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  • 1
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    Cambridge University Press
    In:  Cambridge, 342 pp., Cambridge University Press, vol. 13, no. XVI:, pp. 227-235, (ISBN 3-540-43528-X)
    Publikationsdatum: 1983
    Schlagwort(e): Textbook of geophysics ; Seismology ; Seismics (controlled source seismology) ; Waves
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  • 2
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    Cambridge University Press
    In:  Boston, 227 pp., Cambridge University Press, vol. Developments in Petroleum Science vol. 15B, no. Publ. No. 12, pp. 9, (ISBN 0-521-66023-8 hc (0-521-66953-7 pb))
    Publikationsdatum: 1982
    Schlagwort(e): Textbook of geophysics ; Seismics (controlled source seismology)
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  • 3
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    Cambridge University Press
    In:  Cambridge, 4th Edition, 470 pp., Cambridge University Press, vol. 106, pp. 503, (ISBN 0-415-24328-9 (hb), 0-203-47128-8 (pb))
    Publikationsdatum: 1985
    Schlagwort(e): Textbook of geophysics ; Seismology
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  • 4
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    Cambridge University Press
    In:  Boston, 227 pp., Cambridge University Press, vol. Developments in Petroleum Science vol. 15B, no. Publ. No. 12, pp. 9, (ISBN 0-521-66023-8 hc (0-521-66953-7 pb))
    Publikationsdatum: 1983
    Schlagwort(e): Textbook of geophysics ; Seismics (controlled source seismology)
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  • 5
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    Cambridge University Press
    In:  New York, Cambridge University Press, vol. 283, no. 2, pp. 15-17, (ISBN: 3-7643-7044-0)
    Publikationsdatum: 1987
    Schlagwort(e): Statistical investigations ; Handbook of mathematics ; Data analysis / ~ processing ; Borehole breakouts ; circular ; angular ; directional ; Staatsbibl. ; B: ; 779785
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  • 6
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    Cambridge University Press
    In:  Cambridge, Cambridge University Press, vol. 7, no. Publ. No. 12, pp. 127, (ISBN 1-58488-323-5)
    Publikationsdatum: 1986
    Schlagwort(e): Inversion ; Handbook of mathematics
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  • 7
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    Cambridge University Press
    In:  Journal of the Marine Biological Association of the United Kingdom, 64 . pp. 573-579.
    Publikationsdatum: 2020-07-16
    Beschreibung: Males of Eledone cirrhosa grow to a size little over 600 g and normally have well-developed, and presumably active, reproductive organs from about 200 g upwards. Total weight of the genital bag is well correlated with total body weight (r= 0·906). Growth of the testis precedes that of the spermatophoric sac, and the size of neither of these reproductive components is predictable from body weight. The sizes of these organs and the estimated number and length of stored spermatophores are given for 100 g intervals of total body weight. No evidence was obtained for a seasonal trend in male maturity.
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  • 8
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    Cambridge University Press
    In:  Journal of the Marine Biological Association of the United Kingdom, 66 . pp. 855-865.
    Publikationsdatum: 2020-07-16
    Beschreibung: A survey of the ecology of the octopus Eledone cirrhosa in Scottish waters is compiled from structured interviews with fishermen, records of occurrence in traps (for lobster and crab), and a research vessel survey. This species is widespread and common throughout the inshore waters covered by fishing activity (shoreline- 140 m) on bottom types ranging through rock, stones, sand and mud. It is caught in all months of the year but is especially common inshore in the summer (July-September) and further offshore on trawling grounds in October-December. The octopus is a normal and regular predator of large Crustacea (Hotnarus, Nephrops, Cancer) caught in commercial traps but gut contents yield little identifiable dietary remains.
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  • 9
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    Cambridge University Press
    In:  Geological Magazine, 64 (6). pp. 263-275.
    Publikationsdatum: 2020-07-31
    Beschreibung: In a recent paper I stated that the hypothesis of a continuously cooling earth had “consistently failed to lead to any adequate explanations of fissure eruptions and other volcanic and tension phenomena, mountain-building processes and their distribution in time and space, and the alternation of marine transgressions and recessions”. It seems to be desirable that I should further justify this sweeping integration of objections, for Dr. Harold Jeffreys, who has actively explored the consequences of this theory during recent years, takes exception to my discouraging view of the position, and claims that the alleged failures include the principal successes of the theory. The evidence on which my summary indictment was based will be reviewed in this paper; and attention will be directed to certain other phenomena—such as the growth of geosynclines—of which the significance has not yet been generally realized. As a preliminary it will be convenient to discuss the gradually converging evidence bearing on the thickness and substructure of the continents.
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  • 10
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    Cambridge University Press
    In:  Journal of the Marine Biological Association of the United Kingdom, 69 (03). pp. 545-553.
    Publikationsdatum: 2020-07-16
    Beschreibung: The importance of feeding pattern is well documented in fish (Jenkins & Green, 1977; Simenstad & Cailliet, 1986) but there are not many reported studies in cephalopods. Feeding patterns, as defined by Jenkins & Green (1977) have been studied, to our knowledge, only in Todarodes pacificus (Okiyama, 1965), Loligo pealei (Vovk, 1972), Loligo opalescens (Karpov & Cailliet, 1978), Illex illecebrosus (Amaratunga et ah, 1979; Amaratunga, 1980) and Nototodarus gouldi (O'Sullivan & Cullen, 1983). Boyle (1983) dealt with aspects of feeding in several cephalopod species but not specifically with feeding pattern. Aspects of feeding in Sepia officinalis have been reviewed by Nixon (1987). The present work describes the daily feeding pattern in Sepia officinalis from data collected in the field.
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  • 11
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    Cambridge University Press
    In:  Geological Magazine, 121 (6). pp. 563-575.
    Publikationsdatum: 2020-07-31
    Beschreibung: We present chemical data on magmatically heterogeneous pyroclastic deposits of late Quaternary age erupted from zoned magma systems underlying Tenerife (Canary Islands), Sao Miguel and Faial (Azores), and Vesuvius. The most fractionated magmas present at each centre are respectively Na-rich phonolite, trachyte, and K-rich phonolite. Within any one deposit, chemical variation is either accompanied by changes in the phenocryst assemblage (petrographic zonation) or is largely manifested in trace element abundances, unaccompanied by any petrographic change (occult zonation). Zoning is analogous to that in calc-alkaline systems where the most fractionated products are high-silica rhyolites. When a range of magma types are considered, a correlation emerges between roofward depletion of trace elements (especially REE) in the zoned system and compatability of those same trace elements in the accessory phenocryst phases present. Thus, allanite- or chevkinite-bearing rhyolitic systems are light-REE depleted roofwards, the sphene-bearing Tenerife system is middle-REE depleted roofwards, the melanite-bearing Vesuvius system is heavy-REE depleted roofwards, while the Azores systems, which lack these phases, display roofward REE enrichment. Therefore, the behaviour of trace elements may in each case be explained by fractionation of observed phenocryst assemblages. The resemblance between features of zoned magma systems and published work on the dynamic consequences of cooling saturated aqueous solutions prompts us to suggest that sidewall crystallization and consequent boundary-layer uprise to form a capping layer at top of the system may be a plausible mechanism for the generation of both petrographic and occult zonation. Reverse zoning occurs among the first-erupted tephra of some deposits, demonstrating that the most highly differentiated magma available is not always the first to be tapped during an eruption from a zoned system.
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  • 12
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    Cambridge University Press
    In:  Journal of the Marine Biological Association of the United Kingdom, 63 . pp. 71-83.
    Publikationsdatum: 2020-07-16
    Beschreibung: Changes in the relative size of the ovary, oviducal glands and eggs are described for Eledone cirrhosa captured from the North Sea off Aberdeen over a 3 year period (N = 488). The analysis is based only on freshly caught animals, excluding those held in aquarium conditions (〉 5 days). Ovary enlargement and egg size estimates are used as indices of sexual maturity. Between 0–15% and 18–95% of total body weight is contributed by the ovary. Maximum egg length in the ovary ranges up to 7 mm. On these criteria, sexual maturation typically occurs at body sizes between 400–1000 g although some animals of 1000–1200 g are found showing no evidence of ovary enlargement. The majority of the monthly sample is always immature but maturation can apparently occur at almost any time of the year. Increase in mean ovary index and mean values for egg size are strongly seasonal and indicate a peak incidence of sexual maturity over 2–3 months in the July-September period. Spawning is presumed to follow within 1 month. Estimates of the fecundity of the females, based on the egg sample from the ovary, range from 2·2 × 103 to 55 × 10 3 eggs with a mean of 11 × 10 3 and a mode of 7·5 × 10 3 eggs.
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  • 13
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    Cambridge University Press
    In:  Journal of the Marine Biological Association of the United Kingdom, 64 . pp. 581-585.
    Publikationsdatum: 2020-07-16
    Beschreibung: Female Eledone cirrhosa held in aquarium conditions for periods of time of five daysand over show relatively enlarged ovary sizes. Values for ovary index considerably exceed thoseof freshly caught animals and the incidence of the final stage of maturity, in which eggs pack the oviducts, is greater. A comparison of maturity indices for fresh and aquarium males was inconclusive. The range of factors associated with aquarium conditions is briefly reviewed and it is concluded that studies of cephalopod reproductive maturation must distinguish fresh and aquarium animals. Introduction External factors effective in inducing sexual maturation in cephalopods have been suggested several times. The influence of the absence of light has been implicated since the experiments of Wells & Wells (1959) showed that blinded Octopus vulgar is matured precociously. An effect of short day length in stimulating the optic glands of Sepia has been found by Defretin & Richard (1967) and Richard (1967) but this is not clearly the case for Octopus (Buckley, 1977). Octopuses kept in aquarium conditions for lengthy periods are said to have larger relative gonad sizes than those fresh from the sea (Wells & Wells, 1975). One of the factors associated with aquarium conditions is often a degree of starvation, and this circumstance alone is held to be a factor in inducing precocious sexual maturation in Eledone (Mangold & Boucher-Rodoni, 1973). In the course of recent studies on the growth and reproduction of Eledone cirrhosa from the North Sea (Boyle & Knobloch, 1982,1983,1984) animals which had remained in aquarium conditions for 5 days or over were separated from the analysis.
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  • 14
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    Cambridge University Press
    In:  Geological Magazine, 126 (02). p. 95.
    Publikationsdatum: 2020-07-31
    Beschreibung: Santorini volcanic field has had 12 major (1–10 km3 or more of magma), and numerous minor, explosive eruptions over the last ~ 200 ka. Deposits from these eruptions (Thera Pyroclastic Formation) are well exposed in caldera-wall successions up to 200 m thick. Each of the major eruptions began with a pumice-fall phase, and most culminated with emplacement of pyroclastic flows. Pyroclastic flows of at least six eruptions deposited proximal lag deposits exposed widely in the caldera wall. The lag deposits include coarse-grained lithic breccias (andesitic to rhyodacitic eruptions) and spatter agglomerates (andesitic eruptions only). Facies associations between lithic breccia, spatter agglomerate, and ignimbrite from the same eruption can be very complex. For some eruptions, lag deposits provide the only evidence for pyroclastic flows, because most of the ignimbrite is buried on the lower flanks of Santorini or under the sea. At least eight eruptions tapped compositionally heterogeneous magma chambers, producing deposits with a range of zoning patterns and compositional gaps. Three eruptions display a silicic–silicic + mafic–silicic zoning not previously reported. Four eruptions vented large volumes of dacitic or rhyodacitic pumice, and may account for 90% or more of all silicic magma discharged from Santorini. The Thera Pyroclastic Formation and coeval lavas record two major mafic-to-silicic cycles of Santorini volcanism. Each cycle commenced with explosive eruptions of andesite or dacite, accompanied by construction of composite shields and stratocones, and culminated in a pair of major dacitic or rhyodacitic eruptions. Sequences of scoria and ash deposits occur between most of the twelve major members and record repeated stratocone or shield construction following a large explosive eruption. Volcanism at Santorini has focussed on a deep NE–SW basement fracture, which has acted as a pathway for magma ascent. At least four major explosive eruptions began at a vent complex on this fracture. Composite volcanoes constructed north of the fracture were dissected by at least three caldera-collapse events associated with the pyroclastic eruptions. Southern Santorini consists of pryoclastic ejecta draped over a pre-volcanic island and a ridge of early- to mid-Pleistocene volcanics. The southern half of the present-day caldera basin is a long-lived, essentially non-volcanic, depression, defined by topographic highs to the south and east, but deepened by subsidence associated with the main northern caldera complex, and is probably not a separate caldera.
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  • 15
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    Cambridge University Press
    In:  Journal of the Marine Biological Association of the United Kingdom, 64 (02). pp. 285-302.
    Publikationsdatum: 2020-07-16
    Beschreibung: A new species of a monogenean Isancistrum subulatae (Gyrodactylidae) has been discovered on the arms and tentacles of the cephalopod mollusc Alloteuthis subulata at Plymouth and I. loliginis, on the gills of the same host, has been re-discovered for the first time since its original description in 1912. I. subulatae, like other gyrodactylids, is viviparous, and has been shown by experiments to transfer to new hosts by contagion. In nature such transfers probably take place during copulation of the hosts and since the parasite may occur in numbers of several thousands per host, it may thereby constitute a venereal disease.
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  • 16
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    Cambridge University Press
    In:  Journal of the Marine Biological Association of the United Kingdom, 66 . pp. 867-879.
    Publikationsdatum: 2020-07-16
    Beschreibung: Serological methods for prey identification have been applied to the gut contents of a field sample of 100 Eledone cirrhosa from the Moray Firth and 7 from the Sound of Jura. Protein extracts from the crop were electrophoresed (Laurell rockets) into antisera raised against potential crustacean prey species, Cancer pagurus, Carcinus maenas, Crangon crangon, Liocarcinus spp. and Nephrops norvegicus. The strengths of the resulting reactions were evaluated on the basis of peak height, staining density and the number of homocentric peaks of immune precipitates. Sixty-two of the 100 Moray Firth animals gave a positive reaction to one or more of the antisera and the most critical assessment of the results ranked the incidence of the prey as Liocarcinus (15) 〉 Nephrops (10) 〉 Cancer (8) 〉 Crangon (2) 〉 Carcinus (0), a total of 35 reactions from 28 animals. Absence of a reaction in the 38 animals from which appreciable sample volumes were also obtained indicates that alternative prey had been consumed. Of the 7 Sound of Jura animals, 4 gave a positive reaction to Nephrops alone. A total of only 24 animals gave any indication of diet by visual recognition of remains. The value and difficulties of the methodology are discussed.
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  • 17
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    Cambridge University Press
    In:  Journal of the Marine Biological Association of the United Kingdom, 62 (2). pp. 277-296.
    Publikationsdatum: 2020-07-16
    Beschreibung: The growth of the octopus Eledone cirrhosa has been studied in a population from the North Sea off Aberdeen. Data are presented for the growth of individuals isolated in aquarium conditions; the growth of size classes in thefieldpopulation; and preliminary information on the growth relationships of gonad, somatic, cardiac and brain components of the body. At 15 °C Eledone cirrhosa is capable of growing from 10 to 1000 g in 270 days. From octopuses which feed readily in captivity, weight specific growth rates of up to about 3–5 % day-1 for animals of 100 g body weight are recorded, falling to a maximum of about 1–5 % day-1 at body sizes above 500 g. Females stop growing when sexually mature, but in the sample captured they were consistently larger than males, a feature which may account for the 7:1 bias towards the incidence of females. On a wet-weight basis, the mean food incorporation into growth is 37 % of the food ingested, which is 49% of the gross weight of crabs killed. Field data for 1978/79 suggest that animals recruited to the population at the beginning of the year grew steadily until December, overwintered without growing, then grew rapidly for several months in the subsequent year before disappearing from the samples. The estimated average age of those animals and by implication, the life span, is 20 months.
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  • 18
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    Cambridge University Press
    In:  Journal of the Marine Biological Association of the United Kingdom UK, 62 . pp. 435-451.
    Publikationsdatum: 2020-07-27
    Beschreibung: The planktonic foraminifer Globigerinoides sacculifer (Brady) was cultured under two different light intensities and in continuous darkness. High light intensity (HLI = 4oo-soo einsteins/m2/s) resulted in a longer lifespan, a greater number of chambers formed, and a larger final shell size compared with individuals cultured under low light intensity (LLI = 20-50 einsteins/m2/s) or in continuous darkness. Shell growth rates were unaffected by increasing light intensity, but gametogenesis was delayed. Continuous darkness induced a rapid onset of gametogenesis in organisms with shell lengths larger than 250 m. Feeding frequency had a greater effect on growth and reproduction than light intensity under conditions of LLI and HLI, but continuous darkness had an overriding effect on growth and reproduction owing to the rapid onset of gametogenesis which terminated the life of the mother cell. Our previous data indicated that the longevity of G. sacculifer was dependent on feeding frequency, and that G. sacculifer cultured under LLI had a lifespan of approximately 2-4 weeks. Present results suggest that the lifespan can vary from a minimum of 8 days for organisms fed daily in continuous darkness to a maximum of 54 days for organisms fed once every 7 days and maintained in HLI. It is concluded that individual G. sacculifer attain a shell size greater than 6oo ,urn only if they maintain their position in the euphotic zone. Prolonged existence below the euphotic zone would result in premature death or gametogenesis following stunted shell growth.
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  • 19
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    Cambridge University Press
    In:  In: Growth and reproductive strategies of freshwater phytoplankton. , ed. by Sandgren, C. D. Cambridge University Press, Cambridge, UK, pp. 227-260. ISBN 0-521-32722-9
    Publikationsdatum: 2018-01-02
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  • 20
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    Cambridge University Press
    In:  Journal of the Marine Biological Association of the United Kingdom, 62 (04). p. 799.
    Publikationsdatum: 2020-07-16
    Beschreibung: Five hundred and twenty-eight specimens of Loligo forbesi Steenstrup, from landings in Horta, Faial, Azores, during the year 1 March 1980 to 28 February 1981, were tudied; 59·3 % were males, 40·7 % females. Of the males 80·2 % were sexually mature, of the females 91·6 %, both sexes showing the highest degree of maturity in spring and he lowest in autumn. The mean dorsal mantle length of the mature males was 56·5 cm, or females 33·5 cm. A weight-length relationship was calculated. he stomachs of 622 specimens were sampled, of which 306 contained food. The prey omponents were studied qualitatively. The main prey was fish (82·0%), of which 0·5 % were horse mackerel, Trachurus picturatus, this being the most important food rganism. Preliminary results of statolith readings are given.
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  • 21
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    Cambridge University Press
    In:  Journal of the Marine Biological Association of the United Kingdom, 66 (02). pp. 483-496.
    Publikationsdatum: 2020-07-16
    Beschreibung: Recently the influence of an electric light on the capture of the main groups of deep sea animals by a midwater trawl was described and discussed (Clarke & Pascoe, 1985). With regard to fish it was shown that at depths close to 800 m the total number, the total volume, the volume of the ten largest and the volume of the single largest fish all increased significantly when an electric light was used on the headline of the trawl when compared with controls with the light off. These experiments were carried out both in the Bay of Biscay and off Madeira.
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  • 22
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    Cambridge University Press
    In:  Journal of the Marine Biological Association of the United Kingdom, 66 (02). pp. 505-526.
    Publikationsdatum: 2020-07-16
    Beschreibung: Growth laminations were first noted in squid statoliths by Clarke (1966), who suggested they might be useful for age determination. Spratt (1978) presented a detailed age analysis of Loligo opalescens Berry, 1911, arguing that some rings in the cephalopod statolith were deposited daily, as are fish otoliths (Panella, 1971). Growth rings in Illex illecebrosus (Lesueur, 1921) statoliths were illustrated by Lipinski (1978) with similar interpretation to that of Spratt (op. cit.). Several further attempts have been made to validate and/or to discuss age determination from statoliths (Hurley, Drew & Radtke, 1979; Hurley et al. 1983; Wiborg, 1979; Hurley & Beck, 1980; Kristensen, 1980; Lipinski, 1980, 1981; Rosenberg, Wiborg & Bech, 1981; Martins, 1982; Radtke, 1983; Dawe et al. 1984), and several other attempts are in preparation (R. J. Hanlon, G. V. Hurley, M. R. Clarke & R. L. Radtke, personal communications).
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  • 23
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    Cambridge University Press
    In:  Journal of the Marine Biological Association of the United Kingdom, 66 (03). p. 711.
    Publikationsdatum: 2020-07-16
    Beschreibung: The effect of two 70 W underwater electric lamps on the catch rate of a commercial bottom otter trawl was determined by comparative trials both at night and in daylight. It was found that, although the overall numbers and weights of fish caught did not differ, most of the species which were caught in large enough numbers for a judgement to be made showed a reaction to light. Three species, Trachurus trachurus, Merlangius merlangus and Trisopterus minutus were attracted and four species, Eutriglagurnardus, Micromesistius poutassou, Merluccius merluccius and Limanda limanda were scared off by light. The possible use of lights to further the development of selective commercial bottom trawling by attracting or scaring particular species is discussed.
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  • 24
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    Cambridge University Press
    In:  Journal of the Marine Biological Association of the United Kingdom, 67 (02). pp. 343-358.
    Publikationsdatum: 2020-07-17
    Beschreibung: Orbulina universa d'Orbigny is a spinose planktonic foraminifer which occurs throughout surface waters of the tropical, subtropical and transition zones of the world ocean (Bé & Tolderlund, 1971). This species is unique among planktonic Foraminifera in that its life cycle is composed of two growth stages. The juvenile stage is a trochospiral form which is enclosed within a terminal spherical chamber in the adult stage. O. universa is relatively omnivorous, and consumes a variety of prey that range in size and quality from phytoplankton to copepods (Bé et al. 1977; Anderson et al. 1979; Spindler et al. 1984). In addition, each individual harbors several thousand zooxanthellae which presumably are an additional source of nutrition for the foraminifer (Be et al. 1977; Hemleben & Spindler, 1983; Spero & Parker, 1985).
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  • 25
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    Cambridge University Press
    In:  Journal of the Marine Biological Association of the United Kingdom, 61 (04). pp. 901-916.
    Publikationsdatum: 2020-07-16
    Beschreibung: Symbiotic luminous bacteria have been described in, and cultured from, a number of species offish and cephalopod. Indeed only in these two groups are extracellular luminous bacteria believed to be utilized as a source of light (see Buchner (1965) and Herring (1978) for references). Despite several earlier investigations of such symbioses in cephalopods the bacteria in these animals have not been adequately identified, nor has the extent of their role been clarified. The ultrastructural relationships between bacteria and the tissues of the squid accessory nidamental gland have been investigated in the non-luminous species Loligo pealei (Lesueur) (Bloodgood, 1977) and Sepia officinalis L. (Van den Branden et al. 1979) but no comparative work on luminous species has been undertaken apart from that on Heteroteuthis dispar (Rüppell), whose photophore does not contain typical luminous bacteria (Dilly & Herring, 1978; cf. Leisman, Cohn & Nealson, 1980). The order Sepioidea contains five families, among which are the two families Sepiolidae and Spirulidae. Though the presence of luminous bacteria is known in some sepiolids (as well as in certain loliginids (order Teuthoidea)) some doubt remains about the source of light in the photophore of Spirula spirula Hoyle. The steady luminescence of this species has prompted speculation that bacteria may be involved (Harvey, 1952). In this paper we compare the anatomy and ultrastructure of the photophores of both Sepiola and Spirula in order to clarify some of these problems.
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  • 26
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    Cambridge University Press
    In:  Journal of the Marine Biological Association of the United Kingdom, 60 (01). p. 151.
    Publikationsdatum: 2020-07-16
    Beschreibung: This is the first detailed analysis of cephalopod beaks from the stomach of a northern bottlenosed whale, Hyperoodon ampullatus (Forster, 1770). The digestive action of many predators barely affects the chitinous beaks of cephalopods and some cetaceans accumulate the beaks in considerable numbers in their stomachs. The present beaks are clean and unbroken. Identification of cephalopod beaks from stomachs of predators such as sperm whales (see Clarke, 1977), seals (Clarke & Trillmich, 1980) and albatrosses (Clarke, Croxall & Prince, 1980) throws considerable light on the biology and relative ecological importance of the species of cephalopods concerned as well as providing useful information on the diet of the predators.
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  • 27
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    Cambridge University Press
    In:  Journal of the Marine Biological Association of the United Kingdom, 65 (04). p. 983.
    Publikationsdatum: 2020-07-16
    Beschreibung: Cephalopods may be divided into five types according to their buoyancy. Members of several families such as the Octopodidae, Loliginidae and Ommastrephidae are negatively buoyant and must swim to stay in midwater and are therefore highly muscular animals. Others have mechanisms to make them neutrally buoyant so they can remain suspended in midwater without effort. Nautilus, Spirula and cuttlefishes have low pressure gas-filled chambers and their flesh is muscular and non-buoyant (Denton & Gilpin-Brown, 1973). Squids of one family, the Gonatidae, have a low density oil in their livers to give buoyancy but most of their body is muscular. Some oceanic octopods have very watery tissues in which lighter chloride ions replace sulphate ions (Denton & Shaw, 1961). In 12 of the 26 teuthoid families the buoyancy is provided by low-density ammonia-rich solution in their body and head tissues or in an expanded coelomic cavity (Clarke, Denton & Gilpin-Brown, 1979). These ammoniacal squids are extremely abundant in the oceans of the world and form a large part of the diet of birds, cetaceans, seals and fish (Clarke, 1977). When their biomass is estimated from their utilization by predators it is important to know their properties as food and, in particular, their calorific values. As pointed out by Croxall & Prince in a review of the calorific values of cephalopods (1982), all the known values are of muscular, negatively buoyant species because they are of value as food for humans but no measurements have been made on the ammoniacal or oily species which are probably as important, or even more important, in the economy of the ocean (Clarke, 1983).
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  • 28
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    Cambridge University Press
    In:  Journal of the Marine Biological Association of the United Kingdom, 60 (02). p. 329.
    Publikationsdatum: 2020-07-16
    Beschreibung: Cephalopod statoliths are paired calcareous stones which lie in cavities, the statocysts, within the skull. They have a form which, though variable, shows promise as a source of criteria for taxonomic and evolutionary studies. As a preliminary to more detailed studies, Clarke (1978) published a description of the form of a generalized teuthoid statolith, coined nomenclature for the various parts and gave a very brief survey of variation of statoliths within the living Cephalopoda. This nomenclature was used in a detailed description of fossilized teuthoid statoliths by Clarke & Fitch (1979). Here, descriptions of the statoliths of the living species Berryteuthis magister (Berry, 1913), Gonatopsis borealis Sasaki, 1923, Gonatopsis (Boreoteuthis) makko Okutani & Nemoto, 1964 and Gonatus fabricii (Lichtenstein, 1818) are given and the fossil Berryteuthis species described in outline by Clarke & Fitch (1979) is compared with B. magister. A statistical analysis of measurements of the statoliths of these five species has been made and the results are presented. This forms the first part of a general description of teuthoid statoliths and similar studies on the Ommastrephidae and the Loliginidae are in preparation.
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  • 29
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    Cambridge University Press
    In:  Journal of Zoology, 218 (4). pp. 549-563.
    Publikationsdatum: 2020-10-09
    Beschreibung: Cephalopod beaks recovered from stomach samples taken from l 4 sea bird species in the southern Benguela region off Southern Africa and from one species at Sub-Antarctic Marion Island, were identified as far as possible, counted and the lower rostral lengths (LRLs) measured. Dorsal mantle lengths (DMLs) and body masses of the cephalopods eaten were estimated. The results of analyses by percentage frequency of occurrence and numerical abundance are discussed with reference to present knowledge of the distribution of cephalopods eaten by sea birds in the areas studied. Division of the cephalopod component of seabird diets into species which float, and species which sink, after death indicates that the birds forage on dead or moribund cephalopods on the surface, rather than catching live bioluminescent cephalopods at night.
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  • 30
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    Royal Society of Edinburgh | Cambridge University Press
    In:  Proceedings of the Royal Society of Edinburgh, 91B . pp. 113-141.
    Publikationsdatum: 2020-11-04
    Beschreibung: Surveys of the interdial macrofauna and sediment characters of Nigg Bay, Moray Firth, were carried out between 1981 and 1985. Permanent stations were located at the intersections of a half-kilometre grid covering the entire interdial area and sampled for infauna using replicate cores. Estimates were also made of mussel and lugworm densities from quadrats and cast counts respectively. The biomass of selected species that constitute important resources for higher tropic levels were also estimated. The sediment for each station was analysed for median particle diameter and slit content. The infaunal data were analysed by Detrended Correspondence Analysis. This indicated that tida height was the most important factor governing the distribution and abundance of the interdial communities. Sediment characters were only poorly related to distribution patterns. The bay has a rich fauna and is biologically similar to other outer bays of the Moray Firth, which, like Nigg, are important areas for wildfowl and waders. Comparison of survey data from different years indicate that there are natural cycles in some sediment and biological characters of Nigg Bay.
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  • 31
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    Cambridge University Press
    Publikationsdatum: 2023-07-19
    Beschreibung: The dissolution rates of spheres of two magnesian olivines, two plagioclases, and quartz in tholeiitic basalt have been determined at three super-liquidus temperatures and one-atmosphere pressure. There are considerable differences in the rates among the minerals, e.g. at 1210°, 12° above the liquidus temperature of the basalt, labradorite dissolves at 86 µm/h. and the magnesian olivines at 9 and 14 µm/h. The rates are not time dependent and this, coupled with the existence of concentration gradients in the composition of quenched melt adjacent to partially dissolved crystals, indicates that the dissolution rates are dictated by a combination of diffusion and convection of components to and from the crystal-liquid interface. Values for the activation enthalpy of dissolution are small for quartz and plagioclase (40–50 kcal mol−1) but large for olivine 73–118 kcal mol−1). Dissolution of plagioclase in rock melts seems to be a much more rapid process than crystal growth, whereas olivines apparently dissolve and grow at similar rates. Crystal dissolution is sufficiently slow that ascending, crystal-bearing magma may become superheated and yet fail to dissolve the crystal fraction before quenching; this may be the reason that olivine phenocrysts are often rounded.
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