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Digitale Medien

Effect of diet on growth rate and reproductive fitness of Turbo sarmaticus (Mollusca: Vetigastropoda: Turbinidae) (1999)

Foster, G. G. ; Hodgson, A. N. ; Balarin, M.

Springer

Marine biology 134 (1999), S. 307-315

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ISSN: 1432-1793

Quelle: Springer Online Journal Archives 1860-2000

Thema: Biologie

Notizen: Abstract Experiments were conducted to determine the effect of four algal diets (Corallina spp., Gelidium pristoides, Ulva rigida and an equal volume mixture of these seaweeds) on growth and reproduction of the South African gastropod Turbo sarmaticus Linnaeus, 1758. The best growth rate of juveniles (up to 13.8 mm shell length and 34.26 g wet body weight increase in 12 months), reproductive fitness of mature specimens (gonad index up to 33%) and energy reserves (up to 4.76 mg glycogen/100 mg foot tissue) were achieved when T. sarmaticus was fed U. rigida or a mixed diet. In addition, the gonad index of individuals fed these diets was almost twice that of similar-sized field specimens. Juveniles fed Corallina spp. only, grew very little (only 2.4 mm shell length and 4.23 g wet body weight increase in 12 months). The reproductive fitness of adults fed on such a diet was also poor (gonad index 〈4.5%) and energy reserves were low (〈3.5 mg glycogen/100 mg foot tissue). Along the southeastern coast of South Africa, T. sarmaticus has a distinct reproductive cycle with gametogenesis occurring from March/April until August/September, whilst maturity (gonad index = 15%) was maintained until December, after which spawning occurred until March.

Materialart: Digitale Medien

URL: http://dx.doi.org/10.1007/s002270050548

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Digitale Medien

Feeding dynamics and respiration of the bottom-dwelling caridean shrimp Nauticaris marionis Bate, 1888 (Crustacea: Decapoda) in the vicinity of Marion Island (Southern Ocean) (1999)

Pakhomov, E. A. ; Froneman, P. W. ; Kuun, P. J. ; [weitere]

Springer

Polar biology 21 (1999), S. 112-121

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ISSN: 1432-2056

Quelle: Springer Online Journal Archives 1860-2000

Thema: Biologie

Notizen: Abstract The feeding dynamics and oxygen uptake of the bottom-dwelling caridean shrimp Nauticaris marionis were studied during the April/May 1984, 1996 and 1997 cruises to Marion Island (Prince Edward Islands, Southern Ocean). N. marionis is thought to have an opportunistic feeding mode. Prey composition varied considerably between the years and sites investigated. Overall, benthic (mainly hydrozoans and bottom-dwelling polychaetes) and, at times, pelagic (largely euphausiids and copepods) prey items dominated in the stomachs of N. marionis both by occurrence and by volume. Generally, pelagic prey contributed more to the diets of smaller shrimps, while benthic prey was a more important component in the guts of larger specimens. Wet, dry and ash-free dry weight were determined for specimens used in respiration experiments. The respiration rates of N. marionis females with carapace length 6.6–11.1 mm ranged from 80 to 250 μl O2 individual−1 · h−1, or from 0.588 to 2.756 μl O2 · mg−1 dry weight h−1. Regression analyses showed highly significant correlations between oxygen consumption and carapace length for N. marionis. Daily ingestion rates estimated using an in situ gut content analysis technique (4.4% of body dry weight) and an energy budget approach (average 4.7% of body dry weight, range 2.0–7.5%) showed good agreement with each other.

Materialart: Digitale Medien

URL: http://dx.doi.org/10.1007/s003000050341

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Digitale Medien

Structure and grazing impact of the protozooplankton community in the waters surrounding the Prince Edward Islands (Southern Ocean) (1998)

Froneman, P. W. ; Balarin, M. G.

Springer

Polar biology 20 (1998), S. 198-205

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ISSN: 1432-2056

Quelle: Springer Online Journal Archives 1860-2000

Thema: Biologie

Notizen: Abstract The structure and grazing dynamics of the protozooplankton community at ten stations in the upstream and downstream region of the Prince Edward Islands (46°38′S, 37°57′E) were investigated during early austral autumn (April/May) 1997. Total chlorophyll-a (chl-a) concentrations throughout the investigation were 〈0.6 μg l−1 and were always dominated by nano- and picophytoplankton (〈20 μm). Although microphytoplankton (〉20 μm) generally contributed 〈10% of the total chl-a, its contribution to total was significantly higher at downstream stations (F= 1.03; P 〈 0.05). Nanoflagellates (〈20 μm) numerically dominated the protozooplankton community while the 〉20 μm fraction was dominated by dinoflagellates. Instantaneous growth rates of phytoplankton at upstream stations ranged from 0.01 to 0.18 day−1 and between 0.01 and 0.19 day−1 at downstream stations. Instantaneous grazing rates of protists on phytoplankton upstream of the islands ranged from 0.03 to 0.07 day−1, which corresponds to a loss of up to 8% (mean = 5%) of the initial phytoplankton standing stock or up to 71% (mean = 37%) of the potential primary production per day. Downstream of the islands, although the grazing rates of the protists were within the same range (0.01–0.07 day−1), the grazing impact was lower, corresponding to up to 7% (mean = 3%) of the initial standing stock or up to 47% (mean = 25%) of the potential primary production per day. The spatial difference in the grazing impact of protozooplankton appears to reflect a shift in the size structure of the phytoplankton community resulting from the “island mass effect”.

Materialart: Digitale Medien

URL: http://dx.doi.org/10.1007/s003000050296

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Digitale Medien

Thermochemische Untersuchungen zu den Systemen Ti/Ni und Ti/Co (1996)

Balarin, M. ; Bartsch, Karl

Weinheim : Wiley-Blackwell

Zeitschrift für anorganische Chemie 622 (1996), S. 919-921

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ISSN: 0044-2313

Schlagwort(e): Thermochemistry ; nickel trititanium ; cobalt trititanium ; standard enthalpy of formation ; Chemistry ; Inorganic Chemistry

Quelle: Wiley InterScience Backfile Collection 1832-2000

Thema: Chemie und Pharmazie

Beschreibung / Inhaltsverzeichnis: Thermochemical Investigations of the Systems Ti/Ni and Ti/CoBy treatment of solid Ni or Co with a H2/TiCl4-gas mixture at sufficient high temperature (T ≥ 900°C) the intermetallic phases TiNi3 and TiCo3, resp., are formed. The conversion grade depends on the H2/TiCl4-ratio. From the experimentally determined conversion grades and the known thermodynamic data of all other species existing in equilibrium the free enthalpies and the heats of formation of TiN3 and TiCo3 have been calculated (TiNi3: ΔHf°(298) = -133.3 ± 6 kJ/mol; TiCo3: ΔHf°(298) = -104.7 ± 6 kJ/mol).

Notizen: Beim Überleiten eines H2/TiCl4-Gasgemisches über Nickel oder Cobalt bilden sich bei ausreichend hohen Temperaturen (T ≥ 900°C) die intermetallischen Phasen Ti/Ni3 bzw. TiCo3. Der Grad der Umsetzung wird durch das H2/TiCl4-Verhältnis bestimmt. Aus den experimentell ermittelten Umsetzungsgraden wurden mit Hilfe der thermodynamischen Daten der übrigen im Gleichgewicht vorliegenden Stoffe die freien Enthalpien der intermetallischen Phasen ermittelt und deren Standardbildungsenthalpien berechnet (Ti/Ni3: ΔHB°(298) = -133,3 ± 6kJ/mol; TiCo3: ΔHB°(298) = -104,7 ± 6 kJ/mol).

Zusätzliches Material: 2 Ill.

Materialart: Digitale Medien

URL: http://dx.doi.org/10.1002/zaac.19966220529

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