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  • 1
    ISSN: 1438-3888
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Stable carbon isotope ratios were measured for the muscle tissue of blue musselMytilus edulis, eelgrassZostera marina, macroalgaeFucus vesiculosus, and phytoplankton in two areas in Kiel Fjord, Germany. Carbon isotope evidence is presented to show the predominance of phytoplanktonic production as a carbon source forM. edulis tissue carbon. Via decomposition processes for both eelgrass and macroalgal primary production, each contributed 0.5–6.5% to mussel carbon.
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  • 2
    ISSN: 1438-3888
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract 387 premetamorphic leptocephali of the familyAnguillidae caught off the west coast of Europe were examined taxonomically and compared with the youngest developmental stages of larvae ofAnguilla anguilla caught in the Sargasso Sea 1979 (Schoth, 1982). The total number of myomeres and the number of myomeres up to the third, opistonephritic blood vessel present features of this species which are significantly different from those of the larvae ofAnguilla rostrata and do not change during the whole larval phase. A combination of these two biometric features enables an infallible species identification of the AtlanticAnguilla larvae at all developmental stages. The number of predorsal and preanal myomeres, the preanal length and features of the head cannot be used for a distinction ofAnguilla larvae. One larva, 68.7 mm long, with 107 myomeres, and 44 myomeres to the opistonephritic blood vessel represents the hitherto southernmost record of anA. rostrata larva in the eastern North Atlantic.
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  • 3
    Electronic Resource
    Electronic Resource
    Springer
    Helgoland marine research 50 (1996), S. 453-456 
    ISSN: 1438-3888
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract A new benthic sled is described.Favourable features of the sled include: simple operation, broad runners, balanced towing position, simple height adjustment of the sediment cutting edge and quick exchange of the collecting bag. Metallic parts are aluminium, making the sled light (15 kg). This sled has functioned well in coastal research for more than a decade.
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  • 4
    ISSN: 1438-3888
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract A redescription of the genusDelectona is provided, based on information gained by the finding of a new species,D. alboransis, from the Alboran Sea (southwestern Mediterranean Sea). Up to now, this genus contained only one species:Delectona higgini, from the Indian Ocean, which has not been recorded since 1880. The presence of megascleres in the new species and the different ranges of amphiaster lengths of the two species are the main features allowing a differentiation. In addition, the excavating capability of sponges of this genus is questioned, following the observations on the external morphology ofD. alboransis. Our results support the hypothesis of other authors that some areas of the circalittoral level of the Alboran Sea may represent a redoubt of relict species with Indo-Pacific affinities.
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  • 5
    Electronic Resource
    Electronic Resource
    Springer
    Helgoland marine research 50 (1996), S. 433-452 
    ISSN: 1438-3888
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The sublittoral macrofauna of the Steingrund, a stony area east-northeast of Helgoland, was investigated from May till October 1991 using a van Veen grab and a small dredge. The diverse endo- and epifauna of the sandy bottoms, pebbles and boulders of this Saalian end moraine comprised 289 taxa, whereby the polychaetesMagelona papillicornis, Lanice conchilega andSpiophanes bombyx dominated in terms of abundance. Species rare in the German Bight, such as the spongeLeucandra fistulosa, the sea urchinEchinus esculentus, and the sea anemoneHaliplanella lineata, were also found. The two sample sets were processed separately with multivariate techniques, and differentiated on the basis of occurrence and numbers of the abundant species. The analysis of the grab samples revealed two types of theTellina-fabula-community. These associations were differentiated by the presence of species of the coarse-sand-inhabitingGoniadella-Spisula-community and were related to the distribution of the grain size of the sediment. Likewise, two epifaunal assemblages were distinguished. Sandy bottoms were characterized byOphiura albida, Liocarcinus holsatus andPagurus bernhardus, while boulders and pebbles were covered by a varied sessile and mobile epifauna dominated by the sessile bryozoanFlustra foliacea and the mobile pantopodeAechelia echinata. Numerical density, biomass and annual production estimates are in the range of values determined for the macrobenthos of the German Bight, while annual P/B ratios mounted up to 5.
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  • 6
    ISSN: 1438-3888
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract During three cruises, carried out in March 1991, October 1991, and January 1992 off the Iberian Peninsula and Morocco, the abundant calanoid copepodCalanus helgolandicus (Claus) was collected from a depth of 1000 m to the surface. Differences in depth preference were correlated with the life stage and geographically differing vertical salinity structures. In autumn and winter, only stage V copepodids (CV) and adults were found, in spring also younger copepodid stages. Within the range of the Mediterranean outflow water (MOW), a sharp decline of abundances of all stages was evident during all cruises. In autumn 1991, the bulk of the population was recorded south of the MOW, in winter 1992 north of it. During winter, numbers had declined by 70%, supporting the idea that winter individuals represent the same generation as was encountered in autumn, and that they had been transported northwards. CV stages preferred the depth layer 400–800 m, in autumn and winter. Adults were found in autumn at the same depth south of the MOW, while they preferred the 0–400 m layers north of it. In winter, the abundance of adults increased, males preferred the 400–600 m depth layer, while females stayed at 200–400 m. In spring 1991, stages younger than CV were found in high densities, all stages concentrating in the upper 200 m. During the crosslope survey in spring off Portugal, an absolute abundance maximum of females was found. In contrast, offshore densities were very low. On the basis of these findings, the hypothesis of a Mediterranean centre of distribution and dispersal into the Atlantic is questioned. It is suggested that a separate, reproductively active population ofC. helgolandicus exists off NW. Africa.
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  • 7
    ISSN: 1438-3888
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The parasite faunas of snails, mussels, crustaceans and small-sized fishes were investigated over a period of six months in the Schlei fjord, on the Baltic coast of Schleswig-Holstein. Two sites differing in salinities were compared: Missunde with 5–9 ‰ and Olpenitz with 12–20 ‰. Prevalences, number of host-parasite combinations, numbers of core and secondary species were generally higher in Olpenitz than in Missunde. In the latter site, only prevalences of cestodans in planktic copepods and the number of rare species were apparent. Specificity of parasites was relatively high in snails, mussels and fishes, but lower in benthic crustaceans. Parasites may survive in an extreme environment like brackish water by means of special strategies which differ from those acquired in the marine milieu: suspension of specificity, adaptation to hosts which are genuine brackish water species, extension of host spectra, and shortening of life-cycles. Although the parasite communities of the Schlei fjord were primarily influenced by the prevailing salinities, the influence of other factors, e.g. environmental stress, was also confirmed. Whereas generally low prevalences in Missunde may contradict Thienemann’s biocoenotic rule, planktic parasites infested their hosts often at higher rates than in Olpenitz. This phenomenon is explained by the poorer environmental condition of the benthal zone in Missunde compared to that of the pelagial or the benthal zones of Olpenitz.
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  • 8
    ISSN: 1438-3888
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The vegetative life cycle, host specificity, morphology, and ultrastructure of a new phagotrophic nanoflagellate are described:Cryothecomonas aestivalis Drebes, Kühn & Schnepf sp. nov. During summer and autumn it is frequently found in the North Sea phytoplankton feeding on the centric diatomGuinardia delicatula. The flagellate penetrates the diatom cell and phagocytizes the host cytoplasm by means of a pseudopodium that emerges from the posterior cell pole. The mature trophont gives rise to eight or more biflagellate swarmers which leave the emptied diatom frustule. Transmission electron microscopy revealed a delicate theca surrounding the swarmers. The pseudopodium protrudes through a gap in the theca. The cytostome consists of a membranous labyrinth. The mitochondria are of the tubular type. The two apically inserted flagella are heterodynamic and of unequal length. They are smooth, and their basal bodies are surrounded by satellites and fibrous strands (“transitional fibres” sensu Thomsen et al., 1990). In the trophonts and dividing flagellates the transition region between the flagellum and the basal body ends apically with a massive transitional cylinder instead of distinct microtubules, and is surrounded by a funnel of the theca. The nuclear envelope disintegrates during mitosis. Due to the fine structural details the new flagellate is placed in the genusCryothecomonas Thomsen et al., a genus of still uncertain position.
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  • 9
    ISSN: 1438-3888
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The complete larval development is described forPorcellana platycheles (Pennant) reared under laboratory conditions. The development consists of two zoeal stages and one megalopa. At 20°C and 35‰ salinity, the megalopa appeared 17–18 days after hatching. Survival was 56% from hatching to the megalopa stage. The morphological features of the zoeal and megalopa stages ofP. platycheles are compared with those of other species ofPorcellana, and a key of the known zoeal stages of the genus is given.
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  • 10
    ISSN: 1438-3888
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract In July 1993, the car carrier “Faust” entered Bremerhaven after a voyage from the North-American Atlantic coast to Europe. In a dockyard, five living specimens of the order Polycladida were collected from the hull of the ship. This could be a possible case of trans-atlantic dispersal of plathelminths living as fouling organisms of ships. The specimens found represent a new species of the genusCryptostylochus Faubel, 1983,Cryptostylochus hullensis sp. nov.
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