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  • 2020-2024  (6)
  • 2010-2014  (35)
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  • 1
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    Dissolved organic matter, chlorophyll a and bacterial abundance measured in water samples of POLARSTERN cruise PS111 (ANT-XXXIII/2) (2021)
    PANGAEA
    Details
    Publication Date: 2023-11-15
    Description: Global warming poses new threats to marine ecosystems since rising seawater temperature potentially induces cascading effects in biogeochemical cycles and food webs. Heterotrophic bacteria are the main producers of CO2 in the ocean, thereby counteracting the biological drawdown of CO2 by primary production. In Antarctic marine systems, low seawater temperature, and the low availability of labile organic matter are major environmental constraints on bacterial growth and degradation activity. However, temperature and the availability of resources for heterotrophic bacteria undergo considerable change induced by climate warming combined with subsequent ice melt and changes in primary productivity. This project aims to test single and combined effects of temperature and organic matter availability on Antarctic marine bacterioplankton. This data set includes biological and biogeochemical parameters measured alongside the CTD casts during the Polarstern cruise PS111 to the Weddell Sea. Samples were collected in the upper 100 m of the water column at the Eastern Weddell Sea Shelf and at the Filchner-Ronne ice shelf. Concentrations of different components of dissolved organic matter and inorganic nutrients as well as chlorophyll a concentrations and bacterial cell numbers are reported.
    Keywords: Alanine; Amino acids, dissolved; Amino acids, dissolved, Carbon; ANT-XXXIII/2; Arabinose; Arginine; Aspartic acid; Auto-analyzer (QuAAtro, Seal analytical); Grasshoff et al., 1983; Bacteria; Bottle number; Carbohydrates, dissolved combined; Carbohydrates, dissolved combined, Carbon; Carbon, organic, dissolved; Chlorophyll a; CombiBac; Cruise/expedition; CTD; CTD/Rosette; CTD-RO; DATE/TIME; Depth, bathymetric; DEPTH, water; Ecology & Environment; Event label; Flow cytometry system, Becton Dickinson, FACSCalibur; Fluorometer; Welschmeyer, 1994; Fucose; Galactosamine; Galactose; Galacturonic acid; gamma-Aminobutyric acid; Glucosamine; Glucose; Glucuronic acid; Glutamic acid; Glycine; High-performance anion-exchange chromatography coupled with pulsed amperometric detection (ICS 3000, Dionex); Engel and Händel (2011); High-temperature catalytic oxidation method (TOC-VCSH, Shimadzu) (Qian and Mopper, 1996); HPLC system (Agilent 1260); Lindroth and Mopper, 1979; Isoleucine; Kombinierte Effekte von Temperatur und Ressourcenverfügbarkeit auf den Abbau von organischem Material durch Antarktisches Bakterioplankton; LATITUDE; Lazarev Sea; Leucine; LONGITUDE; Mannose/Xylose; Microbiology; Nitrate; Nitrite; Phenylalanine; Phosphate; Polarstern; Priority Programme 1158 Antarctic Research with Comparable Investigations in Arctic Sea Ice Areas; PS111; PS111_101-1; PS111_10-2; PS111_12-2; PS111_123-1; PS111_131-1; PS111_132-1; PS111_137-2; PS111_140-1; PS111_14-1; PS111_16-1; PS111_17-1; PS111_22-1; PS111_28-1; PS111_33-1; PS111_37-2; PS111_40-3; PS111_47-1; PS111_51-1; PS111_58-1; PS111_62-1; PS111_68-1; PS111_74-1; PS111_82-1; PS111_89-1; PS111_9-3; Rhamnose; Sample ID; Serine; Silicate, inorganic, dissolved; South Atlantic Ocean; SPP1158; Station label; Threonine; Tyrosine; Valine; Weddell Sea
    Type: Dataset
    Format: text/tab-separated-values, 5156 data points
    Location Call Number Limitation Availability
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    DATA PANGAEA
  • 2
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    Seawater carbonate chemistry and microbial polysaccharide degradation during experiments with phytoplankton Emiliania huxleyi (strain PML B92/11) and natural bacteria community, 2010 (2010)
    PANGAEA
    In:  Supplement to: Piontek, Judith; Lunau, Mirko; Händel, Nicole; Borchard, Corinna; Wurst, Mascha; Engel, Anja (2010): Acidification increases microbial polysaccharide degradation in the ocean. Biogeosciences, 7(5), 1615-1625, https://doi.org/10.5194/bg-7-1615-2010
    Details
    Publication Date: 2023-11-15
    Description: With the accumulation of anthropogenic carbon dioxide (CO2), a proceeding decline in seawater pH has been induced that is referred to as ocean acidification. The ocean's capacity for CO2 storage is strongly affected by biological processes, whose feedback potential is difficult to evaluate. The main source of CO2 in the ocean is the decomposition and subsequent respiration of organic molecules by heterotrophic bacteria. However, very little is known about potential effects of ocean acidification on bacterial degradation activity. This study reveals that the degradation of polysaccharides, a major component of marine organic matter, by bacterial extracellular enzymes was significantly accelerated during experimental simulation of ocean acidification. Results were obtained from pH perturbation experiments, where rates of extracellular alpha- and beta-glucosidase were measured and the loss of neutral and acidic sugars from phytoplankton-derived polysaccharides was determined. Our study suggests that a faster bacterial turnover of polysaccharides at lowered ocean pH has the potential to reduce carbon export and to enhance the respiratory CO2 production in the future ocean.
    Keywords: alpha-glucosidase activity per cell; Bacteria; Bacteria, abundance, standard deviation; beta-glucosidase activity per cell; Carbon, organic, particulate; Carbon, organic, particulate, standard deviation; Cell-specific glucosidase activity; Cell-specific glucosidase activity, standard deviation; Combined glucose loss; Combined glucose loss, standard deviation; Element analyser CNS, EURO EA; EPOCA; European Project on Ocean Acidification; Experimental treatment; FACSCalibur flow-cytometer (Becton Dickinson); High Performance anion-exchange chromatography; Light:Dark cycle; Measured; Particulate organic carbon loss; Particulate organic carbon loss, standard deviation; pH; Polysacchrides loss; Polysacchrides loss, standard deviation; Radiation, photosynthetically active; Sample ID; see reference(s); Temperature, water; Time, incubation; WTW 340i pH-analyzer and WTW SenTix 81-electrode
    Type: Dataset
    Format: text/tab-separated-values, 452 data points
    Location Call Number Limitation Availability
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    DATA PANGAEA
  • 3
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    Bacterial biomass production measured in water samples of POLARSTERN cruise PS111 (ANT-XXXIII/2) (2021)
    PANGAEA
    Details
    Publication Date: 2023-10-28
    Description: Global warming poses new threats to marine ecosystems since rising seawater temperature potentially induces cascading effects in biogeochemical cycles and food webs. Heterotrophic bacteria are the main producers of CO2 in the ocean, thereby counteracting the biological drawdown of CO2 by primary production. In Antarctic marine systems, low seawater temperature, and the low availability of labile organic matter are major environmental constraints on bacterial growth and degradation activity. However, temperature and the availability of resources for heterotrophic bacteria undergo considerable change induced by climate warming combined with subsequent ice melt and changes in primary productivity. This project aims to test single and combined effects of temperature and organic matter availability on Antarctic marine bacterioplankton. This data set includes measurements on bacterial biomass production at 0°C and 3°C measured alongside the CTD casts during the Polarstern cruise PS111 to the Weddell Sea. Samples were collected in the upper 100 m of the water column at the Eastern Weddell Sea Shelf and at the Filchner-Ronne ice shelf.
    Keywords: ANT-XXXIII/2; Bacterial production; CombiBac; CTD/Rosette; CTD-RO; DEPTH, water; Ecology & Environment; Estimated; Event label; Incorporation of 14C-leucine (Simon and Azam, 1989, http://www.int-res.com/articles/meps/51/m051p201.pdf; Simon et al. 2004, doi:10.4319/lo.2004.49.4.1035); Incubation temperature; Kombinierte Effekte von Temperatur und Ressourcenverfügbarkeit auf den Abbau von organischem Material durch Antarktisches Bakterioplankton; Lazarev Sea; Microbiology; Polarstern; Priority Programme 1158 Antarctic Research with Comparable Investigations in Arctic Sea Ice Areas; PS111; PS111_101-1; PS111_10-2; PS111_12-2; PS111_123-1; PS111_131-1; PS111_132-1; PS111_137-2; PS111_140-1; PS111_14-1; PS111_16-1; PS111_17-1; PS111_22-1; PS111_28-1; PS111_33-1; PS111_37-2; PS111_40-3; PS111_47-1; PS111_51-1; PS111_58-1; PS111_62-1; PS111_68-1; PS111_74-1; PS111_82-1; PS111_89-1; PS111_9-3; Sample ID; South Atlantic Ocean; SPP1158; Weddell Sea
    Type: Dataset
    Format: text/tab-separated-values, 2548 data points
    Location Call Number Limitation Availability
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    DATA PANGAEA
  • 4
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    Impact of CO2 enrichment on organic matter dynamics during nutrient induced coastal phytoplankton blooms (2014)
    PANGAEA
    In:  GEOMAR - Helmholtz Centre for Ocean Research Kiel | Supplement to: Engel, Anja; Piontek, Judith; Grossart, Hans-Peter; Riebesell, Ulf; Schulz, Kai Georg; Sperling, Martin (2014): Impact of CO2 enrichment on organic matter dynamics during nutrient induced coastal phytoplankton blooms. Journal of Plankton Research, 36(3), 641-657, https://doi.org/10.1093/plankt/fbt125
    Details
    Publication Date: 2024-02-01
    Description: A mesocosm experiment was conducted to investigate the impact of rising fCO2 on the build-up and decline of organic matter during coastal phytoplankton blooms. Five mesocosms (~38 m³ each) were deployed in the Baltic Sea during spring (2009) and enriched with CO2 to yield a gradient of 355-862 µatm. Mesocosms were nutrient fertilized initially to induce phytoplankton bloom development. Changes in particulate and dissolved organic matter concentrations, including dissolved high-molecular weight (〉1 kDa) combined carbohydrates, dissolved free and combined amino acids as well as transparent exopolymer particles (TEP), were monitored over 21 days together with bacterial abundance, and hydrolytic extracellular enzyme activities. Overall, organic matter followed well-known bloom dynamics in all CO2 treatments alike. At high fCO2, higher dPOC:dPON during bloom rise, and higher TEP concentrations during bloom peak, suggested preferential accumulation of carbon-rich components. TEP concentration at bloom peak was significantly related to subsequent sedimentation of particulate organic matter. Bacterial abundance increased during the bloom and was highest at high fCO2. We conclude that increasing fCO2 supports production and exudation of carbon-rich components, enhancing particle aggregation and settling, but also providing substrate and attachment sites for bacteria. More labile organic carbon and higher bacterial abundance can increase rates of oxygen consumption and may intensify the already high risk of oxygen depletion in coastal seas in the future.
    Keywords: BIOACID; Biological Impacts of Ocean Acidification; SOPRAN; Surface Ocean Processes in the Anthropocene
    Type: Dataset
    Format: application/zip, 2 datasets
    Location Call Number Limitation Availability
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    DATA PANGAEA
  • 5
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    Svalbard 2010 team (2010): EPOCA Svalbard mesocosm experiment 2010 depth-integrated (0-12m) variables (2013)
    PANGAEA
    Details
    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
    Location Call Number Limitation Availability
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    DATA PANGAEA
  • 6
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    CO2 increases 14C-primary production in an Arctic plankton community (2013)
    Copernicus Publications (EGU)
    In:  Biogeosciences (BG), 10 (3). pp. 1291-1308.
    Details
    Publication Date: 2019-09-23
    Description: Responses to ocean acidification in plankton communities were studied during a CO2-enrichment experiment in the Arctic Ocean, accomplished from June to July 2010 in Kongsfjorden, Svalbard (78°56′ 2′′ N, 11°53′ 6′′ E). Enclosed in 9 mesocosms (volume: 43.9–47.6 m3), plankton was exposed to CO2 concentrations, ranging from glacial to projected mid-next-century levels. Fertilization with inorganic nutrients at day 13 of the experiment supported the accumulation of phytoplankton biomass, as indicated by two periods of high chl a concentration. This study tested for CO2 sensitivities in primary production (PP) of particulate organic carbon (PPPOC) and of dissolved organic carbon (PPDOC). Therefore, 14C-bottle incubations (24 h) of mesocosm samples were performed at 1 m depth receiving about 60% of incoming radiation. PP for all mesocosms averaged 8.06 ± 3.64 μmol C L−1 d−1 and was slightly higher than in the outside fjord system. Comparison between mesocosms revealed significantly higher PPPOC at elevated compared to low pCO2 after nutrient addition. PPDOC was significantly higher in CO2-enriched mesocosms before as well as after nutrient addition, suggesting that CO2 had a direct influence on DOC production. DOC concentrations inside the mesocosms increased before nutrient addition and more in high CO2 mesocosms. After addition of nutrients, however, further DOC accumulation was negligible and not significantly different between treatments, indicating rapid utilization of freshly produced DOC. Bacterial biomass production (BP) was coupled to PP in all treatments, indicating that 3.5 ± 1.9% of PP or 21.6 ± 12.5% of PPDOC provided on average sufficient carbon for synthesis of bacterial biomass. During the later course of the bloom, the response of 14C-based PP rates to CO2 enrichment differed from net community production (NCP) rates that were also determined during this mesocosm campaign. We conclude that the enhanced release of labile DOC during autotrophic production at high CO2 exceedingly stimulated activities of heterotrophic microorganisms. As a consequence, increased PP induced less NCP, as suggested earlier for carbon-limited microbial systems in the Arctic.
    Type: Article , PeerReviewed , info:eu-repo/semantics/article
    Format: text
    DOI: 10.5194/bg-10-1291-2013
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    OceanRep: Article in a Scientific Journal - peer-reviewed
  • 7
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    Impact of CO2 enrichment on organic matter dynamics during nutrient induced coastal phytoplankton blooms (2014)
    Oxford Univ. Press
    In:  Journal of Plankton Research, 36 (3). pp. 641-657.
    Details
    Publication Date: 2019-09-23
    Description: A mesocosm experiment was conducted to investigate the impact of rising fCO2 on the build-up and decline of organic matter during coastal phytoplankton blooms. Five mesocosms (∼38 m³ each) were deployed in the Baltic Sea during spring (2009) and enriched with CO2 to yield a gradient of 355–862 µatm. Mesocosms were nutrient fertilized initially to induce phytoplankton bloom development. Changes in particulate and dissolved organic matter concentrations, including dissolved high-molecular weight (〉1 kDa) combined carbohydrates, dissolved free and combined amino acids as well as transparent exopolymer particles (TEP), were monitored over 21 days together with bacterial abundance, and hydrolytic extracellular enzyme activities. Overall, organic matter followed well-known bloom dynamics in all CO2 treatments alike. At high fCO2, higher ΔPOC:ΔPON during bloom rise, and higher TEP concentrations during bloom peak, suggested preferential accumulation of carbon-rich components. TEP concentration at bloom peak was significantly related to subsequent sedimentation of particulate organic matter. Bacterial abundance increased during the bloom and was highest at high fCO2. We conclude that increasing fCO2 supports production and exudation of carbon-rich components, enhancing particle aggregation and settling, but also providing substrate and attachment sites for bacteria. More labile organic carbon and higher bacterial abundance can increase rates of oxygen consumption and may intensify the already high risk of oxygen depletion in coastal seas in the future.
    Type: Article , PeerReviewed
    Format: text
    DOI: 10.1093/plankt/fbt125
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    OceanRep: Article in a Scientific Journal - peer-reviewed
  • 8
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    Response of bacterioplankton activity in an Arctic fjord system to elevated pCO2: results from a mesocosm perturbation study (2013)
    Copernicus Publications (EGU)
    In:  Biogeosciences (BG), 10 . pp. 297-314.
    Details
    Publication Date: 2019-09-23
    Description: The effect of elevated seawater carbon dioxide (CO2) on the activity of a natural bacterioplankton community in an Arctic fjord system was investigated by a mesocosm perturbation study in the frame of the European Project on Ocean Acidification (EPOCA). A pCO2 range of 175–1085 μatm was set up in nine mesocosms deployed in the Kongsfjorden (Svalbard). The bacterioplankton communities responded to rising chlorophyll a concentrations after a lag phase of only a few days with increasing protein production and extracellular enzyme activity and revealed a close coupling of heterotrophic bacterial activity to phytoplankton productivity in this experiment. The natural extracellular enzyme assemblages showed increased activity in response to moderate acidification. A decrease in seawater pH of 0.5 units roughly doubled rates of β-glucosidase and leucine-aminopeptidase. Activities of extracellular enzymes in the mesocosms were directly related to both seawater pH and primary production. Also primary production and bacterial protein production in the mesocosms at different pCO2 were positively correlated. Therefore, it can be suggested that the efficient heterotrophic carbon utilization in this Arctic microbial food web had the potential to counteract increased phytoplankton production that was achieved under elevated pCO2 in this study. However, our results also show that the transfer of beneficial pCO2-related effects on the cellular bacterial metabolism to the scale of community activity and organic matter degradation can be mitigated by the top-down control of bacterial abundances in natural microbial communities.
    Type: Article , PeerReviewed , info:eu-repo/semantics/article
    Format: text
    DOI: 10.5194/bg-10-297-2013
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  • 9
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    Contrasting responses of DMS and DMSP to ocean acidification in Arctic waters (2013)
    Copernicus Publications (EGU)
    In:  Biogeosciences (BG), 10 . pp. 1893-1908.
    Details
    Publication Date: 2019-09-23
    Description: Increasing atmospheric CO2 is decreasing ocean pH most rapidly in colder regions such as the Arctic. As a component of the EPOCA pelagic mesocosm experiment off Spitzbergen in 2010, we examined the consequences of decreased pH and increased pCO2 on the concentrations of dimethylsulphide (DMS). DMS is an important reactant and contributor to aerosol formation and growth in the Arctic troposphere. In the nine mesocosms with initial pH 8.3 to 7.5, equivalent to pCO2 of 180 to 1420 μatm, highly significant but inverse responses to acidity (hydrogen ion concentration [H+]) occurred following nutrient addition. Compared to ambient [H+], average concentrations of DMS during the most representative phase of the 30 d experiment were reduced by approximately 60% at the highest [H+] and by 35% at [H+] equivalent to 750 μatm pCO2, as predicted for 2100. In contrast, concentrations of dimethylsulphoniopropionate (DMSP), the precursor of DMS, were elevated by approximately 50% at the highest [H+] and by 30% at [H+] corresponding to 750 μatm pCO2. Measurements of the specific rate of synthesis of DMSP by phytoplankton indicate increased production at high [H+], in parallel to rates of inorganic carbon fixation. The elevated DMSP production at high [H+] was largely a consequence of increased dinoflagellate biomass and in particular, the increased abundance of the species Heterocapsa rotundata. We discuss both phytoplankton and bacterial processes that may explain the reduced ratios of DMS:DMSPt at higher [H+]. The experimental design of eight treatment levels provides comparatively robust empirical relationships of DMS and DMSP concentration, DMSP production and dinoflagellate biomass versus [H+] in Arctic waters.
    Type: Article , PeerReviewed , info:eu-repo/semantics/article
    Format: text
    DOI: 10.5194/bg-10-1893-2013
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  • 10
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    Regulation of bacterioplankton activity in Fram Strait (Arctic Ocean) during early summer: The role of organic matter supply and temperature (2014)
    Elsevier
    In:  Journal of Marine Systems, 132 . pp. 83-94.
    Details
    Publication Date: 2019-09-23
    Description: Highlights: • Activity of Arctic bacterioplankton in summer is regulated by concentration and composition of organic matter. • Bacterial production in Fram Strait is significantly related to concentrations of total amino acids. • Bacterioplankton in Polar Water show enhanced enzymatic hydrolysis of combined carbohydrates compared to Atlantic Water. Abstract The bacterial turnover of organic matter was investigated in Fram Strait at 79°N. Both Atlantic Water (AW) inflow and exported Polar Water (PW) were sampled along a transect from Spitsbergen to the eastern Greenland shelf during a late successional stage of the main annual phytoplankton bloom in summer. AW showed higher concentrations of amino acids than PW, while organic matter in PW was enriched in combined carbohydrates. Bacterial growth and degradation activity in AW and PW were related to compositional differences of organic matter. Bacterial production and leucine-aminopeptidase along the transect were significantly correlated with concentrations of amino acids. Activity ratios between the extracellular enzymes β-glucosidase and leucine-aminopeptidase indicate the hydrolysis potential for polysaccharides relative to proteins. Along the transect, these ratios showed a higher hydrolysis potential for polysaccharides relative to proteins in PW than in AW, thus reflecting the differences in organic matter composition between the water masses. Q10 values for bacterial production ranged from 2.4 (± 0.8) to 6.0 (± 6.8), while those for extracellular enzymes showed a broader range of 1.5 (± 0.5) to 23.3 (± 11.8). Our results show that in addition to low seawater temperature also organic matter availability contributes to the regulation of bacterial growth and enzymatic activity in the Arctic Ocean.
    Type: Article , PeerReviewed
    Format: text
    DOI: 10.1016/j.jmarsys.2014.01.003
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