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  • 1
    ISSN: 1432-1793
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Lignocellulose was found to comprise the bulk of various anatomical structures of the salt marsh grass Spartina alterniflora, as well as of detritus derived from this plant; although concentrations of both lignin and lignocellulose varied with plant height-form, age, and anatomical structure. Changes in the relative concentrations of lignin and polysaccharide in lignocellulose due to long-term degradation by natural marsh microflora were determined using standard gravimetric assay procedures and a new procedure utilizing specifically-radiolabelled 14C-(cellulose)-lignocellulose and 14C-(lignin)-lignocellulose prepared from S. alterniflora. Results obtained with the two methods agreed, thus validating the new procedures. Mineralization of the cellulose moiety was more rapid than mineralization of the lignin moiety resulting in relative enrichment of S. alterniflora detritus in lignin. Rates of mineralization of both moieties decreased over time such that extent of mineralization was a function of the logarithm of aging time.
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    Springer
    Marine biology 64 (1981), S. 43-51 
    ISSN: 1432-1793
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract We determined concentrations of dissolved adenosine triphosphate (DATP) and rates of its uptake by marine bacteria in seawater from the continental shelf and Gulf Stream off the southeastern USA. Dissolved adenosine triphosphate (DATP) concentrations (22 to 568 ng l−1) were highest in nearshore surface waters and at the interfaces of continental shelf water and upwelled water from the cold wall of the Gulf Stream; lowest concentrations were found in surface water furthest from shore and in subsurface waters. Bacterial population density and DATP uptake velocities were determined to calculate average rates of DATP uptake per-cell. In general, percell rates of uptake were highest in samples having the highest in situ concentrations of DATP and varied markedly with small-scale temporal and spatial changes. Per-cell uptake by attached bacteria was one to two orders of magnitude faster than uptake by free-living bacteria; this difference could be accounted for by the much larger average cell volume of the former.
    Type of Medium: Electronic Resource
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  • 3
    ISSN: 1432-184X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract A variety of freshwater marsh and swamp habitats are found interspersed in a mosaic pattern throughout the Okefenokee Swamp, Georgia, USA. We examined spatial and temporal patterns in standing stocks and activity in the microbial community of five habitats within this heterogeneous ecosystem. Standing stock dynamics were studied by measuring microbial biomass (ATP) and bacterial numbers (AODC) in both water and sediments over a 14 month period. Abundance varied temporally, being generally lower in winter months than in spring and summer months. However, a large proportion of the measured variability was not correlated with temporal patterns in temperature or with bulk nutrient levels. Spatial variability was characteristic of the Okefenokee at a variety of large and small scales. Habitat-level heterogeneity was evident when microbial standing stocks and activity (measured as [14C]lignocellulose mineralization) were compared across the five communities, although abundance differences among sites were restricted to nonwinter months when microbial biomass was high. Spatial variation within habitats was also found; patches of surface sediment with differing microbial activity or abundance were measured at scales from 30 cm to 150 m.
    Type of Medium: Electronic Resource
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  • 4
    ISSN: 1432-184X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Temperature dependence and seasonal variations in rates of microbial degradation of the lignin and polysaccharide components of specifically radiolabeled lignocelluloses were determined in sediment and water samples from a Georgia salt marsh and the nearby Okefenokee Swamp. Although temperature regimes in the two ecosystems were similar, rates of mineralization ofSpartina alterniflora lignocellulose in salt marsh sediments increased eightfold between winter and summer, whereas rates of mineralization of lignocellulose from an analogous freshwater macrophyte,Carex walteriana, in Okefenokee sediments increased only twofold between winter and summer. Temperature was the major factor influencing seasonal variations in rates of lignocellulose degradation in both environments. At any given temperature, no substantial differences in lignocellulolytic potential were observed with sediment samples collected at each season. In both ecosystems, the bulk of the lignocellulosic detritus was not degraded at the time of its peak deposition during the fall and winter. Instead, the periods of maximal decomposition occurred during the following spring and summer. These results suggest that periods of maximal nutrient regeneration from the mineralization of lignocellulosic detritus coincide with periods of highest primary production, and that, depending on hydrologic conditions, significant horizontal transport of essentially intact lignocellulosic material is possible due to the lag period between deposition and microbial degradation.
    Type of Medium: Electronic Resource
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  • 5
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Publishing Ltd
    Journal of fish diseases 10 (1987), S. 0 
    ISSN: 1365-2761
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology , Medicine
    Type of Medium: Electronic Resource
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  • 6
    Electronic Resource
    Electronic Resource
    Springer
    Bulletin of environmental contamination and toxicology 41 (1988), S. 742-745 
    ISSN: 1432-0800
    Source: Springer Online Journal Archives 1860-2000
    Topics: Energy, Environment Protection, Nuclear Power Engineering , Medicine
    Type of Medium: Electronic Resource
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  • 7
    Electronic Resource
    Electronic Resource
    Springer
    Bulletin of environmental contamination and toxicology 34 (1985), S. 876-882 
    ISSN: 1432-0800
    Source: Springer Online Journal Archives 1860-2000
    Topics: Energy, Environment Protection, Nuclear Power Engineering , Medicine
    Type of Medium: Electronic Resource
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