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  • 1
    ISSN: 1432-1793
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The distribution and activity of bacterioplankton, and the turnover of dissolved organic matter (DOM) were examined in McMurdo Sound, Antarctica. On the eastern side of the Sound, bacteria averaged 6.5×108 l-1, and turnover rates of dissolved adenosine triphosphate, D-glucose and l-leucine averaged 16, 116 and 124 h, respecitvely. These molecules as well as thymidine were taken up maximally from 0° to 5°C and near-maximally from -1.5° to 0°C, indicating bacterial adaptation to rapid turnover of dissolved organic matter at the ambient temperature. On the west side of the Sound, bacteria averaged only 0.65×108 l-1, and turnover times for adenosine triphosphate, D-glucose and lleucine averaged 59, 20454, and 3070 h, respectively. Total microbial adenosine triphosphate (an indicator of total microbial biomass) and chlorophyll a were also much lower at the western than at the eastern side stations. Moreover, no primary production could be detected at one western side station (New Harbor). Thus, in McMurdo Sound, the western side is highly oligotrophic, but the eastern side has an abundant active bacterioplankton, comparable to that of temperate coastal waters.
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    Springer
    Marine biology 108 (1991), S. 329-339 
    ISSN: 1432-1793
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Sea surface microlayer (film) and subsurface microbial populations (biomass and activities) were studied in the Damariscotta (Maine) estuary in May and September, 1987. Dissolved free and combined amino acids (DFAA, DCAA), bacterial numbers, microbial ATP, bacterial and microbial DNA synthesis (via3H-thymidine and3H-adenine), and amino acid (3H-glutamic acid) metabolism were measured. DFAA and DCAA were typically enriched in the surface microlayers relative to surface waters, although utilization of glutamic acid was usually more rapid in subsurface waters, as was incorporation of thymidine. Bacteria represented 12 to 40% of the microbial biomass as determined by ATP, except during microalgal blooms in the microlayer. Bacteria were generally not enriched in the surface films, although ATP usually was enriched. Rain input appeared to deplete population densities but stimulated population activities. Two stations which contained similar microbial populations (as estimated by bacterial counts, chlorophylla and ATP) showed very different microbial activities, apparently due to the effects of a substantial rainstorm on one of the stations. The bacterially-dominated processes utilizing thymidine and glutamic acid were enhanced approx five-fold after the rain. Autotrophic carbon production increased approx two-fold, while total microbal community DNA synthesis (as estimated by adenine incorporation into DNA) increased nearly tenfold. The observations of this study indicate that surface microlayers in the temperate waters off the coast of Maine contain highly active heterotrophic and autotrophic populations. The microbial community responds rapidly to changes in nutrient and dissolved organic matter concentrations resulting from both seasonal and temporal effects, including rain and runoff.
    Type of Medium: Electronic Resource
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  • 3
    Electronic Resource
    Electronic Resource
    Springer
    Marine biology 7 (1970), S. 161-166 
    ISSN: 1432-1793
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The relative importance of 3 different sources for biological production of nitrite in seawater was studied. Decomposition of fecal pellets of the copepod Calanus helgolandicus (at a concentration of approximately 12 μg-at N/l), in seawater medium, released small amounts of ammonia over a 6 week period. It nitrifying bacteria were added to the fecal pellets nitrite was barely detectable over the same period. Decomposition of phytoplankton (present at a concentration of about 8 μg-at particulate plant N/l) with added heterotrophic bacteria, released moderate amounts of ammonia over a 12 week period. If the ammonia-oxidizing bacterium Nitrosocystis oceanus was added to the decomposing algae, nitrite was produced at a rate of 0.2 μg-at N/l/week. Heterotrophic nitrification was not observed when 7 open-ocean bacteria were tested for their ability to oxidize ammonia. The diatom Skeletonema costatum, either non-starved or starved of nitrogen, produced nitrite when growing with 150 or 50 μg-at NO 2 - -N/l at a light intensity of about 0.01 ly/min. When nitrate in the medium was exhausted, S. costatum assimilated nitrite. If starved of vitamin B12, both non-N-starved and N-starved cells of S. costatum produced nitrite in the medium with 150 μg-at NO 3 - -N/l. Nitrate was not exhausted and cell densities reached 2x105/ml due to vitamin B12 deficiency. If light intensity was reduced to 0.003 ly/min under otherwise similar conditions, cells did not grow due to insufficient light, and nitrite was not produced. In the sea, it appears that, in certain micro-environments, decomposition of particulate matter releases ammonia with its subsequent oxidation to nitrite. The amounts of these nutrients and the rate at which they are produced are dependent upon the nature of the materials undergoing decomposition and the associated bacteria. In certain other areas of the sea, where phytoplankton standing stock is high and nitrate is non-limiting, excretion by these organisms is a major source of nitrite.
    Type of Medium: Electronic Resource
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  • 4
    ISSN: 1432-1793
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Microheterotrophic dissolved free amino acid (DFAA) utilization, and microbial community and bacterial community carbon production and growth were studied using 3H-labeled organics as tracers in marine surface-film and subsurface (10 cm) waters off Baja California in November 1983. DFAA utilization was generally more rapid during the day (0.14 to 0.38 nM h-1) than at night (0.04 to 0.14 nM h-1) in surface-film and subsurface waters, but the percent of utilized amino acid which was respired was always greater during the night (22 to 57%) compared to the day (14 to 18%). Utilization of DFAA-carbon was estimated to range from 0.3 to 5.3 μg C l-1 d-1 for all stations studied. In six of the 8 samples examined, the percentage of microbial carbon accounted for by the bacterial component of the population (1.4 to 5.9%) was strikingly similar to the percentage of microbial carbon production accounted for by bacterial carbon production (1.9 to 5.1%). In all of these six samples, total microbial specific-growth rates and bacterial specific-growth rates were approximately equivalent (0.9 to 2.2 d-1 for the microbial community; 0.7 to 1.9 d-1 for bacteria). The two exceptions were samples apparently influenced by transient flagellate populations migrating into the surface or subsurface waters at night. These observations support the conclusion that surface films contain unique and highly active microbial populations.
    Type of Medium: Electronic Resource
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  • 5
    Electronic Resource
    Electronic Resource
    [s.l.] : Nature Publishing Group
    Nature 181 (1958), S. 904-904 
    ISSN: 1476-4687
    Source: Nature Archives 1869 - 2009
    Topics: Biology , Chemistry and Pharmacology , Medicine , Natural Sciences in General , Physics
    Notes: [Auszug] Extraction of the pigment directly from dried organisms1 with petroleum ether (b.p. 40-60 C.) provided a lipid extract and poor pigment yield. The pigment failed to migrate on MgO-'Celite' (1:1) and disappeared rapidly from this adsorbent. The following method, however, gave good quantities of ...
    Type of Medium: Electronic Resource
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  • 6
    Electronic Resource
    Electronic Resource
    [s.l.] : Nature Publishing Group
    Nature 262 (1976), S. 810-811 
    ISSN: 1476-4687
    Source: Nature Archives 1869 - 2009
    Topics: Biology , Chemistry and Pharmacology , Medicine , Natural Sciences in General , Physics
    Notes: [Auszug] We have determined the doubling time in batch culture for this low nutrient bacterium (referred to as 169 and able to grow well in unenriched seawater) in deep-sea water at 5, 13 and 20 C and under 200 atmospheres of hydrostatic pressure (equivalent to a depth of 2,000m). The doubling time was 260 ...
    Type of Medium: Electronic Resource
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  • 7
    Electronic Resource
    Electronic Resource
    [s.l.] : Nature Publishing Group
    Nature 211 (1966), S. 483-484 
    ISSN: 1476-4687
    Source: Nature Archives 1869 - 2009
    Topics: Biology , Chemistry and Pharmacology , Medicine , Natural Sciences in General , Physics
    Notes: [Auszug] SERIOUS difficulties are encountered in the culture of marine bacteria and algae, as well as in investigations of their physiology, on account of the toxic effects of natural sea-waters1-5. In order to overcome such effects the use of 'aged' sea-water in the preparation of media has been ...
    Type of Medium: Electronic Resource
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  • 8
    Electronic Resource
    Electronic Resource
    Springer
    Cellular and molecular life sciences 22 (1966), S. 229-230 
    ISSN: 1420-9071
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Résumé Les bactéries suivantes:Nitrosocystis oceanus, Nitrosomonas europaea, Nitrobacter agilis et Thiobacillus thiooxidans ont été cultivées en milieu solide dans une atmosphère dont on a varié la teneur en oxygène. On a trouvé que la croissance de toute ces bactéries a été arrêtée en présence d'un excès d'oxygène (90%). D'autre part l'oxydation de l'ammonium du nitrite et du thiosulfate n'a pas été inhibée par oxygène.
    Type of Medium: Electronic Resource
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  • 9
    ISSN: 1432-1793
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Rates of microheterotrophic utilization (incorporation+respiration) of 3H-leucine and 3H-glutamic acid were measured in seawater surface films from oligotrophic, eutrophic and mesotrophic waters incubated in situ off Baja California in July 1981 and off Southern California in November 1982. Neither visible nor ultraviolet radiation had a marked detrimental effect on microbial heterotrophy, although solar radiation sometimes appeared to be stimulatory. Film microheterotrophs utilized glutamic acid at rates between 0.07 and 0.13 nM h-1 for oligotrophic waters and between 0.43 and 2.1 nM h-1 for eutrophic waters; the respective turnover times ranged between 101 and 313 h and between 8.6 and 21.5 h. Film microheterotrophs from oligotrophic waters utilized leucine at rates comparable to those observed for glutamic acid, but turnover times were shorter. Leucine metabolism rates of film microheterotrophs in eutrophic waters were slower than glutamic acid rates, but turnover times were similar. Naturally varying amino acid concentrations accounted, in part, for differences in turnover times. In oligotrophic waters, higher utilization rates were observed for surface-film microheterotrophs than for subsurface (10 cm) microheterotrophs, whereas in eutrophic waters, utilization rates were similar for surface-film microheterotrophs and subsurface microheterotrophs. Surface-film microheterotrophs, in most cases, had an average of 63% amino acid carbon assimilation efficiency, similar to euphotic-zone heterotrophs. Surface-film microheterotrophs are actively involved in the metabolism and turnover of amino acids.
    Type of Medium: Electronic Resource
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  • 10
    Electronic Resource
    Electronic Resource
    Springer
    Naturwissenschaften 65 (1978), S. 541-542 
    ISSN: 1432-1904
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology , Natural Sciences in General
    Type of Medium: Electronic Resource
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