References of "Capet, Arthur"
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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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See detailBenthic contributions to Adriatic and Mediterranean biogeochemical cycles
Capet, Arthur ULiege; Lazzari, Paolo; Spagnoli, Federico et al

in European Geosciences Union (Ed.) EGU General Assembly 2017 (2017, April)

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See detailBenthic hypoxia and early diagenesis in the Black Sea shelf sediments
Plante, Audrey ULiege; Roevros, Nathalie; Capet, Arthur ULiege et al

Poster (2017, April)

Marine waters of semi-enclosed seas are affected by a major environmental issue which is oxygen depletion in bottom waters. Deoxygenation is one of the most widespread man-induced consequences which can ... [more ▼]

Marine waters of semi-enclosed seas are affected by a major environmental issue which is oxygen depletion in bottom waters. Deoxygenation is one of the most widespread man-induced consequences which can be catastrophic for living species. Between 1970 and 1990, the benthic compartment of the Black Sea underwent modifications due to the occurrence and increase of hypoxia. Indeed, these changes might cause a deterioration of the structure and functioning of the ecosystems. Nowadays, some regions, such as the north-western shelf, are still affected seasonally by this phenomenon.Within the framework of the BENTHOX project, a biogeochemical study focusing on the early diagenesis is conducted in the Black Sea. It aims (1) to obtain a better understanding of the impact of benthic hypoxia on the diagenetic pathways, (2) to contribute to a new dataset of biogeochemical measurements in the sediments including porewaters. During a cruise (Emblas II – May 2016), on board the RV Mare Nigrum, sediment cores were taken at 4 stations on the Ukrainian shelf. Porewaters were extracted on board the ship using Rhizon technique under N2 atmosphere and will be analyzed for dissolved nutrients and major ions. In addition, sediments were sliced and will be determined for major solid phases and trace element contents. A multi-proxies (biological, sedimentological, mineralogical and geochemical) approach will be used to identify the hypoxic events and to reconstruct the history of bottom hypoxia. The results obtained will be presented and discussed with emphasis on the first outcomes and the major biogeochemical processes involved in the early diagenesis. [less ▲]

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

Poster (2017, March 03)

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 detailA Multiplatform Experiment to Unravel Meso- and Submesoscale Processes in an Intense Front (AlborEx)
Pascual, Ananda; Ruiz, Simon; Olita, Antonio et al

in Frontiers in Marine Science (2017)

The challenges associated with meso- and submesoscale variability (between 1 and 100 km) require high-resolution observations and integrated approaches. Here we describe a major oceanographic experiment ... [more ▼]

The challenges associated with meso- and submesoscale variability (between 1 and 100 km) require high-resolution observations and integrated approaches. Here we describe a major oceanographic experiment designed to capture the intense but transient vertical motions in an area characterized by strong fronts. Finescale processes were studied in the eastern Alboran Sea (Western Mediterranean) about 400 km east of the Strait of Gibraltar, a relatively sparsely sampled area. In-situ systems were coordinated with satellite data and numerical simulations to provide a full description of the physical and biogeochemical variability. Hydrographic data confirmed the presence of an intense salinity front formed by the confluence of Atlantic Waters, entering from Gibraltar, with the local Mediterranean waters. The drifters coherently followed the northeastern limb of an anticyclonic gyre. Near real time data from acoustic current meter data profiler showed consistent patterns with currents of up to 1 m/s in the southern part of the sampled domain. High-resolution glider data revealed submesoscale structures with tongues of chlorophyll-a and oxygen associated with the frontal zone. Numerical results show large vertical excursions of tracers that could explain the subducted tongues and filaments captured by ocean gliders. A unique aspect of AlborEx is the combination of high-resolution synoptic measurements of vessel-based measurements, autonomous sampling, remote sensing and modeling, enabling the evaluation of the underlying mechanisms responsible for the observed distributions and biogeochemical patchiness. The main findings point to the importance of fine-scale processes enhancing the vertical exchanges between the upper ocean and the ocean interior. [less ▲]

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See detailFrontal dynamics boost primary production in the summer stratified Mediterranean sea
Olita, Antonio; Capet, Arthur ULiege; Claret, Mariona et al

in Ocean Dynamics (2017), 67(6), 767-782

BSTRACT: Bio-physical glider measurements from a unique process-oriented experiment in the Eastern Alboran Sea (AlborEx) allowed us to observe the distribution of the deep chlorophyll maximum (DCM) across ... [more ▼]

BSTRACT: Bio-physical glider measurements from a unique process-oriented experiment in the Eastern Alboran Sea (AlborEx) allowed us to observe the distribution of the deep chlorophyll maximum (DCM) across an intense density front, with a resolution (∼ 400 m) suitable for investigating sub-mesoscale dynamics. This front, at the interface between Atlantic and Mediterranean waters, had a sharp density gradient (Δρ ∼ 1 kg/m3 in ∼ 10 km) and showed imprints of (sub-)mesoscale phenomena on tracer distributions. Specifically, the chlorophyll-a concentration within the DCM showed a disrupted pattern along isopycnal surfaces, with patches bearing a relationship to the stratification (buoyancy frequency) at depths between 30 and 60 m. In order to estimate the primary production (PP) rate within the chlorophyll patches observed at the sub-surface, we applied the Morel and Andrè (J Geophys Res 96:685–698 1991) bio-optical model using the photosynthetic active radiation (PAR) from Argo profiles collected simultaneously with glider data. The highest production was located concurrently with domed isopycnals on the fresh side of the front, suggestive that (sub-)mesoscale upwelling is carrying phytoplankton patches from less to more illuminated levels, with a contemporaneous delivering of nutrients. Integrated estimations of PP (1.3 g C m−2d−1) along the glider path are two to four times larger than the estimations obtained from satellite-based algorithms, i.e., derived from the 8-day composite fields extracted over the glider trip path. Despite the differences in spatial and temporal sampling between instruments, the differences in PP estimations are mainly due to the inability of the satellite to measure DCM patches responsible for the high production. The deepest (depth > 60 m) chlorophyll patches are almost unproductive and probably transported passively (subducted) from upper productive layers. Finally, the relationship between primary production and oxygen is also investigated. The logarithm of the primary production in the DCM interior (chlorophyll (Chl) > 0.5 mg/m3) shows a linear negative relationship with the apparent oxygen utilization, confirming that high chlorophyll patches are productive. The slope of this relationship is different for Atlantic, mixed interface waters and Mediterranean waters, suggesting the presence of differences in planktonic communities (whether physiological, population, or community level should be object of further investigation) on the different sides of the front. In addition, the ratio of optical backscatter to Chl is high within the intermediate (mixed) waters, which is suggestive of large phytoplankton cells, and lower within the core of the Atlantic and Mediterranean waters. These observations highlight the relevance of fronts in triggering primary production at DCM level and shaping the characteristic patchiness of the pelagic domain. This gains further relevance considering the inadequacy of optical satellite sensors to observe DCM concentrations at such fine scales. [less ▲]

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See detailContribution of mesoscale eddies to Black Sea ventilation
Capet, Arthur ULiege; Mason, Evan; Pascual, Ananda et al

Poster (2017)

The shoaling of the Black Sea oxycline is one of the most urgent environmental issues in the Black Sea. The permanent oxycline derives directly from the Black Sea permanent stratification and has shoaled ... [more ▼]

The shoaling of the Black Sea oxycline is one of the most urgent environmental issues in the Black Sea. The permanent oxycline derives directly from the Black Sea permanent stratification and has shoaled alarmingly in the last decades, due to a shifting balance between oxygen consumption and ventilation processes (Capet et al. 2016). The understanding of this balance is thus of the utmost importance and requires to quantify 1) the export of nutrients and organic materials from the shelf regions to the open sea and 2) the ventilation processes. These two rocesses being influenced by mesoscale features, it is critical to understand the role of the semi-permanent mesoscale structures in horizontal (center/periphery) and vertical (diapycnal and isopycnal) exchanges. A useful insight can be obtained by merging observations from satellite altimeter and in situ profilers (ARGO). In such composite analyses, eddies are first automatically identified and tracked from altimeter data (Mason et al. 2014, py-eddy-tracker). Vertical ARGO profiles are then expressed in terms of their position relative to eddy centers and radii. Derived statistics indicate how consistently mesoscale eddies alter the vertical structure, and provide a deeper understanding of the associated horizontal and vertical fluxes. However, this data-based approach is limited in the Black Sea due to the lower quality of gridded altimetric products in the vicinity of the coast, where semi-permanent mesoscale structures prevail. To complement the difficult analysis of this sparse dataset, a compositing methodology. is also applied to model outputs from the 5km GHER-BHAMBI Black Sea implementation (CMEMS BS-MFC). Characteristic biogeochemical anomalies associated with eddies in the model are analyzed per se, and compared to the observation-based analysis. Capet, A., Stanev, E. V., Beckers, J.-M., Murray, J. W., and Grégoire, M.: Decline of the Black Sea oxygen inventory, Biogeosciences, 13, 1287-1297, doi:10.5194/bg-13-1287-2016, 2016. Mason, Evan, Ananda Pascual, and James C. McWilliams. "A new sea surface height–based code for oceanic mesoscale eddy tracking." Journal of Atmospheric and Oceanic Technology 31.5 (2014): 1181-1188. [less ▲]

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See detailDeveloping a hydrodynamical model of the Southern Bight of the North Sea for impact studies
Ivanov, Evgeny ULiege; Capet, Arthur ULiege; Barth, Alexander ULiege et al

Poster (2016, November 08)

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

In the frame of the Brain FaCE-It project (Functional biodiversity in a Changing sedimentary Environment: Implications for biogeochemistry and food webs in a managerial setting), the impact of fining and hardening resulting from dredging and wind farms installation on the sediment grain size distribution has to be assessed at the scale of the Southern Bight of the North Sea (SBNS) with a particular focus on the Belgian Coastal Zone (BCZ). With this aim, the ROMS-COAWST tri-dimensional (3D) hydrodynamic model is implemented to simulate the hydrodynamics in the SBNS. At its open boundaries with the Atlantic Ocean and the North Sea, the model is forced with the results of a coarse resolution model available from Mercator. A high resolution of 250 m is used in the area of the BCZ where the accuracy of model predictions needs to be refined. Model currents, tides, temperature and salinity fields will be described and first validation exercises with satellite and local data will be presented and discussed in regards with the objectives of FaCE-It. In a next step, the model will be coupled with a sediment transport in order to describe the dynamics of suspended particulate materials (SPM) and the distribution of the seafloor sediment grain size. When finalized the hydrodynamic model will be coupled with a diagenetic model and will provide environmental conditions for scaling up local foodweb studies that are performed in the frame of FaCE-iT. The final aim is to assess the impact of substrate modifications due to aggregate extraction and wind farms on the biogeochemistry, benthic functionality and food webs at local (around the wind farm) and regional scales (SBNS). [less ▲]

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See detailThe BFM benthic module
Capet, Arthur ULiege; Lazzari, Paolo; Solidoro, Cosimo

Scientific conference (2016, October)

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See detailPotential for Composite Analysis in the Black Sea
Capet, Arthur ULiege; Mason, Evan; Troupin, Charles et al

Conference (2016, October)

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See detailOperational forecasting of the Black sea: merging model simulations and satellite products
Vandenbulcke, Luc ULiege; Capet, Arthur ULiege; Ivanov, Evgeny ULiege et al

Scientific conference (2016, September 29)

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See detailDINEOF analyses of Sea Surface Temperature data in the Black Sea
Alvera Azcarate, Aida ULiege; Vandenbulcke, Luc ULiege; Barth, Alexander ULiege et al

Scientific conference (2016, September 29)

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See detailDecline of the Black Sea Oxygen Inventory
Capet, Arthur ULiege; Stanev, Emil; Beckers, Jean-Marie ULiege et al

Poster (2016, September)

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See detailImpact of vertical and horizontal advection on nutrient distribution in the southeast Pacific
Barceló-Llull, Barbara; Mason, Evan; Capet, Arthur ULiege et al

in Ocean Science (2016), 12(4), 1003-1011

An innovative approach is used to analyze the impact of vertical velocities associated with quasi-geostrophic (QG) dynamics on the redistribution and uptake of nitrate in the southeast Pacific (SEP). A ... [more ▼]

An innovative approach is used to analyze the impact of vertical velocities associated with quasi-geostrophic (QG) dynamics on the redistribution and uptake of nitrate in the southeast Pacific (SEP). A total of 12 years of vertical and horizontal currents are derived from an observation based estimate of the ocean state. Horizontal velocities are obtained through the application of thermal wind balance to weekly temperature and salinity fields. Vertical velocities are estimated by integration of the QG omega equation. Seasonal variability of the synthetic vertical velocity and kinetic energy associated with the horizontal currents is coincident, with peaks in austral summer (November–December) in accord with published observations. The impact of vertical velocity on SEP nitrate uptake rates is assessed by using two Lagrangian particle tracking experiments that differ according to vertical forcing (ω = ωQG vs. ω = 0). From identical initial distributions of nitrate-tagged particles, the Lagrangian results show that vertical motions induce local increases in nitrate uptake reaching up to 30 %. Such increases occur in low uptake regions with high mesoscale activity. Despite being weaker than horizontal currents by a factor of up to 10−4, vertical velocity associated with mesoscale activity is demonstrated to make an important contribution to nitrate uptake, hence productivity, in low uptake regions. [less ▲]

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See detailBio-irrigation in simple diagenetic models: A study in the northwestern Adriatic
Capet, Arthur ULiege; Soetaert, Karline; De Vittor, Cinzia et al

Poster (2016, April)

In the process of setting up a benthic-pelagic coupled model for the northern adriatic Sea, the OMEXDIA model has been used to analyze through model calibration, pore-water profiles and in-situ flux data ... [more ▼]

In the process of setting up a benthic-pelagic coupled model for the northern adriatic Sea, the OMEXDIA model has been used to analyze through model calibration, pore-water profiles and in-situ flux data in that area. Both enhanced biodiffusive and non-local exchange formalisms were tested to represent the impact on bioirrigation on pore water solute profiles and benthic fluxes. Bayesian calibration procedure revealed that only the non-local exchange formalism allows to render simultaneously the pore water solutes profiles and fluxes at the sediment water interface when inorganic carbon, oxygen, nitrate, ammonium and phosphate dy- namics are considered jointly. While the enhanced-biodiffusive formalism is convenient to compare diffusive and total benthic fluxes of a single vari- able (derived from solutes profiles and incubation chambers respectively), it is not suited for multivariate modelling purposes. We evidence that the impact of bioirrigation on benthic-pelagic coupling strongly differ accord- ing the the chosen formalism, in particular in terms of the N:P ratio of remineralised fluxes. [less ▲]

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See detailThe two faces of Black Sea deoxygenation
Capet, Arthur ULiege; Stanev, Emil; Beckers, Jean-Marie ULiege et al

Conference (2016, February)

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See detailIntegrating sediment biogeochemistry into 3D oceanic models: A study of benthic-pelagic coupling in the Black Sea
Capet, Arthur ULiege; Meysman, Filip; Akoumianaki, Ioanna et al

in Ocean Modelling (2016), 101

Three-dimensional (3D) ecosystem models of shelf environments should properly account for the biogeochemical cycling within the sea floor. However, a full and explicit representation of sediment ... [more ▼]

Three-dimensional (3D) ecosystem models of shelf environments should properly account for the biogeochemical cycling within the sea floor. However, a full and explicit representation of sediment biogeochemistry into 3D ocean models is computationally demanding. Here, we describe a simplified approach to include benthic processes in 3D ocean models, which includes a parameterization of the different pathways for organic matter mineralization and allows for organic matter remobilization by bottom currents and waves. This efficient approach enables decadal simulations that resolve the inertial contribution of the sea floor to the biogeochemical cycling in shelf environments. The model was implemented to analyze the benthic-pelagic coupling in the northwestern shelf of the Black Sea. Three distinct biogeochemical provinces were identified on the basis of fluxes and rates associated with benthic-pelagic coupling. Our model simulations suitably capture the seasonal variability of in situ flux data as well as their regional variation, which stresses the importance of incorporating temporally varying sediment biogeochemistry and resuspension/redeposition cycles in shelf ecosystem models. [less ▲]

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See detailDecline of the Black Sea oxygen inventory
Capet, Arthur ULiege; Stanev, Emil; Beckers, Jean-Marie ULiege et al

in Biogeosciences (2016), 13

Detailed reference viewed: 54 (11 ULiège)