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  • 1
    Electronic Resource
    Electronic Resource
    Modelling the photosynthetic production by sponges on Davies Reef, Great Barrier Reef (1991)
    Springer
    Marine biology 109 (1991), S. 13-18 
    Details
    ISSN: 1432-1793
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Sponge populations on Australia's Great Barrier Reef (GBR) may contain a mix of both phototrophic and heterotrophic species. The distribution of many of these sponges on reefs is assumed to be determined by light. A model was developed to investigate how the distribution of phototrophic sponges over depth is restricted by the availability of photosynthetically active radiation. Estimates of the balance between photosynthetic production and the total respiratory demand of entire sponge communities on Davies Reef (a middle-shelf reef of the Great Barrier Reef) are provided. These estimates are based upon published data for community composition and biomass, whilst photokinetic parameters have been determined for a variety of sponge species from oxygenexchange measurements. Phototrophic sponges on the fore-reef slope are predicted to exist at or above a state of net 24 h compensation (i.e., photosynthetic oxygen production by sponges balances or exceeds respiration over a 24 h period) to a depth of 30 m. It is proposed that phototrophic sponges are obligate phototrophs because the availability of light for photosynthesis corresponds with the lower depth limit of their distribution. Sponge communities (including both phototrophs and heterotrophs) from the fore-reef and lagoon exist close to a state of net 24 h compensation to a depth of 10 to 15 m. This balance shows diurnal variations, associated with the activity of phototrophs, such that instantaneous compensation of the community may occur to depths of 20 to 25 m when light is maximal.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01320226
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  • 2
    Electronic Resource
    Electronic Resource
    Genetic structure of dictyoceratid sponge populations on the western Coral Sea reefs (1994)
    Springer
    Marine biology 119 (1994), S. 335-345 
    Details
    ISSN: 1432-1793
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Allozyme variation at six polymorphic loci was examined in foliose dictyoceratid sponges from isolated reefs in the western Coral Sea. Four major genetic groups corresponding to the species Phyllospongia lamellosa, P. alcicornis, Carterospongia flabellifera and Collospongia auris were examined. A further two rare morphotypes from individual reefs formed genetic outliers to the P. lamellosa group, and may represent further taxa related to P. lamellosa. Gene frequencies in individual reef populations were largely in Hardy-Weinberg equilibrium, suggesting that random mating occurred in local populations of all four common species. Genetic variability was high and observed heterozygosities within populations ranged from 0.13 to 0.40. All four taxa showed significant genetic differentiation among populations (F ST=0.05 to 0.36). Genetic distances (Nei's D) among populations within species ranged from 0 to 0.723 and increased with increasing geographical separation. There was evidence that genetic differentiation between populations to the north and to the south of the southern limit of the South Equatorial Current (SEC) divergence was greater than expected on the basis of their geographical separation. The SEC divergence may form a partial barrier to gene flow among populations of these ecologically important sponges on the submerged Queensland Plateau. Levels of migration among populations of three of the species was less than those required to prevent divergence of the populations through genetic drift (Nm〈1). Restricted migration among populations may provide a mechanism to explain the occurrence of highly divergent populations of dictyoceratid sponges whose specific identity is not clear, and may allow them additionally to develop partial reproduction isolation from other populations.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00347530
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  • 3
    Electronic Resource
    Electronic Resource
    Rates of nitrogen fixation on coral reefs across the continental shelf of the central Great Barrier Reef (1984)
    Springer
    Marine biology 80 (1984), S. 255-262 
    Details
    ISSN: 1432-1793
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract This study was undertaken in 1981 to determine whether there were major variations in potential rates of nitrogen fixation on apparently bare coralline substrate from reefs across the continental shelf of the central Great Barrier Reef. Nitrogen fixation, measured as rates of ethylene production (nmol cm-2h-1), was significantly lower on substrata from two inner-shelf reefs, (0.46 and 1.07) than on two middle-shelf reefs (2.10 and 2.97) and on two outer-shelf reefs (3.20 and 3.81). By contrast, algal biomass (mg cm-2) on experimental substrate was significantly higher on inner-shelf reefs (80.8 and 59.4) than on middleshelf (27.1 and 23.8) and outer-shelf reefs (26.4 and 22.4). The rate of nitrogen fixation was positively correlated with the proportion of “bare” substratum and significantly higher concentrations of dissolved inorganic nitrogen were found in waters over the reefs than in water flowing onto those reefs. The abundance of algal-grazing fishes was reported previously to be significantly lower on inner-shelf reefs. It is suggested that this cross-shelf variation in the activity of algal-grazing fishes may be a determinant of the observed cross-shelf variations in potential nitrogen fixation.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00392820
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  • 4
    Electronic Resource
    Electronic Resource
    Grooved substrata facilitate in vitro healing of completely divided flexor tendons (1995)
    Springer
    Journal of materials science 6 (1995), S. 266-271 
    Details
    ISSN: 1573-4838
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine , Technology
    Notes: Multiple grooved substrata with groove depth 5 μm were found to facilitate the healing of completely divided rat flexor tendons in vitro. Sections of tendons cultured on plain substrata showed only partial healing with incompletely sealed epitenon layers and immature thin collagen fibres. Tendons cultured on patterned substrata healed with complete restoration of the epitenon layer and reconstitution of the internal structure of collagen fibres. Epitenon fibroblasts isolated from the surface of rat flexor tendons were shown to be more sensitive to topographical features than fibroblasts of the same size BHK fibroblasts. They remained more elongated and better aligned to the groove direction than BHK cells. Multiple grooved substrata facilitated epitenon cell movement. Cells were found to move with higher speed on patterned substrata than on plain substrata. In summary, we conclude that the use of multiple grooved substrata promotes tendon healing in vitro and may find application in clinical practice in tendon repair.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00120269
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  • 5
    Electronic Resource
    Electronic Resource
    Microbial associations in sponges. I. Ecology, physiology and microbial populations of coral reef sponges (1978)
    Springer
    Marine biology 49 (1978), S. 161-167 
    Details
    ISSN: 1432-1793
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Illumination, current strength and physical turbulence influence the distribution of 4 tropical sponges. Three sponges with cyanobacteria in exposed tissues grow only in poen shallow habitats: Pericharax heteroraphis in moderate-current, lowturbulence regions on the reef slope; Jaspis stellifera in low-current, moderate-turbulence regions of the outer reef flat; and Neofibularia irata in moderate-current, high-turbulence areas below the reef crest. Ircinia wistarii contains no cyanobacteria and occurs in deeper, strong-current, high-turbulence regions. N. irata agressively overgrows neighbouring corals and its growth form is influenced by the current strength. The sponges efficiently filter bacteria from the water. The efficiency is related to the aquiferous structure, particularly the size of choanocyte chambers, and is unrelated to the existing bacterial populations in sponge tissue. The numbers of bacteria associated with the sponges are proportional to the sponge mesohyl density, with the dense sponges J. stellifera and I. wistarii containing many bacteria whereas P. heteroraphis is not dense and has few bacteria.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00387115
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  • 6
    Electronic Resource
    Electronic Resource
    Microbial associations in sponges. II. Numerical analysis of sponge and water bacterial populations (1978)
    Springer
    Marine biology 49 (1978), S. 169-176 
    Details
    ISSN: 1432-1793
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Three taxonomically distant sponges Pericharax heteroraphis, Jaspis stellifera and Neofibularia irata contain phenotypically similar bacterial symbionts which differ from bacteria in the ambient water. These symbionts are predominant in the sponges and were detected after computer analysis of 526 heterotrophic bacterial strains tested for 76 characters. These facultative anaerobic symbionts metabolize a wide range of compounds and may be important in removing waste products while the sponges are not circulating water. The bacteria produce sticky-mucoid colonies and thus would contribute to sponge structural rigidity. The fourth sponge Ircinia wistarii contains a mixed aerobic population similar to that in the ambient water. The majority of the bacteria are located around the inhalant canals, facilitating the uptake of dissolved organic matter and oxygen from the incoming water.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00387116
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  • 7
    Electronic Resource
    Electronic Resource
    Microbial associations in sponges. III. Ultrastructure of the in situ associations in coral reef sponges (1978)
    Springer
    Marine biology 49 (1978), S. 177-185 
    Details
    ISSN: 1432-1793
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Symbiotic cyanobacteria are associated with marine sponges in three ways: the majority are free-living in the mesohyl; large aggregates occur in “cyanocytes” (specialized, vacuolated archeocytes); and few are present in digestive vacuoles. The cyanobacteria in Jaspis stellifera and Neofibularia irata are morphologically similar to those described in Mediterranean sponges, whereas those in Pericharax heteroraphis are different. The freeliving bacterial populations are morphologically similar, although the number of bacteria varies between the species. The fourth sponge Ircinia wistarii contains a mixed bacterial population unlike those in the other sponges. Sponge digestion of microbial associates is rare and not considered to contribute significant nutrients.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00387117
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  • 8
    Electronic Resource
    Electronic Resource
    Magnetic structure of ludlamite, Fe3(PO4)2·4H2O (1990)
    Springer
    Hyperfine interactions 54 (1990), S. 651-653 
    Details
    ISSN: 1572-9540
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract 57Fe Mössbauer spectra for a natural single crystal of ludlamite have been recorded at temperatures between room temperature and 4.2 K. Computer analysis reveals that at 4.2 K the Fe2+ moments lie on two distinct magnetic sublattices separated by at least 35°.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02396106
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  • 9
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    Thick and deformed Antarctic sea ice mapped with autonomous underwater vehicles (2014)
    Springer Nature
    Details
    Publication Date: 2014-12-24
    Description: Nature Geoscience 8, 61 (2015). doi:10.1038/ngeo2299 Authors: G. Williams, T. Maksym, J. Wilkinson, C. Kunz, C. Murphy, P. Kimball & H. Singh
    Print ISSN: 1752-0894
    Electronic ISSN: 1752-0908
    Topics: Geosciences
    Published by Springer Nature
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  • 10
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    Evolution of starburst galaxies in the Illustris simulation (2018)
    Oxford University Press
    Details
    Publication Date: 2018-06-07
    Description: There is a consensus in the literature that starburst galaxies are triggered by interaction events. However, it remains an open question as to what extent both merging and non-merging interactions have in triggering starbursts. In this study, we make use of the Illustris simulation to test how different triggering mechanisms can affect starburst events. We examine the star formation rate, colour, and environment of starburst galaxies to determine if this could be why we witness a bimodality in post-starburst populations within observational studies. Further, we briefly test the extent of quenching due to active galactic nuclei feedback. From Illustris, we select 196 starburst galaxies at |$z$| = 0.15 and split them into post-merger and pre-merger/harassment-driven starburst samples. We find that 55  % of this sample have not undergone a merger in the past 2 Gyr. Both of our samples are located in low-density environments within the filament regions of the cosmic web; however, we find that pre-merger/harassment-driven starbursts are in higher-density environments than post-merger-driven starbursts. We also find that pre-merger/harassment starbursts are redder than post-merger starbursts; this could be driven by environmental effects. Both, however, produce nuclear starbursts of comparable strengths.
    Print ISSN: 0035-8711
    Electronic ISSN: 1365-2966
    Topics: Physics
    Published by Oxford University Press on behalf of The Royal Astronomical Society.
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