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  • 1
    ISSN: 1476-4687
    Quelle: Nature Archives 1869 - 2009
    Thema: Biologie , Chemie und Pharmazie , Medizin , Allgemeine Naturwissenschaft , Physik
    Notizen: [Auszug] Changes in iron supply to oceanic plankton are thought to have a significant effect on concentrations of atmospheric carbon dioxide by altering rates of carbon sequestration, a theory known as the ‘iron hypothesis’. For this reason, it is important to understand the response of ...
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 2
    ISSN: 1476-4687
    Quelle: Nature Archives 1869 - 2009
    Thema: Biologie , Chemie und Pharmazie , Medizin , Allgemeine Naturwissenschaft , Physik
    Notizen: [Auszug] The growth of populations is known to be influenced by dispersal, which has often been described as purely diffusive. In the open ocean, however, the tendrils and filaments of phytoplankton populations provide evidence for dispersal by stirring. Despite the apparent importance of ...
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 3
    Digitale Medien
    Digitale Medien
    Oxford, UK : Blackwell Publishing Ltd
    FEMS microbiology ecology 29 (1999), S. 0 
    ISSN: 1574-6941
    Quelle: Blackwell Publishing Journal Backfiles 1879-2005
    Thema: Biologie
    Notizen: Prokaryotic microbes play a critical role in oceanic Fe cycling. They contain most of the biogenic Fe in offshore waters and are responsible for a large portion of the Fe uptake by the plankton community. In the subarctic North Pacific, surface populations of heterotrophic species assimilate more than 50% of the dissolved Fe and thus compete directly with phytoplankton for this limiting resource. In oligotrophic tropical and subtropical waters, photosynthetic bacteria become more important in Fe cycling as the number of unicellular cyanobacteria increases and the nitrogen-fixing Trichodesmium, which contains most of the biogenic Fe in the mixed layer, becomes abundant. Like their terrestrial counterparts, heterotrophic and phototrophic marine bacteria produce Fe-binding siderophores that are involved in Fe acquisition. Evidence exists that bacteria may modify Fe chemistry in the sea through the production of these ligands and thereby play a significant role in regulating production of eukaryotic phytoplankton.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 4
    Digitale Medien
    Digitale Medien
    [s.l.] : Nature Publishing Group
    Nature 383 (1996), S. 330-332 
    ISSN: 1476-4687
    Quelle: Nature Archives 1869 - 2009
    Thema: Biologie , Chemie und Pharmazie , Medizin , Allgemeine Naturwissenschaft , Physik
    Notizen: [Auszug] We measured intracellular iron concentrations of five oceanic bacterial isolates maintained in synthetic ocean water medium9 enriched with an organic carbon substrate extracted from a diatom culture. Under iron-sufficient conditions (concentrations of inor-ganic iron, [Fe'] 40 nM), bacterial iron ...
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 5
    facet.materialart.
    Unbekannt
    PANGAEA
    In:  Supplement to: Croot, Peter L; Bowie, Andrew R; Frew, Russell; Maldonado, Maria T; Hall, Julie A; Safi, Karl A; La Roche, Julie; Boyd, Philip W; Law, Cliff S (2001): Retention of dissolved iron and Fe II in an iron induced Southern Ocean phytoplankton bloom. Geophysical Research Letters, 28(18), 3425-3428, https://doi.org/10.1029/2001GL013023
    Publikationsdatum: 2023-01-13
    Beschreibung: During the 13 day Southern Ocean Iron RE-lease Experiment (SOIREE), dissolved iron concentrations decreased rapidly following each of three iron-enrichments, but remained high (〉1 nM, up to 80% as FeII) after the fourth and final enrichment on day 8. The former trend was mainly due to dilution (spreading of iron-fertilized waters) and particle scavenging. The latter may only be explained by a joint production-maintenance mechanism; photoreduction is the only candidate process able to produce sufficiently high FeII, but as such levels persisted overnight (8 hr dark period) -ten times the half-life for this species- a maintenance mechanism (complexation of FeII) is required, and is supported by evidence of increased ligand concentrations on day 12. The source of these ligands and their affinity for FeII is not known. This retention of iron probably permitted the longevity of this bloom raising fundamental questions about iron cycling in HNLC (High Nitrate Low Chlorophyll) Polar waters.
    Schlagwort(e): Comment; Date/Time of event; DEPTH, water; Error; Event label; GOFLO; Go-Flo bottles; Iron, dissolved; Iron, dissolved, conditional complex stability; Iron-binding ligand, dissolved; Latitude of event; Longitude of event; SOIREE; Southern Ocean - Australasian-Pacific Sector; T1136-1; T1139-1; T1140-6; T1141-6; T1144-6; T1151-5; T1152-5; T1158-5; T1159-6; T1160-3; T1162-4; T1171-5; Tangaroa; Voltammetry
    Materialart: Dataset
    Format: text/tab-separated-values, 64 data points
    Standort Signatur Erwartet Verfügbarkeit
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  • 6
    facet.materialart.
    Unbekannt
    PANGAEA
    In:  Supplement to: Hoppe, Clara Jule Marie; Schuback, Nina; Semeniuk, David M; Giesbrecht, Karina E; Mol, Jacoba; Thomas, H; Maldonado, Maria T; Rost, Björn; Varela, Diana E; Tortell, Philippe Daniel (2018): Resistance of Arctic phytoplankton to ocean acidification and enhanced irradiance. Polar Biology, 41(3), 399-413, https://doi.org/10.1007/s00300-017-2186-0
    Publikationsdatum: 2023-01-13
    Beschreibung: The Arctic Ocean is a region particularly prone to on-going ocean acidification (OA) and climate-driven changes. The influence of these changes on Arctic phytoplankton assemblages, however, remains poorly understood. In order to understand how OA and enhanced irradiances (e.g. resulting from sea-ice retreat) will alter the species composition, primary production and ecophysiology of Arctic phytoplankton, we conducted an incubation experiment to investigate the effects of OA and enhanced irradiance levels on an assemblage from Baffin Bay (71°N, 68°W). Seawater was collected from just below the deep Chl a maximum, and the resident phytoplankton were exposed to 380 and 1000 µatm pCO2 at both 15% and 35% incident irradiance. On-deck incubations, in which temperatures were 6°C above in situ conditions, were monitored for phytoplankton growth, biomass stoichiometry, net primary production, photo-physiology and taxonomic composition. During the 8-day experiment, taxonomic diversity decreased and the diatom Chaetoceros socialis became increasingly dominant irrespective of light or CO2 levels. We found no statistically significant effects from either higher CO2 or light on physiological properties of phytoplankton during the experiment. We did, however, observe an initial 2-day stress response in all treatments, and slight photo-physiological responses to higher CO2 and light during the first five days of the incubation. Our results thus indicate high resistance of Arctic phytoplankton to OA and enhanced irradiance levels, challenging the commonly predicted stimulatory effects of enhanced CO2 and light availability for primary production.
    Materialart: Dataset
    Format: application/vnd.openxmlformats-officedocument.spreadsheetml.sheet, 43.8 kBytes
    Standort Signatur Erwartet Verfügbarkeit
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  • 7
    facet.materialart.
    Unbekannt
    PANGAEA
    In:  Supplement to: Hoppe, Clara Jule Marie; Schuback, Nina; Semeniuk, David M; Maldonado, Maria T; Rost, Björn (2017): Functional Redundancy Facilitates Resilience of Subarctic Phytoplankton Assemblages toward Ocean Acidification and High Irradiance. Frontiers in Marine Science, 4, 14 pp, https://doi.org/10.3389/fmars.2017.00229
    Publikationsdatum: 2023-02-24
    Beschreibung: In order to understand how ocean acidification (OA) and enhanced irradiance levels might alter phytoplankton eco-physiology, productivity and species composition, we conducted an incubation experiment with a natural plankton assemblage from sub-surface Subarctic waters (Davis Strait, 63°N). The phytoplankton assemblage was exposed to 380 and 1,000 µatm pCO2 at both 15 and 35% surface irradiance over 2 weeks. The incubations were monitored and characterized in terms of their photo-physiology, biomass stoichiometry, primary production and dominant phytoplankton species. We found that the phytoplankton assemblage exhibited pronounced high-light stress in the first days of the experiment (20-30% reduction in photosynthetic efficiency, Fv/Fm). This stress signal was more pronounced when grown under OA and high light, indicating interactive effects of these environmental variables. Primary production in the high light treatments was reduced by 20% under OA compared to ambient pCO2 levels. Over the course of the experiment, the assemblage fully acclimated to the applied treatments, achieving similar bulk characteristics (e.g., net primary production and elemental stoichiometry) under all conditions. We did, however, observe a pCO2-dependent shift in the dominant diatom species, with Pseudonitzschia sp. dominating under low and Fragilariopsis sp. under high pCO2 levels. Our results indicate an unexpectedly high level of resilience of Subarctic phytoplankton to OA and enhanced irradiance levels. The co-occurring shift in dominant species suggests functional redundancy to be an important, but so-far largely overlooked mechanism for resilience toward climate change.
    Schlagwort(e): GEOTRACES; Global marine biogeochemical cycles of trace elements and their isotopes
    Materialart: Dataset
    Format: application/vnd.openxmlformats-officedocument.spreadsheetml.sheet, 48.6 kBytes
    Standort Signatur Erwartet Verfügbarkeit
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  • 8
    facet.materialart.
    Unbekannt
    PANGAEA
    In:  Supplement to: Abraham, Edward R; Law, Cliff S; Boyd, Philip W; Lavender, Samantha J; Maldonado, Maria T; Bowie, Andrew R (2000): Importance of stirring in the development of an iron-fertilized bloom. Nature, 407(6805), 727-730, https://doi.org/10.1038/35037555
    Publikationsdatum: 2024-02-01
    Beschreibung: The growth of populations is known to be influenced by dispersal, which has often been described as purely diffusive (Kierstead and Slobodkin, 1953; Okubo, 1980). In the open ocean, however, the tendrils and filaments of phytoplankton populations provide evidence for dispersal by stirring (Gower et al., 1980, doi:10.1038/288157a0; Holligan et al., 1993, doi:10.1029/93GB01731). Despite the apparent importance of horizontal stirring for plankton ecology, this process remains poorly characterized. Here we investigate the development of a discrete phytoplankton bloom, which was initiated by the iron fertilization of a patch of water (7 km in diameter) in the Southern Ocean (Boyd et al., 2000, doi:10.1038/35037500). Satellite images show a striking, 150-km-long bloom near the experimental site, six weeks after the initial fertilization. We argue that the ribbon-like bloom was produced from the fertilized patch through stirring, growth and diffusion, and we derive an estimate of the stirring rate. In this case, stirring acts as an important control on bloom development, mixing phytoplankton and iron out of the patch, but also entraining silicate. This may have prevented the onset of silicate limitation, and so allowed the bloom to continue for as long as there was sufficient iron. Stirring in the ocean is likely to be variable, so blooms that are initially similar may develop very differently.
    Schlagwort(e): CT; DATE/TIME; File format; File size; JGOFS; Joint Global Ocean Flux Study; Latitude of event; Longitude of event; SOIREE; SOIREE-track; Southern Ocean - Australasian-Pacific Sector; Tangaroa; Underway cruise track measurements; Uniform resource locator/link to raw data file
    Materialart: Dataset
    Format: text/tab-separated-values, 24 data points
    Standort Signatur Erwartet Verfügbarkeit
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  • 9
    Publikationsdatum: 2024-03-15
    Schlagwort(e): Alkalinity, total; Aragonite saturation state; Arctic; Assemblage; Bicarbonate ion; Biogenic silica; Biomass/Abundance/Elemental composition; Bottles or small containers/Aquaria (〈20 L); Calcite saturation state; Calculated using seacarb after Nisumaa et al. (2010); Carbon, inorganic, dissolved; Carbon, organic, particulate; Carbon, organic, particulate/Biogenic silica; Carbon, organic, particulate/Nitrogen, organic, particulate ratio; Carbon/Chlorophyll a ratio; Carbonate ion; Carbonate system computation flag; Carbon dioxide; Chlorophyll a; Confidence interval; Entire community; Experiment; Experiment duration; Fugacity of carbon dioxide (water) at sea surface temperature (wet air); Growth/Morphology; Growth rate; Identification; Laboratory experiment; Light; Light-depended increase in 14C uptake; Light-depended increase in conversion factors; Light-depended increase in initial charge separation in reaction center II; Light saturated rate of initial charge separation in 14C uptake, maximum; Light saturated rate of initial charge separation in conversion factors, maximum; Light saturated rate of initial charge separation in reaction center II, maximum; Light saturation; Net primary production of carbon; Net primary production of carbon per particulate organic carbon; Nitrogen, organic, particulate; OA-ICC; Ocean Acidification International Coordination Centre; Open ocean; Partial pressure of carbon dioxide (water) at sea surface temperature (wet air); Pelagos; pH; Picoplankton; Picoplankton per particulate organic carbon; Polar; Primary production/Photosynthesis; Primary production of carbon per chlorophyll a; Production of silica per day; Salinity; Temperature, water; Treatment; Type
    Materialart: Dataset
    Format: text/tab-separated-values, 1192 data points
    Standort Signatur Erwartet Verfügbarkeit
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  • 10
    Publikationsdatum: 2024-03-15
    Schlagwort(e): Alkalinity, total; Alkalinity, total, standard deviation; Aragonite saturation state; Arctic; Bicarbonate ion; Biogenic silica; Biomass/Abundance/Elemental composition; Bottles or small containers/Aquaria (〈20 L); Calcite saturation state; Calculated using seacarb after Nisumaa et al. (2010); Carbon, inorganic, dissolved; Carbon, inorganic, dissolved, standard deviation; Carbon, organic, particulate; Carbon, organic, particulate/Biogenic silica; Carbon, organic, particulate/Nitrogen, organic, particulate ratio; Carbon/Chlorophyll a ratio; Carbonate ion; Carbonate system computation flag; Carbon dioxide; Chlorophyll a; Community composition and diversity; Confidence interval; Davis_Strait; Entire community; EXP; Experiment; Experiment duration; Fugacity of carbon dioxide (water) at sea surface temperature (wet air); Identification; Laboratory experiment; Light; Light-depended increase in 14C uptake; Light-depended increase in conversion factors; Light-depended increase in initial charge separation in reaction center II; Light saturated rate of initial charge separation in 14C uptake, maximum; Light saturated rate of initial charge separation in conversion factors, maximum; Light saturated rate of initial charge separation in reaction center II, maximum; Light saturation; Net primary production of carbon per particulate organic carbon; Nitrate; Nitrate, standard deviation; Nitrogen, organic, particulate; OA-ICC; Ocean Acidification International Coordination Centre; Open ocean; Partial pressure of carbon dioxide, standard deviation; Partial pressure of carbon dioxide (water) at sea surface temperature (wet air); Pelagos; pH; pH, standard deviation; Phosphate; Phosphate, standard deviation; Picoplankton per particulate organic carbon; Polar; Potentiometric titration; Primary production/Photosynthesis; Primary production of carbon per chlorophyll a; Salinity; Silicate; Silicate, standard deviation; Temperature, water; Temperature, water, standard deviation; Time point, descriptive; Treatment; Type
    Materialart: Dataset
    Format: text/tab-separated-values, 1181 data points
    Standort Signatur Erwartet Verfügbarkeit
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