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  • 1
    Electronic Resource
    Electronic Resource
    The effect of sewage effluent on Grasmere (English Lake District) with particular reference to inorganic nitrogen transformations (1978)
    Oxford, UK : Blackwell Publishing Ltd
    Freshwater biology 8 (1978), S. 0 
    Details
    ISSN: 1365-2427
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology
    Notes: SUMMARY. In the summer of 1971 the village of Grasmere was converted from septic tank to mains drainage with sewage treatment at an activated sludge plant. The effluent was discharged into the River Rothay, the main inflow of a nearby small lake (Grasmere). This paper describes some of the effects on the lake. The mean areal hypolimnetic oxygen deficit increased from 274 to 434 mg O2 m−2 day−1 with an accompanying marked increase in the degree of deoxygenation in the hypolimnion. Plate counts of bacteria in the surface water increased for 2 years but this increase was not sustained. The mean summer soluble reactive phosphorus concentration did, however, increase significantly (P= 0.05), but the same was not true of nitrate levels. This paper is particularly concerned with inorganic nitrogen transformations and analyses of the main inflow have shown that 50–98% of the ammonia and 10–40% of the nilrate entering in this river was derived from the sewage effluent. The concentrations in the main body of the lake were usually lower, possibly due to assimilation and denitrification in the shallower reaches of the lake. Seasonal changes in the inorganic nitrogen species in the hypolimnion showed three distinct phases of activity, ammonification, nitrification and denitrification. Nitrification accounted for approximately a quarter of the oxygen uptake in the hypolimnion.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1365-2427.1978.tb01438.x
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  • 2
    Electronic Resource
    Electronic Resource
    The effect of sewage effluent on denitrification in Grasmere (English Lake District) (1980)
    Oxford, UK : Blackwell Publishing Ltd
    Freshwater biology 10 (1980), S. 0 
    Details
    ISSN: 1365-2427
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology
    Notes: SUMMARY. Denitrification processes in Grasmere were studied using several techniques. Sediments were analysed for nitrate reductase activity and the accumulation of nitrogenous gases in samples incubated in the laboratory. Changes in the concentrations of inorganic nitrogen species in the water column and the release of gas bubbles into gas traps suspended above the sediment were also measured. Sewage effluent entered the lake via the main inflow and faecal bacteria were used as tracers to map the path of the river (and effluent) across the lake. The main river flow was west of the island in the centre of the lake and across the smaller of the two main basins. A preliminary study indicated that this western basin was the site of most active denitrification and this was confirmed in the following year when a seasonal survey showed that deoxygenation, nitrate reduction and ammonium accumulation was more advanced at this site. In addition, this basin was the only area where consistent discharge of nitrogen and methane from the profundal zone was observed. The nitrate reductase assay demonstrated that the sediment was the major site of denitrification, and that activity in the water column was higher in the anoxic hypolimnion than in the euphotic zone. Gas evolution from incubated sediment samples was analysed by gas liquid chromatography (GLC) and indicated that maximum denitrifying activity occurred below the mud surface in oxidized sediments. There was reasonable agreement between the enzyme assay and the GLC technique but neither predicted events in the field satisfactorily. Viable, most probable number (MPN) counts of denitrifying bacteria had similar limitations. A bimodal seasonal pattern of nitrate reductase activity was observed at four sites during thermal stratification, but this could not be explained fully. The major site of denitrification was identified and it was calculated that the nitrogen gas discharged was equivalent to c. 54% of the nitrate removed from the water column.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1365-2427.1980.tb01207.x
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  • 3
    Electronic Resource
    Electronic Resource
    Long-term research and the future: Résumé (1990)
    Oxford, UK : Blackwell Publishing Ltd
    Freshwater biology 23 (1990), S. 0 
    Details
    ISSN: 1365-2427
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1365-2427.1990.tb00260.x
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  • 4
    Electronic Resource
    Electronic Resource
    Gliding motility of Peloploca spp., and their distribution in the sediment and water column of a eutrophic lake (1984)
    Springer
    Archives of microbiology 140 (1984), S. 44-49 
    Details
    ISSN: 1432-072X
    Keywords: Peloploca spp. ; Gas-vacuolate bacteria ; Gliding motility ; Vertical migration ; Anoxic hypolimnion ; Lake sediment ; Microcapillary tubes
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Observations indicating gliding motility in the gas-vacuolate, filamentous organism Peloploca were made using microcapillary tubes. Tubes containing semi-solid agar, incubated in sediment cores gave good enrichments of Peloploca spp. The organisms, which had the form of helical bundles of filaments, were seen to corkscrew through the agar at up to 2–3 μm s-1. The vertical distribution of Peloploca spp. in the sediment and water column of a eutrophic lake was examined periodically during summer stratification. The organisms were confined to anoxic conditions in the sediment prior to stratification. With increasing anoxia in the hypolimnion, the population shifted upwards in the sediment, and towards the end of stratification, in the most reducing conditions, appeared in the lower hypolimnion. Anaerobically incubated sediment cores also showed the movement of the Peloploca population from sediment into the overlying water. It is suggested that the gliding motility and helical morphology of Peloploca bundles enable them to migrate through sediment in response to oxygen and Eh gradients, in addition to their use of gas vacuoles to adjust their position in the water column. The taxonomic implications of gliding motility in Peloploca spp. are discussed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00409770
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  • 5
    Electronic Resource
    Electronic Resource
    Distribution and regulation of nitrate and nitrite reduction by Desulfovibrio and Desulfotomaculum species (1986)
    Springer
    Archives of microbiology 144 (1986), S. 35-40 
    Details
    ISSN: 1432-072X
    Keywords: Sulphate-reducing bacteria ; Dissimilatory nitrate reduction ; Ammonium formation ; Nitrite reductase regulation ; Desulfovibrio ; Desulfotomaculum
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Rates of nitrate and nitrite reduction by cultures and washed suspensions of both natural isolates and culture collection strains of sulphate-reducing bacteria have been determined. Neither activity was detected in the Desulfotomaculum strains, but all Desulfovibrio strains reduced nitrite. Only the Desulfovibrio natural isolate FBA 20a was also able to reduce nitrate. Nitrate reduction by washed suspensions of strain FBA 20a was far more rapid than previously reported rates for sulphate-reducing bacteria [6.6 μmol NO 3 - reduced h-1 (mg dry weight)-1] and was regulated by nitrate induction and sulphate repression: it was insensitive to the product of nitrate reduction, ammonium ions. Cell yields from sulphate-limited cultures were proportional to the concentration of nitrate added with a yield coefficient of 28.0 g bacterial dry weight per mol of nitrate reduced. These results indicate that although the ability of strain FBA 20a to reduce nitrate is a physiologically significant process, it is a specialized property of only a few strains of Desulfovibrio isolates.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00454953
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  • 6
    Electronic Resource
    Electronic Resource
    Comparison of fatty acid content and DNA homology of the filamentous gliding bacteriaVitreoscilla, Flexibacter, Filibacter (1986)
    Springer
    Archives of microbiology 146 (1986), S. 1-6 
    Details
    ISSN: 1432-072X
    Keywords: Filamentous gliding bacteria ; DNA homology ; Membrane fatty acids
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract DNA hybridization experiments showed that there was a high degree of homology amongVitreoscilla strains but not with DNA fromFilibacter limicola. Flexibacter spp were much more heterogeneous indicating a low genetic similarity. These results were also reflected in the membrane fatty acids of the bacteria. TheVitreoscilla strains were very similar with the 16:1ω7c fatty acid being dominant. The membrane fatty acids ofF. limicola were dominated by a15:0 and a17:0 components which provided additional support for its relatedness to the genusBacillus. There was much greater diversity in the fatty acid patterns of theFlexibacter spp.F. aurantiacus, F. ruber andF. elegans shared the common dominant fatty acids 16:1ω7c with theVitreoscilla strains, but this was replaced by the 16:1ω6c acid inF. flexilis. F. ruber was distinguished by the absence of branched odd-chain monounsaturated fatty acids andF. elegans by the dominance of the β-OH i15:0 acid. Precise determination of fatty acid double bond positions and geometry are essential for correct interpretation of increasingly complex ecological and taxonomic data sets.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00690149
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  • 7
    Electronic Resource
    Electronic Resource
    Nutritional strategy of a benthic filamentous bacterium (1986)
    Springer
    Microbial ecology 12 (1986), S. 323-330 
    Details
    ISSN: 1432-184X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Filibacter limicola is a filamentous gliding bacterium isolated from the profundal sediment of a eutrophic lake. It is an obligate amino acid utilizer. The kinetic parameters for the metabolism of four amino acids byF. limicola, Vitreoscilla spp. and the bacterial populations of water and sediment samples were compared.F. limicola exhibited low half-saturation constants (K) which were of the same order as those obtained with water samples. The K values for theVitreoscilla spp. and the sediment were an order of magnitude higher. It would appear that the bacterium is a specialist, inhabiting a niche which is sufficiently nutrient rich to support an organism with a limited substrate range. It also possesses a high affinity uptake system for some amino acids which may permit it to compete effectively during periods of nutrient depletion.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02098573
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  • 8
    Electronic Resource
    Electronic Resource
    Gas chromatographic determination of total amino acids and protein in sediments using the ninhydrin-CO2 reaction (1983)
    Springer
    Hydrobiologia 101 (1983), S. 189-194 
    Details
    ISSN: 1573-5117
    Keywords: amino acids ; protein ; sediments ; ninhydrin reaction ; gas chromatography
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract A sensitive modification of the ninhydrin-CO2 method involving the gas chromatographic determination of the total protein and amino acid content of sediment is described. The method gives a linear response over the amino acid concentration range 10−5 M to 4 × 10−2 M. It can be used for whole sediment, hydrolysates and interstitial water. The performance of the method is compared with the fluorescamine method for primary amines.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00009874
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  • 9
    Electronic Resource
    Electronic Resource
    Gas chromatographic determination of total amino acids and protein in sediments using the ninhydrin-CO2 reaction (1982)
    Springer
    Hydrobiologia 97 (1982), S. 81-86 
    Details
    ISSN: 1573-5117
    Keywords: amino acids ; protein ; sediments ; ninhydrin reaction ; gas chromatography
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract A sensitive modification of the ninhydrin-CO2 method involving the gas chromatographic determination of the total protein and amino acid content of sediment is described. The method gives a linear response over the amino acid concentration range 10−5 M to 4 × 10−2 M. It can be used for whole sediment, hydrolysates and interstitial water. The performance of the method is compared with the fluorescamine method for primary amines.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00014961
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