GLORIA

GEOMAR Library Ocean Research Information Access

X
Suchhistorie löschen
feed icon rss

Ihre E-Mail wurde erfolgreich gesendet. Bitte prüfen Sie Ihren Maileingang.

Leider ist ein Fehler beim E-Mail-Versand aufgetreten. Bitte versuchen Sie es erneut.

Vorgang fortführen?

Exportieren
  • 1
    Digitale Medien
    Digitale Medien
    Divergent members of the bacterial division Verrucomicrobiales in a temperate freshwater lake (1998)
    Oxford, UK : Blackwell Publishing Ltd
    FEMS microbiology ecology 25 (1998), S. 0 
    Details
    ISSN: 1574-6941
    Quelle: Blackwell Publishing Journal Backfiles 1879-2005
    Thema: Biologie
    Notizen: Bacterial diversity in the water column of a freshwater lake in the Netherlands was investigated by analysis of 16S rRNA gene sequences recovered through PCR amplification from total community DNA. Among 23 unique cloned sequences, two appeared to belong to the recently described bacterial division Verrucomicrobiales. One of the two sequences was most similar to a group of environmental clones that form a distinct lineage within the division. The other sequence was divergent (less than 85% similarity) from all 16S rRNA gene sequences, both from cultivated species and from environmental clones, known in this division to date. Analysis by denaturing gradient gel electrophoresis (DGGE) and sequencing of DNA recovered through excision from the DGGE gel showed that the two sequence types were present in the lake throughout the year.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1111/j.1574-6941.1998.tb00469.x
    Standort Signatur Einschränkungen Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    Artikel (Nationallizenzen)
    Volltext
  • 2
    Digitale Medien
    Digitale Medien
    Energy requirements for growth and maintenance of Scenedesmus protuberans Fritsch in light-limited continuous cultures (1980)
    Springer
    Archives of microbiology 125 (1980), S. 9-17 
    Details
    ISSN: 1432-072X
    Schlagwort(e): Scenedesmus protuberans Fritsch ; Continuous culture ; Light limitation ; Temperature effect ; Irradiance effect ; Growth efficiency ; Maintenance energy ; Green algae
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract Scenedesmus protuberans Fritsch was grown in light-limited continuous cultures with a light-dark cycle, at temperatures of 20° and 28° C. At 20° irradiances of 12 and 38 W m−2 were used, at 28° 38 W m−2. The relationships between growth rate and light uptake rate were of diphasic linear character. With the lower growth rates the relationships were defined with the parameters μ e , i.e. the specific maintenance rate constant, and c, the “true” efficiency of light energy conversion into biomass. The μ e -value was dependent on temperature, the c on irradiance. In cultures, incubated in prolonged darkness, decrease rates of biomass were comparable to the derived μ e -values. Both diphasic linear relationships between growth rate and light uptake rate and the same order of magnitude of μ e -values could be derived from literature data on other green algae.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00403192
    Standort Signatur Einschränkungen Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    Artikel (Nationallizenzen)
    Volltext
  • 3
    Digitale Medien
    Digitale Medien
    Structural and functional characteristics of epiphyton and epipelon in relation to their distribution in Lake Vechten (1982)
    Springer
    Hydrobiologia 95 (1982), S. 79-114 
    Details
    ISSN: 1573-5117
    Schlagwort(e): periphyton ; submerged macrophytes ; sediment ; artificial substrates ; oxygen exchange ; production ; decomposition ; sedimentation
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract Epiphyton and epipelon were quantitatively collected, respectively, from the submerged macrophytes and the sandy lake bottom of Lake Vechten (The Netherlands). On a weight basis, epiphyton was maximal in autumn and epipelon in summer. In winter the chemical composition of epiphyton and epipelon was similar. In summer the epiphyton had on a unit weight basis more organic matter and carbonate, and had per unit organic matter a higher algal number, nitrogen and energy content than the epipelon. Algae predominating the epiphyton were filamentous greens and pennate diatoms; those in the epipelon were pennate diatoms and blue-green algae. In both cases, species known to frequent the phytoplankton were abundant. The diatoms were quantified using paper chromatographic pigment analyses. Both the epiphyton and the epipelon exhibited maximal photosynthesis in mid summer. That light was generally the limiting factor was evident from periphyton developed on artificial substrates. This periphyton differed widely in its composition from that on the natural substrates, mainly because the latter collected much more sedimenting matter. In dense Ceratophyllum stands light was severely attenuated and the significant gradients in oxygen and pH were caused by the differences with depth in the proportions of photosynthesis and respiration. The oxygen content and pH at the bottom decreased owing to epipelic respiration. The epiphytic composition depended greatly on the degree of light attenuation. The epiphytic and epipelic respiration, except during part of the early summer, exceeded photosynthesis on a 24 h basis; this included the macrophytic photosynthesis during the time the vegetation was maximally developed. During the growing season import of organic matter, i.e. deposited seston, greatly exceeded that due to the photosynthetic production. After the summer maximum, the epipelon decreased faster than predicted from its oxygen exchange. It was concluded that sedimentation and resuspension determined mainly the changes in epiphyton and epipelon. Especially when covered with vegetation, the lower littoral of Lake Vechten plays a large part in the aerobic decomposition of sestonic organic matter.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00044478
    Standort Signatur Einschränkungen Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    Artikel (Nationallizenzen)
    Volltext
  • 4
    Digitale Medien
    Digitale Medien
    Algal growth and loss rates in Lake Loosdrecht: first evaluation of the roles of light and wind on a basis of steady state kinetics (1990)
    Springer
    Hydrobiologia 191 (1990), S. 129-138 
    Details
    ISSN: 1573-5117
    Schlagwort(e): Loosdrecht lakes ; eutrophication ; underwater light ; resuspension ; wind effect ; Prochlorothrix hollandica
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract Lake Loosdrecht (The Netherlands) is shallow, highly eutrophic and subject to frequent wind-induced resuspension of settled algae and detritus. The summer phytoplankton consists of filamentous prokaryotic species. Chlorophyll a levels are rather stable over the summer at a concentration of ca. 160 mg m−3; losses due to grazing and sinking are small. Epipelic chlorophyll a concentrations range from 0 to 250, but ca. 50 mg m−2 is typical. In situ rates of change of chlorophyll a in the water column were related to specific growth rates predicted by a model for light-limited growth. In the model, incident light is partitioned among algae, tripton and background colour, to determine the light available for algal growth and cell maintenance. Model coefficients were derived primarily from laboratory studies of the growth of Prochlorothrix hollandica, an abundant species in the lake in summer. Presuming constant rates of loss due to grazing and sinking, for summers 1985 and 1986 some 56% of the variation in the chlorophyll a in the lake water was explained by change in light conditions alone and 77% by light and wind-driven resuspension of epipelic chlorophyll a together. These factors had little influence on the phytoplankton biomass in 1983 and 1984; other environmental conditions, e.g. phosphorus availability, may have been important. Also, the laboratory-derived growth kinetics of P. hollandica may not have been equally suitable for modelling in the four summers.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00026047
    Standort Signatur Einschränkungen Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    Artikel (Nationallizenzen)
    Volltext
  • 5
    Digitale Medien
    Digitale Medien
    Light-limited algal growth in Lake Loosdrecht: steady state studies in laboratory scale enclosures (1990)
    Springer
    Hydrobiologia 191 (1990), S. 241-248 
    Details
    ISSN: 1573-5117
    Schlagwort(e): Loosdrecht lakes ; eutrophication ; Prochlorothrix hollandica ; growth kinetics of algae ; continuous cultures ; light attenuation
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract Phytoplankton growth in the shallow, turbid Lake Loosdrecht (The Netherlands) is importantly influenced by light availability, and thus the concentrations of the various light-attenuating materials. The system is highly eutrophic and supports an algal biomass of ca. 160 mg Chl m−3. A model is proposed here which predicts algal growth in the lake as a function of the light received and subsequent attenuation in the water column by phytoplankton, tripton and background colour. The model is based on an energy balance which relates growth rate to the ‘true’ growth yield on light energy and the energy demand for cell maintenance. The coefficients for energy conversion (Y = 0.002 gDW kJ−1) and cell maintenance (µe = 0.031 day−1) were determined from steady state growth kinetics of Prochlorothrix hollandica in light-limited laboratory flow systems with the same depth as the lake and receiving summer average conditions of irradiance. Light attenuation by phytoplankton and tripton were quantified using specific attenuation coefficients: 0.011 m2 mg−1 Chl for the phytoplankton and 0.23 m2 g−1 DW for tripton. The growth studies demonstrated that Lake Loosdrecht can support a much higher algal biomass in the absence of non-algal particulate matter. The proposed model is used to predict chlorophyll a concentrations in dependence on growth rate and levels of tripton. Since approximately 75% of the sestonic dry weight in Lake Loosdrecht may be attributed to tripton, it is concluded that the algal biomass is markedly lowered by the abundance of tripton in the water column. A knowledge of the sources and fate of tripton in the lake is thus of fundamental importance in modelling phytoplankton dynamics.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00026057
    Standort Signatur Einschränkungen Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    Artikel (Nationallizenzen)
    Volltext
  • 6
    Digitale Medien
    Digitale Medien
    Characterization of the light field in laboratory scale enclosures of eutrophic lake water (Lake Loosdrecht, The Netherlands) (1992)
    Springer
    Hydrobiologia 238 (1992), S. 99-109 
    Details
    ISSN: 1573-5117
    Schlagwort(e): laboratory scale enclosure ; underwater light field ; shallow lakes ; phytoplankton ; cyanobacteria ; spectral light distribution
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract Light conditions in laboratory scale enclosures (LSE) of shallow, eutrophic Lake Loosdrecht (The Netherlands), including a method for simulating a ‘natural’ incident light course, are described. Total PAR (400–700 nm) and spectral irradiance distribution were measured at sestonic chlorophyll a and dry weight concentrations ≥ 100 mg m−3 and 16 g m−3, respectively. Phytoplankton was dominated by Oscillatoria spp. The euphotic depth (Z eu) was 0.7–1.0 m. Shortly after filling the LSE with lake water, diffuse attenuation coefficients ranged from 14 m−1 for blue to 5 m−1 for red light. Around Z eu, attenuation in the blue region was markedly lower and irradiance reflectance (R) continued to increase; these anomalies were caused by lateral incident light from the LSE's waterbath. Spectrophotometry indicated that absorption was mainly by particles, but dissolved humic substances (gilvin) were also important. The particles were likely to be dominated by detritus absorbing more blue relative to red light. Subsurface R in lake water in the LSE had a maximum around 705 nm and low values in the blue band, but was lower than that previously reported for measurements in situ. Wash-out of detritus, presumably both dissolved and particulate fractions, by flow-through with synthetic medium, greatly affected the spectral reflectance measured outside the LSE. The maximum value of R decreased from 0.022 to 0.009, and the peak shifted to 550 nm.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00048778
    Standort Signatur Einschränkungen Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    Artikel (Nationallizenzen)
    Volltext
  • 7
    Digitale Medien
    Digitale Medien
    The ‘true’ growth efficiency of phytoplankton as influenced by light attenuation and insolation: implications of the photosynthesis-irradiance relationship (1992)
    Springer
    Hydrobiologia 238 (1992), S. 169-176 
    Details
    ISSN: 1573-5117
    Schlagwort(e): growth efficiency ; areal quantum efficiency ; light attenuation ; Oscillatoria limnetica ; shallow lakes
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract The ‘true’ growth efficiency (c) relates the light energy absorbed by phytoplankton to the production of biomass corrected for constant energy requirement of maintenance. Continuous culture studies have shown that, at constant incident irradiance, the value of c for both prokaryotic and eukaryotic species is constant. Culture data for the relevant conditions of incident light may be used for directly estimating the growth rate from daily insolation of optically deep, fully mixed lakes, when the light absorption by the phytoplankton can be established. In order to examine the influence of vertical light attenuation and daily insolation on c, computations were made on a basis of a photosynthesis-irradiance curve of light-limited Oscillatoria limnetica. For steady state growth, the ‘true’ growth efficiency is linearly related to the areal quantum efficiency of photosynthesis (ϕ a ). The computations showed that ϕ a remains constant at fluctuating vertical light attenuation, no matter whether the concentration of tripton or phytoplankton changes. The effect of insolation is great: ϕ a is 0.108 mol O2/E at very low light, but only 0.014 mol O2/E at 400 W m−2 subsurface downward irradiance. The results imply that a c-value obtained from cultures for summer averaged insolation must be corrected: between cloudy and clear days the value may vary by a factor of 2. The ‘true’ growth efficiency for cultures will decrease by about 10% when the same daily irradiation is dosed sinusoidally instead of constantly.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00048785
    Standort Signatur Einschränkungen Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    Artikel (Nationallizenzen)
    Volltext
  • 8
    Digitale Medien
    Digitale Medien
    Interspecific variation in pigmentation: implications for production estimates for shallow eutrophic lakes using an incubator (1992)
    Springer
    Hydrobiologia 238 (1992), S. 197-202 
    Details
    ISSN: 1573-5117
    Schlagwort(e): primary production ; spectral light distribution ; incubator ; laboratory scale enclosure ; Oscillatoria limnetica ; Prochlorothrix hollandica
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract In shallow, eutrophic Lake Loosdrecht, light attenuation and spectral changes with depth are pronounced due to high concentration of algae and tripton. Calculations of integrated daily primary production have been based on the photosynthesis-irradiance relationship (P/E-curve) obtained with the incubator technique. The suitability of this technique for estimating primary production in such a turbid lake was investigated by comparing P/E-curves for two differently pigmented algae, Oscillatoria limnetica and Prochlorothrix hollandica, in two laboratory systems differing in light regime. System (1) consisted of an incubator filled with tapwater, and system (2) was an algal culture in a laboratory scale enclosure (LSE). For O. limnetica the P/E-curves were identical. The P/E-curves for P. hollandica diverged considerably: the photosynthetic efficiency in the LSE (0.19 mg O2 (mg Chl)−1 h−1 (W m−2)−1 was about half of that obtained in the incubator (0.35 mg O2 (mg Chl)−1 h−1 (W m−2)−1. These results were explained by the interspecific variation in pigmentation. The photosynthetic efficiency of P. hollandica changed due to the dependence on the chlorophyll specific absorption for the whole photosynthetic waveband on the spectral light distribution, which for O. limnetica was approximately the same in the two light regimes. Column-integrated primary production computed with the photosynthetic characteristics of P. hollandica obtained in LSE, was 10–30% lower than the production based on incubator data.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00048789
    Standort Signatur Einschränkungen Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    Artikel (Nationallizenzen)
    Volltext
  • 9
    Digitale Medien
    Digitale Medien
    Optical teledetection of the vertical attenuation coefficient for downward quantum irradiance of photosynthetically available radiation in turbid inland waters (1997)
    Springer
    Aquatic ecology 31 (1997), S. 299-311 
    Details
    ISSN: 1573-5125
    Schlagwort(e): irradiance reflectance ; large rivers ; phytoplankton production ; remote sensing ; shallow lakes ; underwater light
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract Depth profiles of downward quantum irradiance of photosynthetically available radiation in situ and spectral subsurface irradiance reflectance, obtained from water-leaving radiance, were determined in different inland water types. These included the large, shallow and eutrophic IJssel lagoon in the Netherlands, eighteen Dutch lakes differing in depth and trophic state, and the large, shallow and eutrophic Lake Tai in China. The attenuation coefficient for downward irradiance ranged from 0.7 to 5.4 m-1. An empirical relationship with the backscattering coefficient in the near-infrared waveband, derived from the reflectance, and three spectral reflectance band ratios explained 91% of the variation. The potential assessment of the spatial distribution of phytoplankton production through shipboard optical teledetection of the concentration of chlorophyll-a and the attenuation coefficient for downward irradiance is discussed.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1023/A:1009902627476
    Standort Signatur Einschränkungen Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    Artikel (Nationallizenzen)
    Volltext
  • 10
    Digitale Medien
    Digitale Medien
    A comparison of primary production measurements using two laboratory systems with differences in light quality (1986)
    Springer
    Aquatic ecology 20 (1986), S. 93-99 
    Details
    ISSN: 1573-5125
    Schlagwort(e): primary production ; oxygen technique ; light quality ; incubator ; laboratory scale enclosure
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract Primary production measurements were carried out simultaneously, using two laboratory systems with different light conditions: (1) a'classical' incubator and (2) a Laboratory Scale Enclosure. The model used for calculating primary production (STEELE, 1965) does not correct for spectral changes caused by high phytoplankton biomass. In the incubator, light of almost all wavelengths decreased more or less according to the attenuation of total PhAR in water. In the LSE, high absorption was found of the blue light and some of the red light, which was due to the high sestonic concentration. The Steele function provided a good fit for both sets of data. The depth integrated gross production values derived from the simultaneous measurements were not significantly different.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF02291154
    Standort Signatur Einschränkungen Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    Artikel (Nationallizenzen)
    Volltext
Schließen ⊗
Diese Webseite nutzt Cookies und das Analyse-Tool Matomo. Weitere Informationen finden Sie hier...