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  • Other Sources  (65)
  • Springer  (65)
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  • 1995-1999  (36)
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  • 1996  (36)
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  • 1
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    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
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    In:  Marine Biology, 121 (2). pp. 267-272.
    Publication Date: 2020-07-14
    Description: Four research surveys of Falkland Island waters were carried out to determine the distribution and abundance of the early life-history stages of Loligo gahi (d'Orbigny, 1835) in the austral winter of 1988 and the austral springs of 1990, 1991 and 1992. Juveniles were caught during three of the four surveys in both Bongo nets and an RMT8 net. In each case, greatest numbers were consistently caught in waters of ≤100 m to the south and east of East Falkland. The use of an opening/closing net in 1992 showed that most L. gahi juveniles aggregate close to the sea floor and are more available to the sampling gear by night than by day. Limited temperature data for the 1991 and 1992 surveys suggest that distribution on the coastal shelf may be associated with water-column structure. In 1992 when temperature data implied a mixed water column, juveniles were caught in deeper water than in 1991 when the water column was stratified. The results suggest that the spawning grounds of L. gahi are probably situated to the south and east of the Falkland Islands, at least for squid hatched in the austral winter/spring.
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  • 4
    Publication Date: 2020-06-10
    Description: A total of 40 (29 female and 11 male) Ross seals were sampled in January over three years. Seals were weighed, measured and age determined by counting dentine lines in teeth. Stomach contents were identified against reference material and species of helminths were determined using standard techniques. Asymptotes in body mass and length are reached at some nine years of age. Age class varied from 2–20 years. Antarctic silverfish Pleurogrammma antarcticum was the only fish species identified. Psychroteuthis glacialis dominated the squid component. Fish was dominant in three samples, squid was the exclusive component in two samples and a minor component in another two. Glandicephalus antarcticus, Diphyllobothrium wilsoni and Contracaecum spp were the dominant helminths present. The high proportion of empty or nearly empty stomachs conforms with the knowledge that this species moults and consequently fasts in January.
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  • 5
    Publication Date: 2020-07-14
    Description: Geographic variation in the squid Loligo forbesi was investigated using multivariate analysis of morphometric and meristic characters in samples of squid taken from 13 localities in the Northeast Atlantic Ocean. Two character sets, body morphometrics and beak morphometrics, indicated similar patterns of variation, with squid from the Azores differing markedly from those on the continental shelf. No consistent pattern was apparent in meristic data. Partial Mantel tests indicated that similarity matrices for morphological data were significantly correlated with distance matrices for (a) geographic proximity, (b) whether the capture site was on the continental shelf or the Azorean bank, and (c) (beak data only) average seasurface temperature at site of capture. Partial Mantel tests on allozyme data for the same individuals support hypothesis (b). The results suggest that L. forbesi in the Azores may reasonably be regarded as a distinct stock, differing significantly from L. forbesi on the continental shelf.
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  • 6
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    In:  Marine Biology, 119 (3). pp. 413-421.
    Publication Date: 2020-07-14
    Description: Abralia trigonura is a small squid that is an important member of the mesopelagic boundary community around Hawaii. Squids were aged by examining statolith growth increments, and various reproductive parameters were measured. Female longevity is ∼6 mo, and they become sexually mature at ∼3.5 mo. Male longevity is the same, but they become sexually mature at ∼2.5 mo. This species appears to be a multiple spawner, and peculiarities in the number of eggs found in the oviducts suggests that they spawn every few days. Possible advantages of this reproductive mode are examined.
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  • 7
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    In:  Marine Biology, 120 (2). pp. 171-180.
    Publication Date: 2017-08-03
    Description: The home range system of the coelacanth Latimeria chalumnae was investigated along 11 km coastline at Grande Comore, Western Indian Ocean, between 1987 and 1991. 67 individuals were identified on individual white dot patterns. The home range consisted of daytime caves where fish aggregated in groups of up to 14 individuals while at night individuals moved singly downwards to a depth of 250 to 300 m in search of food. Site fidelity of at least 5 yr was found. The coelacanths used several caves within their home ranges. Cave size, cave occupation rate, average and maximum group size and cave preferences were studied. Tracking experiments with ultrasonic transmitters revealed horizontal home ranges of at least 8 km width. Population estimates of 200 to 230 individuals at Grande Comore confirm earlier counts. Large home ranges and highly mobility in a topographically narrow habitat apparently favoured inbreeding of the small local island population.
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  • 8
    Publication Date: 2019-09-23
    Description: Eleven fish species from the Weddell Sea (Antarctic) were examined for infestation with anisakid nematodes. Two species of the genus Contracaecum and the sealworm Pseudoterranova decipiens were isolated from the liver and the body cavity of fish affected. Only two specimens of P. decipiens (1.4%) partly invaded the belly flaps. The following fish species were infested by P. decipiens at the given prevalences: Cygnodraco mawsoni (74.4%), Trematomus scotti (23.2%), Pagetopsis maculatus (10.0%), Cryodraco antarcticus (7.1%), Trematomus lepidorhinus (3.0%), and Dolloidraco longedorsalis (2.7%). All of these, except Trematomus scotti, are new host records. Chaenodraco wilsoni, Chionodraco myersi, Gerlachea australis, Racovitzia glacialis and T. eulepidotus were not infested. The reasons for low prevalence and intensity of infestation are seen in the difficulties of P. decipiens in completing its benthic life cycle in the Weddell Sea environment, in the absence of shallow coastal waters due to the floating shelf-ice. Cygnodraco mawsoni is a crucial intermediate host, without which completion of the parasite life cycle might not be possible. In order to clarify the taxonomical position of Antarctic Pseudoterranova, morphological comparisons with specimens of P. decipiens from the German and Norwegian coast were made using scanning electron microscopy. Results revealed no differences; hence, all specimens studied belong to the same species P. decipiens.
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  • 9
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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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  • 10
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    In:  In: Carbon cycling in the glacial ocean: Constraints in the ocean's role in global change. , ed. by Zahn, R., Pederson, T. F., Kannish, M. A. and Labeyrie, L. NATO ASI Series, 1 (17). Springer, Berlin, Germany, pp. 87-104. ISBN ISBN 0-387-57594-4
    Publication Date: 2020-04-14
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  • 11
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    In:  In: Understanding the North Sea System. Springer, Heidelberg, Germany, pp. 97-113. ISBN 978-94-010-4540-7
    Publication Date: 2015-10-07
    Description: Coupling of physical, biological and chemical processes associated with particle resuspension and seston flux was investigated at three sites in the North Sea with contrasting water column (mixed/stratified) and seabed (cohesive/non-cohesive) characteristics.
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  • 12
    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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  • 13
    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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  • 14
    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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  • 15
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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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  • 16
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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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  • 17
    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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  • 18
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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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  • 19
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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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  • 20
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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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  • 21
    Publication Date: 2018-06-06
    Description: RNA/DNA ratios in individual herring (Clupea harengus) larvae (collected from Kiel Bay, Baltic Sea, in 1989) were measured and proved suitable for determining nutritional status. Significant differences between fed and starving larvae appeared after 3 to 4 d of food deprivation in larvae older than 10 d after hatching. The RNA/DNA ratio showed an increase with age or length of the larvae and was less pronounced in starving larvae compared to fed larvae. The individual variability of RNA/DNA ratios in relation to larval length of fed larvae and of larvae deprived of food for intervals of 6 to 9 d is presented. Based on the length dependency and the individual variability found within the RNA/DNA ratios, a laboratory calibration is given to determine whether a larva caught in the field has been starving or not. An example for a field application is shown.
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  • 22
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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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  • 23
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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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  • 24
    Publication Date: 2016-09-08
    Description: A hierarchy of ENSO (El Niño/Southern Oscillation) prediction schemes has been developed which includes statistical schemes and physical models. The statistical models are, in general, based on advanced statistical techniques and can be classified into models which use either low-frequency variations in the atmosphere (sea level pressure or surface wind) or upper ocean heat content as predictors. The physical models consist of coupled ocean-atmosphere models of varying degrees of complexity, ranging from simplified coupled models of the lsquoshallow waterrsquo-type to coupled general circulation models. All models, statistical and physical, perform considerably better than the persistence forecast on predicting typical indices of ENSO on lead times of 6 to 12 months. The most successful prediction schemes, the fully physical coupled ocean-atmosphere models, show significant prediction abilities at lead times exceeding one year period. We therefore conclude that ENSO is predictable at least one year in advance. However, all of this applies to gross indices of ENSO such as the Southern Oscillation Index. Despite the demonstrated predictability, little is known about the predictability of specific features known to be associated with ENSO (e.g. Indian Monsoon rainfall, Southern African drought, or even off-equatorial sea surface temperature). Nor has the relative importance for prediction of different regional anomalies or different physical processes yet been established. A seasonal dependence in predictability is well established, but the processes responsible for it are not fully understood.
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  • 25
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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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  • 26
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    In:  Naturwissenschaften, 83 (3). pp. 127-129.
    Publication Date: 2017-03-07
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  • 27
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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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  • 28
    Publication Date: 2018-01-24
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  • 29
    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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  • 30
    Publication Date: 2016-06-22
    Description: The Cenozoic margins of the Norwegian-Greenland Sea offer ideal conditions for passive margin studies. A series of structural elements, first observed on these margins, led to the concept of volcanic passive margins. Questions still remain about the development of such features and the location of the boundary between oceanic and continental crust. Despite the thin sediment cover of the margins, seismic reflection data are not able to image the deeper structures due to the occurrence of igneous rocks at shallow depth. This paper presents a 320-km long profile perpendicular to the strike of the main structural units of the Lofoten Margin in Northern Norway. A geological model is proposed, based on observations made with ocean bottom seismographs, which recorded seismic refraction data and wide angle reflections, along with a seismic reflection profile covering the same area. Ray-tracing was used to calculate a geophysical model from the shelf area into the Lofoten basin. The structures typical of a volcanic passive margin were found, showing that the Lofoten Margin was influenced by increased volcanic activity during its evolution. The ocean/continent transition is located in a 30-km wide zone landwards of the Vøring Plateau escarpment. The whole margin is underlain by a possibly underplated, high velocity layer. Evidence for a pre-rift sediment basin landwards of the escarpment, overlain by basalt flows, was seen. These structural features, related to extensive volcanism on the Lofoten Margin, are not as distinct as further south along the Norwegian Margin. Viewed in the light of the hot-spot theory of White and McKenzie (1989) the Lofoten Margin can be interpreted as a transitional type between volcanic and non-volcanic passive margin.
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  • 31
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    In:  Climate Dynamics, 10 (6-7). pp. 267-276.
    Publication Date: 2016-09-08
    Description: Based on a combined data set of sea surface temperature, zonal surface wind stress and upper ocean heat content the dynamics of the El Niño phenomenon is investigated. In a reduced phase space spanned by the first four EOFs two different stochastic models are estimated from the data. A nonlinear model represented by a simulated neural network is compared with a linear model obtained with the principal oscillation pattern (POP) analysis. While the linear model is limited to damped oscillations onto a fix point attractor, the nonlinear model recovers a limit cycle attractor. This indicates that the real system is located above the bifurcation point in parameter space supporting self-sustained oscillations. The results are discussed with respect to consistency with current theory.
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  • 32
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    In:  Springer, Berlin, Germany, 644 pp. ISBN 3-540-62079-6
    Publication Date: 2020-03-25
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  • 33
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    In:  Polar Biology, 14 (3). pp. 205-210.
    Publication Date: 2020-10-05
    Description: Energy requirements of resting Adélie (Pygoscelis adeliae), Gentoo (P. papua) and Chinstrap (P. antarcticd) penguin chicks were determined with respect to body mass via respirometry in Antarctica. Resting metabolic rates of all Pygoscelid penguin chicks were similar (ANOVA p=0.91) and best described by E=0.0096 M0.98 (n=24, r2=0.97), where E is power (W) and M is mass (g). Using the results obtained here and data published in the literature, I determined a) the amount of food needed from hatching to fledging as 29.8, 31.7 and 56.4 kg per chick for Adélie, Chinstrap and Gentoo penguins, respectively and b) the average amount of food left daily to the parent after feeding the brood throughout the breeding period. Parents keep only a minimum of food for themselves just prior to the time when chicks begin forming crèches. Thereafter, nest relief intervals are increased, and the amount of food parents can keep for themselves rises. The results of both models are discussed with respect to available data on Pygoscelid penguin food requirements.
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  • 34
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    In:  Hydrobiologia, 292-293 (1). pp. 271-282.
    Publication Date: 2019-03-15
    Description: Multiple opening-closing nets of 0.05 mm mesh size were employed to study the community structure and vertical distribution of microcopepods at selected stations in the Red Sea, Arabian Sea and Eastern Mediterranean Sea down to a maximum depth of 1850 m. Calanoids, cyclopoids (Oithona and Paroithona) and poecilostomatoids (mainly Oncaea) were the 3 most abundant orders. In the epipelagic zone (0–100 m), these orders occurred at similar abundance levels, whereas in the meso- and bathypelagic zones the poecilostomatoid genus Oncaea dominated numerically by about 60–80% of all copepodids. The species diversity of Oncaea in the Red Sea is compared with preliminary results from the two adjacent regions. In the deep Eastern Mediterranean Sea, the number of species appears to be similar to that in the deep Red Sea and low as compared to the deep Arabian Sea. In this latter area an extremely speciose Oncaea fauna was found at depth below the oxygen-minimum-zone (900–1850 m). The results are related to the differences in the hydrographic conditions of these 3 areas.
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  • 35
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    In:  Boundary-Layer Meteorology, 69 (3). pp. 335-339.
    Publication Date: 2019-03-14
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  • 36
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    In:  Marine Biology, 118 (3). pp. 353-357.
    Publication Date: 2019-03-15
    Description: Many researchers use external recording or transmitting devices to elucidate the marine ecology of fish, mammals and birds. Deleterious effects of these instruments on the parameters researchers wish to measure are hardly ever discussed in the literature. Research has shown that, in penguins, volume and cross-sectional area of instruments negatively correlate with swimming speed. dive depth and breeding success, and that device colour affects bird behaviour. Here, a large (200 g, cross-sectional area 2100 mm2) streamlined device was attached to the lower back of Adélie penguins (Pygoscelis adeliae on Ardley Island, South Shetland Island in 1992) and its effects on bird swimming speed and energetics were measured in a water canal in Antarctica. Although the device was 10.5% of penguin cross-sectional area, swimming speed was reduced by only 8.3% and mean power input increased by only 5.6% while swimming. Although our streamlined device was five times more voluminous than one of our older units, the effect on swimming energetics could be reduced by 87%.
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  • 37
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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., Pedersen, T. F., Kaminski, M. A. and Labeyrie, L. NATO ASI Series I: Global Environmental Change, 17 . Springer, Berlin, pp. 367-382.
    Publication Date: 2019-06-24
    Description: We reconstructed past variations in CO2 partial pressure (local PCO2) in the surface waters of the East Atlantic equatorial upwelling zone over the last 330,000 years, based on the δ13C record of the (marine) organic matter in ‘Meteor’ core 16772. To deduce the initial δ13Corganic values of plankton and the CO2 solubility in surface water, the δ13C record was adjusted for i) past variations in (winter) sea surface temperature, ii) variations in the δ13C composition of inorganic carbon dissolved in the surface waters, using the δ13C values of G. ruber (white), and iii) isotopic fractionation during the degradation of settling organic matter in the water column and on the sediment surface. The calculated paleo-PCO2 variations in the surface waters show a strong signal at the obliquity frequency and are approximately parallel to the VOSTOK ice-core record of atmospheric PCO2 over the last 140,000 years. Holocene PCO2 values varied within the range of modern local PCO2, which is 350–400 ppmv compared to a pre-industrial atmospheric pCO2 level of 280 ppmv. This positive anomaly demonstrates the persistent CO2 release from upwelled subsurface water. The glacial-to-interglacial amplitudes of local PCO2 (at the core site) exceeded those of atmospheric pCO2 by 20–60%, with values of less than 250 to 300 ppmv during cold isotopic stages, which indicate a decreased net carbon outgassing from the ocean to the atmosphere. The close correlation between high paleo-PCO2 and low paleo-nutrient contents and paleoproductivity (r=0.7–0.8) suggests that the local PCO2 variations resulted mainly from CO2 transfer by phytoplankton production, especially over the last 170,000 years.
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  • 38
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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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  • 39
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    In:  Marine Geophysical Researches, 16 (4). pp. 287-301.
    Publication Date: 2019-06-28
    Description: Vesteris Seamount is a solitary submarine volcano located at 73-degrees-30' N, 9-degrees-10' W in the Greenland Basin. Steeply rising from a base depth of 3100 m to a minimum depth of approximately 130 m and striking 030-degrees/210-degrees, the feature lies approximately 300 km east of the east Greenland margin on an otherwise nearly flat and featureless seafloor. The main body of the seamount appears to have been formed episodically, the last of which culminated about 110 000 years ago. Subsequent, lower intensity volcanic activity continued sporadically until about 25 000 years ago, as evidenced by ash layers found in cores near the base of the feature. The smoothed surfaces at the summit make it likely that the seamount actually broached the surface during the Weichselian glacial period, between 8000 and 13 000 years ago. Two multibeam bathymetric investigations aboard PFS Polarstern during ARKTIS II/4 (1984) and ARKTIS VII/1 (1990), combined with geologic sampling. single-channel seismic profiling and underwater television coverage, have resulted in a new interpretation of both the morphology and origins of the seamount. Data collected aboard Polarstern from ARKTIS II/4 (1984) have been previously reported by Hempel et al. (1991), however, when combined with the ARKTIS VII/1 (1990) data set, a more detailed interpretation of the morphology and structure was feasible. This included the elongated shape of the feature and showed the existence of several small volcanic cones on the seamount flanks.
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  • 40
    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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  • 41
    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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  • 42
    Publication Date: 2019-09-23
    Description: Standing stock and size composition of the zooplankton comunity (〉100 μm) were studied in four depth strata of the upper 200 m of the water column during a “Meteor” cruise to the central Red Sea and Gulf of Aden in spring 1987. The central Red Sea was divided into a northern area of higher salinity and a less saline southern part. Both areas exhibited significant differences in zooplankton abundance and standing stock. The latter increased by the ratio 1:2:3 from the northern central Red Sea to its southern part and further south to the Gulf of Aden. For size structure analysis samples were fractionated into three size classes (100 to 300, 300 to 500, 500 to 5000 μm). In the central Red Sea the smallest size was dominant whereas in the Gulf of Aden the largest size fraction played a greater relative role than in the central Red Sea. This shift in size structure of the zooplankton community from the Red Sea to the Gulf of Aden is apparently primarily related to ecosystem difference between both areas, leading to a change in species composition. In addition, size reduction of individual species common to both seas may be of some significance in the extreme environment of the Red Sea.
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  • 43
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    In:  In: Global Precipitations and Climate Change. , ed. by Desbois, M. and Desalmand, F. NATO ASI Series, 26 . Springer, Berlin, Germany, pp. 249-264. ISBN 978-3-642-79270-0
    Publication Date: 2019-09-23
    Description: The application of microwave radiometry for rainfall estimation is discussed. The first part presents a description of processes by which hydrometeors affect microwave radiation. In order to show the state-of-art of rainfall estimation with space-borne microwave radiometry five algorithms are intercompared in the second part. Two are based on scattering, one on emission and two are mixed algorithms, which include both emission and scattering. The algorithms are applied to SSM/I observations over the Atlantic Ocean. The retrieved rainfall rates by the different algorithms partly differ a great deal. The differences depend on climatic regions, demonstrating that the algorithms are probably tuned to certain atmospheric conditions. The question arises whether a globally applicable algorithm is possible at all. A severe problem is the validation of the retrieved precipitation because hardly any direct observations are available. Thus an intercomparison of algorithms is today the only way to understand the behaviour of a scheme in different weather and climate situations and assess its results.
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  • 44
    Publication Date: 2018-08-14
    Description: In March/April 1991 hydrographic parameters (salinity, temperature) and hydrochemical parameters (concentrations of phosphate, nitrate, nitrite, ammonia, silicate and pH) were measured continuously in the surface water of the Baltic Sea and the North Sea. The hydrographic parameters were determined by means of a TS,pH probe and the chemical parameters were determined by means of an Auto Analyser. The cruise track through the Baltic Proper, the western Baltic Sea, the transition area to the North Sea and the North Sea with the mouth of the river Elbe was around 2050 nautical miles long and included some 2100 data-points. The different phases of the Baltic Sea's spring diatom bloom were inferred from the different nutrient concentrations measured; a comparison with the hydrographic data revealed that the bloom was largely unconnected to the hydrography. The same situation was encountered in the North Sea except that the spring bloom there had already reached a later phase. In those regions of the Baltic Sea where a plankton bloom had already occurred or was still under way, strong patchiness of the hydrochemical parameters was also observed; it was sometimes possible to relate it to the topography. This patchiness was far less pronounced in the North Sea and in regions of the Baltic Sea where conditions were still wintry. This paper discusses the advantages and possible applications of the method of continuous measurement of hydrochemical parameters across large areas with high temporal and spatial resolution.
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  • 45
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    In:  Meteorology and Atmospheric Physics, 54 (1-4). pp. 157-171.
    Publication Date: 2018-08-17
    Description: A method is presented to infer cloud liquid water path (LWP in kg/m2) over the ocean from passive microwave measurements of SSM/I. The algorithm to retrieve LWP is based on simulated satellite observations. They are calculated with a radiative transfer model applied to about 3000 radiosonde ascents over the Atlantic Ocean. Since radiosonde observations do not contain direct information about cloud water and ice, these parameters are parameterized based on relative humidity and temperature using modified adiabatic liquid water density profiles. A multiple linear regression is applied to the simulated radiances and the calculated LWP to derive the algorithm. The retrieval accuracy based on the regression analysis including instrumental noise is 0.03 kg/m2. Validation of the LWP-algorithm was pursued through a comparison with measurements of a ground-based 33 GHzmicrowave radiometer on board of R.V. “Poseidon” during the International Cirrus Experiment 1989 at the North Sea (ICE'89). The LWP values agree within the range of uncertainty caused by the different sampling characteristics of the observing systems. The retrieval accuracy for clear-sky cases determined using colocated METEOSAT data over the North Sea is 0.037 kg/m2 and confirms the accuracy estimated from regression analysis for the low liquid water cases. The algorithm was used to derive maps of monthly mean LWP over the Atlantic Ocean. As an example the Octobers of the 5 years 1987–1991 were selected to demonstrate the interannual variability of LWP. The results were compared with the cloud water content produced by the climate model ECHAM-T2 from the Max-Planck-Institut Hamburg. Observations during ICE'89 were used to check the accuracy of the applied radiative transfer model. Brightness temperatures were calculated from radiosonde ascents launched during the overpass of DMSP-F8 in cloud-free situations. The channel-dependent differences range from about −2 to 3 K. The possibility to identify different cloud types using microwave and infrared observations was examined. The main conclusion is that simultaneous microwave and infrared measurements enable the separation of dense cirrus and cirrus with underlying water clouds. A classification of clouds with respect to their top heights and LWP was carried out using a combination of SSM/I derived LWP and simultaneously recorded Meteosat IR-data during ICE'89.
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  • 46
    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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  • 47
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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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  • 48
    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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  • 49
    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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  • 50
    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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  • 51
    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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  • 52
    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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  • 53
    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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  • 54
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    In:  Oceanology, 34 (3). pp. 373-379.
    Publication Date: 2020-11-19
    Description: Some species of wide-spread tropical squids and pelgic octopuses (Histioteuthis hoylei, Alloposus mollis and others), based on beak findings in sperm whale stomachs, were common in the 1950s and early 1960s and widely distributed along the Kuril' Islands, eastern Kamchatka, in the Bering Sea, near the Aleutian Islands and the Gulf of Alaska, but later they were never recorded north of northwastern Honshu or southeast of the southern Kuril's. In 1990-1992 the squid Watasenia scintillans extended north to the middle Kuril's and, in smaller quantities, to the northern Kuril's while H. hoylei extended to the western Bering Sea. In the summer of 1992, Ancistrocheirus lesueurii, Mastigoteuthis dentata?, Eledonella pygmaea, and Allopsus mollis were also caught off the Shikotan, Kunashir, and Iturup Islands. A. lesueurii and E. pygmaea were caught in the Russian EEZ for the first time. We discuss why the warm-water species appear in the Russian Far Eastern seas again, after a long period of absence.
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  • 55
    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.
    Type: Article , PeerReviewed
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  • 56
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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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  • 57
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    In:  Springer, Berlin, Germany, 274 pp. ISBN 3-540-57676-2
    Publication Date: 2012-02-28
    Type: Book , NonPeerReviewed
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  • 58
    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.
    Type: Article , PeerReviewed
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  • 59
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    Springer
    In:  Characteristic Multifractal Element Distributions in Recent Bioactive Marine Sediments | Fractals and Dynamic Systems in Geoscience
    Publication Date: 2022-03-21
    Type: info:eu-repo/semantics/bookPart
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  • 60
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    Springer
    In:  From No-Man's Land to a Congested Paradise: An Environmental History of Mauritius | Population-Development-Environment: Understanding their Interactions in Mauritius
    Publication Date: 2022-03-21
    Type: info:eu-repo/semantics/bookPart
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  • 61
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    In:  Modeling the Water Systems | Population-Development-Environment: Understanding their Interactions in Mauritius
    Publication Date: 2022-03-21
    Type: info:eu-repo/semantics/bookPart
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  • 62
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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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  • 63
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    In:  Population-Development-Environment: Understanding their Interactions in Mauritius
    Publication Date: 2022-03-21
    Type: info:eu-repo/semantics/book
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  • 64
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    Springer
    In:  Psychologische und gesellschaftliche Dimensionen globaler KlimaverSnderungen | Internationaler Naturschutz
    Publication Date: 2022-03-21
    Type: info:eu-repo/semantics/bookPart
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  • 65
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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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