ALBERT

All Library Books, journals and Electronic Records Telegrafenberg

Your email was sent successfully. Check your inbox.

An error occurred while sending the email. Please try again.

Proceed reservation?

Export
  • 1
    facet.materialart.
    Unknown
    Springer
    In:  Bull., Polar Proj. OP-O3A4, Handbuch zur Erkundung des Untergrundes von Deponien und Altlasten hrsg. von der Bundesanstalt für Geowissenschaften und Rohstoffe, Heidelberg, Springer, vol. 3, no. 1, pp. 81-92, (ISBN: 3-540-23712-7)
    Publication Date: 1997
    Keywords: Applied geophysics ; environment ; waste ; disposal ; Seismics (controlled source seismology) ; Geoelectrics ; Gravimetry, Gravitation ; RADAR ; Borehole geophys. ; Physical properties of rocks ; Handbook of geophysics ; Knodel
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 2
    facet.materialart.
    Unknown
    Springer
    In:  Bull., Polar Proj. OP-O3A4, Contributions to the 6th Annual KTB-Colloquium: Geoscientific Results, Berlin, Springer, vol. 66, no. 2, pp. 277-291, (ISBN 0-87590-532-3, AGU Code: GD0305323)
    Publication Date: 1997
    Keywords: Earth tides ; poro-elasticity ; pressure ; permeability ; porosity ; Fluids ; Review article
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 3
    Publication Date: 2017-07-21
    Description: There are some active bottom currents on the northern continental slope of the South China Sea (SCS). Reflection seismic profiles show that the bottom current channels occur in the water depth range of 1000 to 2700 m, extending from the NE to the SW, leading to accumulation of discontinuous drifts with higher sedimentation rates on the eastern side of the channel. The stacking pattern of the layers suggests that these drifts propagated southwestward, following the direction of the bottom currents. One sedimentary drift to the southeast of the Dongsha Islands has the highest sedimentation rate of 97cm/ka in the last 12 ka. The sedimentary characteristics of the sediment layers indicate that these bottom currents are most likley caused by the water movement of a branch of the West Pacific Ocean Current, which enters the northern SCS via the Bashi Strait. Once formed, the bottom currents transport sediments along the northern slope of SCS southwestward and finally disappear into the central basin of the SCS. Due to the bottom current activity, the deep-sea sedimentary process in the northern SCS is complex.
    Type: Article , PeerReviewed
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 4
    Publication Date: 2017-06-27
    Description: Cold-water coral carbonate mounds, owing their presence mainly to the framework building coral Lophelia pertusa and the activity of associated organisms, are common along the European margin with their spatial distribution allowing them to be divided into a number of mound provinces. Variation in mound attributes are explored via a series of case studies on mound provinces that have been the most intensely investigated: Belgica, Hovland, Pelagia, Logachev and Norwegian Mounds. Morphological variation between mound provinces is discussed under the premise that mound morphology is an expression of the environmental conditions under which mounds are initiated and grow. Cold-water coral carbonate mounds can be divided into those exhibiting “inherited” morphologies (where mound morphology reflects the morphology of the colonised features) and “developed” morphology (where the mounds assume their own gross morphology mainly reflecting dominant hydrodynamic controls). Finer-scale, surface morphological features mainly reflecting biological growth forms are also discussed.
    Type: Article , PeerReviewed
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 5
    facet.materialart.
    Unknown
    Springer
    In:  Marine Biology, 150 (6). pp. 1153-1160.
    Publication Date: 2017-06-27
    Description: Sponges of warm- and temperate- but also cold-waters are known to synthesize structurally diverse primary and secondary metabolites. These compounds fulfill a variety of functions including adaptations of the cell membranes to environmental conditions. We show here that boreal sponges of the order Halichondrida are rich sources of brominated lipid fatty acids. The comparison of lipid compositions of halichondrid Demospongiae from boreal and warmer waters indicates an accumulation of brominated fatty acids in sponges from colder settings. Moreover, the spatial distribution of brominated fatty acids in the sponge tissue of one widely distributed sponge of the North-East Atlantic (Phakellia ventilabrum) hints to a function related to membrane fluidity and permeability rather than to defense against predation. However, brominated fatty acids are diagnostic for the presence of bromoperoxidases in sponges and may therefore be potentially useful as markers in a chemical screening for secondary metabolites of pharmacological interest.
    Type: Article , PeerReviewed
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 6
    facet.materialart.
    Unknown
    Springer
    In:  In: The Evolution and History of Human Populations in South Asia. , ed. by Petraglia, M. D. and Allchin, B. Springer, Dordrecht, pp. 173-200.
    Publication Date: 2017-11-24
    Type: Book chapter , NonPeerReviewed
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 7
    Publication Date: 2020-06-12
    Description: Two new compounds, 2, 3, 5-trimethyl-6-(3-oxobutan-2-yl)-4H-pyran-4-one (1) and (2R)-2, 3-dihydro-7-hydroxy-6, 8-dimethyl-2-[(E)-prop-1-enyl] chromen-4-one (2), together with six known compounds (3–8), were isolated from a deep-sea fungus, identified as Aspergillus sydowi, by a bioassay-guided method. Their structures were elucidated by spectroscopic methods and the cytotoxicities were evaluated by SRB method.
    Type: Article , PeerReviewed
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 8
    Publication Date: 2018-01-19
    Type: Article , PeerReviewed
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 9
    Publication Date: 2017-07-06
    Description: A method for attaching acoustic transmitters externally to deep-water fishes in situ is described. Tags, each comprising a transmitter connected to a dart, were fired at fish from a pneumatic gun held by the manipulator arm of a submersible. The method was applied successfully for tagging coelacanths and may have application for use with other species of fishes living at depths to about 1000 m. The usefulness of direct observation for monitoring the effects of tags on fish is evaluated in relation to the effects of the tagging method on coelacanths.
    Type: Article , PeerReviewed
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 10
    Publication Date: 2018-01-19
    Description: Species of the genus Hysterothylacium are among the most common marine nematode fish parasites in the northern Atlantic. Due to recent findings of cryptic speciation in other parasitic ascaridoid nematodes, a similar pattern of sibling species was hypothesized also for Hysterothylacium aduncum. By investigating a 886- to 890-bp-long genomic DNA fragment including ITS-1, 5.8S rDNA and ITS-2 of 40 specimens of H. aduncum of sprat (Sprattus sprattus) of four different biogeographical regions (North Sea, English Channel, Bay of Biscay, Adriatic Sea), we could not detect significant genetic variability and therefore cryptic speciation. Nevertheless, while ITS-1 and 5.8S rDNA sequences were identical for all analysed specimens, ITS-2 sequences showed a population-specific pattern with the differentiation of an English Channel/Bay of Biscay group from a North Sea/Mediterranean Sea group.
    Type: Article , PeerReviewed
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 11
    Publication Date: 2017-03-22
    Description: A stable and specific bacterial community was shown to be associated with the Mediterranean sponge Chondrilla nucula. The associated bacterial communities were demonstrated to be highly similar for all studied specimens regardless of sampling time and geographical region. In addition, analysis of 16S rDNA clone libraries revealed three constantly C. nucula-associated bacterial phylotypes belonging to the Acidobacteria, the Gamma- and Deltaproteobacteria present in sponge specimens from two Mediterranean regions with distinct water masses (Ligurian Sea and Adriatic Sea). For the first time, candidate division TM7 bacteria were found in marine sponges. A major part (79%) of the C. nucula-derived 16S rDNA sequences were closely related to other sponge-associated bacteria. Phylogenetic analysis identified 14 16S rRNA gene sequence clusters, seven of which consisted of exclusively sponge-derived sequences, whereas the other seven clusters contained additional environmental sequences. This study adds to a growing database on the stability and variability of microbial consortia associated with marine sponges.
    Type: Article , PeerReviewed
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 12
    Publication Date: 2019-09-23
    Description: Mombacho is a deeply dissected volcano belonging to the Quaternary volcanic chain of Nicaragua. The southern, historic collapse crater (El Crater) currently hosts a fumarolic field with a maximum temperature of 121°C. Chemical and isotopic data from five gas-sampling field campaigns carried out in 2002, 2003 and 2005 highlight the presence of high-temperature gas components (e.g. SO2, HCl and HF), which indicate a significant contribution of juvenile magmatic fluids to the hydrothermal system feeding the gas discharges. This is strongly supported by the mantle-derived helium and carbon isotopic signatures, although the latter is partly masked by either a sedimentary subduction-related or a shallow carbonate component. The observed chemical and isotopic composition of the Mombacho fluids seems to indicate that this volcanic system, although it has not experienced eruptive events during the last centuries, can be considered active and possibly dangerous, in agreement with the geophysical data recorded in the region. Systematic geochemical monitoring of the fumarolic gas discharges, coupled with a seismic and ground deformation network, is highly recommended in order to monitor a possible new eruptive phase.
    Type: Article , PeerReviewed
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 13
    Publication Date: 2018-01-19
    Description: We investigated the effect of commercially available enzymes (α-amylase, α-galactosidase, papain, trypsin, and lipase) as well as proteases from deep-sea bacteria on the larval attachment of the bryozoan Bugula neritina L. The 50% effective concentrations (EC50) of the commercial proteases were 10 times lower than those of other enzymes. Crude proteases from six deep-sea Pseudoalteromonas species significantly decreased larval attachment at concentrations of 0.03 to 1 mIU ml−1. The EC50 of the pure protease from the bacterium Pseudoalteromonas issachenkonii UST041101-043 was close to 1 ng ml−1 (0.1 mIU ml−1). The protease and trypsin individually incorporated in a water-soluble paint matrix inhibited biofouling in a field experiment. There are certain correlations between production of proteases by bacterial films and inhibition of larval attachment. None of the bacteria with biofilms that induced attachment of B. neritina produced proteolytic enzymes, whereas most of the bacteria that formed inhibitive biofilms produced proteases. Our investigation demonstrated the potential use of proteolytic enzymes for antifouling defense.
    Type: Article , PeerReviewed
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 14
    Publication Date: 2021-08-27
    Description: We have applied the novel analytical method NanoSIMS to cephalopod statoliths for the first time in order to analyse their chemical microstructure, using a spatial resolution of 400 nm. This technique makes it possible to analyse in situ nano-scale chemical variations between increment layers. In statoliths of the boreoatlantic armhook squid Gonatus fabricii, we found distinct concentration patterns indicating a periodicity in strontium and sodium distributions. Sr and Na show a negative relation, both elements showing alternating patterns where the increments vary in width between approximately 1 and 5 μm. Results suggest, that aragonite deposited during the night is rich in Na and poor in Sr, while aragonite deposited during the day is rich in Sr and poor in Na. This study demonstrates the excellent suitability of NanoSIMS for nano-scale microchemical analyses of aragonite, providing new information on calcification processes and individual life histories. Possible future fields of application include not only cephalopod statoliths, but also virtually all biomineralized tissues in aquatic organisms like fish otoliths, gastropod statoliths, bivalve shells, foraminifers and corals.
    Type: Article , PeerReviewed
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 15
    Publication Date: 2019-09-23
    Description: An indoor mesocosm system was set up to study the response of phytoplankton and zooplankton spring succession to winter and spring warming of sea surface temperatures. The experimental temperature regimes consisted of the decadal average of the Kiel Bight, Baltic Sea, and three elevated regimes with 2°C, 4°C, and 6°C temperature difference from that at baseline. While the peak of the phytoplankton spring bloom was accelerated only weakly by increasing temperatures (1.4 days per degree Celsius), the subsequent biomass minimum of phytoplankton was accelerated more strongly (4.25 days per degree Celsius). Phytoplankton size structure showed a pronounced response to warming, with large phytoplankton being more dominant in the cooler mesocosms. The first seasonal ciliate peak was accelerated by 2.1 days per degree Celsius and the second one by 2.0 days per degree Celsius. The over-wintering copepod populations declined faster in the warmer mesocosm, and the appearance of nauplii was strongly accelerated by temperature (9.2 days per degree Celsius). The strong difference between the acceleration of the phytoplankton peak and the acceleration of the nauplii could be one of the “Achilles heels” of pelagic systems subject to climate change, because nauplii are the most starvation-sensitive life cycle stage of copepods and the most important food item of first-feeding fish larvae.
    Type: Article , PeerReviewed
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 16
    Publication Date: 2019-07-03
    Description: Stable isotope signatures of primary producers display high inter- and intraspecific variation. This is assigned to species-specific differences in isotope fractionation and variable abiotic conditions, e.g., temperature, and nutrient and light availability. As consumers reflect the isotopic signature of their food source, such variations have direct impacts on the ecological interpretation of stable isotope data. To elucidate the variability of isotope fractionation at the primary producer level and the transfer of the signal through food webs, we used a standardised marine tri-trophic system in which the primary producers were manipulated while the two consumer levels were kept constant. These manipulations were (1) different algal species grown under identical conditions to address interspecific variability and (2) a single algal species cultivated under different nutrient regimes to address nutrient-dependent variability. Our experiments resulted in strong interspecific variation between different algal species (Thalassiosira weissflogii, Dunaliella salina, and Rhodomonas salina) and nutrient-dependent shifts in stable isotope signatures in response to nutrient limitation of R. salina. The trophic enrichment in 15N and 13C of primary and secondary consumers (nauplii of Acartia tonsa and larval herring) showed strong deviations from the postulated degree of 1.0‰ enrichment in δ13C and 3.4‰ enrichment in δ15N. Surprisingly, nauplii of A. tonsa tended to keep “isotopic homeostasis” in terms of δ15N, a pattern not described in the literature so far. Our results suggest that the diets’ nutritional composition and food quality as well as the stoichiometric needs of consumers significantly affect the degree of trophic enrichment and that these mechanisms must be considered in ecological studies, especially when lower trophic levels, where variability is highest, are concerned.
    Type: Article , PeerReviewed
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 17
    facet.materialart.
    Unknown
    Springer
    In:  Geologische Rundschau, 87 (2). pp. 518-521.
    Publication Date: 2018-01-25
    Description: Rubrik "Neues aus dem Geologenarchiv (1997)"
    Type: Article , PeerReviewed
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 18
    Publication Date: 2015-09-21
    Description: Comparison of five deep-water coral (DWC)/mound ecosystems along the European Continental Margin shows that suspended particulate organic matter (sPOM), a potential food source, is lipid rich and of high quality. However, there are differences between the sites. The Darwin and Pelagia Mounds (N. Rockall Trough and N. Porcupine Bank, respectively) have higher proportions of labile particulate lipids (including high proportions of polyunsaturated fatty acids) in the benthic boundary layer than Logachev, Hovland and Belgica Mounds (Rockall Bank, S. Porcupine Bank and Porcupine Seabight, respectively). The high quality sPOM could be transported downslope from the euphotic zone. There is some evidence for inter-annual variability at some sites (e.g. Hovland and Logachev Mounds) as large differences in suspended lipid and particulate organic carbon concentrations were observed over the sampling period. Elevated total organic carbon contents of sediments at mound sites, relative to control sites in some cases (particularly Darwin Mounds), probably reflect local hydrodynamic control and the trapping of sPOM by the DWC. Fresh POM can be relatively rapidly transferred to significant depth (up to 8 cm) through bioturbation that is evident at all sites. There is no clear evidence of present day hydrocarbon seepage at any of the sites.
    Type: Article , PeerReviewed
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 19
    Publication Date: 2017-02-07
    Description: In spite of the fundamental role the Atlantic Meridional Overturning Circulation (AMOC) plays for global climate stability, no direct current measurement of the Denmark Strait Overflow, which is the densest part of the AMOC, has been available until recently that resolve the cross-stream structure at the sill for long periods. Since 1999, an array of bottom-mounted acoustic instruments measuring current velocity and bottom-to-surface acoustic travel times was deployed at the sill. Here, the optimization of the array configuration based on a numerical overflow model is discussed. The simulation proves that more than 80% of the dense water transport variability is captured by two to three acoustic current profilers (ADCPs). The results are compared with time series from ADCPs and Inverted Echo Sounders deployed from 1999 to 2003, confirming that the dense overflow plume can be reliably measured by bottom-mounted instruments and that the overflow is largely geostrophically balanced at the sill.
    Type: Article , PeerReviewed
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 20
    facet.materialart.
    Unknown
    Springer
    In:  Boundary-Layer Meteorology, 124 (3). pp. 361-381.
    Publication Date: 2017-12-31
    Description: The experiment IGLOS (Investigation of the Greenland Boundary Layer Over Summit) was conducted in June and July 2002 in the central plateau of the Greenland inland ice. The German research aircraft Polar2, equipped with the turbulence measurement system Meteopod, was used to investigate turbulence and radiation flux profiles near research station “Summit Camp”. Aircraft measurements are combined with measurements of radiation fluxes and turbulent quantities made from a 50 m tower at Summit Camp operated by Eidgenössische Technische Hochschule (ETH) Zürich. During all six flight missions, well-developed stable boundary layers were found. Even in high-wind conditions, the surface inversion thickness did not exceed roughly 100 m. The turbulent height of the stable boundary layer (SBL) was found to be much smaller than the surface inversion thickness. Above the surface layer, significant turbulent fluxes occurred only intermittently in intervals on the order of a few kilometres. Turbulent event fraction in the upper SBL shows the same dependence on gradient Richardson number as reported for near-surface measurements. Clear-air longwave radiation divergence was always found to contribute significantly to the SBL heat budget. In low-wind cases, radiative cooling even turned out to be dominant.
    Type: Article , PeerReviewed
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 21
    facet.materialart.
    Unknown
    Springer
    In:  Origins of Life and Evolution of Biospheres, 37 (2). pp. 189-200.
    Publication Date: 2018-01-01
    Description: Methanogenic archaea from Siberian permafrost complementary to the already well-studied methanogens from non-permafrost habitats were exposed to simulated Martian conditions. After 22 days of exposure to thermo-physical conditions at Martian low- and mid-latitudes up to 90% of methanogenic archaea from Siberian permafrost survived in pure cultures as well as in environmental samples. In contrast, only 0.3%–5.8% of reference organisms from non-permafrost habitats survived at these conditions. This suggests that methanogens from terrestrial permafrost seem to be remarkably resistant to Martian conditions. Our data also suggest that in scenario of subsurface lithoautotrophic life on Mars, methanogenic archaea from Siberian permafrost could be used as appropriate candidates for the microbial life on Mars.
    Type: Article , PeerReviewed
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 22
    Publication Date: 2019-01-10
    Description: In nature, multiple-species rather than single-species microbial associations with plant or animal (including human) hosts are the rule more than the exception. Prominent examples are the microbial consortia of vertebrate intestines and cattle rumen. As many demosponges are associated with enormous amounts of microorganisms, contributing up to 40-60% of the sponge biomass, they are excellent models for marine multi-species, microbe-host associations. Representatives of at least eight different phyla, many of which contain few or no cultivated representatives, have been identified as specific members of the sponge-associated microbiota. Recent studies show that vertical transmission of symbionts through the larval stages rather than horizontal acquisition from seawater appears to be an important mechanism by which the complex and possibly ancient microbial consortia of sponges are formed.
    Type: Article , PeerReviewed
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 23
    Publication Date: 2015-08-06
    Description: Many sponge species contain large and diverse communities of microorganisms. Some of these microbes are suggested to be in a mutualistic interaction with their host sponges, but there is little evidence to support these hypotheses. Stable nitrogen isotope ratios of sponges in the Key Largo, Florida (USA) area grouped sponges into species with relatively low δ15N ratios and species with relatively high δ15N ratios. Using samples collected in June 2002 from Three Sisters Reef and Conch Reef in the Key Largo, Florida area, transmission electron microscopy (TEM) and denaturing gradient gel electrophoresis were performed on tissues of the sponges Ircinia felix and Aplysina cauliformis, which are in the low δ15N group, and on tissue of the sponge Niphates erecta, which is in the high δ15N group. Results showed that I. felix and A. cauliformis have large and diverse microbial communities, while N. erecta has a low biomass of one bacterial strain. As the low δ15N ratios indicated a microbial input of nitrogen, these results suggested that I. felix and A. cauliformis were receiving nitrogen from their associated microbial community, while N. erecta was obtaining nitrogen solely from external sources. Sequence analysis of the microbial communities showed a diversity of metabolic capabilities among the microbes of the low δ15N group, which are lacking in the high δ15N group, further supporting metabolic differences between the two groups. This research provides support for hypotheses of mutualisms between sponges and their associated microbial communities.
    Type: Article , PeerReviewed
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 24
    Publication Date: 2017-01-05
    Description: The skeleton morphology of the azooxanthellate cold-water coral Lophelia pertusa can be strongly influenced by invasive boring sponges that infest corallites in the still living part of the colony. Atypically swollen corallites of live Lophelia pertusa from the Galway Mound (Belgica Carbonate Mound Province, Porcupine Seabight, NE Atlantic), heavily excavated by boring organisms, have been examined with a wide range of non-destructive and destructive methods: micro-computed tomography, macro- and microscopic observations of the outer coral skeleton, longitudinal and transversal thin sections and SEM analyses of coral skeleton casts. As a result, three excavating sponge species have been distinguished within the coral skeleton: Alectona millari, Spiroxya heteroclita and Aka infesta. Furthermore, four main coral/sponge growth stages have been recognised: (1) cylindrical juvenile corallite/no sponge cavities; (2) flared juvenile corallite/linear sponge cavities (if present); (3) slightly swollen adult corallites/chambered oval sponge cavities; (4) very swollen adult corallites/widespread cavities. The inferred correlation between corallite morphology and boring sponge infestation has been detected in micro-computed tomography (micro-CT) images and confirmed in sponge trace casts and peculiar features of coral skeleton microstructure.
    Type: Article , PeerReviewed
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 25
    Publication Date: 2015-09-25
    Description: Cold-water coral carbonate mounds, owing their presence mainly to the framework building coral Lophelia pertusa and the activity of associated organisms, are common along the European margin with their spatial distribution allowing them to be divided into a number of mound provinces. Variation in mound attributes are explored via a series of case studies on mound provinces that have been the most intensely investigated: Belgica, Hovland, Pelagia, Logachev and Norwegian Mounds. Morphological variation between mound provinces is discussed under the premise that mound morphology is an expression of the environmental conditions under which mounds are initiated and grow. Cold-water coral carbonate mounds can be divided into those exhibiting “inherited” morphologies (where mound morphology reflects the morphology of the colonised features) and “developed” morphology (where the mounds assume their own gross morphology mainly reflecting dominant hydrodynamic controls). Finer-scale, surface morphological features mainly reflecting biological growth forms are also discussed.
    Type: Article , PeerReviewed
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 26
    facet.materialart.
    Unknown
    Springer
    In:  Microbial Ecology, 53 (2). pp. 355-365.
    Publication Date: 2015-08-07
    Description: Sponges (Porifera) are filter feeders that take up microorganisms from seawater and digest them by phagocytosis. At the same time, many sponges are known to harbor massive consortia of symbiotic microorganisms, which are phylogenetically distinct from those in seawater, within the mesohyl matrix. In the present study, feeding experiments were performed to investigate whether phylogenetically different bacterial isolates, hereafter termed “food bacteria,” microbial seawater consortia, and sponge symbiont consortia are taken up and processed differently by the host sponge. Aplysina aerophoba retained high numbers of bacterial isolates and microbial seawater consortia with rates of up to 2.76 × 106 bacteria (g sponge wet weight)–1 h–1, whereas the retention of sponge symbionts was lower by nearly two orders of magnitude [5.37 × 104 bacteria (g sponge wet weight)−1 h–1]. In order to visualize the processing of a food bacterium within sponge tissues, the green fluorescent protein-labeled Vibrio strain MMW1, which had originally been isolated from A. aerophoba, was constructed. Incubation of this strain with A. aerophoba and subsequent visualization in tissue cryosections showed its presence in the choanocytes and/or endopinacocytes lining the canals but, unlike latex beads, not in deeper regions of the mesohyl, which suggests digestion of the bacteria upon contact with the host. Denaturing gradient gel electrophoresis (DGGE) was performed on the incubation seawater to monitor the changes in phylogenetic composition after incubation of the sponge with either seawater or sponge symbiont consortia. However, the DGGE experiment provided no evidence for selective processing of individual lineages by the host sponge. In conclusion, this study extends early studies by Wilkinson et al. (Proc R Soc London B 220:519–528, 1984) that sponges, here A. aerophoba, are able to differentiate between food bacteria and their own bacterial symbionts.
    Type: Article , PeerReviewed
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 27
    Publication Date: 2015-08-06
    Description: The Caribbean sponge, Plakortis simplex, is known to contain a large array of secondary metabolites, including the antimalarial polyketide plakortin, several unusual glycolipids, and some hopanoids, which closely resemble typical bacterial metabolites. The hypothesis that they could be products of bacterial metabolism was tested by localizing specific metabolites in cells using physical separation of sponge cells, bacterial symbionts and supernatant by differential centrifugation. The obtained fractions were analysed separately for the typical P. simplex metabolites by NMR and mass spectrometry, and most of them were shown to be present in the bacterial cells but not in the sponge cells. In addition, PCR screening showed that the biosynthetic pathway for glycosphingolipids was present in the bacterial cells. Isolation of a Sphingomonas strain PS193 from P. simplex and subsequent glycosphingolipid analysis resulted in the detection of a known glycosphingolipid, GSL-1, that did, however, not match the glycosphingolipid profile of P. simplex. Therefore, it is unlikely that Sphingomonas strain PS193 is an abundant member of the microbial community associated with P. simplex. Other glycosphingolipid producing bacteria in P. simplex remain to be identified. In conclusion, this study provides experimental evidence that the glycolipids and hopanoids and possibly also the polyketide plakortin are produced by microbial symbionts rather than the sponge from which the metabolites were originally isolated.
    Type: Article , PeerReviewed
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 28
    facet.materialart.
    Unknown
    Springer
    In:  Marine Geophysical Researches, 28 (4). pp. 355-371.
    Publication Date: 2015-11-18
    Description: Two single-channel seismic (SCS) data sets collected in 2000 and 2005 were used for a four-dimensional (4D) time-lapse analysis of an active cold vent (Bullseye Vent). The data set acquired in 2000 serves as a reference in the applied processing sequence. The 4D processing sequence utilizes time- and phase-matching, gain adjustments and shaping filters to transform the 2005 data set so that it is most comparable to the conditions under which the 2000 data were acquired. The cold vent is characterized by seismic blanking, which is a result of the presence of gas hydrate in the subsurface either within coarser-grained turbidite sands or in fractures, as well as free gas trapped in these fracture systems. The area of blanking was defined using the seismic attributes instantaneous amplitude and similarity. Several areas were identified where blanking was reduced in 2005 relative to 2000. But most of the centre of Bullseye Vent and the area around it were seen to be characterized by intensified blanking in 2005. Tracing these areas of intensified blanking through the three-dimensional (3D) seismic volume defined several apparent new flow pathways that were not seen in the 2000 data, which are interpreted as newly generated fractures/faults for upward fluid migration. Intensified blanking is interpreted as a result of new formation of gas hydrate in the subsurface along new fracture pathways. Areas with reduced blanking may be zones where formerly plugged fractures that had trapped some free gas may have been opened and free gas was liberated.
    Type: Article , PeerReviewed
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 29
    facet.materialart.
    Unknown
    Springer
    In:  Geologische Rundschau, 86 (2). pp. 471-491.
    Publication Date: 2019-01-22
    Description: The climate of the Holocene is not well suited to be the baseline for the climate of the planet. It is an interglacial, a state typical of only 10% of the past few million years. It is a time of relative sea-level stability after a rapid 130-m rise from the lowstand during the last glacial maximum. Physical geologic processes are operating at unusual rates and much of the geochemical system is not in a steady state. During most of the Phanerozoic there have been no continental ice sheets on the earth, and the planet’s meridional temperature gradient has been much less than it is presently. Major factors influencing climate are insolation, greenhouse gases, paleogeography, and vegetation; the first two are discussed in this paper. Changes in the earth’s orbital parameters affect the amount of radiation received from the sun at different latitudes over the course of the year. During the last climate cycle, the waxing and waning of the northern hemisphere continental ice sheets closely followed the changes in summer insolation at the latitude of the northern hemisphere polar circle. The overall intensity of insolation in the northern hemisphere is governed by the precession of the earth’s axis of rotation, and the precession and ellipticity of the earth’s orbit. At the polar circle a meridional minimum of summer insolation becomes alternately more and less pronounced as the obliquity of the earth’s axis of rotation changes. Feedback processes amplify the insolation signal. Greenhouse gases (H2O, CO2, CH4, CFCs) modulate the insolation-driven climate. The atmospheric content of CO2 during the last glacial maximum was approximately 30% less than during the present interglacial. A variety of possible causes for this change have been postulated. The present burning of fossil fuels, deforestation, and cement manufacture since the beginning of the industrial revolution have added CO2 to the atmosphere when its content due to glacial-interglacial variation was already at a maximum. Anthropogenic activity has increased the CO2 content of the atmosphere to 130% of its previous Holocene level, probably higher than at any time during the past few million years. During the Late Cretaceous the atmospheric CO2 content was probably about four times that of the present, the level to which it may rise at the end of the next century. The results of a Campanian (80 Ma) climate simulation suggest that the positive feedback between CO2 and another important greenhouse gas, H2O, raised the earth’s temperature to a level where latent heat transport became much more significant than it is presently, and operated efficiently at all latitudes. Atmospheric high- and low-pressure systems were as much the result of variations in the vapor content of the air as of temperature differences. In our present state of knowledge, future climate change is unpredictable because by adding CO2 to the atmosphere we are forcing the climate toward a “greenhouse” mode when it is accustomed to moving between the glacial–interglacial “icehouse” states that reflect the waxing and waning of ice sheets. At the same time we are replacing freely transpiring C3 plants with water-conserving C4 plants, producing a global vegetation complex that has no past analog. The past climates of the earth cannot be used as a direct guide to what may occur in the future. To understand what may happen in the future we must learn about the first principles of physics and chemistry related to the earth’s system. The fundamental mechanisms of the climate system are best explored in simulations of the earth’s ancient extreme climates.
    Type: Article , PeerReviewed
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 30
    facet.materialart.
    Unknown
    Springer
    In:  Climate Dynamics, 28 (5). pp. 517-531.
    Publication Date: 2016-09-13
    Description: In this paper it is suggested that a stochastic isotropic diffusive process, representing a spatial first order auto regressive process (AR(1)-process), can be used as a null hypothesis for the spatial structure of climate variability. By comparing the leading empirical orthogonal functions (EOFs) of a fitted null hypothesis with EOF modes of an observed data set, inferences about the nature of the observed modes can be made. The concept and procedure of fitting the null hypothesis to the observed EOFs is in analogy to time analysis, where an AR(1)-process is fitted to the statistics of the time series in order to evaluate the nature of the time scale behavior of the time series. The formulation of a stochastic null hypothesis allows one to define teleconnection patterns as those modes that are most distinguished from the stochastic null hypothesis. The method is applied to several artificial and real data sets including the sea surface temperature of the tropical Pacific and Indian Ocean and the Northern Hemisphere wintertime and tropical sea level pressure.
    Type: Article , PeerReviewed
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 31
    facet.materialart.
    Unknown
    Springer
    In:  In: Microbial Sulfur Metabolism. , ed. by Dahl, C. and Friedrich, C. G. Springer, Heidelberg, pp. 238-258. ISBN 978-3-540-72679-1
    Publication Date: 2012-02-23
    Type: Book chapter , PeerReviewed
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 32
    Publication Date: 2018-06-07
    Description: Cephalopod beaks retrieved from stomachs of dead emperor penguin chicks at Pointe Géologie, Terre Adélie, provide information on taxonomic and size composition of the penguin’s squid diet, on the trophic range of the squid species preyed upon and on the fractional trophic impact of the penguin on the whole food web. Emperor penguins prey upon four squid species (Psychroteuthis glacialis, Kondakovia longimana, Gonatus antarcticus, Alluroteuthis antarcticus) and do not take squid larger than 480 mm mantle length. Larger squid live either below the penguin’s diving range or are beyond its handling capacity. Nitrogen stable isotope ratios indicate that squids cover a range of about two trophic levels (2.5–8‰ δ15N). The impact of the emperor penguin, however, concentrates on the upper part of this range, about 68% of its squid prey being 〉6‰ δ15N. The principal components of the emperor’s diet, fish, krill and squid, differ distinctly in average trophic level. Consequently the trophic position of the emperor penguin changes accordingly with diet composition and may differ by almost one trophic level between different emperor penguin colonies.
    Type: Article , PeerReviewed
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 33
    Publication Date: 2017-05-18
    Description: On- and off-mound sediment cores from Propeller Mound (Hovland Mound province, Porcupine Seabight) were analysed to understand better the evolution of a carbonate mound. The evaluation of benthic foraminiferal assemblages from the off-mound position helps to determine the changes of the environmental controls on Propeller Mound in glacial and interglacial times. Two different assemblages describe the Holocene and Marine Isotope Stage (MIS) 2 and late MIS 3 (∼31 kyr BP). The different assemblages are related to changes in oceanographic conditions, surface productivity and the waxing and waning of the British Irish Ice Sheet (BIIS) during the last glacial stages. The interglacial assemblage is related to a higher supply of organic material and stronger current intensities in water depth of recent coral growth. During the last glaciation the benthic faunas showed high abundances of cassidulinid species, implying cold bottom waters and a reduced availability of organic matter. High sedimentation rates and the domination of Elphidium excavatum point to shelf erosion related to sea-level lowering (∼50 m) and the progradation of the BIIS onto the shelf. A different assemblage described for the on-mound core is dominated by Discanomalina coronata, Gavelinopsis translucens, Planulina ariminensis, Cibicides lobatulus and to a lower degree by Hyrrokkin sarcophaga. These species are only found or show significantly higher relative abundances in on-mound samples and their maximum contribution in the lower part of the record indicates a higher coral growth density on Propeller Mound in an earlier period. They are less abundant during the Holocene, however. This dataset portrays the boundary conditions of the habitable range for the cold-water coral Lophelia pertusa, which dominates the deep-water reefal ecosystem on the upper flanks of Propeller Mound. The growth of this ecosystem occurs during interglacial and interstadial periods, whereas a retreat of corals is documented in the absence of glacial sediments on-mound. Glacial conditions with cold intermediate waters, a weak current regime and high sedimentation rates provide an unfavourable environmental setting for Lophelia corals to grow. A Late Pleistocene decrease is observed in the mound growth for Propeller Mound, which might face its complete burial in the future, as it already happened to the buried mounds of the Magellan Mound province further north.
    Type: Article , PeerReviewed
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 34
    Publication Date: 2017-03-22
    Description: Quorum sensing (QS) signals have been considered to play important roles in biofilm development and in the attractiveness of biofilms to higher organisms in marine ecosystem. In this study, bacterial QS signalsacylated homoserine lactone derivatives (AHLs) were detected in 2-, 4-, and 6-day-old subtidal biofilms by using AHLs reporter strains. N-dodecanoyl-homoserine lactone (C12-HSL) was identified in 6-day-old biofilm at a concentration of 9.04 μg cm−minus;2 (3.36 mmol l−minus;1). To investigate the possible role of AHLs in the consequent eventlarval settlement of the polychaete Hydroides elegans onto subtidal biofilmsseven biofilm-derived bacteria that effectively induced larval settlement of H. elegans, were screened for AHL production. One of them, the Vibrio sp. UST950701-007, produced N-hexanoyl-homoserine lactone (C6-HSL). Larval settlement bioassay showed that C6-HSL, C12-HSL, and 3-oxo-octanoyl-homoserine lactone (3-oxo-C8-HLS) at certain concentrations induced some initial larval settlement behaviors such as reducing swimming speed, crawling on the bottom. However, these AHLs did not effectively induce larval settlement in comparison to the effective settlement inducer 3-isobutyl-1-methylxanthine. The possible chemokinetic mechanism and indirect effects of AHLs on larval settlement are suggested.
    Type: Article , PeerReviewed
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 35
    Publication Date: 2018-03-21
    Description: Iridium enrichments, at or close to the K/T boundary, are often cited as evidence for impacts of cosmic bodies or volcanic events, or both, that resulted in mass extinctions. A third possible explanation for the high Ir concentrations, that the enrichments were caused by the cosmic micrometeorite flux during times of slow Sediment accumulation, has generally been rejected. In this study we examine the Ir/Au ratios and conclude that they may indicate enrichment of siderophile elements by slow sedimentation. In addition, the concept of slow sedimentation at the K/T boundary is consistent with many aspects of the K/T boundary research such as the gradual decline of the species before the major extinction level and recent reports of faunal transitions from Cretaceous to Tertiary without sudden extinctions, hiatuses or Ir anomalies.
    Type: Article , PeerReviewed
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 36
    facet.materialart.
    Unknown
    Springer
    In:  Space Science Reviews, 125 (1-4). pp. 273-286.
    Publication Date: 2016-06-21
    Description: Because of its chemical and radiative properties, atmospheric ozone constitutes a key element of the Earth's climate system. Absorption of sunlight by ozone in the ultraviolet wavelength range is responsible for stratospheric heating, and determines the temperature structure of the middle atmosphere. Changes in middle atmospheric ozone concentrations result in an altered radiative input to the troposphere and to the Earth's surface, with implications on the energy balance and the chemical composition of the lower atmosphere. Although a wide range of ground- and satellite-based measurements of its integrated content and of its vertical distribution have been performed since several decades, a number of uncertainties still remain as to the response of middle atmospheric ozone to changes in solar irradiance over decadal time scales. This paper presents an overview of achieved findings, including a discussion of commonly applied data analysis methods and of their implication for the obtained results. We suggest that because it does not imply least-squares fitting of prescribed periodic or proxy data functions into the considered times series, time-domain analysis provides a more reliable method than multiple regression analysis for extracting decadal-scale signals from observational ozone datasets. Applied to decadal ground-based observations, time-domain analysis indicates an average middle atmospheric ozone increase of the order of 2% from solar minimum to solar maximum, which is in reasonable agreement with model results.
    Type: Article , PeerReviewed
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 37
    Publication Date: 2017-01-31
    Description: This study aimed at simulating different degrees of winter warming and at assessing its potential effects on ciliate succession and grazing-related patterns. By using indoor mesocosms filled with unfiltered water from Kiel Bight, natural light and four different temperature regimes, phytoplankton spring blooms were induced and the thermal responses of ciliates were quantified. Two distinct ciliate assemblages, a pre-spring and a spring bloom assemblage, could be detected, while their formation was strongly temperature-dependent. Both assemblages were dominated by Strobilidiids; the pre-spring bloom phase was dominated by the small Strobilidiids Lohmaniella oviformis, and the spring bloom was mainly dominated by large Strobilidiids of the genus Strobilidium. The numerical response of ciliates to increasing food concentrations showed a strong acceleration by temperature. Grazing rates of ciliates and copepods were low during the pre-spring bloom period and high during the bloom ranging from 0.06 (Δ0°C) to 0.23 day−1 (Δ4°C) for ciliates and 0.09 (Δ0°C) to 1.62 day−1 (Δ4°C) for copepods. During the spring bloom ciliates and copepods showed a strong dietary overlap characterized by a wide food spectrum consisting mainly of Chrysochromulina sp., diatom chains and large, single-celled diatoms.
    Type: Article , PeerReviewed
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 38
    facet.materialart.
    Unknown
    Springer
    In:  In: Submarine mass movements and their consequences. , ed. by Lykousis, V., Sakellariou, D. and Locat, J. Springer, Dordrecht, pp. 337-345.
    Publication Date: 2012-07-05
    Type: Book chapter , PeerReviewed
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 39
    Publication Date: 2017-02-01
    Description: We assessed the temporal changes in and the relationships between the structures of the macroinvertebrate communities and the environmental conditions of the French Rhône River (the river from Lake Geneva to the Mediterranean Sea) over the last 20 years (1985–2004). Multisite environmental and biological datasets were analysed using multiple CO-inertia analysis (MCOA) and Procrustean analysis. Changes in environmental conditions were mainly marked by an improvement in water quality between 1985 and 1991 and by an increase in water temperature from 1985 onwards due to climate change. Improvement in water quality seemed to delay changes in community structures under global warming. We then observed trends in community structures coupled with high temperatures and a decrease in oxygen content. Interestingly, we observed both gradual changes and rapid switches in community states. These shifts seemed coupled to extreme hydroclimatic events (i.e. pulse disturbances). Floods and the 2003 heatwave enhanced the development of eurytolerant and invasive taxa which were probably able to take advantage of gradual warming environmental conditions. Despite various site-specific “press” constraints (e.g. hydropower schemes, nuclear power plants), similar changes in community structures were observed along the French Rhône River. Such consistency in temporal processes at large geographical scales underlined the strength of hydroclimatic constraints on community dynamics compared to specific local disturbances. Finally, community structures did not show any sign of recovery, and their relative sensitivities to extreme hydroclimatic events seemed to increase with time. Thus, our results suggest that global changes may reduce the resilience of current community states.
    Type: Article , PeerReviewed
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 40
    facet.materialart.
    Unknown
    Springer
    In:  In: Continental Scientific Drilling - a Decade of Progress and Challenges for the Future. , ed. by Harms, U., Koeberl, C. and Zoback, M. D. Springer, Berlin, pp. 289-335.
    Publication Date: 2019-09-23
    Type: Book chapter , PeerReviewed
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 41
    Publication Date: 2021-08-27
    Description: The use of statolith chemistry to trace migration pathways and distinguish populations of cephalopods is based on the assumption that the elemental composition of statoliths is influenced by physicochemical properties of the ambient environment. However, such influences have not been investigated experimentally up until now. This study presents the first microchemical analyses of cephalopod statoliths obtained from laboratory experiments under different controlled temperature and salinity conditions. Our results show that statolith chemical composition is strongly related to both salinity and temperature in ambient waters. The Ba/Ca ratio is negatively related to temperature and shows no relation to salinity. The I/Ca ratio is positively related to temperature and negatively to salinity. No Sr/Ca relation was found to either salinity or temperature, suggesting that the well-established proxy strontium is not as useful in cephalopod statoliths as in other biomineralized aragonites. Microanalysis of trace elements, however, shows an enormous potential for field studies on distribution, migration and stock separation of cephalopods. Furthermore, Synchrotron X-ray Fluorescence Analysis is introduced as a promising novel method for statolith analysis, providing a spatial resolution of typically 10–15 μm combined with detection limits down to 0.5 ppm.
    Type: Article , PeerReviewed
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 42
    facet.materialart.
    Unknown
    MAIK Nauka/Interperiodica | Springer
    In:  Izvestiya, Atmospheric and Oceanic Physics, 43 . pp. 687-695.
    Publication Date: 2020-08-05
    Description: The spatial structure of surface air temperature (SAT) anomalies in the extratropical latitudes of the Northern Hemisphere (NH) during the 20th century is studied from the data obtained over the period 1892–1999. The expansion of the mean (over the winter and summer periods) SAT anomalies into empirical orthogonal functions (EOFs) is used for analysis. It is shown that variations in the mean air temperature in the Arctic region (within the latitudes 60°–90°N) during both the winter and summer periods can be described with a high accuracy by two spatial orthogonal modes of variability. For the winter period, these are the EOF related to the leading mode of variability of large-scale atmospheric circulation in the NH, the North Atlantic Oscillation, and the spatially localized (in the Arctic) EOF, which describes the Arctic warming of the mid-20th century. The expansion coefficient of this EOF does not correlate with the indices of atmospheric circulation and is hypothetically related to variations in the area of the Arctic ice cover that are due to long-period variations in the influx of oceanic heat from the Atlantic. On the whole, a significantly weaker relation to the atmospheric circulation is characteristic of the summer period. The first leading variability mode describes a positive temperature trend of the past decades, which is hypothetically related to global warming, while the second leading EOF describes a long-period oscillation. On the whole, the results of analysis suggest a significant effect of natural climatic variability on air-temperature anomalies in the NH high latitudes and possible difficulties in isolating an anthropogenic component of climate changes.
    Type: Article , PeerReviewed
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 43
    Publication Date: 2016-05-26
    Description: A new phototrophic purple bacterium was isolated from a flat, laminated microbial mat in a salt marsh near Woods Hole, Mass., USA. The spiral-shaped bacterium was highly motile and had bipolar tufts of flagella and intracytoplasmic membranes of the vesicular type. The major photosynthetic pigments were identified as the carotenoid tetrahydrospirilloxanthin and bacteriochlorophyll b. The long wavelength in vivo absorption maximum of the bacteriochlorophyll was at 986 nm. The marine bacterium showed optimal growth in the presence of 2% NaCl. It utilized a number of organic substrates as carbon and energy sources and required vitamins and sulfide as a reduced sulfur source for growth. In the presence of sulfide, elemental sulfur globules were formed outside the cells. Elemental sulfur was not further oxidized to sulfate. The new isolate had a unique lipid and fatty acid composition, and according to the 16S rRNA gene sequence, it is most similar to Rhodospirillum rubrum. It is described as a new species and assigned to a new genus with the proposed name Rhodospira trueperi.
    Type: Article , PeerReviewed
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 44
    Publication Date: 2019-09-23
    Description: Ecological forecasts predict the immigration of boreal species into Arctic waters as one consequence of rising sea temperatures. Here, we report the finding of Atlantic snake pipefish (Entelurus aequoreus) off the western coast of Spitsbergen at 79°N in August 2006. This syngnathid fish species, which was presumed to be confined to waters south of Iceland, has dramatically increased in population size in its core distribution area in the northeastern Atlantic since 2002, probably in response to greater reproduction success due to higher water temperatures. We conclude that our finding is an indication of the predicted northward extension of the distribution range of boreal species.
    Type: Article , PeerReviewed
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 45
    Publication Date: 2016-05-26
    Description: From the microbial mats that develop in Solar Lake, a new purple sulfur bacterium was isolated. This strain (Chromatium strain SL 3201) was morphologically similar to Chromatium gracile and Chromatium minutissimum. Chromatium SL 3201 was found to be a moderate halophile with a growth range between 2 and 20% NaCl (optimum 4-5% NaCl) and was able to grow photo-organotrophically using glycolate and glycerol. It is the first described phototrophic sulfur bacterium able to use glycolate. According to NaCl requirements and utilization of organic compounds, the strain is not related to any known species of the genus Chromatium. On the basis of its 16S rRNA gene sequence, it clusters with other Chromatium species and is most similar to Chromatium salexigens and Chr. gracile, but it is sufficiently separated to be considered as a new species of the genus. It is, therefore, described as Chromatium glycolicum sp. nov.
    Type: Article , PeerReviewed
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 46
    Publication Date: 2019-09-23
    Description: The distribution of platinum group elements (PGEs) in massive sulfides and hematite–magnetite±pyrite assemblages from the recently discovered basalt-hosted Turtle Pits hydrothermal field and in massive sulfides from the ultramafic-hosted Logatchev vent field both on the Mid-Atlantic Ridge was studied and compared to that from selected ancient volcanic-hosted massive sulfide (VHMS) deposits. Cu-rich samples from black smoker chimneys of both vent fields are enriched in Pd and Rh (Pd up to 227 ppb and Rh up to 149 ppb) when compared to hematite–magnetite-rich samples from Turtle Pits (Pd up to 10 ppb, Rh up to 1.9 ppb). A significant positive correlation was established between Cu and Rh in sulfide samples from Turtle Pits. PGE chondrite-normalized patterns (with a positive Rh anomaly and Pd and Au enrichment), Pd/Pt and Pd/Au ratios close to global MORB, and high values of Pd/Ir and Pt/Ir ratios indicate mafic source rock and seawater involvement in the hydrothermal system at Turtle Pits. Similarly shaped PGE chondrite-normalized patterns and high values of Pd/Pt and Pd/Ir ratios in Cu-rich sulfides at Logatchev likely reflect a similar mechanism of PGE enrichment but with involvement of ultramafic source rocks.
    Type: Article , PeerReviewed
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 47
    Publication Date: 2018-06-07
    Description: Seasonal lipid dynamics of various developmental stages were investigated in Pseudocalanus minutus and Oithona similis. For P. minutus, the dominance of 16:1(n−7), 16:4(n−3) and 20:5(n−3) fatty acids indicated a diatom-based nutrition in spring, whereas 22:6(n−3), 16:0, 18:2(n−6) and 18:1(n−9) pointed to a flagellate-based diet during the rest of the year as well as omnivorous/carnivorous low-level feeding during winter. The shorter-chain fatty alcohols 14:0 and 16:0 prevailed, also reflecting biosynthetic processes typical of omnivores or carnivores. Altogether, the lipid signatures characterized P. minutus as an opportunistic feeder. In contrast, O. similis had consistently high amounts of the 18:1(n−9) fatty acid in all stages and during all seasons pointing to a generally omnivorous/carnivorous/detritivorous diet. Furthermore, the fatty alcohol 20:1(n−9) reached high percentages especially in adult females and males, and feeding on Calanus faecal pellets is suggested. Fatty alcohols, as wax ester moieties, revealed significant seasonal variations in O. similis and a seasonal trend towards wax ester accumulation in autumn in P. minutus. P. minutus utilized its lipid deposits for development in the copepodite stages III and IV and for gonad maturation in CV and females during the dark season. However, CVs and females depended on the spring phytoplankton bloom for final maturation processes and reproduction. O. similis fueled gonad maturation and egg production for reproduction in June by wax esters, whereas reproduction in August/September co-occurred with the accumulation of new depot lipids. Both species revealed significantly higher wax ester levels in deeper (〉50 m) as compared to surface (0–50 m) dwelling individuals related to a descent prior to overwintering.
    Type: Article , PeerReviewed
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 48
    facet.materialart.
    Unknown
    Springer
    In:  Helgoland Marine Research, 61 (2). pp. 153-155.
    Publication Date: 2018-05-28
    Description: After the discovery of large densities of Mnemiopsis leidyi in the Baltic Sea near Kiel by Javidpour et al. (First record of Mnemiopsis leidyi A. Agassiz 1865 in the Baltic Sea, 2006) in October 2006, we investigated the gelatinous zooplankton in the North Sea near Helgoland and recorded Mnemiopsis leidyi for the first time in the North Sea, albeit in much lower densities than those recorded in the Baltic Sea.
    Type: Article , PeerReviewed
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 49
    Publication Date: 2019-09-23
    Description: A novel selective enrichment method is described for phototrophic green sulfur bacteria even in the presence of purple sulfur and purple nonsulfur bacteria using sulfanilate, which was discovered during efforts to selectively isolate sulfanilate-metabolizing anoxygenic phototrophic bacteria from marine habitats. Samples for these experiments were obtained from beaches, saltpans, subsurface mangrove soils, fish and prawn aquaculture ponds and backwaters of the East and West coasts of India. Photoorganoheterotrophic and photolithoautotrophic enrichments in the absence of sulfanilate predominantly yielded purple bacterial enrichments. In contrast, photolithoautotrophic enrichments in the presence of sulfanilate yielded green-colored enrichments from the same samples. Whole cell absorption spectra of the enrichment cultures revealed the presence of bacteriochlorophyll c and thus green phototrophic bacteria. Microscopic observation demonstrated the presence of sulfur globules outside the bacterial cells and the presence of non-motile cells, some of which had prosthecae. 16S rDNA sequences obtained from green sulfur bacterial strains isolated from enrichment cultures confirmed the presence of representatives of the green sulfur bacterial genera Prosthecochloris and Chlorobaculum. The selective pressure of sulfanilate exerted through inhibition of phototrophic purple sulfur bacteria was demonstrated by inhibition studies using the purple sulfur bacteria Marichromatium indicum JA100 and Marichromatium sp. JA120 (JCM 13533) and the green sulfur bacterium Prosthecochloris sp. JAGS6 (JCM 13299).
    Type: Article , PeerReviewed
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 50
    facet.materialart.
    Unknown
    Springer
    In:  In: Mantle plumes - a multidisciplinary approach. , ed. by Ritter, R. and Christensen, U. Springer, Heidelberg, pp. 241-322.
    Publication Date: 2012-02-23
    Type: Book chapter , PeerReviewed
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 51
    facet.materialart.
    Unknown
    Springer
    In:  Physics and Chemistry of Minerals, 24 . pp. 281-293.
    Publication Date: 2017-01-03
    Description: Mössbauer spectroscopy was applied to characterize the valence states Fe(II) and Fe(III) in sedimentary minerals from a core of the Peru Basin. The procedure in unraveling this information includes temperature-dependent measurements from 275 K to very low temperature (300 mK) in zero–field and also at 4.2 K in an applied field (up to 6.2 T) and by mathematical procedures (least-squares fits and spectral simulations) in order to resolve individual spectral components. The depth distribution of the amount of Fe(II) is about 11% of the total Fe to a depth of 19 cm with a subsequent steep increase (within 3 cm) to about 37%, after which it remains constant to the lower end of the sediment core (at about 40 cm). The steep increase of the amount of Fe(II) defines a redox boundary which coincides with the position where the tan/green color transition of the sediment occurs. The isomer shifts and quadrupole splittings of Fe(II) and Fe(III) in the sediment are consistent with hexacoordination by oxygen or hydroxide ligands as in oxide and silicate minerals. Goethite and traces of hematite are observed only above the redox boundary, with a linear gradient extending from about 20% of the total Fe close to the sediment surface to about zero at the redox boundary. The superparamagnetic relaxation behavior allows to estimate the order of magnitude for the size of the largest goethite and hematite particles within the particle-site distribution, e.g. ∼170 Å and ∼50 Å, respectively. The composition of the sediment spectra recorded at 300 mK in zero-field, apart from the contributions due to goethite and hematite, resembles that of the sheet silicates smectite, illite and chlorite, which have been identified as major constituents of the sediment in the 〈2 μm fraction by X-ray diffraction. The specific “ferromagnetic” type of magnetic ordering in the sediment, as detected at 4.2 K in an applied field, also resembles that observed in sheet silicates and indicates that both Fe(II) and Fe(III) are involved in magnetic ordering. This “ferromagnetic” behavior is probably due to the double-exchange mechanism known from other mixed-valence Fe(II)–Fe(III) systems. A significant part of the clay-mineral iron is redox sensitive. It is proposed that the color change of the sediment at the redox boundary from tan to green is related to the increase of Fe(II)–Fe(III) pairs in the layer silicates, because of the intervalence electron transfer bands which are caused by such pairs.
    Type: Article , PeerReviewed
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 52
    Publication Date: 2018-01-19
    Description: In the marine environment, biofilms on submerged surfaces can promote or discourage the settlement of invertebrate larvae and macroalgal spores. The settlement-mediating effects of biofilms are believed to involve a variety of biofilm attributes including surface chemistry, micro-topography, and a wide range of microbial products from small-molecule metabolites to high-molecular weight extracellular polymers. The settled organisms in turn can modify microbial species composition of biofilms and thus change the biofilm properties and dynamics. A better understanding of biofilm dynamics and chemical signals released and/or stored by biofilms will facilitate the development of antifouling and mariculture technologies. This review provides a brief account of 1) existing knowledge of marine biofilms that are relevant to settlement mediation, 2) biotechnological application of biofilms with respect to developing non-toxic antifouling technologies and improving the operation of aquaculture facilities, and 3) challenges and future directions for advancing our understanding of settlement-mediating functions of biofilms and for applying this knowledge to real-life situations.
    Type: Article , PeerReviewed
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 53
    Publication Date: 2019-09-23
    Type: Article , PeerReviewed
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 54
    facet.materialart.
    Unknown
    Springer
    In:  International Journal of Earth Sciences, 96 (1). pp. 201-213.
    Publication Date: 2017-05-18
    Description: This is the first in-depth study of a cluster of cold-water coral reefs, the Fugløy Reefs, found at 70°N on the Norwegian margin. Combining high resolution seismic reflection data, side-scan sonar, video-images, and oceanographic measurements reveals the geologic, geomorphologic and oceanographic setting in which the reefs occur. The reefs consist mainly of the scleractinian ahermatypic Lophelia pertusa, and exist below the thermocline at water depths between 140 m and 190 m. The reefs appear as cone-shaped, acoustically transparent features on seismic reflection data, consistently located in places characterized by the availability of hard substrate, high relief, and periodical exposure to high tidal cur-rents (〉30 cm/s). These currents transport water of the Norwegian Atlantic Current to the reefs from an area with fluid expulsion-related pockmarks. The spatial relationship between reef and pockmark locations and current directions suggests that seepage of biogenic gas might be a catalyst to reef growth. With a height of more than 40 m some of the Fugløy reefs are among the highest reported from the Norwegian Margin. This indicates highly fa-vourable growth conditions, and conservative estimates indicate a net growth rate for the reefs of ~5 mm/yr. We expect that cold-water reefs will be found further north along the Barents Sea margin as general awareness on the geophysical signature and appearance of the reefs increases, because all known factors involved in reef establishment and growth are within the required intervals also further north. Introduction
    Type: Article , PeerReviewed
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 55
    facet.materialart.
    Unknown
    Springer
    In:  International Journal of Earth Sciences, 96 (6). pp. 1033-1046.
    Publication Date: 2017-05-18
    Description: The symmetry or asymmetry of the process of continental breakup has been much debated over the last 20 years, with various authors proposing asymmetric simple shear models, others advocating more symmetric, pure shear models and some combinations of the two. The unroofing of vast expanses of sub-continental mantle at non-volcanic margins has led some authors to argue in favour of simple shear models, but supporting evidence is lacking. Subsidence evidence from conjugate margin pairs is equivocal, and the detailed crustal and lithospheric structure of such pairs not generally well enough known to draw firm conclusions. In the Porcupine Basin, where the final stages of break-up are preserved, the development of structural asymmetry is demonstrable, and apparently related to late stage coupling of the crust to the mantle following the complete embrittlement of the crust. This agrees with theoretical modelling results, which predict that asymmetric models can develop only on a lithospheric scale when the crust and mantle are tightly coupled. However, whether such asymmetry is maintained during continued exhumation of the mantle is unclear.
    Type: Article , PeerReviewed
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 56
    Publication Date: 2017-03-22
    Description: Specific associations of bacteria with phytoplankton have recently been reported in the literature. In our study, we analyzed bacterial communities of microalgal cultures related to algal growth phases. Seven freshly isolated key diatom and dinoflagellate species from Helgoland Roads, North Sea, were investigated. The community composition of associated bacteria as well as the cell numbers, the photosynthetic efficiency of the algae, and the depletion of inorganic nutrients in the medium were recorded over a period of 8 weeks in batch cultures. Diversity and succession of bacterial communities was analyzed by ribosomal intergenic spacer analysis. Phylogenetic analysis of bacterial populations was performed by denaturing gradient gel electrophoresis of 16S rRNA genes followed by DNA sequence analysis. Members of Alphaproteobacteria and Gammaproteobacteria and the Flavobacteria–Sphingobacteria group within the Bacteroidetes phylum predominated in the cultures. Differences in free-living and attached bacterial populations were observed between the phylogenetic groups. Shifts in the bacterial communities could not be correlated to changes of nutrient levels or algal growth phases. Regarding our results, it should not be generalized that the compositions of the bacterial communities are strictly species specific for microalgae. The importance of factors like the composition of exudates is apparent.
    Type: Article , PeerReviewed
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 57
    Publication Date: 2016-05-26
    Description: A new marine phototrophic purple sulfur bacterium (strain CE2203) was isolated in pure culture from a man-made coastal lagoon located on the Atlantic coast (Arcachon Bay, France). Single cells were coccus-shaped, did not contain gas vesicles, and were highly motile. Intracellular photosynthetic membranes were of the vesicular type. Bacteriochlorophyll a and carotenoids of the normal spirilloxanthin series were present as photosynthetic pigments. Hydrogen sulfide, thiosulfate, elemental sulfur, and molecular hydrogen were used as electron donors during photolithotrophic growth under anoxic conditions, while carbon dioxide was utilized as carbon source. Acetate, propionate, lactate, glycolate, pyruvate, fumarate, succinate, fructose, sucrose, ethanol, and propanol were photoassimilated in the presence of hydrogen sulfide. During growth on sulfide, elemental sulfur globules were stored inside the cells. Chemotrophic growth under microoxic conditions in the dark was possible. The DNA base composition was 66.9 mol% G+C. Comparative sequence analysis of the 16S rRNA gene confirmed the membership of strain CE2203 in the family Chromatiaceae. Morphological characteristics of strain CE2203 indicated a close affiliation to the genera Thiocystis and Thiocapsa. However, the phylogenetic treeing revealed no closer relationship to Thiocystis spp. than to Thiocapsa roseopersicina or other known members of the Chromatiaceae. Consequently, strain CE2203 is proposed as the type strain of a new genus and species, Thiorhodococcus minus gen. nov., sp. n
    Type: Article , PeerReviewed
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 58
    facet.materialart.
    Unknown
    Springer
    In:  Hydrobiologia, 355 (1/3). pp. 49-59.
    Publication Date: 2014-03-12
    Description: In many benthic communities predators play a crucial role in the population dynamics of their prey. Surface characteristics of the prey are important for recognition and handling by the predator. Because the establishment of an epibiotic assemblage on the surface of a basibiont species creates a new interface between the epibiotized organism and its environment, we hypothesised that epibiosis should have an impact on consumer-prey interactions. In separate investigations, we assessed how epibionts on macroalgae affected the susceptibility of the latter to herbivory by the urchin Arbacia punctulata and how epibionts on the blue mussel Mytilus edulis affected its susceptibility to predation by the shore crab Carcinus maenas. Some epibionts strongly affected consumer feeding behavior. When epibionts were more attractive than their host, consumer pressure increased. When epibionts were less attractive than their host or when they were repellent, consumer pressure decreased. In systems that are controlled from the top-down, epibiosis can strongly influence community dynamics. For the Carcinus/Mytilus system that we studied, the insitu distribution of epibionts on mussels reflected the epibiosis-determined preferences of the predator. Both direct and indirect effects are involved in determining these epibiont-prey-consumer interactions.
    Type: Article , PeerReviewed
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 59
    Publication Date: 2018-06-01
    Description: Of 45 bacterial isolates from healthy tips of Gracilaria conferta (Schousboe ex Montagne) J. et G. Feldmann, 29% were identified as 'conditional inducers' of an apical necrosis. That is, the isolates induced necrotic tips in G. conferta within 16 h after elimination of most of the resident microflora from the alga. Several disinfectants and antibiotics were screened for their ability to induce algal susceptibility to the bacteria and to suppress uncontrolled appearance of tip necrosis. Treatment with 100 mg L-1 Cefotaxim + 100 mg L-1 Vancomycin over three days was the least damaging and most efficient. Tip necrosis was related to isolates of the Corynebacterium-Arthrobacter-group and to the Flavobacterium-Cytophaga-group. The damaging effect occurred due to the bacterial excretion of active agents and was not correlated with a capability to degrade agar. The damaging influence of four Cytophaga-like strains was inhibited by 20 of 40 isolates. This protective effect was caused by very different organisms. In five of six cases examined further, the effect was not cellbound, but due to the excretion of agents. These were not antimicrobially active, but inactivated necrosis-inducing excretions. These results indicate that epiphytic bacterial degradation or inactivation of damaging agents is a protecting factor in Gracilaria, which prevents the alga from being harmed by epiphytes.
    Type: Article , PeerReviewed
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 60
    Publication Date: 2019-04-03
    Description: Coastal areas are exposed to a variety of threats due to high population densities and rapid economic development. How will this affect human welfare and our dependence on nature's capacity to provide ecosystem goods and services? This paper is original in evaluating this concern for major habitats (macroalgae, seagrasses, blue mussel beds, and unvegetated soft bottoms) in a temperate coastal setting. More than 40 categories of goods and services are classified into provisional, regulating, and cultural services. A wide variety of Swedish examples is described for each category, including accounts of economic values and the relative importance of different habitats. For example, distinguishing characteristics would be the exceptional importance of blue mussels for mitigation of eutrophication, sandy soft bottoms for recreational uses, and seagrasses and macroalgae for fisheries production and control of wave and current energy. Net changes in the provision of goods and services are evaluated for three cases of observed coastal ecosystem shifts: i) seagrass beds into unvegetated substrate; ii) unvegetated shallow soft bottoms into filamentous algal mat dominance; and iii) macroalgae into mussel beds on hard substrate. The results are discussed in a management context including accounts of biodiversity, interconnectedness of ecosystems, and potential of economic valuation.
    Type: Article , PeerReviewed
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 61
    facet.materialart.
    Unknown
    Springer
    In:  AMBIO: A Journal of the Human Environment, 26 (7). pp. 424-431.
    Publication Date: 2019-04-04
    Description: A large, densely populated catchment area dominating water quality of land runoff, stratification of the brackish water, a residence time of 25 years, intermittent renewal of oxygenated bottom water from the North Sea, few plant and animal species already stressed by low salinity, make the Baltic Sea vulnerable to changes in external forcings such as increased inputs of nutrients and toxic substances. A severalfold increase of nutrient inputs and primary production since the beginning of the century has increased the area of anoxic bottoms, decreased the transparency of the water by 2.5-3 m, favored filamentous annual algae at the expense of coarse, perennial ones-like the important bladderwrack (Fucus vesiculosus)-changed the fish community from cod, salmon, pike and perch toward herring, sprat, bream, and roach. Because they are a major source of external nitrogen, a shift in current agricultural practices has to be made including: tree curtains to increase patchiness, biodiversity and natural pest control; catch crops along rivers; matching animal density and crop types to achieve optimal recycling of nutrients. So far, integrated land use, based on operative ecological-socioeconomic models, is the most powerful policy instrument for a sustainable agriculture.
    Type: Article , PeerReviewed
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 62
    Publication Date: 2018-01-19
    Description: Scleractinian corals are increasingly used as recorders of modern and paleoclimates. The microstructure of four common reef-building coral genera is documented here: Acropora, Pocillopora, Goniastrea, and Porites. This study highlights the complexity and spatial variability of skeletal growth in different coral genera and suggests that a single growth model is too generalized to allow the accurate depiction of the variability observed in the four genera studied. New models must be introduced in order for coral skeletogenesis to be understood adequately to allow coral skeletons to serve as repositories of temporally constrained geochemical data. Owing to differences in microstructural patterns in different genera, direct observation of microstructural elements and growth lines may be necessary to allow microsamples to be placed into series that represent temporal sequences with known degrees of time averaging. Such data are critical for constraining microsampling strategies aimed at developing true time series geochemical data at very fine spatial and temporal scales.
    Type: Article , PeerReviewed
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 63
    Publication Date: 2021-01-19
    Description: Individuals of the deepwater squid Moroteuthis ingens were obtained from New Zealand waters at depths between 500 and 1452m. Depth distribution suggested that there was an ontogenetic migration to deeper water by females in association with maturity. Males did not show any clear pattern in their depth distribution. Statoliths increment analysis was also undertaken to obtain putative age and life span information. Based on statolith age estimates, M. ingens appears to be predominantly an annual species with the oldest individuals aged at 358 and 393 days for males and females respectively. The form of growth over the size range sampled was linear with females having a growth rate almost twice that of males. Back-calculated hatching dates revealed a peak in hatching in the austral winter between June and August. maturation in males was more closely related to size rather than age whereas in females the pattern in ovary growth in relation to both mantle length and age was similar.
    Type: Article , PeerReviewed
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 64
    facet.materialart.
    Unknown
    Springer
    In:  Polar Biology, 18 (3). pp. 161-165.
    Publication Date: 2021-04-19
    Description: Effects of summer food shortage on king penguin Aptenodytes patagonicus chicks were studied at South Georgia. Two cohorts were compared, fledging in the austral summers of 1992 (n = 32) and 1994 (n = 33) when availability of food was judged good and poor, respectively. The former cohort had a higher pre-fledging mean mass (12.78 kg vs ≤ 10.03 kg), fledged earlier (median 5 January vs 21 January), and a higher proportion was re-sighted within 2 years of fledging (28% vs 0%). Within 4 years, 47% of the former cohort had been re-sighted (i.e. post-fledge survival); in addition, one was observed at the Falkland Islands, and 22% had bred (i.e. recruitment) in their colony of origin. The re-sighted chicks of the 1992 cohort fledged earlier than those not re-sighted (median 24 December vs 10 January), but it remain unclear if they were heavier at fledging. All chicks in this study (n = 65) were marked with both transponders (subcutaneously implanted) and flipper bands (on one flipper), and no losses of any markings were found (controlled up to 4 years afterwards). Therefore, data on chick post-fledging survival and recruitment were not adjusted for losses of markings, as has been done in other studies.
    Type: Article , PeerReviewed
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 65
    facet.materialart.
    Unknown
    Springer
    In:  Polar Biology, 17 (4). pp. 371-383.
    Publication Date: 2021-06-14
    Description: Annual observations of seabirds within Prydz Bay, East Antarctica, between the 1980/1981 and 1992/1993 seasons revealed siginificant changes in abundance of the 9 resident and 15 non-resident species. An estimated 4.85 million individual residents and 2.35 million individual non-residents were present each season. For resident and non-resident species, mean abundance was 3.75 and 1.81 birds/km2, and mean biomass was 6.67 and 1.70 kg/km2, respectively. Based on estimated abundances, the total consumption of marine resources by the seabird community within Prydz Bay ranged from 471,000 to 1.1 million tonnes (mean 752,000±176,000 tonnes) per 6-month summer, or between 2.02 and 4.53 kg/km2 per day (mean 3.23±0.76 kg/km2 per day). The mean energy flux to the seabird community within Prydz Bay each summer was 3.13*1012 kJ, (range: 2.0*1012 kJ–4.4*1012 kJ), of which 66% went to the resident species. Regional abundance and biomass estimates for resident and non-resident species were both negatively correlated; when the estimated abundance and biomass of resident species were high, those of non-resident species were low.
    Type: Article , PeerReviewed
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 66
    Publication Date: 2021-08-05
    Description: We describe the feeding habits of 70 blue sharks (Prionace glauca) and 39 salmon sharks (Lamna ditropis) caught at 0–7 m depth at night by research drift gillnets in the transition region of the western North Pacific during April–May of 1999 and 2000. Blue sharks of 50–175 cm total length fed on a large variety of prey species, consisting of 24 species of cephalopods and 16 species of fishes. Salmon sharks of 69–157 cm total length fed on a few prey species, consisting of 10 species of cephalopods and one species of fish. Important prey for the blue sharks were large, non-active, gelatinous, meso- to bathypelagic cephalopods (e.g., Chiroteuthis calyx, Haliphron atlanticus, Histioteuthis dofleini and Belonella borealis) and small myctophid fishes. Important prey for the salmon sharks were mid-sized, active, muscular, epi- to mesopelagic squids (e.g. Gonatopsis borealis, Onychoteuthis borealijaponica and Berryteuthis anonychus). Our results suggest that blue sharks feed on cephalopods mainly during the daytime when they descend to deep water. Salmon sharks may feed opportunistically with no apparent diurnal feeding period. Blue sharks and salmon sharks have sympatric distribution in the transition region in spring; they have different feeding habits and strategies that reduce competition for food resources.
    Type: Article , PeerReviewed
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 67
    facet.materialart.
    Unknown
    Springer
    In:  Reviews in Fish Biology and Fisheries, 17 (2-3). pp. 477-485.
    Publication Date: 2021-09-06
    Description: During hydroacoustic observations in November 2002, a large concentration of chokka squid (Loligo reynaudi) was monitored for three days during fairly constant wind speed and direction, that marginally improved during the period of observations. During this period, the concentration (estimated biomass 48 t) disintegrated into small, separate aggregations. Most often, such dispersal is weather-related, but obviously not in this case. Instead, a bottom trawl made adjacent to the concentration, as well as underwater camera observations revealed an unusually large number of predators, mostly bronze whaler sharks (Carcharhinus brachyurus). Most whaler sharks caught in the trawl had chokka in their stomachs. Therefore, one explanation for the break-up of this squid concentration was the unusual predator activity. Video observations revealed, that these attacks occurred on the bottom where squid spawn; while none were observed in the water column where squid pair, mate and swim in a circular motion preparing for descent to the egg bed. The disintegration of the whole concentration suggested that disrupted spawning affects the upper part of the typical mushroom-shaped structure as well, and squid subsequently disperse and/or move away as a result of predation by whaler sharks.
    Type: Article , PeerReviewed
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 68
    facet.materialart.
    Unknown
    Springer
    In:  Polar Biology, 17 (1). pp. 87-90.
    Publication Date: 2021-04-20
    Description: The composition of Antarctic fur seal prey was assessed through analysis of scats collected in March 1994 on Ile de Croy, Iles Nuageuses. Fish remains predominated in samples, occurring in 95% of droppings. A total of 968 otoliths allowed the identification of 16 fish species. Myctophid fish (12 species) dominated the diet both by number (94% of the otoliths) and by fish reconstituted mass (76%). Three fish species constituted together 87% of the reconstituted mass: the myctophids Gymnoscopelus nicholsi (52%) and G. piabilis (12%), and the channichthyid Champsocephalus gunnari (23%). Prey distribution suggests that during late summer seals forage in upper slope waters in the northeast of the Kerguelen Archipelago.
    Type: Article , PeerReviewed
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 69
    Publication Date: 2021-04-22
    Description: Samples of the Antarctic octopus Pareledone turqueti were taken from three locations on the Scotia Ridge in the Southern Ocean. The genetic homogeneity of these populations was investigated using isozyme electrophoresis. Whilst panmixia appeared to be maintained around South Georgia (F ST = 0) gene flow between this island and Shag Rocks, an island only 150 km away but separated by great depths, was extremely limited (F ST = 0.74). These results are examined with respect to the discontinuous distribution of P. turqueti throughout Antarctica. An estimate of effective population size was also calculated (N e = 3600).
    Type: Article , PeerReviewed
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 70
    Publication Date: 2021-04-22
    Description: Statolith microstructure was studied in 56 Ancistrocheirus lesueurii (25 to 423 mm of mantle length, ML) caught in the central-east Atlantic. Statolith growth increments were grouped into three main growth zones, distinguished mainly by increment width. The second transition in the statolith microstructure (from Zone 2 to Zone 3) coincides with the life history shift from epipelagic and upper mesopelagic to a bathyal habitat. Second-order bands (mean 27.65 growth increments) and sub-bands (mean 13.6 growth increments) within statolith microstructure appeared to be related to the lunar cycle. Striking sexual dimorphism is reflected in the age and growth rates: males live ca. 1 yr, while females only start maturing at this age and obviously live 〉1.5 yr. A. lesueurii is a slow growing squid, attaining 25 to 30 mm ML at the age of 100 d. After ontogenetic migrations into bathypelagic waters at ML 〉 30 to 35 mm, growth rates gradually decrease to the minimum known values for squids. Based on back-calculated hatching dates, A. lesueurii hatches throughout the year with a peak between November and March.
    Type: Article , PeerReviewed
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 71
    Publication Date: 2021-08-09
    Description: A two day workshop on Southern Ocean cephalopods was held in Hobart, Tasmania, Australia prior to the triennial 2006 Cephalopod International Advisory Council (CIAC) symposium. The workshop provided a second international forum to present the current state of research and new directions since the last Southern Ocean cephalopod meeting held in 1993. A major focus of the workshop was trophic ecology and the use of a variety of tools that can be applied in Southern Ocean trophic studies for both cephalopod and predator researchers. New tools that are being used as trophic indicators and tracers in food chain pathways include stable isotope, heavy metal and fatty acid signature analysis. Progress is also being made on understanding squid population dynamics in relation to other key components of the ecosystem by incorporating squid data in ecosystem models. Genetic barcoding is now of great value to fish taxonomy as well as other groups and it is expected that a cephalopod barcoding initiative will be an important tool for cephalopod taxonomy. There is a current initiative to produce a new cephalopod beak identification guide to assist predator biologists in identifying cephalopod prey items. There were also general discussions on specific taxonomic issues, Southern Ocean Cephalopod paralarvae and parasites, and suggestions for future CIAC workshop topics.
    Type: Article , PeerReviewed
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 72
    Publication Date: 2021-07-23
    Description: The pharaoh cuttle Sepia pharaonis Ehrenberg, 1831 (Mollusca: Cephalopoda: Sepiida) is a broadly distributed species of substantial fisheries importance found from east Africa to southern Japan. Little is known about S. pharaonis phylogeography, but evidence from morphology and reproductive biology suggests that Sepia pharaonis is actually a complex of at least three species. To evaluate this possibility, we collected tissue samples from Sepia pharaonis from throughout its range. Phylogenetic analyses of partial mitochondrial 16S sequences from these samples reveal five distinct clades: a Gulf of Aden/Red Sea clade, a northern Australia clade, a Persian Gulf/Arabian Sea clade, a western Pacific clade (Gulf of Thailand and Taiwan) and an India/Andaman Sea clade. Phylogenetic analyses including several Sepia species show that S. pharaonis sensu lato may not be monophyletic. We suggest that “S. pharaonis” may consist of up to five species, but additional data will be required to fully clarify relationships within the S. pharaonis complex.
    Type: Article , PeerReviewed
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 73
    Publication Date: 2021-07-27
    Description: Coleoid cephalopods show flexibility in their reproductive strategies or mode of spawning, which can range from simultaneous terminal spawning over a short period at the end of the animal’s life to continuous spawning over a long period of the animal’s life. Although a simultaneous terminal spawning strategy is typical of shallow water temperate octopuses, it is not known whether deep-sea octopods would have the same reproductive strategy. The reproductive strategies and fecundity were investigated in nine species of deep-sea incirrate octopuses: Bathypolypus arcticus, Bathypolypus bairdii, Bathypolypus ergasticus, Bathypolypus sponsalis, Bathypolypus valdiviae, Benthoctopus levis, Benthoctopus normani, Benthoctopus sp., and Graneledone verrucosa (total n = 85). Egg-length frequency graphs and multivariate analysis (principal components analysis) suggest that B. sponsalis has a synchronous ovulation pattern and therefore a simultaneous terminal spawning strategy. Although a simultaneous terminal spawning strategy is most likely for B. levis and B. normani, the egg-length frequency graphs and multivariate analysis also suggest a greater variation in egg-lengths which could lead to spawning over an extended period.
    Type: Article , PeerReviewed
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 74
    facet.materialart.
    Unknown
    Springer
    In:  Reviews in Fish Biology and Fisheries, 17 (2-3). pp. 337-344.
    Publication Date: 2021-08-23
    Description: The concept of a Barcode of Life Database (BoLD) for the Class Cephalopoda (Phylum Mollusca) was introduced at the Cephalopod International Advisory Council (CIAC) symposium in Hobart, Australia, February 2006. This suggestion was met with significant interest, concern and debate. This review attempts to describe the concept of the BoLD initiative and to outline considerations and concerns specific to a cephalopod BoLD.
    Type: Article , PeerReviewed
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 75
    facet.materialart.
    Unknown
    Springer
    In:  Reviews in Fish Biology and Fisheries, 17 (2-3). pp. 353-365.
    Publication Date: 2021-08-27
    Description: We describe here two new species of oegopsid squids. The first is an Asperoteuthis (Chiroteuthidae), and it is based on 18 specimens. This new species has sucker dentition and a funnel–mantle locking apparatus that are unique within the genus. The second new species is a Promachoteuthis (Promachoteuthidae), and is based on a unique specimen. This new species has tentacle ornamentation which is unique within the genus. We also describe a new genus and a new species of sepioid squid in the subfamily Heteroteuthinae (Sepiolidae) and it is based on four specimens. This new genus and species exhibits unique modifications of the arms in males.
    Type: Article , PeerReviewed
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 76
    Publication Date: 2021-02-22
    Description: The behaviour of cirrate octopods of the genera Cirroteuthis and Grimpoteuthis in their natural habitat was studied using video recordings. Sequences were filmed during the French cruise “Faranaut”, from the manned submersible “Nautile” at depths between 2702 and 4527 m, in two zones in the Fifteen-Twenty Fracture Zone on the Mid-Atlantic Ridge. Four different modes of active locomotion, namely crawling, take-off, fin-swimming, and pumping, and one apparently passive mode of locomotion, umbrella-style drifting, were observed. Jet-propulsion, a characteristic mode of locomotion typically employed by cephalopods, was not observed in the cirrate octopods filmed, although breathing movements of the mantle to aerate the gills were assumed to generate some slight propulsion through the funnel. Fin-swimming was the mode of active locomotion most frequently observed. Neutral buoyancy was confirmed in one individual after capture. This buoyancy enables passive drifting in the umbrella-style attitude observed in Cirroteuthis spp., possibly using near-bottom ocean currents. Pumping, a mode of slow locomotion generated by peristaltic waves in the primary and intermediate webs, also observed in Cirroteuthis sp., is described here for the first time. The take-off mode of locomotion, a sudden, single contraction of the brachial crown and web, is also described; it was always followed by fin-swimming. No medusoid swimming of the type previously described for opisthoteuthid cirrates was observed. A flight response to the approach of or contact with a strange object, i.e. the submersible, using the crawling, take-off, or fin-swimming modes was observed. A ballooning response was observed in a high-stress situation when a C.magna individual was captured.
    Type: Article , PeerReviewed
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 77
    facet.materialart.
    Unknown
    Springer
    In:  Reviews in Fish Biology and Fisheries, 17 (2-3). pp. 305-335.
    Publication Date: 2021-08-02
    Description: Onychoteuthid squids are among the most common cephalopods found in New Zealand waters, and comprise a major portion of the regional diets of teuthophagous marine mammals. Although several recent publications have addressed aspects of various species’ biology and reproduction, the systematics of the group remains poorly understood. Herein the ontogenetic and adult morphologies of regionally occurring known species of the genera Moroteuthis, Onychoteuthis, and Notonykia are redescribed, and Notonykia nesisi sp. nov. is described for the first time. Ontogenetic and sexually dimorphic variation in characters and character states associated with body proportions, and beak, radula, tentacular hook, palatine tooth and gladius morphologies are also described and compared between local onychoteuthid taxa for the first time.
    Type: Article , PeerReviewed
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 78
    facet.materialart.
    Unknown
    Springer
    In:  Marine Biology, 152 (4). pp. 981-990.
    Publication Date: 2021-09-06
    Description: Deep-sea squids, Moroteuthis ingens and Gonatus antarcticus, were collected in the slope waters off the Falkland Islands and their reproductive systems preserved and investigated onshore. Changes in oocyte length-frequencies at maturation and spawning, and their fecundity were studied. These squids, as well as many other species, are characterised by a synchronous oocyte growth and ovulation. Oviducts are not used for ripe egg accumulation and consequently the universal scale of Lipinski (1979) cannot be applied to assign female maturity. M. ingens spawns near the bottom; its fecundity is 168–297 thousand eggs. Maximum egg size is 1.8–2.7 mm. G. antarcticus spawns midwater; its fecundity is 10–25 thousand eggs. Egg size is 3.2–3.3 mm. In M. ingens spawning takes place in the austral autumn and winter, in G. antarcticus—in austral winter. Our data and the literature data show that the so-called “synchronous ovulation” probably occurs in all deepwater squids. This pattern is very rare among fish, but is quite common among benthic octopods that brood their egg masses.
    Type: Article , PeerReviewed
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 79
    Publication Date: 2021-09-07
    Description: Lycoteuthis lorigera is an oceanic squid that is abundant in the Benguela system. Little is known about the biology of this squid except that it is eaten in large numbers by numerous oceanic predators and that males grow to larger size than females, which is unique for oegopsid squid. The aim of this study was to better understand the biology of this species by investigating its age and growth, as well as its mating system. Toward this end, the age of 110 individuals, ranging from 35 to 110 mm, was estimated by counting statolith growth increments. Estimates of age ranged from 131 to 315 days and varied with mantle length. No significant differences were found in the size of males and females of equivalent ages. The relationship between ML and age for both sexes was best described by an exponential growth curve, probably because no early life stages were aged in this study. Only one mature male (ML 160 mm) was aged, and preliminary estimates suggest it was 386 days old. Instantaneous growth rates were low (0.54% ML/day and 1.4% BM/day) but consistent with enoploteuthid growth rates. When the growth rate of L. lorigera was corrected for temperature encountered during the animal’s life, the growth rate was fast (0.47% BM/degree-days) and consistent with the hypothesis that small cephalopods grow fast and that large cephalopods grow older, rather than fast. Mature females were often mated and had spermatangia in a seminal receptacle on the dorsal pouch behind the nuchal cartilage. Males probably transfer spermatangia to the females using their long second and/or third arm pair since the paired terminal organs open far from the mantle opening.
    Type: Article , PeerReviewed
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 80
    Publication Date: 2021-08-31
    Description: Pholidoteuthis is unusual amongst genera of squid in that the mantle is beset with close-packed dermal cushions (scales). Despite frequent reference to species in this genus, considerable systematic confusion surrounds usage of the generic name, erected prematurely given that the same systematic characters apply for the earlier Tetronychoteuthis Pfeffer, 1900, and species attributed to it. The synonymy and ontogenetic morphology of Pholidoteuthis massyae (Pfeffer 1912) new comb., the senior synonym of P. boschmai Adam, 1950, is reported. The relationship between this species and others referred to Tetronychoteuthis, Lepidoteuthis, the Pholidoteuthidae Adam, 1950, Lepidoteuthidae Pfeffer, 1912 and Octopoteuthidae Berry, 1912, is discussed. A conjectural account of the mechanics of mating in P. massyae is provided based on the nature of spermatophore insertion in the female mantle, and modification to the terminal region of the male’s genital apparatus.
    Type: Article , PeerReviewed
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 81
    facet.materialart.
    Unknown
    Springer
    In:  Reviews in Fish Biology and Fisheries, 17 (2-3). pp. 183-195.
    Publication Date: 2021-09-03
    Description: The aim of this study was to determine how size, age, somatic and reproductive condition, abundance and egg production of southern calamary spawning aggregations changed during the spawning season in each of 2 years. During the spawning period in at least one of the years there was a decline as much as 20% in average size, 50% in somatic condition, 28–34% in size-at-age, 26–29% in reproductive status, as well as abundance and reproductive output of the stock declining during the spawning season. However, this change was not a function of the population becoming reproductively exhausted, as the aggregation was composed of different individuals with different biological characteristics. In each month the average age of individuals was ca. 6 mo, indicating that squid that had hatched at different times had entered the spawning aggregations, suggesting that the aggregation was made-up of a succession of microcohorts. Currently, management of many squid populations assumes that there is a single cohort in the aggregation. Therefore, estimating stock biomass at the start of the spawning season cannot be used as the population is constantly changing as micro-cohorts move into the aggregation. An instantaneous estimate of the spawning biomass, independent of fishing activity may be obtained by quantifying the density of deposited eggs. The strategy of individuals with a diversity of life history characteristics coming together in a single spawning aggregation may ensure the phenotypic and genetic diversity required to guarantee successful recruitment of this short-lived species. Therefore, temporally structured protection from harvest throughout the spawning season will ensure maintenance of this population diversity.
    Type: Article , PeerReviewed
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 82
    facet.materialart.
    Unknown
    Springer
    In:  Polar Biology, 18 (6). pp. 371-375.
    Publication Date: 2021-02-15
    Description: A total of 41 faeces and 5 vomits of the Weddell seal Leptonychotes weddelli was collected at Harmony Point, Nelson Island, South Shetland Islands, from 14 January to 1 February 1996. The diet indicated by the remains in the samples was diverse and comprised both pelagic and benthic-demersal species. Fish were the most frequent (95.7%) and numerous prey (46.2%), but molluscs were the most important by mass (65.8%). Octopods, mainly Pareledone charcoti, constituted the bulk of the diet (63.1% by mass), but the importance of the remaining molluscs was negligible. Otoliths represented 510 fish of which 491 were identified as belonging to 5 species: Gymnoscopelus nicholsi, Electrona antarctica, Lepidonotothen nudifrons, Gobionotothen gibberifrons and Nototheniops nybelini. The myctophid Gymnoscopelus nicholsi was the most important fish prey, and the contribution of benthic-demersal species was low. However, the importance of that fish was over-estimated since 96% of the specimens were obtained from the five vomits analysed. The biases associated with the faecal analysis technique are discussed.
    Type: Article , PeerReviewed
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 83
    Publication Date: 2021-06-17
    Description: The diets of 1219 southern bluefin tuna, Thunnus maccoyii, from inshore (shelf) and offshore (oceanic) waters off eastern Tasmania were examined between 1992 and 1994. Immature fish (〈 155 cm fork length) made up 88% of those examined. In all, 92 prey taxa were identified. Inshore, the main prey were fish (Trachurus declivis and Emmelichthys nitidus) and juvenile squid (Nototodarus gouldi). Offshore, the diversity was greater, reflecting the diversity of micronekton in these waters. Interestingly, macrozooplankton prey (e.g. Phronima sedentaria) were prevalent in tuna 〉 150 cm. The offshore tuna, when in subantarctic waters, ate relatively more squid than when in the East Australia Current. In the latter, fish and crustacea were more important, although there were variations between years. No relationship was found between either prey type or size with size of tuna. Feeding was significantly higher in the morning than at other times of the day. The mean weight of prey was significantly higher in inshore-caught tuna than in those caught offshore. We estimated that the mean daily ration of southern bluefin tuna off eastern Tasmania was 0.97% of wet body weight day−1. However, the daily ration of inshore-caught tuna was ∼ 3 times higher (2.7%) than for tuna caught offshore (0.8%) indicating that feeding conditions on the shelf were better than those offshore. Our results indicate that the inshore waters of eastern Tasmania are an important feeding area for, at least, immature southern bluefin tuna.
    Type: Article , PeerReviewed
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 84
    facet.materialart.
    Unknown
    Springer
    In:  Reviews in Fish Biology and Fisheries, 17 (2-3). pp. 283-294.
    Publication Date: 2021-08-04
    Description: In the northwestern Bering Sea in autumn, the epipelagic cephalopod community was represented by the boreal fauna, and was found to be composed of three families and nine species of the order Teuthida: Gonatidae (Berryteuthis magister, Boreoteuthis borealis, Gonatopsis japonicus, Gonatus madokai, Gonatus kamtschaticus, Gonatus onyx, and Gonatus pyros), Chiroteuthidae (Chiroteuthis calyx) and Onychoteuthidae (Onychoteuthis borealijaponica). Two pelagic gonatid species (B. borealis and G. kamtschaticus) dominated the cephalopod community in the upper 50 m. The distribution patterns of B. borealis and G. onyx were associated with diel vertical migrations of these squid. The distribution of two distinct size groups of G. kamtschaticus suggested ontogenetic migration of larger squid to deeper layers, and adds to previous data suggesting that this species may be a heterogeneous assemblage. Demersal B. magister rarely occurred in the surface waters. The occurrence of maturing O. borealijaponica in the southern marine area indicated that these were occasional seasonal migrants from the ocean. The occurrence of juvenile C. calyx suggested that these squid may conduct vertical forage migrations from deep waters to the surface layers.
    Type: Article , PeerReviewed
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 85
    facet.materialart.
    Unknown
    Springer
    In:  Reviews in Fish Biology and Fisheries, 17 (2-3). Art.-Nr.: 101.
    Publication Date: 2021-08-18
    Description: Statolith size and growth was used to determine the influence of abiotic factors on the growth of Loligo vulgaris and Sepioteuthis australis embryos. Recently spawned egg masses collected from the field were incubated in the laboratory under different levels of light intensity, photoperiod, or short periods of low salinity (30‰). Double tetracycline staining was used to follow statolith growth. In L. vulgaris constant light conditions produced significantly slower growth in the embryonic statoliths and embryos held at summer photoperiod had slower statolith growth than those held at winter photoperiods. However once they hatched out there was no evidence that photoperiod affected statolith growth. After hatching, in all photoperiods statolith growth rates decreased in comparison with late embryonic rates. In S. australis embryos, differences between the high and medium light intensities for summer and intermediate photoperiods were found, suggesting that under summer incubation temperature, longer daylengths at medium light intensity favoured higher statolith growth for this species. In comparison to controls, slower statolith growth in S. australis embryos due to low salinity only occurred when exposed for 72 h. Comparison with previous studies indicates that temperature seems to be the main abiotic factor influencing statolith growth during early stages, however, interactions among all abiotic factors needs to be determined as well as the unknown influence of other isolated factors, e.g., oxygen concentration within the egg mass.
    Type: Article , PeerReviewed
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 86
    Publication Date: 2016-11-09
    Description: Seasonal activities of the digestive enzyme trypsin were measured between August 1998 and May 1999 to study different nutritional strategies of the two copepods Pseudocalanus minutus and Oithona similis in the Arctic Kongsfjorden (Svalbard) using a highly sensitive fluorescence technique. Stage-, depth- and season-specific characteristics of digestive activity were reflected in the trypsin activity. P. minutus females and stage V copepodids (C) had highest trypsin activities in spring during reproduction (197.5 and 145.7 nmol min−1 ng C−1, respectively). In summer stages CIII–V and in autumn stages CIV and V had high activities (80–116 nmol min−1 ng C−1) in the shallow layer (〈 100 m) presumably as a consequence of prolonged feeding before descending to overwintering depth. Trypsin activities at depth (〉 100 m) in summer and autumn were low in stages CIII and CIV (29–60 nmol min−1 ng C−1) and in winter in all stages in both layers (20–43 nmol min−1 ng C−1). Based on low trypsin activity, males most likely did not feed. In O. similis, the spring phytoplankton bloom did not significantly affect trypsin activity as compared to the other seasons. O. similis CV and females had high trypsin activities in summer in the deep stratum (304.5 nmol min−1 ng C−1), which was concomitant with reproductive processes and energy storage for overwintering. In autumn, stage CV and female O. similis had significantly higher activities than stage CIV (130–152 versus 78 nmol min−1 ng C−1), which is in accordance with still ongoing developmental and reproductive processes in CVs and females. Comparisons of both species revealed different depth-related responses emphasizing different nutritional preferences: the mainly herbivorous P. minutus is more actively feeding in the shallow layer, where primary production occurs, whereas the omnivorous O. similis is not as much restricted to a certain depth layer, when searching for food. P. minutus had lower levels of trypsin activity during all seasons. In contrast to P. minutus, higher enzyme activities in males of O. similis suggest that they continue to feed and survive after fertilization of females.
    Type: Article , PeerReviewed
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 87
    Publication Date: 2017-05-22
    Description: Ikaite crystals (CaCO3×6H2O) have been found at 232- to 238-cm sediment depth in R/V Polarstern core PS2460-4 from the Laptev Sea continental margin in a water depth of 204 m. δ13C values of this phase average −36.3±0.4‰ PDB (N=2), which is significantly outside the range of normal marine carbonates. The CO2 involved in the precipitation of the ikaite is most probably derived from methane, which has extremely depleted 13C isotope values. Two possible sources of methane in these sediments are: (1) methanogenesis (decomposition of organic matter under anaerobic conditions); and (2) gas hydrates, which are known to occur in the Siberian shelf regions.
    Type: Article , PeerReviewed
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 88
    Publication Date: 2018-06-07
    Description: Natural heterogeneity in ecological parameters, like population abundance, is more widely recognized and investigated than variability in the processes that control these parameters. Experimental ecologists have focused mainly on the mean intensity of predictor variables and have largely ignored the potential to manipulate variances in processes, which can be considered explicitly in experimental designs to explore variation in causal mechanisms. In the present study, the effect of the temporal variance of disturbance on the diversity of marine assemblages was tested in a field experiment replicated at two sites on the northeast coast of New Zealand. Fouling communities grown on artificial settlement substrata experienced disturbance regimes that differed in their inherent levels of temporal variability and timing of disturbance events, while disturbance intensity was identical across all levels. Additionally, undisturbed assemblages were used as controls. After 150 days of experimental duration, the assemblages were then compared with regard to their species richness, abundance and structure. The disturbance effectively reduced the average total cover of the assemblages, but no consistent effect of variability in the disturbance regime on the assemblages was detected. The results of this study were corroborated by the outcomes from simultaneous replicate experiments carried out in each of eight different biogeographical regions around the world.
    Type: Article , PeerReviewed
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 89
    Publication Date: 2016-09-14
    Description: Cephalopod movement occurs during all phases of the life history, with the abundance and location of cephalopod populations strongly influenced by the prevalence and scale of their movements. Environmental parameters, such as sea temperature and oceanographic processes, have a large influence on movement at the various life cycle stages, particularly those of oceanic squid. Tag recapture studies are the most common way of directly examining cephalopod movement, particularly in species which are heavily fished. Electronic tags, however, are being more commonly used to track cephalopods, providing detailed small- and large-scale movement information. Chemical tagging of paralarvae through maternal transfer may prove to be a viable technique for tracking this little understood cephalopod life stage, as large numbers of individuals could be tagged at once. Numerous indirect methods can also be used to examine cephalopod movement, such as chemical analyses of the elemental and/or isotopic signatures of cephalopod hard parts, with growing interest in utilising these techniques for elucidating migration pathways, as is commonly done for fish. Geographic differences in parasite fauna have also been used to indirectly provide movement information, however, explicit movement studies require detailed information on parasite-host specificity and parasite geographic distribution, which is yet to be determined for cephalopods. Molecular genetics offers a powerful approach to estimating realised effective migration rates among populations, and continuing developments in markers and analytical techniques hold the promise of more detailed identification of migrants. To date genetic studies indicate that migration in squids is extensive but can be blocked by major oceanographic features, and in cuttlefish and octopus migration is more locally restricted than predictions from life history parameters would suggest. Satellite data showing the location of fishing lights have been increasingly used to examine the movement of squid fishing vessels, as a proxy for monitoring the movement of the squid populations themselves, allowing for the remote monitoring of oceanic species.
    Type: Article , PeerReviewed
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 90
    facet.materialart.
    Unknown
    Springer
    In:  In: Naturrisiken. , ed. by Felgentreff, C. and Glade, T. Springer, Heidelberg, pp. 141-150.
    Publication Date: 2012-02-23
    Type: Book chapter , PeerReviewed
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 91
    Publication Date: 2017-01-05
    Description: A fossil primnoid gorgonian skeleton (Octocorallia) was recovered on the eastern Galician Massif in the Bay of Biscay (NE Atlantic) from 720 m water depth. The skeleton shows a growth banding of alternating Mg–calcitic and organic (gorgonin) increments in the inner part, surrounded by a ring of massive fibrous calcite. Three calcite-dominated cycles, bounded by thick organic layers, consist of five light-dark couplets of calcite and gorgonin. Two AMS-14C datings of the fossil skeleton give ages of 10,880 and 10,820 ± 45 14C years before present (BP). We arrive at a calibrated age range of 11,829–10,072 cal. years BP (two σ), which comprises the late Younger Dryas to the earliest part of the Holocene. The cyclic calcitic–organic growth banding may be controlled by a constant rate of calcite secretion with a fluctuating rate of gorgonin production, possibly related to productivity cycles. The skeletal fabric change of alternating calcitic–organic increments to massive fibrous calcite may be the result of hydrographic changes during the deglaciation as reflected by preliminary stable isotope data. If this hypothesis proves to be correct, primnoid gorgonians are able to match with varying hydrodynamic conditions by changing their biomineralisation mode.
    Type: Article , PeerReviewed
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 92
    Publication Date: 2019-09-23
    Description: During recent cruises aboard RV Polarstern in the Antarctic Peninsula region, a new species of benthic octopodid was discovered whose generic affinities based on morphological characteristics were uncertain. Molecular sequence analysis of six mitochondrial and nuclear genes allows this species to be placed with confidence within the genus Pareledone. The species is described herein and morphological diagnostic characters are provided for its identification.
    Type: Article , PeerReviewed
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 93
    facet.materialart.
    Unknown
    Springer
    In:  In: Nonlinear Dynamics in Geosciences. , ed. by Tsonis, A. A. and Elsner, J. B. Springer, New York.
    Publication Date: 2012-02-23
    Type: Book chapter , PeerReviewed
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 94
    facet.materialart.
    Unknown
    Springer
    In:  Hydrobiologia, 342/343 . pp. 27-34.
    Publication Date: 2016-04-21
    Description: Sediment cores were collected from two of the Norfolk Broadsandtwo of the West Midland Meres, to test the hypothesis thatrootedmacrophytes increase the sediment release rate of phosphorusduringthe growing season.These were taken from inside and outside plant beds (mixedMyriophyllum spicatum and Chara sp. in Hickling BroadandNuphar lutea in Burntfen Broad, Mere Mere and LittleMere).The overlying water was replaced with a standard waterdesigned tomimic lowland freshwater. After an overnight ‘batch’incubation thewater was analysed for TP and SRP. From this their releaserateswere calculated. Interstitial measurements of SRP were alsomadefor some of the Broads cores at the end of the incubationperiod.The data were analysed using General Linear Models. TP and SRPwerethe responses for both data sets. Factors for the Broads wereinside/outside plant beds, date, and site, whilst for theMeres thefactors of date and site could not be delineated.Release rates in this study were affected by a number offactors(plants, site and date). The picture emerging so far is thatwhenrooted macrophytes have a significant effect on phosphorusreleasethey increase it. However the large variability betweenreplicateshighlights the logistical difficulties in running suchexperiments.
    Type: Article , PeerReviewed
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 95
    Publication Date: 2022-03-07
    Description: High resolution studies from the Propeller Mound, a cold-water coral carbonate mound in the NE Atlantic, show that this mound consists of 〉50% carbonate justifying the name ‘carbonate mound’. Through the last ~300,000 years approximately one third of the carbonate has been contributed by cold-water corals, namely Lophelia pertusa and Madrepora oculata. This coral bound contribution to the carbonate budget of Propeller Mound is probably accompanied by an unknown portion of sediments buffered from suspension by the corals. However, extended hiatuses in Propeller Mound sequences only allow the calculation of a net carbonate accumulation. Thus, net carbonate accumulation for the last 175 kyr accounts for only 〈0.3 g/cm2/kyr, which is even less than for the off-mound sediments. These data imply that Propeller Mound faces burial by hemipelagic sediments as has happened to numerous buried carbonate mounds found slightly to the north of the investigated area.
    Type: Article , PeerReviewed
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 96
    Publication Date: 2022-03-10
    Description: The Quepos, Nicoya and Herradura oceanic igneous terranes in Costa Rica are conspicuous features of a Mid to Late Cretaceous regional magmatic event that encompasses similar terranes in Central America, Colombia, Ecuador and the Caribbean. The Quepos terrane (66 Ma), which consists of ol-cpx phyric, tholeiitic pillow lavas overlain by highly vesicular hyaloclastites, breccias and conglomerates, is interpreted as an uplifted seamount/ocean island complex. The Nicoya (∼90 Ma) and Herradura terranes consist of fault-bounded sequences of sediments, tholeiitic volcanics (pillow lavas and massive sheet flows) and plutonic rocks. The volcanic rocks were emplaced at relatively high eruption rates in moderate to deep water, possibly forming part of an oceanic plateau. Major and trace element data from Nicoya/Herradura tholeiites indicate higher melting temperatures than inferred for normal mid-ocean-ridge basalts (MORB) and/or a different source composition. Sr–Nd–Pb isotopic ratios from all three terranes are distinct from MORB but resemble those from the Galápagos hotspot. The volcanological, petrological and geochemical data from Costa Rican volcanic terranes, combined with published age data, paleomagnetic results and plate tectonic reconstructions of this region, provide strong evidence for a Mid Cretaceous (∼90Ma) age for the Galápagos hotspot, making it one of the oldest known, active hotspots on Earth. Our results also support an origin of the Caribbean Plate through melting of the head of the Galápagos starting plume.
    Type: Article , PeerReviewed
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 97
    facet.materialart.
    Unknown
    Springer
    In:  Gap Models, Forest Dynamics and the Response of Vegetation to Climate Change Huntley, B.; Cramer, W.; Morgan, A.V.; Prentice, H.C.; Allen J.R.M. Past and Future Rapid Environmental Changes: The Spatial and Evolutionary Responses of Terrestrial Biota
    Publication Date: 2022-03-21
    Type: info:eu-repo/semantics/bookPart
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 98
    facet.materialart.
    Unknown
    Springer
    In:  Welt im Wandel: Wege zu einem nachhaltigen Umgang mit Süßwasser
    Publication Date: 2022-03-21
    Type: info:eu-repo/semantics/book
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 99
    facet.materialart.
    Unknown
    Springer
    In:  Modelling water and nutrient dynamics in soil-crop systems. Applications of different models to common data sets - Proceedings of a workshop held 2004 in Müncheberg, Germany
    Publication Date: 2022-03-21
    Type: info:eu-repo/semantics/bookPart
    Format: application/pdf
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 100
    facet.materialart.
    Unknown
    Springer
    In:  Gap models, forest dynamics and the response of vegetation to climate change | Past and future rapid environmental changes: the spatial and evolutionary responses of terrestrial b, 47
    Publication Date: 2022-03-21
    Type: info:eu-repo/semantics/bookPart
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...