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  • Climate - Biogeochemistry Interactions in the Tropical Ocean; SFB754  (8)
  • BIOACID; Biological Impacts of Ocean Acidification  (2)
  • Electronic books.
Schlagwörter
Verlag/Herausgeber
Sprache
Erscheinungszeitraum
  • 1
    Online-Ressource
    Online-Ressource
    Tübingen :Mohr Siebeck,
    Schlagwort(e): Synoptic climatology. ; Electronic books.
    Materialart: Online-Ressource
    Seiten: 1 online resource (326 pages)
    Ausgabe: 1st ed.
    ISBN: 9783161565960
    Serie: Texts and Studies in Ancient Judaism ; v.33
    DDC: 551.6
    Sprache: Deutsch
    Standort Signatur Einschränkungen Verfügbarkeit
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  • 2
    facet.materialart.
    Unbekannt
    PANGAEA
    In:  Supplement to: Wannicke, Nicola; Endres, Sonja; Engel, Anja; Grossart, Hans-Peter; Unger, Juliane; Voss, Maren (2012): Response of Nodularia spumigena to pCO2 - Part 1: Growth, production and nitrogen cycling. Biogeosciences, 9(8), 2973-2988, https://doi.org/10.5194/bg-9-2973-2012
    Publikationsdatum: 2023-05-12
    Beschreibung: Heterocystous cyanobacteria of the genus Nodularia form extensive blooms in the Baltic Sea and contribute substantially to the total annual primary production. Moreover, they dispense a large fraction of new nitrogen to the ecosystem when inorganic nitrogen concentration in summer is low. Thus, it is of ecological importance to know how Nodularia will react to future environmental changes, in particular to increasing carbon dioxide (CO2) concentrations and what consequences there might arise for cycling of organic matter in the Baltic Sea. Here, we determined carbon (C) and dinitrogen (N2) fixation rates, growth, elemental stoichiometry of particulate organic matter and nitrogen turnover in batch cultures of the heterocystous cyanobacterium Nodularia spumigena under low (median 315 µatm), mid (median 353 µatm), and high (median 548 µatm) CO2 concentrations. Our results demonstrate an overall stimulating effect of rising pCO2 on C and N2 fixation, as well as on cell growth. An increase in pCO2 during incubation days 0 to 9 resulted in an elevation in growth rate by 84 ± 38% (low vs. high pCO2) and 40 ± 25% (mid vs. high pCO2), as well as in N2 fixation by 93 ± 35% and 38 ± 1%, respectively. C uptake rates showed high standard deviations within treatments and in between sampling days. Nevertheless, C fixation in the high pCO2 treatment was elevated compared to the other two treatments by 97% (high vs. low) and 44% (high vs. mid) at day 0 and day 3, but this effect diminished afterwards. Additionally, elevation in carbon to nitrogen and nitrogen to phosphorus ratios of the particulate biomass formed (POC : POP and PON : POP) was observed at high pCO2. Our findings suggest that rising pCO2 stimulates the growth of heterocystous diazotrophic cyanobacteria, in a similar way as reported for the non-heterocystous diazotroph Trichodesmium. Implications for biogeochemical cycling and food web dynamics, as well as ecological and socio-economical aspects in the Baltic Sea are discussed.
    Schlagwort(e): BIOACID; Biological Impacts of Ocean Acidification
    Materialart: Dataset
    Format: application/zip, 3 datasets
    Standort Signatur Einschränkungen Verfügbarkeit
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  • 3
    facet.materialart.
    Unbekannt
    PANGAEA
    In:  Supplement to: Browning, Thomas J; Achterberg, Eric Pieter; Yong, Jaw-Chuen; Rapp, Insa; Utermann, Caroline; Engel, Anja; Moore, C M (2017): Iron limitation of microbial phosphorus acquisition in the tropical North Atlantic. Nature Communications, 8(1), 15465, https://doi.org/10.1038/ncomms15465
    Publikationsdatum: 2023-10-28
    Beschreibung: Here we demonstrate enhanced natural community APase activity following iron amendment within the low zinc and moderately low iron Western North Atlantic. In contrast we find no evidence for trace metal limitation of APase activity beneath the Saharan dust plume in the Eastern Atlantic. Such intermittent iron limitation of microbial phosphorus acquisition provides an additional facet in the argument for iron controlling the coupling between oceanic nitrogen and phosphorus cycles.
    Schlagwort(e): Climate - Biogeochemistry Interactions in the Tropical Ocean; SFB754
    Materialart: Dataset
    Format: application/zip, 2 datasets
    Standort Signatur Einschränkungen Verfügbarkeit
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  • 4
    facet.materialart.
    Unbekannt
    PANGAEA
    In:  Supplement to: Engel, Anja; Wagner, Hannes; Le Moigne, Frédéric A C; Wilson, Samuel T (2017): Particle export fluxes to the oxygen minimum zone of the eastern tropical North Atlantic. Biogeosciences, 14(7), 1825-1838, https://doi.org/10.5194/bg-14-1825-2017
    Publikationsdatum: 2023-10-28
    Beschreibung: In the ocean, sinking of particulate organic mat- ter (POM) drives carbon export from the euphotic zone and supplies nutrition to mesopelagic communities, the feeding and degradation activities of which in turn lead to export flux attenuation. Oxygen (O2) minimum zones (OMZs) with suboxic water layers (〈 5 µmol O2 kg-1 ) show a lower carbon flux attenuation compared to well- oxygenated waters (〉 100 µmol O2 kg-1), supposedly due to reduced heterotrophic activity. This study focuses on sinking particle fluxes through hypoxic mesopelagic waters (〈 60 µmol O2 kg-1); these represent about 100 times more ocean volume globally compared to suboxic waters, but they have less been studied. Particle export fluxes and attenuation coefficients were determined in the eastern tropical North Atlantic (ETNA) using two surface-tethered drifting sediment trap arrays with seven trapping depths located between 100 and 600 m.
    Schlagwort(e): Climate - Biogeochemistry Interactions in the Tropical Ocean; SFB754
    Materialart: Dataset
    Format: application/zip, 6 datasets
    Standort Signatur Einschränkungen Verfügbarkeit
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  • 5
    facet.materialart.
    Unbekannt
    PANGAEA
    In:  Supplement to: Schulz, Kai Georg; Bellerby, Richard G J; Brussaard, Corina P D; Büdenbender, Jan; Czerny, Jan; Engel, Anja; Fischer, Matthias; Krug, Sebastian; Lischka, Silke; Koch-Klavsen, Stephanie; Ludwig, Andrea; Meyerhöfer, Michael; Nondal, G; Silyakova, Anna; Stuhr, Annegret; Riebesell, Ulf (2013): Temporal biomass dynamics of an Arctic plankton bloom in response to increasing levels of atmospheric carbon dioxide. Biogeosciences, 10(1), 161-180, https://doi.org/10.5194/bg-10-161-2013
    Publikationsdatum: 2023-10-21
    Beschreibung: Ocean acidification and carbonation, driven by anthropogenic emissions of carbon dioxide (CO2), have been shown to affect a variety of marine organisms and are likely to change ecosystem functioning. High latitudes, especially the Arctic, will be the first to encounter profound changes in carbonate chemistry speciation at a large scale, namely the under-saturation of surface waters with respect to aragonite, a calcium carbonate polymorph produced by several organisms in this region. During a CO2 perturbation study in 2010, in the framework of the EU-funded project EPOCA, the temporal dynamics of a plankton bloom was followed in nine mesocosms, manipulated for CO2 levels ranging initially from about 185 to 1420 matm. Dissolved inorganic nutrients were added halfway through the experiment. Autotrophic biomass, as identified by chlorophyll a standing stocks (Chl a), peaked three times in all mesocosms. However, while absolute Chl a concentrations were similar in all mesocosms during the first phase of the experiment, higher autotrophic biomass was measured at high in comparison to low CO2 during the second phase, right after dissolved inorganic nutrient addition. This trend then reversed in the third phase. There were several statistically significant CO2 effects on a variety of parameters measured in certain phases, such as nutrient utilization, standing stocks of particulate organic matter, and phytoplankton species composition. Interestingly, CO2 effects developed slowly but steadily, becoming more and more statistically significant with time. The observed CO2 related shifts in nutrient flow into different phytoplankton groups (mainly diatoms, dinoflagellates, prasinophytes and haptophytes) could have consequences for future organic matter flow to higher trophic levels and export production, with consequences for ecosystem productivity and atmospheric CO2.
    Schlagwort(e): BIOACID; Biological Impacts of Ocean Acidification
    Materialart: Dataset
    Format: application/zip, 2 datasets
    Standort Signatur Einschränkungen Verfügbarkeit
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  • 6
    facet.materialart.
    Unbekannt
    PANGAEA
    In:  Supplement to: Maßmig, Marie; Lüdke, Jan; Krahmann, Gerd; Engel, Anja (2020): Bacterial degradation activity in the eastern tropical South Pacific oxygen minimum zone. Biogeosciences, 17(1), 215-230, https://doi.org/10.5194/bg-17-215-2020
    Publikationsdatum: 2023-12-05
    Beschreibung: Oxygen minimum zones in the ocean increased during the past 50 years and changed microbial biogeochemical cycling; thereby research was focusing on changes in the nitrogen cycle. Earlier studies suggested higher efficiency of carbon export in those regions due to reduced microbial degradation activity. However, previous findings on the effect of oxygen on microbial activity are ambiguous. Here, we present first results on bacterial biomass production (estimated by 3H leucine incorporation) and extracellular enzyme rates (leucine aminopeptidase and ß-glucosidase), for the oxygen minimum zone off Peru, which is part of one of the largest anoxic zones in the ocean. We observed no reduction in bacterial biomass production, or extracellular enzyme rates and no reduced cell abundance in anoxic and suboxic waters, compared to more oxygenated waters at the oxyclines, suggesting that microbial degradation rate does not necessarily slow down under low oxygen conditions. We estimated a mean microbial carbon uptake of 548 µmol m-3 d-1, thereby only an average of 11 % got transformed into bacterial biomass. The remaining part was respired to carbon dioxide (average: 496 µmol m-3 d-1), that was potentially released to the atmosphere and accounted on average for 32 % of the oxygen reduction in the upper 80 m. Our study therewith proposes that microbial degradation of organic matter significantly contributes to the formation of the oxygen minimum zone off Peru and can proceed at relatively high rate within anoxic waters. This indicates that carbon dioxide production by heterotrophic microbial degradation in the OMZ off Peru, is not necessarily reduced under anoxia, and driven by anaerobic heterotrophic respiration pathways like denitrification.
    Schlagwort(e): Climate - Biogeochemistry Interactions in the Tropical Ocean; SFB754
    Materialart: Dataset
    Format: application/zip, 3 datasets
    Standort Signatur Einschränkungen Verfügbarkeit
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  • 7
    facet.materialart.
    Unbekannt
    PANGAEA
    In:  Supplement to: Thomsen, Soeren; Karstensen, Johannes; Kiko, Rainer; Krahmann, Gerd; Dengler, Marcus; Engel, Anja (2019): Remote and local drivers of oxygen and nitrate variability in the shallow oxygen minimum zone off Mauritania in June 2014. Biogeosciences, 16(5), 979-998, https://doi.org/10.5194/bg-16-979-2019
    Publikationsdatum: 2024-02-20
    Beschreibung: Upwelling systems play a key role in the global carbon and nitrogen cycles and are also of local relevance due to their high productivity and fish resources. To capture and understand the high spatial and temporal variability of physical and biogeochemical parameters found in these regions novel measurement technics have to be combined in an interdisciplinary manner. Here we use high-resolution glider-based physical-biogeochemical observations in combination with ship-based underwater vision profiler, sensor and bottle data to investigate the drivers of oxygen and nitrate variability across the shelf break off Mauritania in June 2014. Distinct oxygen and nitrate variability shows up in our glider data. High oxygen and low nitrate anomalies were clearly related to water mass variability and probably linked to ocean transport. Low oxygen and high nitrate patches co-occurred with enhanced turbidity signals close to the seabed, which suggests locally high microbial respiration of resuspended organic matter near the sea floor. This interpretation is supported by high particle abundance observed by the underwater vision profiler and enhanced particle-based respiration rate estimates close to the seabed. Discrete in-situ measurements of dissolved organic carbon and amino acids suggest the formation of dissolved organic carbon due to particle dissolution near the seabed fueling additional microbial respiration. Our high-resolution interdisciplinary observations highlight the complex interplay of remote and local physical-biogeochemical drivers of oxygen and nitrate variability off Mauritania, which cannot be captured by classical shipboard observations alone.
    Schlagwort(e): Climate - Biogeochemistry Interactions in the Tropical Ocean; SFB754
    Materialart: Dataset
    Format: application/zip, 5 datasets
    Standort Signatur Einschränkungen Verfügbarkeit
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  • 8
    facet.materialart.
    Unbekannt
    PANGAEA
    In:  Supplement to: Cisternas Novoa, Carolina; Le Moigne, Frédéric A C; Engel, Anja (2019): Composition and vertical flux of particulate organic matter to the oxygen minimum zone of the central Baltic Sea: impact of a sporadic North Sea inflow. Biogeosciences, 16(4), 927-947, https://doi.org/10.5194/bg-16-927-2019
    Publikationsdatum: 2024-02-16
    Beschreibung: Here, we investigate the composition and vertical fluxes of POM in two deep basins of the Baltic Sea (GB: Gotland Basin and LD: Landsort Deep).
    Schlagwort(e): Climate - Biogeochemistry Interactions in the Tropical Ocean; SFB754
    Materialart: Dataset
    Format: application/zip, 7 datasets
    Standort Signatur Einschränkungen Verfügbarkeit
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  • 9
    facet.materialart.
    Unbekannt
    PANGAEA
    Publikationsdatum: 2024-03-28
    Beschreibung: Particulate organic matter (POM) distribution in the water column as on several cruises determined after filtration onto pre-combusted, acid-washed GF/F filters (Franz et al., 2012a). Particulate organic phosphorus (POP) collected on GF/F filters was determined colorimetrically. Samples for phytoplankton pigment concentrations were collected by filtration of seawater from the CTD/rosette through GF/F filters, and stored at -80°C immediately after filtration. Transparent exopolymer particles (TEP) and Coomassie stainable particles were filtered under low pressure (〈 150 mbar) onto 25 mm Nuclepore membrane filters (0.4 μm pore size, Whatman Ltd.) and stained with Alcian Blue and Coomassie Brilliant Blue, respectively. Export flux of was characterized using surface-tethered sediment traps (Engel et al., 2017), with Particle Interceptor-Traps (PIT) following Knauer et al. (1979).
    Schlagwort(e): Climate - Biogeochemistry Interactions in the Tropical Ocean; SFB754
    Materialart: Dataset
    Format: 10 datasets
    Standort Signatur Einschränkungen Verfügbarkeit
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  • 10
    Publikationsdatum: 2024-03-28
    Beschreibung: Dissolved Organic Matter, Cell Abundance and Extracellular Enzyme Rates and Bacterial Production from several cruises and experiments from 2008-2018
    Schlagwort(e): Climate - Biogeochemistry Interactions in the Tropical Ocean; SFB754
    Materialart: Dataset
    Format: 9 datasets
    Standort Signatur Einschränkungen Verfügbarkeit
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