Publications of Marilaure Grégoire
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See detailMultidisciplinary Observing in the World Ocean’s Oxygen Minimum Zone regions: from climate to fish- the VOICE initiative
Garçon, Véronique; Karstensen, Johannes; Palacz, Artur et al

in Frontiers in Marine Science (2020)

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See detailThe chlorophyll seasonal dynamics in the Black Sea as inferred from Biogeochemical-Argo floats
Ricour, Florian ULiege; Capet, Arthur ULiege; Delille, Bruno ULiege et al

Poster (2019, April)

Biogeochemical-Argo (BGC-Argo) floats offer the opportunity to investigate the spatial and temporal dynamics of chlorophyll a (Chla) profiles. In the Black Sea, the unusual abundance of colored dissolved ... [more ▼]

Biogeochemical-Argo (BGC-Argo) floats offer the opportunity to investigate the spatial and temporal dynamics of chlorophyll a (Chla) profiles. In the Black Sea, the unusual abundance of colored dissolved organic matter (CDOM) and the absence of oxygen below ∼80-100m require a revision of the classic formulation used to link the fluorescence signal and the algal chlorophyll concentration (e.g. Xing et al., 2017). Indeed, the very high content of CDOM in the basin is thought to be responsible for the apparent increase of Chla concentrations at depth, where it should be zero due to the absence of light. Here, the classic formulation to link fluorescence and Chla is revised based on a reference Chla dataset sampled during a scientific cruise onboard RV Akademik and analysed with High Performance Liquid Chromatography (HPLC). Then, using the established equation to remove the contribution of CDOM to the fluorescence signal, we estimated the Chla profiles from 4 BGC-Argo floats during the period 2014-2017. All Chla profiles were thus highly quality controlled by using the Argo documentation (Schmechtig et al., 2015). Especially, we removed bad data (e.g. spikes, outliers) and we corrected the Non-Photochemical Quenching effect, a photoprotective mechanism resulting in a decrease in the fluorescence signal at the surface. The Chla profiles are categorized based on fitting algorithms (e.g. sigmoid, exponential, gaussian) and empirical criteria. They display a large variety of shapes across the seasons (e.g. homogeneity in the mixed layer, subsurface maximum, double peaks below the surface, etc.) with roughly homogeneous profiles dominating between November and February while subsurface maxima are present during the rest of the year, with in summer a clearly-marked deep chlorophyll maximum (DCM). We then investigate the formation mechanism of DCMs based on the hysteresis hypothesis for the temperate ocean proposed by Navarro et al., (2013). For this, we looked at the correlation between the position of DCMs and the potential density anomaly of the mixed layer when it is maximum in winter, usually between February and March. We show that DCMs are highly correlated with the potential density anomaly of the previous winter mixed layer where a winter bloom initiated while the correlation with the 10% and 1% light levels is poor. This is in agreement with the hysteresis hypothesis that assumes that in regions where a bloom forms in late winter/early spring, this bloom remains established at a fixed density (i.e. the density of the mixed layer when it is maximum) until the end of summer acting as a barrier for the diffusion of nutrients from below and preventing the occurrence of deeper blooms due to a shading effect. This bloom is finally progressively eroded in autumn, when the depth of the mixed layer increases again. [less ▲]

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See detailOxygen
Garçon, Véronique; Grégoire, Marilaure ULiege; Isensee, Kirsten et al

in Encyclopedia of Ocean Sciences 3rd Edition (2019)

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See detailWhat is ocean deoxygenation?
Grégoire, Marilaure ULiege; Gilbert, Denis; Oschlies, Andreas et al

in Baxter, John; Lafolley, Daniel (Eds.) Ocean deoxygenation: everyone’s problem. Causes, impacts, consequences and solutions (2019)

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See detailAdvancing marine biogeochemical and ecosystem reanalyses and forecasts as tools for monitoring and managing ecosystem health
Fennel, K.; Gehlen, M.; Brasseur, P. et al

in Frontiers in Marine Science (2019), 6(MAR),

Ocean ecosystems are subject to a multitude of stressors, including changes in ocean physics and biogeochemistry, and direct anthropogenic influences. Implementation of protective and adaptive measures ... [more ▼]

Ocean ecosystems are subject to a multitude of stressors, including changes in ocean physics and biogeochemistry, and direct anthropogenic influences. Implementation of protective and adaptive measures for ocean ecosystems requires a combination of ocean observations with analysis and prediction tools. These can guide assessments of the current state of ocean ecosystems, elucidate ongoing trends and shifts, and anticipate impacts of climate change and management policies. Analysis and prediction tools are defined here as ocean circulation models that are coupled to biogeochemical or ecological models. The range of potential applications for these systems is broad, ranging from reanalyses for the assessment of past and current states, and short-term and seasonal forecasts, to scenario simulations including climate change projections. The objectives of this article are to illustrate current capabilities with regard to the three types of applications, and to discuss the challenges and opportunities. Representative examples of global and regional systems are described with particular emphasis on those in operational or pre-operational use. With regard to the benefits and challenges, similar considerations apply to biogeochemical and ecological prediction systems as do to physical systems. However, at present there are at least two major differences: (1) biogeochemical observation streams are much sparser than physical streams presenting a significant hinderance, and (2) biogeochemical and ecological models are largely unconstrained because of insufficient observations. Expansion of biogeochemical and ecological observation systems will allow for significant advances in the development and application of analysis and prediction tools for ocean biogeochemistry and ecosystems, with multiple societal benefits. © 2019 Fennel, Gehlen, Brasseur, Brown, Ciavatta, Cossarini, Crise, Edwards, Ford, Friedrichs, Gregoire, Jones, Kim, Lamouroux, Murtugudde, Perruche and the GODAE OceanView Marine Ecosystem Analysis and Prediction Task Team. [less ▲]

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See detailBlack Sea observing System
Palazov, Atanas; Ciliberti, S; Peneva, E et al

in Frontiers in Marine Science (2019)

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See detailFrom observation to information and users: The Copernicus Marine Service Perspective
Le Traon, P. Y.; Reppucci, A.; Fanjul, E. A. et al

in Frontiers in Marine Science (2019), 6(May),

The Copernicus Marine Environment Monitoring Service (CMEMS) provides regular and systematic reference information on the physical and biogeochemical ocean and sea-ice state for the global ocean and the ... [more ▼]

The Copernicus Marine Environment Monitoring Service (CMEMS) provides regular and systematic reference information on the physical and biogeochemical ocean and sea-ice state for the global ocean and the European regional seas. CMEMS serves a wide range of users (more than 15,000 users are now registered to the service) and applications. Observations are a fundamental pillar of the CMEMS value-added chain that goes from observation to information and users. Observations are used by CMEMS Thematic Assembly Centres (TACs) to derive high-level data products and by CMEMS Monitoring and Forecasting Centres (MFCs) to validate and constrain their global and regional ocean analysis and forecasting systems. This paper presents an overview of CMEMS, its evolution, and how the value of in situ and satellite observations is increased through the generation of high-level products ready to be used by downstream applications and services. The complementary nature of satellite and in situ observations is highlighted. Long-term perspectives for the development of CMEMS are described and implications for the evolution of the in situ and satellite observing systems are outlined. Results from Observing System Evaluations (OSEs) and Observing System Simulation Experiments (OSSEs) illustrate the high dependencies of CMEMS systems on observations. Finally future CMEMS requirements for both satellite and in situ observations are detailed. © 2019 Le Traon, Reppucci, Alvarez Fanjul, Aouf, Behrens, Belmonte, Bentamy, Bertino, Brando, Kreiner, Benkiran, Carval, Ciliberti, Claustre, Clementi, Coppini, Cossarini, De Alfonso Alonso-Muñoyerro, Delamarche, Dibarboure, Dinessen, Drevillon, Drillet, Faugere, Fernández, Fleming, Garcia-Hermosa, Sotillo, Garric, Gasparin, Giordan, Gehlen, Gregoire, Guinehut, Hamon, Harris, Hernandez, Hinkler, Hoyer, Karvonen, Kay, King, Lavergne, Lemieux-Dudon, Lima, Mao, Martin, Masina, Melet, Buongiorno Nardelli, Nolan, Pascual, Pistoia, Palazov, Piolle, Pujol, Pequignet, Peneva, Pérez Gómez, Petit de la Villeon, Pinardi, Pisano, Pouliquen, Reid, Remy, Santoleri, Siddorn, She, Staneva, Stoffelen, Tonani, Vandenbulcke, von Schuckmann, Volpe, Wettre and Zacharioudaki. [less ▲]

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See detail3.6 Decline of the Black Sea oxygen inventory. In: Copernicus Marine Service Ocean State Report, Issue 2
Capet, Arthur ULiege; Vandenbulcke, Luc ULiege; Veselka, Marinova et al

in Journal of Operational Oceanography (2018), 11(sup1),

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See detailGlobal Ocean Oxygen Network 2018. The ocean is losing its breath: Declining oxygen in the world’s ocean and coastal waters.
Breitburg, Denise; Grégoire, Marilaure ULiege; Isensee, Kirsten et al

in IOC-UNESCO, IOC Technical Series, (2018), 137

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See detailModelling the hydrodynamics of the Southern Bight of the North Sea: Skills assessment of different configurations (i.e. nesting) in the perspective of coupling with sediment transport
Ivanov, Evgeny ULiege; Capet, Arthur ULiege; Barth, Alexander ULiege et al

Poster (2018, May)

The impact of offshore wind farm installation and dredging activities on the spatial distribution and dynamics of sediment grain size, biogeochemistry and biodiversity will be estimated in the Southern ... [more ▼]

The impact of offshore wind farm installation and dredging activities on the spatial distribution and dynamics of sediment grain size, biogeochemistry and biodiversity will be estimated in the Southern Bight of the North Sea (SBNS) with a focus on the Belgian Coastal Zone (BCZ) in the frame of the FaCE-It research project (Functional biodiversity in a Changing sedimentary Environment: Implications for biogeochemistry and food webs in a managerial setting). The three-dimensional hydrodynamical model ROMS-COAWST was implemented for simulation of the complex hydrodynamics of SBNS and sediment transport. The first level of nesting with the resolution of 1 km was used in the area of Belgian Economical Zone. In order to reach a fine resolution of 250 m in the BCZ, the second level of nesting will be used. Six-hourly ECMWF ERA-interim meteorological data was used to force the model at the sea-air boundary and the coarse resolution model results available from Copernicus Marine Environment Monitoring Service were used to force the model at the open boundaries. Tides and rivers were also considered. Next types of long-run simulations have been conducted: a 10-years climatological simulation and an interannual simulation over 2004-2013 in order to investigate the interannual dynamics. The model accuracy was evaluated through validation of its outputs against observed salinity, temperature and currents data (remote sensing and in-situ). Results validation of currents and temperature and salinity horizontal fields and vertical profiles against available satellite fields and in-situ data, i.e. from the project field campaign, is conducted and discussed. Application of the nested grid and its benefits for results accuracy is also presented. [less ▲]

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See detailHydrodynamic and sediment transport modelling in the North Sea. Assessment of wind farms impact
Ivanov, Evgeny ULiege; Capet, Arthur ULiege; Barth, Alexander ULiege et al

Scientific conference (2018, April 26)

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See detailGlobal Warming altered the Black Sea ventilation regime
Capet, Arthur ULiege; Vandenbulcke, Luc ULiege; Grégoire, Marilaure ULiege

Conference (2018, April)

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See detailApplication of two way nesting model to upscale sediment processes of the Southern Bight of the North Sea: full model validation
Ivanov, Evgeny ULiege; Capet, Arthur ULiege; Barth, Alexander ULiege et al

Poster (2018, March)

The BRAIN project FaCE-iT (Functional biodiversity in a Changing sedimentary Environment: Implications for biogeochemistry and food webs in a managerial setting) funded by BELSPO aims at evaluating the ... [more ▼]

The BRAIN project FaCE-iT (Functional biodiversity in a Changing sedimentary Environment: Implications for biogeochemistry and food webs in a managerial setting) funded by BELSPO aims at evaluating the influence of offshore wind farms settlements and dredging activities on the distribution of sediment grain size over the Southern Bight of the North Sea (SBNS) and the Belgian Coastal Zone (BCZ), as well as associated impacts on biodiversity and biogeochemistry.In this framework an implementation of the tri-dimensional hydrodynamical and sediment transport model ROMS-COAWST was set-up to conduct scenario experiment relating offshore activities to resulting alteration of the seafloor structure. This implementation combines high resolution nested grids covering the Belgian Coastal Zone, embedded into a coarser grid covering the Southern Bight of the North Sea and is forced by ECMWF ERA-Interim data at the air-sea interface, CMEMS data at the open boundaries, TPXO data to introduce/force the tidal impact, and consider the discharge of four main rivers. Currently, the work focuses on assessing the skills of this modelling system to resolve the dynamics of the complex shallow and highly tidal region. The 3-year climatological run for 2006-2009 was performed to test the model ability to simulate the interannual dynamics. The model skills were evaluated by validation against remote-sensing temperature fields, tidal elevations and currents at the Meetnet pylons, and in situ temperature and salinity data provided by the Lifewatch network. We evaluate how grid refinement and different set-up of the nesting strategy enhance essential model skills in relation with sediment transport The further step will be to confront the sediment transport dynamics stemming from the nested system to that resolved from the coarser parent alone. A diagenetic model developed in the frame of FaCE-iT will be joint with the sediment model in order to upscale locally derived alteration of the biogeochemistry and benthic functionality stemming from seafloor texture alteration. [less ▲]

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See detailDeclining oxygen in the global ocean and coastal waters
Breitburg, Denise; Levin, Lisa; Oschlies, Andreas et al

in Science (2018), 359(46),

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See detailEvolution of the Black Sea ventilation regime during the last decades
Capet, Arthur ULiege; Vandenbulcke, Luc ULiege; Grégoire, Marilaure ULiege

in Ocean Deoxygenation : Drivers and Consequences, Past, Present, Future, Kiel, Sept 2018 (2018)

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See detailThe Ocean is lossing its breath: declining oxygen in the global and coastal ocean
Breitburg, Denise; Grégoire, Marilaure ULiege; Isensee, Kirsten

Book published by IOC-Unesco (2018)

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See detailThree-dimensional modelling of the hydrodynamics of the Southern Bight of the North Sea: first results
Ivanov, Evgeny ULiege; Capet, Arthur ULiege; Barth, Alexander ULiege et al

Poster (2017, April 28)

In the frame of the Belgian research project FaCE-It (Functional biodiversity in a Changing sedimentary Environment: Implications for biogeochemistry and food webs in a managerial setting), the impact of ... [more ▼]

In the frame of the Belgian research project FaCE-It (Functional biodiversity in a Changing sedimentary Environment: Implications for biogeochemistry and food webs in a managerial setting), the impact of dredging activities andoffshorewindfarminstallationonthespatialdistributionofsedimentgrainsize,biodiversityandbiogeochemistry will be estimated in the Southern Bight of the North Sea (SBNS) with a focus on the Belgian Coastal Zone (BCZ). To reach this goal, the three-dimensional hydrodynamical model ROMS-COAWST is implemented in the SBNS in order to simulate the complex hydrodynamics and sediment transport. Two levels of nesting are used to reach a resolutionof250mintheBCZ.Themodelisforcedattheair-seainterfacebythe6-hourlyECMWFERA-interim atmospheric dataset and at the open boundaries by the coarse resolution model results available from CMEMS (Copernicus Marine Environment Monitoring Service), and also considers tides and 4 main rivers (Scheldt, Rhine with Maas, Thames and Seine). Two types of simulations have been performed: a 10-years climatological simulation and a simulation over 20032013toinvestigatetheinterannualdynamics.Themodelskillsareevaluatedbycomparingitsoutputstohistorical data (e.g. salinity, temperature and currents) from remote sensing and in-situ. The sediment transport module will then be implemented and its outputs compared to historical and newly collected (in the frame of FaCE-iT) observations on grain size distribution as well as with satellite Suspended Particulate Matter (SPM) images. This will allow assessing the impact of substrate modification due to offshore human activities at local and regional scales. [less ▲]

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