ALBERT

All Library Books, journals and Electronic Records Telegrafenberg

X
feed icon rss

Your email was sent successfully. Check your inbox.

An error occurred while sending the email. Please try again.

Proceed reservation?

Export
  • 1
    Electronic Resource
    Electronic Resource
    Annual variation of dissolved free primary amines in estuarine water and sediment (1979)
    Springer
    Oecologia 40 (1979), S. 207-217 
    Details
    ISSN: 1432-1939
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary The concentration of dissolved free primary amines (DFPA), determined as fluorescamine positive material, was quantified during a one year period of a small estuary. In the water, the concentration of DFPA ranged from 1.8 μM in winter, to 26.5 μM in summer. In the sediment, from 16 to 56 μM of DFPA occurred. The concentration varied with depth and season, and in summer months a maximum of DFPA was observed in the redox discontinuity layer. The DFPA peak in water and sediment coincided with maximum of the macrophytal biomass. About 80% of the fluorescamine positive material was identified as amino acids. Origin and distribution of primary amines in the estuarine environment are discussed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00347938
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 2
    Electronic Resource
    Electronic Resource
    Are dissolved free amino acids free? (1984)
    Springer
    Microbial ecology 10 (1984), S. 301-316 
    Details
    ISSN: 1432-184X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Microbial assimilation of 3 amino acids (glutamic acid, alanine, and ornithine) was characterized in 3 lakes and 2 marine stations using the Michaelis-Menten kinetic approach. The calculated Kt + Sn concentrations were related to chemical concentration measurements of dissolved free amino acids (DFAA) to evaluate the biological and the chemical determinations of the DFAA pools. Concentrations of Kt + Sn always were larger than chemical measurements of the Sn concentrations. Kt + Sn and Sn varied from 11.5 and 9.5 nM (alanine, oligotrophic lake) to 288.7 and 89.9 nM (ornithine, marine harbor station), respectively. Subtracting Sn from the Kt + Sn concentrations, Kt was found to range from 12–897% of the chemically measured Sn concentrations. To test whether the DFAA actually were free, dissolved molecules, dissolved material in the water samples was separated into various molecular size classes by means of gel permeation chromatography. From 47–116% of the DFAA in the untreated water samples was recovered in the low molecular fraction (〈700 Daltons). Variation in recoveries mainly appeared to be due to an incomplete chromatographic separation and difficulties in obtaining proper blank levels. The present observations suggest that labeled tracers can be used in the study of DFAA assimilation and that the DFAA are free, dissolved molecules. This partly conflicts with previously published reports.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02015556
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 3
    Electronic Resource
    Electronic Resource
    Zooplankton induced changes in dissolved free amino acids and in production rates of freshwater bacteria (1986)
    Springer
    Microbial ecology 12 (1986), S. 247-258 
    Details
    ISSN: 1432-184X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract This study examined the importance of zooplankton in the flux of dissolved free amino acids (DFAA) in the water and into bacteria. DFAA release rates were followed in laboratory grazing experiments usingDaphnia galeata andEudiaptomus graciloides as grazers, andScenedesmus acutus andSynechococcus elongatus as food sources. Except for minor initial peaks, DFAAs were released continuously during the first 2 hours and made up 6–12% (in one experiment 50%) of the calculated ingestion rates. During three diel studies in lakes, effects of removal and increase of the density of zooplankton (〉200μm) on the pools of DFAA as well as on the bacterial production were followed. During two of the diel studies, higher DFAA pools were measured when 3–4 times the natural zooplankton density was present, and in one study a minor increase also occurred in the bacterial production, compared with results from experiments without zooplankton and with a natural zooplankton density. The increase in bacterial growth coincided with a decline in DFAA. During the third study, neither DFAA nor the bacterial production changed significantly when the zooplankton density was increased 3 times. Removal of zooplankton, however, caused a decline in both DFAA and bacterial production. Our data suggest a close relationship between occurrence of zooplankton and release of DFAA, but the factors regulating the amount of DFAA released and its effect on bacterial growth are not yet understood.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02011168
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 4
    Electronic Resource
    Electronic Resource
    Pelagic food web processes in an oligotrophic lake (1988)
    Springer
    Hydrobiologia 164 (1988), S. 271-286 
    Details
    ISSN: 1573-5117
    Keywords: primary production ; extracellular release ; bacterial production ; pelagic carbon budgets
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Major pelagic carbon pathways, including primary production, release of extracellular products (EOC), bacterial production and zooplankton grazing were measured in oligotrophic Lake Almind (Denmark) and in enclosures (7 m3) subjected to artificial eutrophication. Simultaneous measurements at three days interval of carbon exchange rates and pools allowed the construction of carbon flow scenarios over a nineteen day experimental period. The flow of organic carbon was dominated by phytoplankton EOC release, which amounted from 44 to 58% of the net fixation of inorganic carbon. Gross bacterial production accounted for 33 to 75% of the primary production. The lower values of EOC release (44%) and bacterial production (33%) were found in the enclosures with added nutrients. The release of recently fixed photosynthetic products was the most important source of organic carbon to the bacterioplankton. Uptake of dissolved free amino acids was responsible for 52 to 62% of the gross bacterial production. Thus, amino acids constituted a significant proportion of the EOC. Zooplankton (〈 50 µm) grazing on algae and bacteria accounted only for a minor proportion of the particulate production in May. Circumstantial evidence is presented that suggests the chrysophycean alga Dinobryon was the most important bacterial remover. The results clearly demonstrated EOC release and bacterial metabolism to be key processes in pelagic carbon cycling in this oligotrophic lake.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00005945
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 5
    Electronic Resource
    Electronic Resource
    Colloidal and dissolved organic matter in lake water: Carbohydrate and amino acid composition, and ability to support bacterial growth (1995)
    Springer
    Biogeochemistry 30 (1995), S. 77-97 
    Details
    ISSN: 1573-515X
    Keywords: amino acids ; carbohydrates ; colloidal organic matter ; dissolved organic matter ; lake water bacteria
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Geosciences
    Notes: Abstract Bacterial utilization of dissolved organic matter (DOM) was studied in water from a humic and a clearwater oligotrophic lake. Indigenous bacteria were inoculated into either 0.2 μm natural filtered lake water, or lake water enriched fivefold with colloidal DOM 〉100 kD but below 0.2 μm. Consumption of DOM was followed from changes in concentrations of total dissolved organic carbon (DOC), dissolved combined and free carbohydrates and amino acids (DCCHO and DFCHO, and DCAA and DFAA, respectively) and by uptake of monosaccharide and amino acid radioisotopes. DCCHO and DCAA made up 8% (humic lake) to 33–44% (clear-water lake) of the natural DOC pools, while DFCHO and DFAA contributed at most 1.7% to the DOC pools. Addition of 〉100 kD DOM increased the DOC concentrations by 50% (clearwater lake) to 92% (humic lake), but it only resulted in a higher bacterial production (by 63%) in the humic lake. During the incubations 13 to 37% of the DOC was assimilated by the bacteria, at estimated growth efficiencies of 4–8%. Despite the measured reduction of DOC, statistically significant changes of specific organic compounds, especially of DCCHO and DCAA, generally did not occur. Probably the presence of high molecular weight DOC interfered with the applied analytical procedures. Addition of radiotracers indicated, however, that DFAA sustained 17–58% and 29–100% of the bacterial carbon and nitrogen requirements, respectively, and that glucose met 1–3% of the bacterial carbon requirements. Thus, our experiments indicate that radiotracers, rather than measurements of concentration changes, should be used in studies of bacterial utilization of DOC in freshwaters with a high content of humic or high molecular weight organic matter.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00002725
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 6
    Electronic Resource
    Electronic Resource
    Diel variation in concentration, assimilation and respiration of dissolved free amino acids in relation to planktonic primary and secondary production in two eutrophic lakes (1983)
    Springer
    Hydrobiologia 107 (1983), S. 107-122 
    Details
    ISSN: 1573-5117
    Keywords: heterotrophic assimilation ; amino acids ; diel variation ; carbon flux ; eutrophic lakes
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Concentration of dissolved free amino acids (DFAA) and assimilation of the 5 most abundant DFAA (glutamic acid, serine, glycine, alanine and ornithine) were measured at 3-h intervals over 27 h in two Danish, eutrophic lakes. The carbon flux of the amino acid assimilation was compared with the major routes of carbon flux, including primary production, bacterial production and zooplankton grazing. In Frederiksborg Slotssø, the mean DFAA concentration was 275 nM with distinct peaks (up to 783 nM) 3 h after sunrise. Assimilation rates of the 5 amino acids amounted on the average to 2.03 µg Cl−1 h−1, but high values up to 7.41 µg Cl−1 h−1 occurred 3 h after sunrise and at midnight. The mean turnover time of the amino acid pools was 3.2 h. In Lake Mossø, the mean DFAA concentration was 592 nM with peak of 1 161 nM at dusk. The assimilation rate averaged 0.44 µg Cl−1 h−1, and the mean turnover time of the amino acid pools was 39 h. In Lake Mossø, similar turnover times of glutamic acid and serine were determined from the 14C-amino acid tracer technique and Michaelis-Menten uptake kinetics, indicating that the tracer technique gave reliable values of the actual assimilation. The average respiration percentages of the assimilated amino acids were 45% in Frederiksborg Slotssø and 51% in Lake Mossø. Extracellular organic carbon (EOC) released from the phytoplankton contributed DFAA to the water. In Lake Mossø, 81% of the ambient EOC pool was 〈700 daltons and 9.3% of the EOC was DFAA. This corresponded to about 2.4% of the DFAA pool. Bacterial productivity, determined by means of ‘frequency of dividing cells’ and 35S-SO4 dark uptake techniques gave similar results and constituted 4.5 and 3.7 µg Cl−1 h−1 in Frederiksborg Slotssø and Lake Mossø, respectively. The bacterial productivity suggested that DFAA were essential substrates to the bacteria, especially in Frederiksborg Slotssø. The zooplankton biomass in Frederiksborg Slotssø was six times larger than that in Lake Mossø, but cladocerans were dominant in both lakes. The zooplankton grazing probably was an important regulatory factor for the bacterial productivity.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00017426
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 7
    Electronic Resource
    Electronic Resource
    Seasonal cycling of putrescine and amino acids in relation to biological production in a stratified coastal salt pond (1995)
    Springer
    Biogeochemistry 29 (1995), S. 131-157 
    Details
    ISSN: 1573-515X
    Keywords: amino acids ; heterotrophic uptake ; organic nitrogen cycling ; putrescine
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Geosciences
    Notes: Abstract Seasonal cycles of concentrations and microbial uptake of dissolved free amino acids and the polyamine, putrescine, were followed during summer stratification of a coastal salt pond. Stratification began in May and was clearly seen in profiles of temperature, salinity, pH and alkalinity. Primary production exhibited a mid-August maximum and the O2-H2S interface shoaled at that time. POC and phytopigments roughly followed the pattern of primary production. Cycling of putresince, like the amino acids, was strongly influenced by primary production and microbial decomposition. Putrescine concentration profiles appeared to follow the pattern of primary production more closely, while amino acids appeared to follow the pattern of microbial production. The absence of production of putrescine during the decomposition of dissolved ornithine and the correlation of putrescine concentration with primary production suggest a direct source from algae in the water column. Microbial uptake of amino acids and putrescine together accounted for 60–90% of the bacterial C production measured in oxic waters and almost 300% of that measured in the anoxic bottom layer. Since other organic carbon and nitrogen compounds are also being taken up, these data suggest that tracer uptake methods as we used them may overestimate the true microbial uptake rates, or release of other organic compounds by microbes occurs at the same time. Further work on carbon and nitrogen budgets is needed to resolve the apparent imbalance between organic C and N incorporation and bacterial production.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00000229
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 8
    facet.materialart.
    Unknown
    Chemical and Sensory Quantification of Geosmin and 2-Methylisoborneol in Rainbow Trout (Oncorhynchus mykiss) from Recirculated Aquacultures in Relation to Concentrations in Basin Water (2011)
    American Chemical Society
    Details
    Publication Date: 2011-12-14
    Print ISSN: 0021-8561
    Electronic ISSN: 1520-5118
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition , Process Engineering, Biotechnology, Nutrition Technology
    Published by American Chemical Society
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    PAPER CURRENT
  • 9
    facet.materialart.
    Unknown
    The biosurfactant viscosin transiently stimulates n-hexadecane mineralization by a bacterial consortium (2014)
    Springer
    Details
    Publication Date: 2014-09-14
    Print ISSN: 0175-7598
    Electronic ISSN: 1432-0614
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Published by Springer
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    PAPER CURRENT
  • 10
    facet.materialart.
    Unknown
    Biomass of pelagic fungi in Baltic rivers (2008)
    Springer
    Details
    Publication Date: 2008-11-29
    Print ISSN: 0018-8158
    Electronic ISSN: 1573-5117
    Topics: Biology
    Published by Springer
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    PAPER CURRENT
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...