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90 Research products, page 1 of 9

  • European Marine Science
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  • 2013-2022
  • FR
  • European Marine Science

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  • Open Access English
    Authors: 
    Waelbroeck, Claire; Tjiputra, Jerry; Guo, Chuncheng; Nisancioglu, Kerim H.; Jansen, Eystein; Vazquez Riveiros, Natalia; Toucanne, Samuel; Eynaud, Frédérique; Rossignol, Linda; Dewilde, Fabien; +3 more
    Project: EC | ICE2ICE (610055), EC | ACCLIMATE (339108)

    We combine consistently dated benthic carbon isotopic records distributed over the entire Atlantic Ocean with numerical simulations performed by a glacial configuration of the Norwegian Earth System Model with active ocean biogeochemistry, in order to interpret the observed Cibicides δ13C changes at the stadial-interstadial transition corresponding to the end of Heinrich Stadial 4 (HS4) in terms of ocean circulation and remineralization changes. We show that the marked increase in Cibicides δ13C observed at the end of HS4 between ~2000 and 4200 m in the Atlantic can be explained by changes in nutrient concentrations as simulated by the model in response to the halting of freshwater input in the high latitude glacial North Atlantic. Our model results show that this Cibicides δ13C signal is associated with changes in the ratio of southern-sourced (SSW) versus northern-sourced (NSW) water masses at the core sites, whereby SSW is replaced by NSW as a consequence of the resumption of deep water formation in the northern North Atlantic and Nordic Seas after the freshwater input is halted. Our results further suggest that the contribution of ocean circulation changes to this signal increases from ~40 % at 2000 m to ~80 % at 4000 m. Below ~4200 m, the model shows little ocean circulation change but an increase in remineralization across the transition marking the end of HS4. The simulated lower remineralization during stadials than interstadials is particularly pronounced in deep subantarctic sites, in agreement with the decrease in the export production of carbon to the deep Southern Ocean during stadials found in previous studies.

  • French
    Authors: 
    Barré , Éric;
    Publisher: HAL CCSD
    Country: France

    n°90

  • Open Access English
    Authors: 
    TRAMOY, Romain; GASPERI, Johnny; COLASSE, Laurent; SILVESTRE, Marie; DUBOIS, Philippe; TASSIN, Bruno;
    Country: France

    Rivers are major pathways of plastics from lands into the Ocean. However, there is still a huge lack of knowledge on how riverine litter, including macroplastics, is transferred into the Ocean. Quantitative measurements of macroplastic emissions in rivers even suggest that a small fraction (0.001 to 3%) of the Mismanaged Plastic Waste (MPW) generated within a river basin finally reach the sea. Instead, macroplastics may remain within the catchment and on coastlines because of complex transport dynamics that delay the transfer of plastic debris. In order to better understand those dynamics, we performed tracking of riverine litter over time. First, hundreds of date-prints items were collected on riverbanks in the Seine estuary. The distribution of their Use-By-Dates suggest that riverine litter may remain stored on riverbanks for decades. Second, we performed real time tracking of floating and sub-floating bottles using GPS-trackers. Between March 2018 and April 2019, 39 trajectories were recorded in the estuary under tidal influence and 11 trajectories upriver, covering a wide range of hydrometeorological conditions. Results show a succession of stranding/remobilization episodes in combination with alternating upstream and downstream transport in the estuary related to tides. In the end, tracked bottles systematically stranded somewhere, for hours to weeks, from one to several times on different sites. The overall picture shows that different hydrometeorological phenomena interact with various time scales ranging from hours/days (high/low tides) to weeks/months (spring/neap tides and highest tides) and years (seasonal river flow, vegetation and geomorphological aspects). Thus, the fate of plastic debris is highly unpredictable with a chaotic-like transfer of plastic debris into the Ocean. The residence time of these debris is much longer than the transit time of water. This offers the opportunity to collect them before they get fragmented and/or reach the Sea.

  • Open Access English
    Authors: 
    Kiko, Rainer; Picheral, Marc; Antoine, David; Babin, Marcel; Berline, L; Biard, Tristan; Boss, Emmanuel; Brandt, Peter; Carlotti, F; Christiansen, Svenja; +32 more
    Publisher: PANGAEA - Data Publisher for Earth & Environmental Science
    Project: EC | TRIATLAS (817578), ANR | TAD (ANR-19-MPGA-0012)

    Particle size distribution data was collected during multiple cruises globally with several regularly intercalibrated Underwater Vision Profilers, Version 5 (UVP5; Picheral et al 2010). During the respective cruises, the UVP5 was mounted on the CTD-Rosette or as a standalone instrument and deployed in vertical mode. The UVP5 takes pictures of an illuminated watervolume of about 1 Liter every few milliseconds. Imaged items are counted, their size measured and abundance and biovolume of the particles is calculated. For different size bins, this information is summarized in the columns "Particle concentration" and "Particle biovolume". For further details please refer to Kiko et al. (in prep.) "A global marine particle size distribution dataset obtained with the Underwater Vision Profiler 5".

  • Open Access
    Authors: 
    GASPERI, Johnny; TRAMOY, Romain; DRIS, Rachid; BLOT, Denis; TASSIN, Bruno;
    Country: France

    Les rivières sont censées être les principales voies de transfert des plastiques des terres vers l'océan (Lebreton et al., 2017 ; Schmidt et al., 2017). Cependant, il existe encore un manque important de connaissances sur la façon dont les déchets fluviaux, y compris les macroplastiques, sont transférés vers l'Océan. Les mesures quantitatives des émissions de macroplastiques dans les rivières suggèrent même qu'une fraction de l'ordre de 0,001 à 3% des déchets plastiques mal gérés (MPW) générés dans un bassin fluvial atteignent finalement la mer (Emmerik et al., 2019 ; Schöneich-Argent et al., 2020 ; Tramoy et al. 2021). Au lieu de cela, les macroplastiques peuvent rester dans le bassin versant et sur les côtes en raison de la dynamique complexe du transport qui retarde le transfert des déchets mal gérés des terres vers l'océan (Olivelli et al., 2020 ; Weideman et al., 2020). Afin de mieux comprendre ces dynamiques, le laboratoire Eau et Environnement et le Laboratoire Eau Environnement et Systèmes Urbains étudient la dynamique des déchets en Seine et en Loire. Pour les macrodéchets plastiques, l'ensemble des travaux engagés sur la Seine permettent de dresser une première esquisse des flux de déchets plastiques transitant en Seine, captés par les dispositifs urbains et/ou collectés par des opérations de nettoyage. Selon nos estimations, entre 100 et 200 tonnes de déchets plastiques transiteraient chaque année en Seine. A l'échelle de l'agglomération parisienne, et bien que ces valeurs s'accompagnent de fortes incertitudes, les eaux pluviales n'apporteraient qu'une part mineure de ces flux, i.e., entre 8 et 33 tonnes par an. L'étude de la dynamique des débris plastiques montre que le transfert des plastiques est loin d'être linéaire et qu'il est soumis à de nombreux phénomènes physiques à de nombreuses échelles temporelles, i.e. d'échelles courtes allant de quelques heures à quelques jours (marées hautes / basses) à des échelles beaucoup plus longues allant de plusieurs semaines (marées de printemps / creuses et marées les plus hautes) à quelques années (crues). La conséquence de ces interactions est que le transfert des débris est chaotique et qu'une part importante de ces flux peut venir s'échouer sur les berges.

  • Open Access English
    Authors: 
    Rasse, Rafael; Claustre, Hervé; Poteau, Antoine;
    Project: EC | NOCEANIC (839062), EC | REMOCEAN (246777), EC | REFINE (834177)

    The shallower oxygen-poor water masses of the ocean confine a majority of the microbial communities that can produce up to 90 % of oceanic N2. This effective N2-yielding section encloses a suspended small-particle layer, inferred from particle backscattering (bbp) measurements. It is thus hypothesized that this layer (hereafter, the bbp-layer) is linked to microbial communities involved in N2 yielding such as nitrate-reducing SAR11 as well as sulfur-oxidizing, anammox, and denitrifying bacteria – a hypothesis yet to be evaluated. Here, data collected by three BGC-Argo floats deployed in the Black Sea are used to investigate the origin of this bbp-layer. To this end, we evaluate how the key drivers of N2-yielding bacteria dynamics impact the vertical distribution of bbp and the thickness of the bbp-layer. In conjunction with published data on N2 excess, our results suggest that the bbp-layer is at least partially composed of the bacteria driving N2 yielding for three main reasons: (1) strong correlations are recorded between bbp and nitrate; (2) the top location of the bbp-layer is driven by the ventilation of oxygen-rich subsurface waters, while its thickness is modulated by the amount of nitrate available to produce N2; and (3) the maxima of both bbp and N2 excess coincide at the same isopycnals where bacteria involved in N2 yielding coexist. We thus advance that bbp and O2 can be exploited as a combined proxy to delineate the N2-yielding section of the Black Sea. This proxy can potentially contribute to refining delineation of the effective N2-yielding section of oxygen-deficient zones via data from the growing BGC-Argo float network.

  • English
    Authors: 
    Thurstan, Ruth H.; Klein, Emily; Caswell, Bryony; Bennema, Floris; Ojaveer, Henn; Mackenzie, Brian; McClenachan, Loren; Hunt, Georgina; Engelhard, Georg; Mckenzie, Matthew; +11 more
    Publisher: HAL CCSD
    Country: France

    The ICES Working Group on the History of Fish and Fisheries (WGHIST) is a forum for interdisciplinary research on social-ecological change in marine and fisheries systems over multi-decadal to centennial timescales.WGHIST comprises a diverse group of researchers, including marine biologists, fisheries scientists, historians, and historical ecologists, from Europe and North America, as well as Australia, Russia, and South Africa. WGHIST provided a platform for the sharing and reporting of a wide range of research on marine and fisheries systems change over time, including the use of novel and non-traditional data sources and methodologies to identify and interpret these changes. WGHIST members also worked with the ICES Secretariat to forward digital tools to make historical resources more accessible and regarding WGHIST’s potential to support ICES Fisheries and Ecosystem Overviews.WGHIST engaged with the larger research community on the following manuscripts, still in development or recently submitted: (1) the acute value of the past in the Anthropocene; (2) the importance of and advice on cross-disciplinary conversations; (3) the legacy of Sidney Holt; (4) the power and consequence of qualitative information; and (5) the social and cultural drivers of technology creep.Finally, WGHIST found extensive evidence for defining elements of blue growth in the past, and explored examples from around the world to delineate lessons for today’s blue growth agendas, research now published in Fish and Fisheries. Future work will forward additional digital tools to access historical resources, develop links to other related data resources, and progress connections between lessons from the past and contemporary management and policy.

  • Open Access English
    Authors: 
    Lee, James E.; Brook, Edward J.; Bertler, Nancy A. N.; Buizert, Christo; Baisden, Troy; Blunier, Thomas; Ciobanu, V. Gabriela; Conway, Howard; Dahl-Jensen, Dorthe; Fudge, Tyler J.; +7 more
    Project: NSF | Collaborative Research: D... (0944307), NSF | Collaborative Research: D... (0944021), EC | ICE2ICE (610055), NSF | Roosevelt Island Climate ... (1042883), NSF | Collaborative Research: A... (0837883)

    In 2013, an ice core was recovered from Roosevelt Island in the Ross Sea, Antarctica, as part of the Roosevelt Island Climate Evolution (RICE) project. Roosevelt Island is located between two submarine troughs carved by paleo-ice-streams. The RICE ice core provides new important information about the past configuration of the West Antarctic Ice Sheet and its retreat during the most recent deglaciation. In this work, we present the RICE17 chronology and discuss preliminary observations from the new records of methane, the isotopic composition of atmospheric molecular oxygen (δ18O-Oatm), the isotopic composition of atmospheric molecular nitrogen (δ15N-N2) and total air content (TAC). RICE17 is a composite chronology combining annual layer interpretations, gas synchronization, and firn modeling strategies in different sections of the core. An automated matching algorithm is developed for synchronizing the high-resolution section of the RICE gas records (60–720 m, 1971 CE to 30 ka) to corresponding records from the WAIS Divide ice core, while deeper sections are manually matched. Ice age for the top 343 m (2635 yr BP, before 1950 C.E.) is derived from annual layer interpretations and described in the accompanying paper by Winstrup et al. (2017). For deeper sections, the RICE17 ice age scale is based on the gas age constraints and the ice age-gas age offset estimated by a firn densification model. Novel aspects of this work include: 1) stratigraphic matching of centennial-scale variations in methane for pre-anthropogenic time periods, a strategy which will be applicable for developing precise chronologies for future ice cores, 2) the observation of centennial-scale variability in methane throughout the Holocene which suggests that similar variations during the late preindustrial period need not be anthropogenic, and 3) the observation of continuous climate records dating back to ∼ 65 ka which provide evidence that the Roosevelt Island Ice Dome was a constant feature throughout the last glacial period.

  • Open Access English
    Authors: 
    Johansson, Sören; Höpfner, Michael; Kirner, Oliver; Wohltmann, Ingo; Bucci, Silvia; Legras, Bernard; Friedl-Vallon, Felix; Glatthor, Norbert; Kretschmer, Erik; Ungermann, Jörn; +1 more
    Project: EC | STRATOCLIM (603557)

    We present the first high-resolution measurements of pollutant trace gases in the Asian summer monsoon upper troposphere and lowermost stratosphere (UTLS) from the Gimballed Limb Observer for Radiance Imaging of the Atmosphere (GLORIA) during the StratoClim (Stratospheric and upper tropospheric processes for better climate predictions) campaign based in Kathmandu, Nepal, 2017. Measurements of peroxyacetyl nitrate (PAN), acetylene (C2H2), and formic acid (HCOOH) show strong local enhancements up to altitudes of 16 km. More than 500 pptv of PAN, more than 200 pptv of C2H2, and more than 200 pptv of HCOOH are observed. Air masses with increased volume mixing ratios of PAN and C2H2 at altitudes up to 18 km, reaching to the lowermost stratosphere, were present at these altitudes for more than 10 d, as indicated by trajectory analysis. A local minimum of HCOOH is correlated with a previously reported maximum of ammonia (NH3), which suggests different washout efficiencies of these species in the same air masses. A backward trajectory analysis based on the models Alfred Wegener InsTitute LAgrangian Chemistry/Transport System (ATLAS) and TRACZILLA, using advanced techniques for detection of convective events, and starting at geolocations of GLORIA measurements with enhanced pollution trace gas concentrations, has been performed. The analysis shows that convective events along trajectories leading to GLORIA measurements with enhanced pollutants are located close to regions where satellite measurements by the Ozone Monitoring Instrument (OMI) indicate enhanced tropospheric columns of nitrogen dioxide (NO2) in the days prior to the observation. A comparison to the global atmospheric models Copernicus Atmosphere Monitoring Service (CAMS) and ECHAM/MESSy Atmospheric Chemistry (EMAC) has been performed. It is shown that these models are able to reproduce large-scale structures of the pollution trace gas distributions for one part of the flight, while the other part of the flight reveals large discrepancies between models and measurement. These discrepancies possibly result from convective events that are not resolved or parameterized in the models, uncertainties in the emissions of source gases, and uncertainties in the rate constants of chemical reactions.

  • Open Access English
    Authors: 
    Rasse, Rafael; Claustre, Hervé; Poteau, Antoine;
    Project: EC | REMOCEAN (246777)

    Upper suboxic water masses confine a majority of the microbial communities that can produce up to 90 % of oceanic N2. This effective N2-yielding section encloses a suspended small-particle layer, inferred from particle backscattering (bbp) measurements. It is thus hypothesized that this layer (hereafter, the bbp-layer) is linked to N2-yielding microbial communities such as anammox and denitrifying bacteria – a hypothesis yet to be evaluated. Here, data collected by three BGC-Argo floats deployed in the Black Sea are used to investigate the origin of this bbp-layer. To this end, we evaluate how key drivers of anammox-denitrifying bacteria dynamics impact on the vertical distribution of bbp and the thickness of the bbp-layer. In conjunction with published data on N2 excess, our results suggest that the bbp-layer is at least partially composed of anammox-denitrifying bacteria for three main reasons: (1) strong correlations are recorded between bbp and nitrate; (2) the top location of the bbp-layer is driven by the ventilation of oxygen-rich subsurface waters, while its thickness is modulated by the amount of nitrate available to produce N2; (3) the maxima of both bbp and N2 excess coincide at the same isopycnals where denitrifying-anammox bacteria coexist. We thus advance that bbp and O2 can be exploited as a combined proxy to delineate the N2-yielding section of the Black Sea. This proxy can potentially contribute to refining delineation of the effective N2-yielding section of oxygen-deficient zones via data from the growing BGC-Argo float network.

Advanced search in Research products
Research products
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Searching FieldsTerms
Any field
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Include:
The following results are related to European Marine Science. Are you interested to view more results? Visit OpenAIRE - Explore.
90 Research products, page 1 of 9
  • Open Access English
    Authors: 
    Waelbroeck, Claire; Tjiputra, Jerry; Guo, Chuncheng; Nisancioglu, Kerim H.; Jansen, Eystein; Vazquez Riveiros, Natalia; Toucanne, Samuel; Eynaud, Frédérique; Rossignol, Linda; Dewilde, Fabien; +3 more
    Project: EC | ICE2ICE (610055), EC | ACCLIMATE (339108)

    We combine consistently dated benthic carbon isotopic records distributed over the entire Atlantic Ocean with numerical simulations performed by a glacial configuration of the Norwegian Earth System Model with active ocean biogeochemistry, in order to interpret the observed Cibicides δ13C changes at the stadial-interstadial transition corresponding to the end of Heinrich Stadial 4 (HS4) in terms of ocean circulation and remineralization changes. We show that the marked increase in Cibicides δ13C observed at the end of HS4 between ~2000 and 4200 m in the Atlantic can be explained by changes in nutrient concentrations as simulated by the model in response to the halting of freshwater input in the high latitude glacial North Atlantic. Our model results show that this Cibicides δ13C signal is associated with changes in the ratio of southern-sourced (SSW) versus northern-sourced (NSW) water masses at the core sites, whereby SSW is replaced by NSW as a consequence of the resumption of deep water formation in the northern North Atlantic and Nordic Seas after the freshwater input is halted. Our results further suggest that the contribution of ocean circulation changes to this signal increases from ~40 % at 2000 m to ~80 % at 4000 m. Below ~4200 m, the model shows little ocean circulation change but an increase in remineralization across the transition marking the end of HS4. The simulated lower remineralization during stadials than interstadials is particularly pronounced in deep subantarctic sites, in agreement with the decrease in the export production of carbon to the deep Southern Ocean during stadials found in previous studies.

  • French
    Authors: 
    Barré , Éric;
    Publisher: HAL CCSD
    Country: France

    n°90

  • Open Access English
    Authors: 
    TRAMOY, Romain; GASPERI, Johnny; COLASSE, Laurent; SILVESTRE, Marie; DUBOIS, Philippe; TASSIN, Bruno;
    Country: France

    Rivers are major pathways of plastics from lands into the Ocean. However, there is still a huge lack of knowledge on how riverine litter, including macroplastics, is transferred into the Ocean. Quantitative measurements of macroplastic emissions in rivers even suggest that a small fraction (0.001 to 3%) of the Mismanaged Plastic Waste (MPW) generated within a river basin finally reach the sea. Instead, macroplastics may remain within the catchment and on coastlines because of complex transport dynamics that delay the transfer of plastic debris. In order to better understand those dynamics, we performed tracking of riverine litter over time. First, hundreds of date-prints items were collected on riverbanks in the Seine estuary. The distribution of their Use-By-Dates suggest that riverine litter may remain stored on riverbanks for decades. Second, we performed real time tracking of floating and sub-floating bottles using GPS-trackers. Between March 2018 and April 2019, 39 trajectories were recorded in the estuary under tidal influence and 11 trajectories upriver, covering a wide range of hydrometeorological conditions. Results show a succession of stranding/remobilization episodes in combination with alternating upstream and downstream transport in the estuary related to tides. In the end, tracked bottles systematically stranded somewhere, for hours to weeks, from one to several times on different sites. The overall picture shows that different hydrometeorological phenomena interact with various time scales ranging from hours/days (high/low tides) to weeks/months (spring/neap tides and highest tides) and years (seasonal river flow, vegetation and geomorphological aspects). Thus, the fate of plastic debris is highly unpredictable with a chaotic-like transfer of plastic debris into the Ocean. The residence time of these debris is much longer than the transit time of water. This offers the opportunity to collect them before they get fragmented and/or reach the Sea.

  • Open Access English
    Authors: 
    Kiko, Rainer; Picheral, Marc; Antoine, David; Babin, Marcel; Berline, L; Biard, Tristan; Boss, Emmanuel; Brandt, Peter; Carlotti, F; Christiansen, Svenja; +32 more
    Publisher: PANGAEA - Data Publisher for Earth & Environmental Science
    Project: EC | TRIATLAS (817578), ANR | TAD (ANR-19-MPGA-0012)

    Particle size distribution data was collected during multiple cruises globally with several regularly intercalibrated Underwater Vision Profilers, Version 5 (UVP5; Picheral et al 2010). During the respective cruises, the UVP5 was mounted on the CTD-Rosette or as a standalone instrument and deployed in vertical mode. The UVP5 takes pictures of an illuminated watervolume of about 1 Liter every few milliseconds. Imaged items are counted, their size measured and abundance and biovolume of the particles is calculated. For different size bins, this information is summarized in the columns "Particle concentration" and "Particle biovolume". For further details please refer to Kiko et al. (in prep.) "A global marine particle size distribution dataset obtained with the Underwater Vision Profiler 5".

  • Open Access
    Authors: 
    GASPERI, Johnny; TRAMOY, Romain; DRIS, Rachid; BLOT, Denis; TASSIN, Bruno;
    Country: France

    Les rivières sont censées être les principales voies de transfert des plastiques des terres vers l'océan (Lebreton et al., 2017 ; Schmidt et al., 2017). Cependant, il existe encore un manque important de connaissances sur la façon dont les déchets fluviaux, y compris les macroplastiques, sont transférés vers l'Océan. Les mesures quantitatives des émissions de macroplastiques dans les rivières suggèrent même qu'une fraction de l'ordre de 0,001 à 3% des déchets plastiques mal gérés (MPW) générés dans un bassin fluvial atteignent finalement la mer (Emmerik et al., 2019 ; Schöneich-Argent et al., 2020 ; Tramoy et al. 2021). Au lieu de cela, les macroplastiques peuvent rester dans le bassin versant et sur les côtes en raison de la dynamique complexe du transport qui retarde le transfert des déchets mal gérés des terres vers l'océan (Olivelli et al., 2020 ; Weideman et al., 2020). Afin de mieux comprendre ces dynamiques, le laboratoire Eau et Environnement et le Laboratoire Eau Environnement et Systèmes Urbains étudient la dynamique des déchets en Seine et en Loire. Pour les macrodéchets plastiques, l'ensemble des travaux engagés sur la Seine permettent de dresser une première esquisse des flux de déchets plastiques transitant en Seine, captés par les dispositifs urbains et/ou collectés par des opérations de nettoyage. Selon nos estimations, entre 100 et 200 tonnes de déchets plastiques transiteraient chaque année en Seine. A l'échelle de l'agglomération parisienne, et bien que ces valeurs s'accompagnent de fortes incertitudes, les eaux pluviales n'apporteraient qu'une part mineure de ces flux, i.e., entre 8 et 33 tonnes par an. L'étude de la dynamique des débris plastiques montre que le transfert des plastiques est loin d'être linéaire et qu'il est soumis à de nombreux phénomènes physiques à de nombreuses échelles temporelles, i.e. d'échelles courtes allant de quelques heures à quelques jours (marées hautes / basses) à des échelles beaucoup plus longues allant de plusieurs semaines (marées de printemps / creuses et marées les plus hautes) à quelques années (crues). La conséquence de ces interactions est que le transfert des débris est chaotique et qu'une part importante de ces flux peut venir s'échouer sur les berges.

  • Open Access English
    Authors: 
    Rasse, Rafael; Claustre, Hervé; Poteau, Antoine;
    Project: EC | NOCEANIC (839062), EC | REMOCEAN (246777), EC | REFINE (834177)

    The shallower oxygen-poor water masses of the ocean confine a majority of the microbial communities that can produce up to 90 % of oceanic N2. This effective N2-yielding section encloses a suspended small-particle layer, inferred from particle backscattering (bbp) measurements. It is thus hypothesized that this layer (hereafter, the bbp-layer) is linked to microbial communities involved in N2 yielding such as nitrate-reducing SAR11 as well as sulfur-oxidizing, anammox, and denitrifying bacteria – a hypothesis yet to be evaluated. Here, data collected by three BGC-Argo floats deployed in the Black Sea are used to investigate the origin of this bbp-layer. To this end, we evaluate how the key drivers of N2-yielding bacteria dynamics impact the vertical distribution of bbp and the thickness of the bbp-layer. In conjunction with published data on N2 excess, our results suggest that the bbp-layer is at least partially composed of the bacteria driving N2 yielding for three main reasons: (1) strong correlations are recorded between bbp and nitrate; (2) the top location of the bbp-layer is driven by the ventilation of oxygen-rich subsurface waters, while its thickness is modulated by the amount of nitrate available to produce N2; and (3) the maxima of both bbp and N2 excess coincide at the same isopycnals where bacteria involved in N2 yielding coexist. We thus advance that bbp and O2 can be exploited as a combined proxy to delineate the N2-yielding section of the Black Sea. This proxy can potentially contribute to refining delineation of the effective N2-yielding section of oxygen-deficient zones via data from the growing BGC-Argo float network.

  • English
    Authors: 
    Thurstan, Ruth H.; Klein, Emily; Caswell, Bryony; Bennema, Floris; Ojaveer, Henn; Mackenzie, Brian; McClenachan, Loren; Hunt, Georgina; Engelhard, Georg; Mckenzie, Matthew; +11 more
    Publisher: HAL CCSD
    Country: France

    The ICES Working Group on the History of Fish and Fisheries (WGHIST) is a forum for interdisciplinary research on social-ecological change in marine and fisheries systems over multi-decadal to centennial timescales.WGHIST comprises a diverse group of researchers, including marine biologists, fisheries scientists, historians, and historical ecologists, from Europe and North America, as well as Australia, Russia, and South Africa. WGHIST provided a platform for the sharing and reporting of a wide range of research on marine and fisheries systems change over time, including the use of novel and non-traditional data sources and methodologies to identify and interpret these changes. WGHIST members also worked with the ICES Secretariat to forward digital tools to make historical resources more accessible and regarding WGHIST’s potential to support ICES Fisheries and Ecosystem Overviews.WGHIST engaged with the larger research community on the following manuscripts, still in development or recently submitted: (1) the acute value of the past in the Anthropocene; (2) the importance of and advice on cross-disciplinary conversations; (3) the legacy of Sidney Holt; (4) the power and consequence of qualitative information; and (5) the social and cultural drivers of technology creep.Finally, WGHIST found extensive evidence for defining elements of blue growth in the past, and explored examples from around the world to delineate lessons for today’s blue growth agendas, research now published in Fish and Fisheries. Future work will forward additional digital tools to access historical resources, develop links to other related data resources, and progress connections between lessons from the past and contemporary management and policy.

  • Open Access English
    Authors: 
    Lee, James E.; Brook, Edward J.; Bertler, Nancy A. N.; Buizert, Christo; Baisden, Troy; Blunier, Thomas; Ciobanu, V. Gabriela; Conway, Howard; Dahl-Jensen, Dorthe; Fudge, Tyler J.; +7 more
    Project: NSF | Collaborative Research: D... (0944307), NSF | Collaborative Research: D... (0944021), EC | ICE2ICE (610055), NSF | Roosevelt Island Climate ... (1042883), NSF | Collaborative Research: A... (0837883)

    In 2013, an ice core was recovered from Roosevelt Island in the Ross Sea, Antarctica, as part of the Roosevelt Island Climate Evolution (RICE) project. Roosevelt Island is located between two submarine troughs carved by paleo-ice-streams. The RICE ice core provides new important information about the past configuration of the West Antarctic Ice Sheet and its retreat during the most recent deglaciation. In this work, we present the RICE17 chronology and discuss preliminary observations from the new records of methane, the isotopic composition of atmospheric molecular oxygen (δ18O-Oatm), the isotopic composition of atmospheric molecular nitrogen (δ15N-N2) and total air content (TAC). RICE17 is a composite chronology combining annual layer interpretations, gas synchronization, and firn modeling strategies in different sections of the core. An automated matching algorithm is developed for synchronizing the high-resolution section of the RICE gas records (60–720 m, 1971 CE to 30 ka) to corresponding records from the WAIS Divide ice core, while deeper sections are manually matched. Ice age for the top 343 m (2635 yr BP, before 1950 C.E.) is derived from annual layer interpretations and described in the accompanying paper by Winstrup et al. (2017). For deeper sections, the RICE17 ice age scale is based on the gas age constraints and the ice age-gas age offset estimated by a firn densification model. Novel aspects of this work include: 1) stratigraphic matching of centennial-scale variations in methane for pre-anthropogenic time periods, a strategy which will be applicable for developing precise chronologies for future ice cores, 2) the observation of centennial-scale variability in methane throughout the Holocene which suggests that similar variations during the late preindustrial period need not be anthropogenic, and 3) the observation of continuous climate records dating back to ∼ 65 ka which provide evidence that the Roosevelt Island Ice Dome was a constant feature throughout the last glacial period.

  • Open Access English
    Authors: 
    Johansson, Sören; Höpfner, Michael; Kirner, Oliver; Wohltmann, Ingo; Bucci, Silvia; Legras, Bernard; Friedl-Vallon, Felix; Glatthor, Norbert; Kretschmer, Erik; Ungermann, Jörn; +1 more
    Project: EC | STRATOCLIM (603557)

    We present the first high-resolution measurements of pollutant trace gases in the Asian summer monsoon upper troposphere and lowermost stratosphere (UTLS) from the Gimballed Limb Observer for Radiance Imaging of the Atmosphere (GLORIA) during the StratoClim (Stratospheric and upper tropospheric processes for better climate predictions) campaign based in Kathmandu, Nepal, 2017. Measurements of peroxyacetyl nitrate (PAN), acetylene (C2H2), and formic acid (HCOOH) show strong local enhancements up to altitudes of 16 km. More than 500 pptv of PAN, more than 200 pptv of C2H2, and more than 200 pptv of HCOOH are observed. Air masses with increased volume mixing ratios of PAN and C2H2 at altitudes up to 18 km, reaching to the lowermost stratosphere, were present at these altitudes for more than 10 d, as indicated by trajectory analysis. A local minimum of HCOOH is correlated with a previously reported maximum of ammonia (NH3), which suggests different washout efficiencies of these species in the same air masses. A backward trajectory analysis based on the models Alfred Wegener InsTitute LAgrangian Chemistry/Transport System (ATLAS) and TRACZILLA, using advanced techniques for detection of convective events, and starting at geolocations of GLORIA measurements with enhanced pollution trace gas concentrations, has been performed. The analysis shows that convective events along trajectories leading to GLORIA measurements with enhanced pollutants are located close to regions where satellite measurements by the Ozone Monitoring Instrument (OMI) indicate enhanced tropospheric columns of nitrogen dioxide (NO2) in the days prior to the observation. A comparison to the global atmospheric models Copernicus Atmosphere Monitoring Service (CAMS) and ECHAM/MESSy Atmospheric Chemistry (EMAC) has been performed. It is shown that these models are able to reproduce large-scale structures of the pollution trace gas distributions for one part of the flight, while the other part of the flight reveals large discrepancies between models and measurement. These discrepancies possibly result from convective events that are not resolved or parameterized in the models, uncertainties in the emissions of source gases, and uncertainties in the rate constants of chemical reactions.

  • Open Access English
    Authors: 
    Rasse, Rafael; Claustre, Hervé; Poteau, Antoine;
    Project: EC | REMOCEAN (246777)

    Upper suboxic water masses confine a majority of the microbial communities that can produce up to 90 % of oceanic N2. This effective N2-yielding section encloses a suspended small-particle layer, inferred from particle backscattering (bbp) measurements. It is thus hypothesized that this layer (hereafter, the bbp-layer) is linked to N2-yielding microbial communities such as anammox and denitrifying bacteria – a hypothesis yet to be evaluated. Here, data collected by three BGC-Argo floats deployed in the Black Sea are used to investigate the origin of this bbp-layer. To this end, we evaluate how key drivers of anammox-denitrifying bacteria dynamics impact on the vertical distribution of bbp and the thickness of the bbp-layer. In conjunction with published data on N2 excess, our results suggest that the bbp-layer is at least partially composed of anammox-denitrifying bacteria for three main reasons: (1) strong correlations are recorded between bbp and nitrate; (2) the top location of the bbp-layer is driven by the ventilation of oxygen-rich subsurface waters, while its thickness is modulated by the amount of nitrate available to produce N2; (3) the maxima of both bbp and N2 excess coincide at the same isopycnals where denitrifying-anammox bacteria coexist. We thus advance that bbp and O2 can be exploited as a combined proxy to delineate the N2-yielding section of the Black Sea. This proxy can potentially contribute to refining delineation of the effective N2-yielding section of oxygen-deficient zones via data from the growing BGC-Argo float network.