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  • 1
    Electronic Resource
    Electronic Resource
    Respiratory quotient and calcification of Nautilus macromphalus (Cephalopoda: Nautiloidea) (1993)
    Springer
    Marine biology 117 (1993), S. 629-633 
    Details
    ISSN: 1432-1793
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Respiration and calcification were investigated in the ectocochleate cephalopod Nautilus macromphalus Sowerby. Specimens were collected off New Caledonia, in October 1991, and kept at the Nouméa Aquarium until December 1991. The respiratory quotient and calcification rate of 5 individuals were measured during 14 short term incubations (63 to 363 min). Oxygen uptake was recorded with a polarographic oxygen sensor. CO2 flux and calcification were calculated from changes in pH and alkalinity (alkalinity-anomaly technique). Several methods were used to compute the respiratory quotient (RQ); a functional regression indicated an RQ of 0.74. CaCO3 exchange rates were linearly related to respiratory quotient, calcification occurring in individuals with a low RQ. CaCO3 uptake from the surrounding water was noncontinuous. From the highest CaCO3 uptake, maximum growth rate was estimated as 7.1 mg shell wt h- (=61 g yr-1).
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00349775
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  • 2
    Electronic Resource
    Electronic Resource
    Phylogenetic characterisation of bacterial symbionts in the accessory nidamental glands of the sepioid Sepia officinalis (Cephalopoda: Decapoda) (2000)
    Springer
    Marine biology 136 (2000), S. 217-222 
    Details
    ISSN: 1432-1793
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract  Female cuttlefish harbour a dense bacterial community in their accessory nidamental glands (ANG), as is also the case for the myopsid squids. Molecular approaches have been applied to explore this symbiotic association in the sepiid species Sepia officinalis. In situ localisation by Bacteria-specific probes in tissue sections of the ANG revealed the presence of a dense bacterial population in the lumina of the organ tubules. The phylogenetic identification of bacterial strains was realised by 16S rRNA gene sequencing analysis. None of the sequences obtained matched perfectly with known sequences in the database. However their similarity percentages allowed us to relate them to various bacterial groups including the taxa Agrobacterium, Roseobacter, Sporichthya, Rhodobium–Xanthobacter and Clostridium. Some bacterial species are common to both sepioids and myopsid teuthoids, others are different.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s002270050679
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  • 3
    Electronic Resource
    Electronic Resource
    Vitesse de Digestion d'Octopus cyanea (Cephalopoda: Octopoda) (1973)
    Springer
    Marine biology 18 (1973), S. 237-242 
    Details
    ISSN: 1432-1793
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Description / Table of Contents: Résumé 1. Des Octopus cyanea Gray de différentes tailles (632 à 2250 g) ont été nourris avec des crabes dont le poids relatif représentait de 8,9 à 20,3%. 2. La quantité de nourriture ingérée, à température constante et en présence d'un seul crabe, dépend essentiellement du poids de l'O. cyanea et en partie de la taille du crabe et de la durée expérimentale de la prise de nourriture. 3. A une température d'environ 30°C, la durée totale de la digestion d'un repas est toujours de 12 h. La digestion débute très rapidement, puis subit un ralentissement progressif. Une heure après le début du repas, environ 38% de la nourriture ingérée sont déjà digérés. 4. O. cyanea règle l'écoulement de la nourriture en fonction de la quantité ingérée, elle-même en relation avec son propre poids corporel, de telle sorte que la quantité de nourriture digérée à 1 h donnée représente un pourcentage constant de la nourriture ingéréc. Le taux de digestion, facteur d'efficacité de la digestion, est de 0,5 environ. 5. La comparaison avec d'autres espèces de céphalopodes, benthiques et pélagiques, et vivant dans des eaux de température différente, montre que la digestion dépend en premier lieu du mode de vie, en second lieu de la température. 6. A mode de vie comparable et température égale, la durée de digestion est plus courte chez les céphalopodes que chez les poissons; leur taux de digestion semble être plus élevé.
    Notes: Abstract In the benthic octopus Octopus cyanea Gray, acclimated to high temperature (30°C), digestion takes 12 h. Animal weight and food intake do not influence the duration of digestion. By regulating the rate of food passage in the alimentary canal, the quantity of digested food (as a percentage of ingested food) is kept constant at a particular time. A comparison with other cephalopod species and with different fish species, leads to the conclusion that the mode of life is the main factor determining the duration of digestion and its efficiency. For a given species, the duration of digestion depends on temperature. For a similar mode of life and at equal temperatures, digestion is more rapid and more efficient in cephalopods than in fishes.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00367990
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  • 4
    Electronic Resource
    Electronic Resource
    Respiration and nitrogen excretion by the squid Loligo forbesi (1989)
    Springer
    Marine biology 103 (1989), S. 333-338 
    Details
    ISSN: 1432-1793
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Respiration and nitrogen excretion rates of mature adult Loligo forbesi were investigated at the Roscoff Laboratory (North Brittany, France) during individual short-term incubation experiments in January 1986. The squids were in post-digestive condition and not actively swimming. Both oxygen uptake and nitrogen excretion are continuous processes. The metabolic rates of this active nektonic species (145 ml kg-1 h-1 oxygen uptake, 18.56 μg g-1 h-1 ammonia excretion) are distinctly higher than those of benthic cephalopods. Proteins constitute the main metabolic substrate for energetic needs. Besides ammonia, urea is also continuously released, in amounts ranging from 5 to 16% of ammonia-excretion values.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00397267
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  • 5
    Electronic Resource
    Electronic Resource
    Ammonia excretion during feeding and starvation in Octopus vulgaris (1985)
    Springer
    Marine biology 86 (1985), S. 193-197 
    Details
    ISSN: 1432-1793
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Ammonia excretion was investigated in relation to oxygen consumption during a feeding regime and during shortterm starvation in two mature male Octopus vulgaris, trawled in spring 1983 off Banyuls-sur-mer. In our study, ammonia excretion is taken to include renal and gill loss. The excretion of primary amines was also studied, but proved to be negligible under our experimental conditions. Ammonia excretion and oxygen consumption are repetitive linear processes over 1 to 2 h incubation periods at 15° to 16°C, in both fed and starved conditions. Starvation induces a decline in ammonia excretion and oxygen consumption and an increase in the atomic O:N ratio, suggesting that O. vulgaris uses up other reserves (lipids) before utilizing an exclusively protein substrate.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00399026
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  • 6
    Electronic Resource
    Electronic Resource
    In situ study of the effect of oyster biomass on benthic metabolic exchange rates (1990)
    Springer
    Hydrobiologia 206 (1990), S. 115-123 
    Details
    ISSN: 1573-5117
    Keywords: oxygen and nitrogen fluxes ; metabolic regulation ; oyster biomass
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Oxygen consumption and dissolved nitrogen fluxes at the water-sediment interface of an oyster-bed were measured in situ using transparent enclosures inserted on undisturbed sediment. Experiments were performed in summer, under dark and light conditions, with various densities of the oyster Crassostrea gigas (0–150 animals m − 2). The influence of oyster biomass on oxygen and ammonia exchange rates was similar in both lighting conditions. Oxygen consumption increased with increasing biomass, though not at the level of prediction for the highest biomasses, suggesting a depressed respiration rate. Ammonia release never matched the rates predicted by adding sediment efflux to oyster excretion, when biomass exceeded 100 g DW m − 2. The coupling between oxygen consumption and ammonia release (O : N ratio) was thus influenced by oyster biomass. Stabilization of nitrogen release was related to enhanced nitrification in the presence of oyster and/or sediment uptake of ammonia against the molecular gradient. Urea release was erratic but appeared uninfluenced by oyster biomass. Fluxes of oxygen and of each nitrogen compound displayed thus a specific response to modifications of the oyster biomass. Both the organisms and the sediment are involved in regulation processes of metabolic exchange rates at the water-sediment interface.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00018637
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    Paper (German National Licenses)
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