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  • 1
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    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
    Publication Date: 2023-10-21
    Description: 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.
    Keywords: BIOACID; Biological Impacts of Ocean Acidification
    Type: Dataset
    Format: application/zip, 2 datasets
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  • 2
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    PANGAEA
    In:  Supplement to: Ray, Jessica L; Töpper, Birte; An, Shu; Silyakova, Anna; Spindelböck, Joachim; Thyrhaug, Runar; DuBow, Michael S; Thingstad, Tron Frede; Sandaa, Ruth-Anne (2012): Effect of increased pCO2 on bacterial assemblage shifts in response to glucose addition in Fram Strait seawater mesocosms. FEMS Microbiology Ecology, 82(3), 713-723, https://doi.org/10.1111/j.1574-6941.2012.01443.x
    Publication Date: 2024-03-15
    Description: Ocean acidification may stimulate primary production through increased availability of inorganic carbon in the photic zone, which may in turn change the biogenic flux of dissolved organic carbon (DOC) and the growth potential of heterotrophic bacteria. To investigate the effects of ocean acidification on marine bacterial assemblages, a two-by-three factorial mescosom experiment was conducted using surface sea water from the East Greenland Current in Fram Strait. Pyrosequencing of the V1-V2 region of bacterial 16S ribosomal RNA genes was used to investigate differences in the endpoint (Day 9) composition of bacterial assemblages in mineral nutrient-replete mesocosms amended with glucose (0 µm, 5.3 µm and 15.9 µm) under ambient (250 µatm) or acidified (400 µatm) partial pressures of CO2 (pCO2). All mesocosms showed low richness and diversity by Chao1 estimator and Shannon index, respectively, with general dominance by Gammaproteobacteria and Flavobacteria. Nonmetric multidimensional scaling analysis and two-way analysis of variance of the Jaccard dissimilarity matrix (97% similarity cut-off) demonstrated that the significant community shift between 0 µm and 15.9 µm glucose addition at 250 µatm pCO2 was eliminated at 400 µatm pCO2. These results suggest that the response potential of marine bacteria to DOC input may be altered under acidified conditions.
    Keywords: Algae abundance; Alkalinity, total; Aragonite saturation state; Arctic; Bacteria, abundance; Bacterial production; Bicarbonate ion; Calcite saturation state; Calculated using seacarb after Nisumaa et al. (2010); Carbon, inorganic, dissolved; Carbonate ion; Carbonate system computation flag; Carbon dioxide; Class; Community composition and diversity; Entire community; EXP; Experiment; Family; Field experiment; Fram_Strait_OA; Fugacity of carbon dioxide (water) at sea surface temperature (wet air); Gene expression (incl. proteomics); Incubation duration; Mesocosm or benthocosm; OA-ICC; Ocean Acidification International Coordination Centre; Open ocean; Operational taxonomic unit; Other metabolic rates; Partial pressure of carbon dioxide (water) at sea surface temperature (wet air); Pelagos; pH; Phosphate; Polar; Salinity; Sequence abundance; Sequence coverage; Silicate; Species; Temperature, water; Treatment
    Type: Dataset
    Format: text/tab-separated-values, 112442 data points
    Location Call Number Limitation Availability
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  • 3
    Publication Date: 2024-03-15
    Keywords: 19-Butanoyloxyfucoxanthin; 1-Iodoethane; 1-Iodopropane; 2-Iodopropane; Algae, biomass as carbon; Algae, fatty acids; Algae abundance; Alkaline phosphatase; Alkalinity, Gran titration (Gran, 1950); Alkalinity, total; Alloxanthin; alpha-Carotene, beta,epsilon-Carotene; Ammonium; Aphanizophyll; Aragonite saturation state; Arctic; Bacteria; Bacteria, biomass as carbon; Bacteria, fatty acids; Bacteria, high DNA fluorescence; Bacteria, low DNA fluorescence; Bacterial/community respiration, oxygen, ratio; Bacterial biomass production of carbon; Bacterial biomass production of carbon, standard deviation; Bacterial production; Bacterial production, standard deviation; beta-Carotene, beta,beta-Carotene; Bicarbonate ion; BIOACID; Biogenic silica; Biological Impacts of Ocean Acidification; Biomass/Abundance/Elemental composition; Bromochloromethane; Bromoiodomethane; Calanus finmarchicus, δ13C; Calcite saturation state; Calculated; Calculated from linear regression; Calculated using CO2SYS; Calculated using seacarb after Nisumaa et al. (2010); Carbon, inorganic, dissolved; Carbon, inorganic, particulate; Carbon, organic, dissolved; Carbon, organic, particulate; Carbon, total, particulate; Carbonate ion; Carbonate system computation flag; Carbon dioxide; Carbon dioxide, flux per mesocosm; Chloroiodomethane; Chlorophyll a; Chlorophyll a, areal concentration; Chlorophyll b; Chlorophyll c1+c2; Chlorophyll c3; Chlorophytes; Cirripedia, larvae, δ13C; Coast and continental shelf; Community composition and diversity; Coulometry; Cryptophytes; Cyanobacteria, biomass per area; DATE/TIME; delta 13C labeling method; Diadinoxanthin; Diatoxanthin; Dibromochloromethane; Dibromomethane; Diiodomethane; Dimethyl sulfide, dissolved; Dimethylsulfoniopropionate; Entire community; EPOCA; EUR-OCEANS; European network of excellence for Ocean Ecosystems Analysis; European Project on Ocean Acidification; Exudation as determined by 14C DOC production; Exudation as determined by 14C DOC production, standard deviation; Field experiment; Flow cytometry; Fucoxanthin; Fugacity of carbon dioxide (water) at sea surface temperature (wet air); Gas chromatography - Mass spectrometry (GC-MS); GC-PFPD; Gross community production of oxygen; Hand-operated CTD (Sea&Sun Technology, CTD 60M); High Performance Liquid Chromatography (HPLC); Identification; Iodomethane; Kongsfjorden-mesocosm; MESO; Mesocosm experiment; Mesocosm or benthocosm; Myxoxanthophyll; Nanoplankton; Neoxanthin; Net community production, standard deviation; Net community production of carbon dioxide; Net community production of oxygen; Nitrate; Nitrite; Nitrogen, organic, dissolved; Nitrogen, organic, particulate; Nitrous oxide; OA-ICC; Ocean Acidification International Coordination Centre; Other metabolic rates; Oxygen; Partial pressure of carbon dioxide (water) at sea surface temperature (wet air); Pelagos; Peridinin; pH; Phosphate; Phosphorus, organic, dissolved; Phosphorus, organic, particulate; Phytoplankton, biomass per area; Picophytoplankton; Polar; Prasinoxanthin; Primary production/Photosynthesis; Primary production of POC as determined by 14C POC production; Primary production of POC as determined by 14C POC production, standard deviation; Pulsed flame photometric detector - gas chromatography; Respiration; Respiration, oxygen, bacterial; Respiration, oxygen, bacterial, standard error; Respiration, oxygen, community; Respiration, oxygen, community, standard error; Salinity; Sample comment; Sigmas; Silicon; Svalbard; Temperature, water; Thymidine incorporation; Time, incubation; Transfer velocity, carbon dioxide; Transfer velocity, dimethyl sulfide; Transfer velocity, nitrous oxide; Tribromomethane; Turbidity (Formazin Turbidity Unit); Violaxanthin; Viral abundance; Virus/bacteria ratio; Viruses; Water content of mesocosm; Zeaxanthin; Δδ13C; δ13C, algae; δ13C, bacteria; δ13C, dissolved inorganic carbon; δ13C, dissolved organic carbon; δ13C, particulate organic carbon
    Type: Dataset
    Format: text/tab-separated-values, 35076 data points
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  • 4
    Publication Date: 2020-10-20
    Description: A large-scale multidisciplinary mesocosm experiment in an Arctic fjord (Kongsfjorden, Svalbard; 78°56.2′N) was used to study Arctic marine food webs and biogeochemical elements cycling at natural and elevated future carbon dioxide (CO2) levels. At the start of the experiment, marine-derived chromophoric dissolved organic matter (CDOM) dominated the CDOM pool. Thus, this experiment constituted a convenient case to study production of autochthonous CDOM, which is typically masked by high levels of CDOM of terrestrial origin in the Arctic Ocean proper. CDOM accumulated during the experiment in line with an increase in bacterial abundance; however, no response was observed to increased pCO2 levels. Changes in CDOM absorption spectral slopes indicate that bacteria were most likely responsible for the observed CDOM dynamics. Distinct absorption peaks (at ~ 330 and ~ 360 nm) were likely associated with mycosporine-like amino acids (MAAs). Due to the experimental setup, MAAs were produced in absence of ultraviolet exposure providing evidence for MAAs to be considered as multipurpose metabolites rather than simple photoprotective compounds. We showed that a small increase in CDOM during the experiment made it a major contributor to total absorption in a range of photosynthetically active radiation (PAR, 400–700 nm) and, therefore, is important for spectral light availability and may be important for photosynthesis and phytoplankton groups composition in a rapidly changing Arctic marine ecosystem.
    Type: Article , PeerReviewed , info:eu-repo/semantics/article
    Format: text
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  • 5
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    Arctic Monitoring and Assessment Programme (AMAP)
    In:  In: AMAP Assessment 2015: Methane as an Arctic climate forcer. Arctic Monitoring and Assessment Programme (AMAP), Oslo, Norway, pp. 27-38. ISBN 978-82-7971-091-2
    Publication Date: 2019-02-26
    Type: Book chapter , NonPeerReviewed , info:eu-repo/semantics/bookPart
    Format: text
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  • 6
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    National Academy of Sciences
    In:  PNAS Proceedings of the National Academy of Sciences of the United States of America, 114 (21). pp. 5355-5360.
    Publication Date: 2020-02-06
    Description: Continued warming of the Arctic Ocean in coming decades is projected to trigger the release of teragrams (1 Tg = 10(6) tons) of methane from thawing subsea permafrost on shallow continental shelves and dissociation of methane hydrate on upper continental slopes. On the shallow shelves (〈100 m water depth), methane released from the seafloor may reach the atmosphere and potentially amplify global warming. On the other hand, biological uptake of carbon dioxide (CO2) has the potential to offset the positive warming potential of emitted methane, a process that has not received detailed consideration for these settings. Continuous sea-air gas flux data collected over a shallow ebullitive methane seep field on the Svalbard margin reveal atmospheric CO2 uptake rates (-33,300 ± 7,900 μmol m(-2)⋅d(-1)) twice that of surrounding waters and ∼1,900 times greater than the diffusive sea-air methane efflux (17.3 ± 4.8 μmol m(-2)⋅d(-1)). The negative radiative forcing expected from this CO2 uptake is up to 231 times greater than the positive radiative forcing from the methane emissions. Surface water characteristics (e.g., high dissolved oxygen, high pH, and enrichment of (13)C in CO2) indicate that upwelling of cold, nutrient-rich water from near the seafloor accompanies methane emissions and stimulates CO2 consumption by photosynthesizing phytoplankton. These findings challenge the widely held perception that areas characterized by shallow-water methane seeps and/or strongly elevated sea-air methane flux always increase the global atmospheric greenhouse gas burden.
    Type: Article , PeerReviewed
    Format: text
    Format: text
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  • 7
    Publication Date: 2024-02-07
    Description: Improved quantification techniques of natural sources is needed to explain variations in atmospheric methane. In polar regions, high uncertainties in current estimates of methane release from the seabed remain. We present two unique 10 and 3 months long time-series of bottom water measurements of physical and chemical parameters from two autonomous ocean observatories deployed at separate intense seabed methane seep sites (91 and 246 m depth) offshore Western Svalbard from 2015 to 2016. Results show high short term (100–1000 nmol L-1 within hours) and seasonal variation, as well as higher (2–7 times) methane concentrations compared to previous measurements. Rapid variability is explained by uneven distribution of seepage and changing ocean current directions. No overt influence of tidal hydrostatic pressure or water temperature variations on methane concentration was observed, but an observed negative correlation with temperature at the 246 site fits with hypothesized seasonal blocking of lateral methane pathways in the sediments. Negative correlation between bottom water methane concentration/variability and wind forcing, concomitant with signs of weaker water column stratification, indicates increased potential for methane release to the atmosphere in fall/winter. We highlight uncertainties in methane inventory estimates based on discrete water sampling and present new information about short- and long-term methane variability which can help constrain future estimates of seabed methane seepage.
    Type: Article , PeerReviewed
    Format: text
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  • 8
    Publication Date: 2019-07-17
    Description: Recent studies on the impacts of ocean acidification on pelagic communities have identified changes in carbon to nutrient dynamics with related shifts in elemental stoichiometry. In principle, mesocosm experiments provide the opportunity of determining temporal dynamics of all relevant carbon and nutrient pools and, thus, calculating elemental budgets. In practice, attempts to budget mesocosm enclosures are often hampered by uncertainties in some of the measured pools and fluxes, in particular due to uncertainties in constraining air–sea gas exchange, particle sinking, and wall growth. In an Arctic mesocosm study on ocean acidification applying KOSMOS (Kiel Off-Shore Mesocosms for future Ocean Simulation), all relevant element pools and fluxes of carbon, nitrogen and phosphorus were measured, using an improved experimental design intended to narrow down the mentioned uncertainties. Water-column concentrations of particulate and dissolved organic and inorganic matter were determined daily. New approaches for quantitative estimates of material sinking to the bottom of the mesocosms and gas exchange in 48 h temporal resolution as well as estimates of wall growth were developed to close the gaps in element budgets. However, losses elements from the budgets into a sum of insufficiently determined pools were detected, and are principally unavoidable in mesocosm investigation. The comparison of variability patterns of all single measured datasets revealed analytic precision to be the main issue in determination of budgets. Uncertainties in dissolved organic carbon (DOC), nitrogen (DON) and particulate organic phosphorus (POP) were much higher than the summed error in determination of the same elements in all other pools. With estimates provided for all other major elemental pools, mass balance calculations could be used to infer the temporal development of DOC, DON and POP pools. Future elevated pCO2 was found to enhance net autotrophic community carbon uptake in two of the three experimental phases but did not significantly affect particle elemental composition. Enhanced carbon consumption appears to result in accumulation of dissolved organic carbon under nutrient-recycling summer conditions. This carbon overconsumption effect becomes evident from mass balance calculations, but was too small to be resolved by direct measurements of dissolved organic matter. Faster nutrient uptake by comparatively small algae at high CO2 after nutrient addition resulted in reduced production rates under future ocean CO2 conditions at the end of the experiment. This CO2 mediated shift towards smaller phytoplankton and enhanced cycling of dissolved matter restricted the development of larger phytoplankton, thus pushing the system towards a retention type food chain with overall negative effects on export potential.
    Repository Name: EPIC Alfred Wegener Institut
    Type: Article , isiRev
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