grown, based on Monin-Obukhov similarity theory for surface boundary layers and on direct and indirect techniques of measuring the fluxes. This has been the basis for providing boundary conditions needed to couple atmospheric and oceanic circulation models that are used to forecast weather and climate. An overview of current understanding is followed by a discussion of parameterisation schemes and a chronicle of some of the experimental work that has tested theories and quantified their conclusions.
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  • 33
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    In:  Applied Physics B, 57 (2). pp. 109-112.
    Publication Date: 2020-04-14
    Description: Here we describe experiments aimed at developing an element-selective ion source for thorium (Th). The technique applied is resonance ionization spectroscopy (RIS) with a thermal atom beam. Ionization schemes for isotopically nonselective ionization of Th as well as for isotopically selective ionization of 230Th are proposed. The RIS-scheme used is two-photon two-colour ionization with excitation in the ultraviolet spectral range between 244 nm and 267 nm or in the visible spectral range between 485 nm and 529 nm. Ionization of the excited atoms is performed either by ultraviolet photons or by visible photons, depending on the energy required for this process.
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  • 34
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    In:  In: The South Atlantic: Present and Past Circulation. , ed. by Wefer, G., Berger, W. H., Siedler, G. and Webb, D. J. Springer, Berlin, Germany, pp. 355-361.
    Publication Date: 2013-01-15
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  • 35
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    In:  In: The South Atlantic: Present and Past Circulation. , ed. by Wefer, G., Berger, W. H., Siedler, G. and Webb, D. J. Springer, Berlin, Germany, pp. 249-260.
    Publication Date: 2019-09-12
    Description: The Deep Basin Experiment (DBE), a part of the World Ocean Circulation Experiment (WOCE), is presently underway in the Brazil Basin of the South Atlantic. The program objectives and design philosophy are reviewed and early results are presented. Observations from a moored array along the southern boundary and neutrally buoyant float trajectories in the North Atlantic Deep Water and Antarctic Bottom Water are described with emphasis on their relationship to the recent flow schemes offered by Reid (1989). Also discussed are the process of cross isotherm mixing within the intense flow regime of the Verna Channel and observations of long period warming of the bottom water.
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  • 36
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    In:  Naturwissenschaften, 83 (7). pp. 293-301.
    Publication Date: 2017-03-07
    Description: This is a selected account of recent developments in plankton ecology. The examples have been chosen for their degree of innovation during the past two decades and for their general ecological importance. They range from plankton autecology over interactions between populations to community ecology. The autecology of plankton is represented by the hydromechanics of plankton (the problem of life in a viscous environment) and by the nutritional ecology of phyto- and zooplankton. Population level studies are represented by competition, herbivory (grazing), and zooplankton responses to predation. Community ecology is represented by the debate about bottom- up vs. top-down control of community organization, by the PEG model of seasonal plankton succession, and by the recent discovery of the microbial food web.
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  • 37
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    In:  Naturwissenschaften, 83 (3). pp. 127-129.
    Publication Date: 2017-03-07
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  • 38
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    In:  In: Decadal Climate Variability: Dynamics and Predictability. , ed. by Anderson, D. L. T. and Willebrand, J. NATO ASI Series I: Global Environmental Change, 44 . Springer, Berlin, Germany, pp. 263-292, 43 pp. ISBN 3-540-61459-1
    Publication Date: 2019-08-08
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  • 39
    Publication Date: 2018-03-21
    Description: U-series ages measured by thermal ionisation mass spectrometry (TIMS) are reported for a Last Interglacial (LI) fossil coral core from the Turtle Bay, Houtman Abrolhos islands, western Australia. The core is 33.4 m long the top of which is approximately 5 m a.p.s.l. (above present sea level). From the232Th concentrations and the reliability of the U-series ages, two sections in the core can be distinguished. Calculated U/Th ages in core section I (3.3 m a.p.s.l to 11 m b.p.s.l) vary between 124±1.7 ka BP (3.3 m a.p.s.l.) and 132.5±1.8 ka (4 m b.p.s.l., i.e. below present sea level), and those of section II (11–23 m b.p.s.l.) between 140±3 and 214±5 ka BP, respectively. The ages of core section I are in almost perfect chronological order, whereas for section II no clear age-depth relationship of the samples can be recognised. Further assessments based on the ϖ234U(T) criteria reveal that none of the samples of core section II give reliable ages, whereas for core section I several samples can be considered to be moderately reliable within 2 ka. The data of the Turtle Bay core complement and extend our previous work from the Houtman Abrolhos showing that the sea level reached a height of approximately 4 m b.p.s.l at approximately 134 ka BP and a sea level highstand of at least 3.3 m a.p.s.l. at approximately 124 ka BP. Sea level dropped below its present position at approximately 116 ka BP. Although the new data are in general accord with the Milankovitch theory of climate change, a detailed comparison reveals considerable differences between the Holocene and LI sea level rise as monitored relative to the Houtman Abrolhos islands. These observation apparently add further evidence to the growing set of data that the LI sea level rise started earlier than recognised by SPECMAP chronology. A reconciliation of these contradictionary observations following the line of arguments presented by Crowley (1994) are discussed with respect to the Milankovitch theory.
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  • 40
    Publication Date: 2018-03-21
    Description: The spatial distribution and species composition of high-Antarctic ichthyonekton was investigated during the EPOS 3 cruise by RV Polarstern in the eastern Weddell Sea during January–February 1989. A multiple rectangular midwater trawl was used to collect samples from the surface to near the sea floor at 11 stations along a 245 kra transect off Halley Bay. Early larval stages of 18 species, representing about 24% of the known Weddell Sea ichthyofauna, were present in the water column. The Antarctic silver-fish, Pleuragramma antarcticum, over-whelmingly dominated the catches comprising 84.5% of the 5022 specimens caught. The abundance of this species markedly increased towards the offshore end of the transect with the highest numbers occurring near the shelf-break front associated with the westerly current of the southern limb of the Weddell Gyre. The increased abundance of P. antarcticum in continental slope waters was attributed to deflection of the East Weddell Coastal Current beyond the shelf/slope break by fringing ice shelves. Most larval and juvenile fish were found in the seasonally warmed upper 0–70 m layer of the Antarctic Surface Water where conditions occurred that appeared to be favourable to both feeding and growth. Cluster analysis indicated that inner-, central-and outer-shelf assemblages were represented and that the species composition was most effectively described by reference to water mass and depth.
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  • 41
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    In:  Springer, Berlin, Germany, 644 pp. ISBN 3-540-62079-6
    Publication Date: 2020-03-25
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  • 42
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    GEOMAR Forschungszentrum für marine Geowissenschaften
    In:  (PhD/ Doctoral thesis), Christian-Albrechts-Universität, Kiel, 121 pp . GEOMAR-Report, 074 . DOI 10.3289/geomar_rep_74_1999 〈http://dx.doi.org/10.3289/geomar_rep_74_1999〉.
    Publication Date: 2017-11-13
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  • 43
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    GEOMAR Forschungszentrum für marine Geowissenschaften
    In:  (PhD/ Doctoral thesis), Christian-Albrechts-Universität, Kiel, 125 pp . GEOMAR-Report, 065 . DOI 10.3289/geomar_rep_65_1997 〈http://dx.doi.org/10.3289/geomar_rep_65_1997〉.
    Publication Date: 2015-01-21
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  • 44
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    GEOMAR Forschungszentrum für marine Geowissenschaften
    In:  (PhD/ Doctoral thesis), Christian-Albrechts-Universität, Kiel, 177 pp . GEOMAR-Report, 067 . DOI 10.3289/geomar_rep_67_1998 〈http://dx.doi.org/10.3289/geomar_rep_67_1998〉.
    Publication Date: 2015-01-21
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  • 45
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    GEOMAR Forschungszentrum für marine Geowissenschaften
    In:  GEOMAR-Report, 023 . GEOMAR Forschungszentrum für marine Geowissenschaften, Kiel, 66 pp.
    Publication Date: 2015-02-11
    Type: Report , NonPeerReviewed
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  • 46
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    GEOMAR Forschungszentrum für marine Geowissenschaften
    In:  (PhD/ Doctoral thesis), Christian-Albrechts-Universität, Kiel, 174 pp . GEOMAR-Report, 066 . DOI 10.3289/geomar_rep_66_1997 〈http://dx.doi.org/10.3289/geomar_rep_66_1997〉.
    Publication Date: 2015-01-21
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  • 47
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    In:  Coral Reefs, 12 (1). pp. 1-17.
    Publication Date: 2019-03-06
    Description: Coral reef bleaching, the whitening of diverse invertebrate taxa, results from the loss of symbiotic zooxanthellae and/or a reduction in photosynthetic pigment concentrations in zooxanthellae residing within the gastrodermal tissues of host animals. Of particular concern are the consequences of bleaching of large numbers of reef-building scleractinian corals and hydrocorals. Published records of coral reef bleaching events from 1870 to the present suggest that the frequency (60 major events from 1979 to 1990), scale (co-occurrence in many coral reef regions and often over the bathymetric depth range of corals) and severity (〉95% mortality in some areas) of recent bleaching disturbances are unprecedented in the scientific literature. The causes of small scale, isolated bleaching events can often be explained by particular stressors (e.g., temperature, salinity, light, sedimentation, aerial exposure and pollutants), but attempts to explain large scale bleaching events in terms of possible global change (e.g., greenhouse warming, increased UV radiation flux, deteriorating ecosystem health, or some combination of the above) have not been convincing. Attempts to relate the severity and extent of large scale coral reef bleaching events to particular causes have been hampered by a lack of (a) standardized methods to assess bleaching and (b) continuous, long-term data bases of environmental conditions over the periods of interest. An effort must be made to understand the impact of bleaching on the remainder of the reef community and the long-term effects on competition, predation, symbioses, bioerosion and substrate condition, all factors that can influence coral recruitment and reef recovery. If projected rates of sea warming are realized by mid to late AD 2000, i.e. a 2°C increase in high latitude coral seas, the upper thermal tolerance limits of many reef-building corals could be exceeded. Present evidence suggests that many corals would be unable to adapt physiologically or genetically to such marked and rapid temperature increases.
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  • 48
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    In:  In: Monitoring and mitigation of volcano hazards. , ed. by Scarpa, R. and Tilling, R. I. Springer, Berlin, pp. 221-256. ISBN 3-540-60713-7
    Publication Date: 2019-02-11
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  • 49
    Publication Date: 2020-11-06
    Description: The systematics of the genus Sepia is not yet clear. Morphological evidence has led to S. officinalis Linnaeus, 1758 being considered as belonging to the subgenus Sepia sensu stricto, and S. obignyana Férusac, 1826 and S. elegans Blainville, 1827 as belonging to the subgenus Rhombosepion. Samples of 30 individuals ocenographic boundary off the north-west Iberian Peninsula, and a sample of S. elegans from the northern side, were collected in 1993-1994. Allozyme electrophoresis for 32 presumptive loci revealed low levels of genetic variability for the three Sepia species (mean expected heterozygosity estimates were 〈0.052). No significant differences in allozyme frequencies were detected among populations of either S. officinalis and S. orbignyana (I=0.12) and of S. elegans (I=0.13) were significantly different from that of S. orbignyana and S. elegans (I=0.49). The former are typical of values for confamiliar genera, and a new generic status is proposed for the latter two species, which become Rhombosepion orbignyana (Férussac, 1826) and R. elegans (Blainville, 1827).
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  • 50
    Publication Date: 2021-04-15
    Description: To investigate the role of sea ice cover on penguin populations we used principal component analysis to compare population variables of Adélie (Pygoscelis adeliae) and chinstrap (Pygoscelis antarctica) penguins breeding on Signy Island, South Orkney Islands with local (from direct observations) and regional (from remote sensing data) sea ice variables. Throughout the study period, the Adélie penguin population size remained stable, whereas that of chinstrap penguins decreased slightly. For neither species were there significant relationships between population size and breeding success, except for an apparent inverse density-dependent relationship between the number of Adélie breeding pairs and the number of eggs hatching. For both species, no general relationship was found between either population size or breeding success and the local sea ice conditions. However, the regional sea ice extent at a particular time prior to the start of the breeding season was related to the number of birds that arrived to breed. For both species, this period occurred before the sea ice reached its maximum extent and was slightly earlier for Adélie than for chinstrap penguins. These results suggest that sea ice conditions outside the breeding season may play an important role in penguin population processes.
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  • 51
    Publication Date: 2016-05-26
    Description: Major outer membrane proteins with porin activity were isolated from cell envelopes of the halophilic strains Ectothiorhodospira shaposhnikovii N1 and Ectothiorhodospira vacuolataβ1. The porins were obtained as oligomers. They dissociated into monomers by heat or EDTA treatment. The molecular masses of the monomers were determined by mass spectrometry to be 39,285 and 37,160 Da for E. shaposhnikovii N1 and E. vacuolataβ1, respectively. Both were shown by analytical ultracentrifugation to be trimers of about 112,000 Da. Circular dichroism spectra indicated predominantly β-sheet structure. The 18 N-terminal amino acid sequences of the two porins were identical except for the amino acids in positions 12 and 14. No sequence similarity with the primary structure of known porins was found. In reconstitution experiments with lipid bilayers, the porins of E. shaposhnikovii N1 and E. vacuolataβ1 formed channels with a single-channel conductance of 1.5 and 0.7 nS, respectively, in 1 M KCl. The single-channel conductance saturated with increasing salt concentration, indicating a putative binding-site for anions in the channel since both porins exhibited anion-selectivity. For the porin of E. vacuolataβ1, but not for that of E. shaposhnikovii N1, an influence of detergent concentration on the single-channel conductance was observed.
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  • 52
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    In:  In: The South Atlantic: Present and Past Circulation. , ed. by Wefer, G., Berger, W. H., Siedler, G. and Webb, D. J. Springer, Berlin, Heidelberg, New York, pp. 239-247.
    Publication Date: 2020-04-03
    Description: Direct measurements of magnitude of the northward flow of the Malvinas (Falkland) Current have recently been made with two types of Lagrangian platforms: ALACE floats which cycled between 750-m depth and the sea surface, and 100-m drogued surface drifters. Each data set clearly delineates the path of the Malvinas Current, and the vertical shears inferred from them are commensurate with historical geostrophic shears. Velocities from the surface drifters are used here to adjust geostrophic shears from historical measurements, and the results confirm a large transport of the current, as previously implied by numerical models and a regional inverse calculation. At 42°S, the northward transport of the Malvinas Current in the upper 3000 m appears to be about 70 Sv, several times larger than estimates obtained by adjusting geostrophic shears to assumed levels of no motion. This large barotropie component may have significance in the cross-frontal transfer of intermediate and deep waters from the circumpolar current to the adjacent flow regimes in the South Atlantic, and thus on the inter-basin exchange of water masses.
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  • 53
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    In:  In: Carbon Cycling in the glacial ocean: Constraints on the Ocean's Role in Global Change. , ed. by Zahn, R. Springer, Heidelberg, Germany, pp. 87-104.
    Publication Date: 2020-04-14
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  • 54
    Publication Date: 2016-09-21
    Description: Mohns Ridge lavas between 71 and 72°30′N (∼360 km) have heterogeneous compositions varying between alkali basalts and incompatible-element-depleted tholeiites. On a large scale there is a continuity of incompatible element and isotopic compositions between the alkali basalts from the island Jan Mayen and Mohns Ridge tholeiites. The variation in isotopes suggests a heterogeneous mantle which appears to be tapped preferentially by low degree melts (∼5%) close to Jan Mayen but also shows its signature much further north on Mohns Ridge. Three lava types with different incompatible element compositions [e.g. chondrite-normalized (La/Sm)N〈1 to 〉2] occur in the area at 72°N and were generated from this heterogeneous mantle. The relatively depleted tholeiitic melts were mixed with a small degree melt from an enriched source. The elements Ba, Rb and K of the enriched melt were probably buffered in the mantle by residual amphibole or phlogopite. That such a residual phase is stable in this region of oceanic mantle suggests both high water contents and low mantle temperatures, at odds with a hotspot origin for Jan Mayen. Instead we suggest that the melting may be induced by the lowered solidus temperature of a “wet” mantle. Mohns MORB (mid ocean ridge basalt) and Jan Mayen area alkali basalts have high contents of Ba and Rb compared to other incompatible elements (e.g. Ba/La 〉10). These ratios reflect the signature of the mantle source. Ratios of Ce/Pb and Rb/Cs are normal MORB mantle ratios of 25 and 80, respectively, thus the enrichments of Ba and Rb are not indicative of a sedimentary component added to the mantle source but were probably generated by the influence of a metasomatizing fluid, as supported by the presence of hydrous phases during the petrogenesis of the alkali basalts. Geophysical and petrological models suggest that Jan Mayen is not the product of hotspot activity above a mantle plume, and suggest instead that it owes its existence to the unique juxtaposition of a continental fragment, a fracture zone and a spreading axis in this part of the North Atlantic.
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  • 55
    Publication Date: 2020-11-16
    Description: The fish component in the diet of Antarctic fur seals, Arctocelaphus gazella, was investigated at Laurie Island, South Orkney Islands from mid January to April 1988. Fish otoliths occured in 78.8% of faecal droppings. Most of the otoliths extracted from scats belonged to Myctophid fish (93.4%), mainly Electrona antarcitca and Gymnoscopelus nicholsi. These two fish species thus constituted the bulk of the diet. A greater percentage of the otoliths from G. nicholsi (31.1%) in this study were considered suitable for measurement in comparison with 10.3% from scats at Heard island in 1990 and 11.4% atMacquarie Island in 1988/98. This lesser degree of erosion would suggest that foraging areas of fur seals during this study were closer to land than during previous studies. During the period studied, the commercial fishery around the South Orkneys was not based on Myctophid fish so there was no direct competition for fish between the fur seals and fisheries.
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  • 56
    Publication Date: 2020-11-16
    Description: In February 1992, 34 faecal samples from non-breeding male Antarctic fur seals, Arctophalus gazella, were collected at Stranger Point, King George Island, South Shetlands. Fish constituted an important part of the diet, occuring in 90% of those scats containing prey remains. From 1162 otoliths found in the Myctophids and nototheniids represented together almost 90% of the fish eaten. The dominant species were Gymnoscopelus nicholsi, Pleuragramma antarcticum and Electrona antarctica, contributing 33.3%, 30.8% and 12.0% of the otoliths respectively. The standard length of these three species was estimated from otoliths with little or no signs of erosion. This study showed that fur seals fed mainly on pelagic fish species that are often associated with krill. These findings are corroborated by fur seal diving patterns.
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  • 57
    Publication Date: 2020-11-16
    Description: The diet of lactating female Antarctic fur seals Arctocephalus gazella at South Georgia was investigated during the pup-rearing period (January/March) of 1991-1994. Antarctic krill Euphausia superba was the main prey item, occuring in 88% of all scats (n=497), whereas fish occured in 47% and squid in 5% of all scats. There was a considerable intra- and inter-annual variation in the characteristics of krill taken by fur seals. The distribution of krill sizes takes suggests that fur seals are not actively selecting particular sizes of krill available around South Georgia. The absence of group 3 krill (44-48mm in length) in the South Georgia area, as indicated by their absence in the diet of seals, is suggested as a possible reason for low availability of krill and the subsequent reproductive failure among krill predators. The frequency of occurence of fish was much higher than in previous studies; the pattern of fish consumption showed a consistent seasonal pattern in 3 of the 4 years studied. Of the total number of the myctophid Protomyctophum choriodon, the most numerous fish taxon, 98% were taken between early February and the middle of March. Champsocephalus gunnari and Lepidonothen larseni agg., which both feed on krill, dominated the fish component of diet outsided this period and together constituted 94% of the total estimated biomass of fish consumed. The intra- and inter-annual variability in the diet of Antarctic fur seals emphasise the need for diet studies to be conducted during the entire pup-rearing periods of several years.
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  • 58
    Publication Date: 2020-11-19
    Description: The diet of king penguins, Aptendonytes patagonicus, rearing chicks was studied during three consecutive austral winters (1990, 1991 and 1992) at Crozet Islands. The mean stomach content mass of the 47 samples was 503g. Percentages of wet and reconstituted masses showed that both fishes (66 and 36% respectively) and squid (34 and 64%) are important components of the winter diet. Juveniles of the demersal onychoteuthid squid Moroteuthis ingens from the bulk of the cephalopod diet, and this was the main species of mycophids eaten in summer by king penguins were either very rare in winter (Electrona carlsbergi) or accounted for a smaller proportion of the diet (Krefftichthys anderssoni = 1.5% by mass and Protomyctophum tenisoni = 4.6%). Five other myctophids, which are rarely consumed in summer, contributed 24% of the diet by mass in winter (Gymnoscopelus piabilis = 18.1%, Lampichthys procerus = 2.4%, G. nicholsi = 1.3%, and Metelectrona ventralis and Electrona subaspera = 1.0%). The greater diversity of prey in winter suggests a more opportunistic feefing behaviour at a time probably marked by a change in prey availability. Both the known ecology of the fish and squid prey and the barely digested state of some items suggest that in winter breeding adults forage in the outer shelf, upper slope and oceanic areas in the close vicinity of the Crozet Islands to feed their chicks. Finally, using kind penguins as biological samplers, the present work provides novel data on the previously unstudied mesopelagic/epibenthic marine community in waters surrounding the Crozet Islands. Seventeen myctophid fish have been identified to species level. These include several poorly known species in the southern Indian Ocean. The occurence of small, nearly intact, cephalopods in the diet of king penguins suggests that spwaning grounds of four squid species may be located near the Crozet Islands. Seventeen myctophid fish have been identified to species level. These include several poorly known species in the southern Indian Ocean. The occurence of small, nearly intact, cephalopods in the diet of king penguins suggest that spawning ground for four squid species may be located near the Crozet Archipelago.
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  • 59
    Publication Date: 2020-11-09
    Description: Confusion abounds regarding the relative generic status of many member species of the squid family Loliginidae. A taxonomic reorganisation within the family has been proposed in which Loligo species from the Indo-Pacific possessing photophores on the ink sac, including Loligo edulis and Loligo chinensis, are removed to the newly created genus Photololigo. This system of classification has not however gauined general acceptance, and some authors have continued to refer to these species as Loligo. Here biochemical genetic data gathererd using allozyme electrophoresis are presented supporting the assertion that L. edulis and L. chinensis should indeed be positioned in a genus distinct from that characterised by the type species Loligo vulgaris vulgaris. Cluster analysis of allele frequency data from 22 putative enzyme-coding loci suggests that L. edulis and L. vulgaris vulgaris as are members of the confamilial genera Alloteuthis, Uroteuthis and Sepioteuthis, and as such warrant separate generic status. We conclude that the genus Photololigo is valid.
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  • 60
    Publication Date: 2020-11-06
    Description: Paralarval behaviour of eight species of the family Gonatidae (Teuthodiea, Cephalopoda) was examined in small 3-1 aquaria on board ship during planktonic surveys, which were carried out above and off the continental slope of the western part of the Bering Sea. Undisturbed paralarvae moved in aquaria with an average frequency of 15-20 mantle contractions per minute. In response to a sudden disturbance (flash of light, impact to the aquarium wall) squids exhibited a defensive body posture, relaxing the mantle and pulling the head with tentacles and arms into the mantle cavity, thereby becoming similar in appearance, size and colour to small jellyfishes Aglantha digitalis (Hydromedusae)
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  • 61
    Publication Date: 2020-11-09
    Description: Beak length analysis was undertaken for the arrow squid Nototodarus sloanii in the New Zealand sector of the Southern Ocean between Stewart Island and the Auckland Islands. N. sloanii has a restricted range and is endemic to the waters around New Zealand and its associated southern islands, where it supports a fishery and is preyed upon by a number of fishes, marine mammals and birds. Lower rostral length (LRL) and upper rostral length (URL) were analysed to see how these beak measurements related to both mantle lentgh (ML) and wet weight (W). Both lower and upper rostral lengths could be used as useful predictors of ML and W in N. sloanii, as relationships had limited scatter and high correlation coefficients. The relationships between LRL and ML, and URL and ML were only linear after regressing log-transformed values of beak length against ML. However, the relationships between LRL and W, and URL and W were linear without transforming either the x or y values. These results are different from previously published beak length analysis of Nototodarus in New Zealand waters.
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  • 62
    facet.materialart.
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    In:  Springer, Berlin, Germany, 192 pp. ISBN 3-540-60307-7
    Publication Date: 2012-02-28
    Type: Book , NonPeerReviewed
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  • 63
    Publication Date: 2017-01-30
    Description: This paper concludes a collection of contributions presented at the 8th Workshop of the International Association of Phytoplankton Taxonomy and Ecology. It derives a consensus as to the virtues and strengths of J. H. Connells Intermediate Disturbance Hypothesis (IDH), its applicability to phytoplank- ton ecology and its theoretical and practical weaknesses. The view is expressed that the IDH is too useful a concept to reject and that, as a word model, it provides a powerful link between diversity and dis- turbance. The more robust investigations that are necessary to consolidate the tenancy of IDH need to concentrate upon the separation and quantification of the stimulus- and response-components of dis- turbance.
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  • 64
    Publication Date: 2017-01-30
    Description: Phytoplankton diversity was studied in two North German lakes of comparable nutrient chemistry but different exposure to winds. In both lakes, phytoplankton was primarily N-limited but diatoms were Si-limited. Plußsee had a very constant mixing depth during summer, while week-to-week changes of several meters were quite common in the more exposed Behler See. In Plußsee, phytoplankton biomass during summer came closer to the carrying capacity as defined by the available total N. In Plußsee there was a marked decline of diversity during the summer maximum of biomass, while this decline was less pronounced in Behler See. It is concluded that disturbances which prevented phytoplankton from reaching the carrying capacity also maintained a high level of diversity. A negative response of diversity to undisturbed conditions became apparent, after phytoplankton biomass had exceeded about 5% of the carrying capacity.
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  • 65
    facet.materialart.
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    Springer
    In:  Oecologia, 93 (2). pp. 276-284.
    Publication Date: 2017-10-09
    Description: In Lake Constance, after several decades of cutrophication, a decrease in phosphorus loading over the last decade has lead to a partial recovery from eutrophication. Here we analyse the shift in the taxonomic composition of phytoplankton during the first decade of oligotrophication in Lake Constance. During the 1980s, spring total P concentrations decreased from ca. 130 to less than 50 mgr·l–1. This decrease was reflected by an approximately proportional decrease in summer phytoplankton biomass while spring phytoplankton biomass seemed unresponsive. Major taxonomic changes occured during both growth seasons. In spring, the proportion of diatoms, green algae and Chrysophyta increased while the proportion of Cryptophyta decreased. The summer trend was very different: the relative importance of diatoms decreased and Cryptophyta and Chrysophyta increased, while Chlorophyta reached their peak around 1985. These trends are also analysed at the genus level. Comparison with taxonomic trends during the eutrophication period shows the expected reversals in most cases. Comparison with other lakes shows general similarities, with the notable exception that Planktothrix rubescens has never been important in Lake Constance. The increase of diatoms during spring is attributed to their improved competitive performance with increasing Si:P ratios. Their decrease during summer is explained by the increasing silicate removal from the epilimnion by increasing spring populations.
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  • 66
    Publication Date: 2017-01-30
    Description: This paper introduces a collection of contributions presented at the 8th Workshop of the International Association of Phytoplankton Taxonomy and Ecology. It compares the substance of with what to limnologists is the more familiar lsquoparadox of the planktonrsquo posed by G. E. Hutchinson. The utility of Connell's Intermediate Disturbance Hypothesis in plankton ecology is, potentially, more instructive but inherent difficulties in relating response to stimulus have to be overcome. A copy of the brief distributed to contributors before the workshop is appended.
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  • 67
    Publication Date: 2018-03-21
    Description: Thorium- and uranium isotopes were measured in a diagenetic manganese nodule from the Peru basin applying alpha- and thermal ionization mass spectrometry (TIMS). Alpha-counting of 62 samples was carried out with a depth resolution of 0.4 mm to gain a high-resolution230Thexcess profile. In addition, 17 samples were measured with TIMS to obtain precise isotope concentrations and isotope ratios. We got values of 0.06–0.59 ppb (230Th), 0.43–1.40 ppm (232Th), 0.09–0.49 ppb (234U) and 1.66–8.24 ppm (238U). The uranium activity ratio in the uppermost samples (1–6 mm) and in two further sections in the nodule at 12.5±1.0 mm and 27.3–33.5 mm comes close to the present ocean water value of 1.144±0.004. In two other sections of the nodule, this ratio is significantly higher, probably reflecting incorporation of diagenetic uranium. The upper 25 mm section of the Mn nodule shows a relatively smooth exponential decrease in the230Thexcess concentration (TIMS). The slope of the best fit yields a growth rate of 110 mm/Ma up to 24.5 mm depth. The section from 25 to 30.3 mm depth shows constant230Thexcess concentrations probably due to growth rates even faster than those in the top section of the nodule. From 33 to 50 mm depth, the growth rate is approximately 60 mm/Ma. Two layers in the nodule with distinct laminations (11–15 and 28–33 mm depth) probably formed during the transition from isotopic stage 8 to 7 and in stage 5e, respectively. The Mn/Fe ratio shows higher values during interglacials 5 and 7, and lower ones during glacials 4 and 6. A comparison of our data with data from adjacent sediment cores suggests (a) a variable supply of hydrothermal Mn to sediments and Mn nodules of the Peru basin or (b) suboxic conditions at the water sediment interface during periods with lower Mn/Fe ratios.
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  • 68
    Publication Date: 2022-03-07
    Description: Despite extensive discussions during the last 20 years stromatolites are still used by many geologists as unequivocal indicators of very shallow-water conditions. We investigated four stratigraphic units from the Lower and Middle Jurassic of southern Germany (Posidonien-Schiefer, Amaltheen-Ton) and of the Northern Calcareous Alps (Adneter Kalk, Klauskalk), which were formerly interpreted as shallow marine sediments by some authors due to the occurrence of stromatolites. Our interpretations of the macro-, micro- and ultrafacies of these sediments are not compatible with shallow-water settings. We therefore propose a deep-marine, aphotic origin of these stromatolites. Former interpretations of the Posidonien-Schiefer as a shallow-water deposit are mainly based on the occurrence of stromatolites. We favour the model of a temporarily stagnant, deep, aphotic basin for these planktonrich sediments. Particles resembling ooids, but lying within mudstones cannot be taken as evidence for shallow agitated water. They either formed within the mud or are allochthonous. The deep-water setting of the red limestone of the Alpine Early and Middle Jurassic is indicated by a lack of platform-typical components like coated grains and phototrophic benthos and by shells of plankton and nekton forming a major part of the sediment. Stromatolites occur on the steep slope of a drowned Rhaetian reef with an estimated relief of 50–100 m and immediately below and within radiolarian limestones, deposited below the aragonite compensation depth (ACD). The aphotic stromatolites show some morphological differences to their shallow water counterparts. In all of our sections they occurred during intervals of reduced sedimentation. They form only thin horizons and probably grew very slowly. Mineralizations by Fe−Mn oxides and phosphate are very common. The presence of a microbial film is evident from binding of sedimentary particles, but the nature of the microbes is not known. Growth habits within the very distinct environments of red limestone and black shales show some common features, but also clear differences. The microproblematicum Frutexites Maslov is a very common component in deep-water stromatolites, but may also itself form small crusts or dendrolites. It occurs in two different forms. Opaque, slender forms with indistinct outlines probably grew within the weakly lithified sediment. Thicker, transparent forms with well defined outlines are found in cavities and probably also grew on the seafloor. Well preserved specimens display an internal fabric of radially arranged fibres of Fe−Mn oxides and calcite. It is suggested that calcite or aragonite were one original mineralogy ofFrutexites, which was later replaced by Fe−Mn oxides or phosphate. It is not certain whether Frutexites is an organic, biomineralized structure or an inorganic mineralization, but the variable mineralogy and growth forms in different environments point to an organic origin. But even if organic, the occurrence in cryptic habitats and negative phototactic growth-directions make it clear that Frutexites was not phototrophic
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  • 69
    facet.materialart.
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    Springer
    In:  Modeling the Possible Impact of Climate Change on Broad-Scale Vegetation Structure - Examples from Northern Europe | Global Change and Arctic Terrestrial Ecosystems
    Publication Date: 2022-03-21
    Type: info:eu-repo/semantics/bookPart
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  • 70
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    Springer
    In:  Psychologische und gesellschaftliche Dimensionen globaler KlimaverSnderungen | Internationaler Naturschutz
    Publication Date: 2022-03-21
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  • 71
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    Publication Date: 2022-03-21
    Description: Klimawirkungsforschung untersucht die Auswirkungen von Klimaänderungen hinsichtlich ökologischer und zivilisatorischer Effekte auf den Menschen und seine Umwelt durch Erarbeitung von Handlungsstrategien. Dieser Statusbericht vermittelt einen Einblick ins Treibhaus aus verschiedenen Blickwinkeln: auf den globalen und regionalen Wandel, als Blick zurück in das geologische Archiv sowie auf die Klimaauswirkungen, auf die Hydro-Morphodynamik und Küstensicherheit, auf die Flora und Fauna, auf Ökosysteme und Stoffkreisläufe sowie auf sozio-ökonomischer Ebene am Beispiel der südlichen Nord- und Ostsee. Küsteningenieure, Geographen und Raumplaner, Geologen, Biologen, Klima-, Sozial- und Wirtschaftsforscher sowie Verantwortliche in den Küstenverwaltungen erhalten einen bisher nicht verfügbaren Überblick über die Zusammenhänge des globalen Wandels an diesem konkreten Raumbeispiel.
    Type: info:eu-repo/semantics/book
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  • 72
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    In:  Klimawirkungsforschung: Mögliche Folgen des Klimawandels für Europa | Klimapolitik - Naturwissenschaftliche Grundlagen internationale Regimebildung und Konflikte, ökonomi
    Publication Date: 2022-03-21
    Type: info:eu-repo/semantics/bookPart
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