References of "Lancelot, C"
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See detailThe dimethylsulfide cycle in the eutrophied Southern North Sea: a model study integrating phytoplankton and bacterial processes
Gypens, N; Borges, Alberto ULiege; Speeckaert, G et al

Conference (2014)

We developed a module describing the dimethylsulfoniopropionate (DMSP) and dimethylsulfide (DMS) dynamics, including biological transformations by phytoplankton and bacteria, and physico-chemical ... [more ▼]

We developed a module describing the dimethylsulfoniopropionate (DMSP) and dimethylsulfide (DMS) dynamics, including biological transformations by phytoplankton and bacteria, and physico-chemical processes (including DMS air-sea exchange). This module was integrated in the MIRO ecological model and applied in a 0D frame in the Southern North Sea (SNS). The DMS(P) module is built on parameterizations derived from available knowledge on DMS(P) sources, transformations and sinks, and provides an explicit representation of bacterial activity in contrast to most of existing models that only include phytoplankton process (and abiotic transformations). The model is tested in a highly productive coastal ecosystem (the Belgian coastal zone, BCZ) dominated by diatoms and the Haptophyceae Phaeocystis, respectively low and high DMSP producers. On an annual basis, the particulate DMSP (DMSPp) production simulated in 1989 is mainly related to Phaeocystis colonies (78%) rather than diatoms (13%) and nanoflagellates (9%). Accordingly, sensitivity analysis shows that the model responds more to changes in the sulfur:carbon (S:C) quota and lyase yield of Phaeocystis. DMS originates equally from phytoplankton and bacterial DMSP-lyase activity and only 3% of the DMS is emitted to the atmosphere. Model analysis demonstrates the sensitivity of DMS emission towards the atmosphere to the description and parameterization of biological processes emphasizing the need of adequately representing in models both phytoplankton and bacterial processes affecting DMS(P) dynamics. This is particularly important in eutrophied coastal environments such as the SNS dominated by high non-diatom blooms and where empirical models developed from data-sets biased towards open ocean conditions do not satisfactorily predict the timing and amplitude of the DMS seasonal cycle. In order to predict future feedbacks of DMS emissions on climate, it is needed to account for hotspots of DMS emissions from coastal environments that, if eutrophied, are dominated not only by diatoms. [less ▲]

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See detailSouthern Ocean CO2 sink: The contribution of the sea ice
Delille, Bruno ULiege; Vancoppenolle, M; Geilfus, N.-X. et al

in Journal of Geophysical Research. Oceans (2014), 119

We report first direct measurements of the partial pressure of CO2 (pCO2) within Antarctic pack sea ice brines and related CO2 fluxes across the air-ice interface. From late winter to summer, brines ... [more ▼]

We report first direct measurements of the partial pressure of CO2 (pCO2) within Antarctic pack sea ice brines and related CO2 fluxes across the air-ice interface. From late winter to summer, brines encased in the ice change from a CO2 large over-saturation, relative to the atmosphere, to a marked under-saturation while the underlying oceanic waters remains slightly oversaturated. The decrease from winter to summer of pCO2 in the brines is driven by dilution with melting ice, dissolution of carbonate minerals crystals and net primary production. As the ice warms, its permeability increases, allowing CO2 transfer at the air-sea ice interface. The sea ice changes from a transient source to a sink for atmospheric CO2. We upscale these observations to the whole Antarctic sea-icesea ice cover using the NEMO-LIM3 large-scale sea ice-ocean, and provide first estimates of spring and summer CO2 uptake from the atmosphere by Antarctic sea ice. Over the spring-summer period, the Antarctic sea-icesea ice cover is a net sink of atmospheric CO2 of 0.029 PgC, about 58% of the estimated annual uptake from the Southern Ocean. Sea ice then contributes significantly to the sink of CO2 of the Southern Ocean. [less ▲]

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See detailThe Dimethylsulfide Cycle in the Eutrophied Southern North Sea: A Model Study Integrating Phytoplankton and Bacterial Processes
Gypens, N; Borges, Alberto ULiege; Speeckaert, Gaëlle ULiege et al

in PLoS ONE (2014), 9(1)(e85862 DOI: 10.1371/journal.pone.0085862),

We developed a module describing the dimethylsulfoniopropionate (DMSP) and dimethylsulfide (DMS) dynamics, including biological transformations by phytoplankton and bacteria, and physico-chemical ... [more ▼]

We developed a module describing the dimethylsulfoniopropionate (DMSP) and dimethylsulfide (DMS) dynamics, including biological transformations by phytoplankton and bacteria, and physico-chemical processes (including DMS air-sea exchange). This module was integrated in the MIRO ecological model and applied in a 0D frame in the Southern North Sea (SNS). The DMS(P) module is built on parameterizations derived from available knowledge on DMS(P) sources, transformations and sinks, and provides an explicit representation of bacterial activity in contrast to most of existing models that only include phytoplankton process (and abiotic transformations). The model is tested in a highly productive coastal ecosystem (the Belgian coastal zone, BCZ) dominated by diatoms and the Haptophyceae Phaeocystis, respectively low and high DMSP producers. On an annual basis, the particulate DMSP (DMSPp) production simulated in 1989 is mainly related to Phaeocystis colonies (78%) rather than diatoms (13%) and nanoflagellates (9%). Accordingly, sensitivity analysis shows that the model responds more to changes in the sulfur:carbon (S:C) quota and lyase yield of Phaeocystis. DMS originates equally from phytoplankton and bacterial DMSP-lyase activity and only 3% of the DMS is emitted to the atmosphere. Model analysis demonstrates the sensitivity of DMS emission towards the atmosphere to the description and parameterization of biological processes emphasizing the need of adequately representing in models both phytoplankton and bacterial processes affecting DMS(P) dynamics. This is particularly important in eutrophied coastal environments such as the SNS dominated by high non-diatom blooms and where empirical models developed from data-sets biased towards open ocean conditions do not satisfactorily predict the timing and amplitude of the DMS seasonal cycle. In order to predict future feedbacks of DMS emissions on climate, it is needed to account for hotspots of DMS emissions from coastal environments that, if eutrophied, are dominated not only by diatoms. [less ▲]

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See detailModelling phytoplankton succession and nutrient transfer along the Scheldt estuary (Belgium, The Netherlands)
Gypens, N.; Delhez, Eric ULiege; Vanhoutte-Brunier, A. et al

in Journal of Marine Systems (2013), 128

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See detailFrom a source to a sink: the role of biological activities on atmospheric CO2 exchange along the river-ocean continuum
Gypens, N; Passy, P; Lancelot, C et al

Poster (2013, April 07)

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See detailHistorical changes in carbon dioxide (CO2) and dimethyl sulphide (DMS) emissions in the eutrophied Southern North Sea
Gypens, N.; Borges, Alberto ULiege; Lancelot, C.

Conference (2012, April 22)

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See detailOptical remote sensing of marine and inland waters “BELCOLOUR-2” (SR/00/104). Final Report.
Ruddick, K.; Astoreca, R; Borges, Alberto ULiege et al

Report (2012)

This report describes the research carried out in the framework of the BELCOLOUR-2 project, funded as a thematic network by the Belgian Science Policy Office (BELSPO) STEREO programme over the period ... [more ▼]

This report describes the research carried out in the framework of the BELCOLOUR-2 project, funded as a thematic network by the Belgian Science Policy Office (BELSPO) STEREO programme over the period December 2006-December 2011. The general objective of the BELCOLOUR-2 project was “to improve the quality of existing optical remote sensing products for marine and inland waters based on new knowledge and to develop new products (including primary production and partial pressure of CO2) for key applications such as aquaculture and air-sea CO2 fluxes.” BELCOLOUR-2 benefited from the experience built up in the previous BELCOLOUR-1 project (2002-6) whose results can be found at http:www.mumm.ac.be/BELCOLOUR. [less ▲]

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See detailSeasonal and inter-annual variability of air-sea CO2 fluxes and seawater carbonate chemistry in the Southern North Sea
Gypens, N.; Lacroix, G.; Lancelot, C. et al

Poster (2011, April 08)

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See detailSeasonal and inter-annual variability of air-sea CO2 fluxes and seawater carbonate chemistry in the Southern North Sea
Gypens, N.; Lacroix, G.; Lancelot, C. et al

in Progress in Oceanography (2011), 88(1-4), 59-77

A 3D coupled biogeochemical–hydrodynamic model (MIRO-CO2&CO) is implemented in the English Channel (ECH) and the Southern Bight of the North Sea (SBNS) to estimate the present-day spatio-temporal ... [more ▼]

A 3D coupled biogeochemical–hydrodynamic model (MIRO-CO2&CO) is implemented in the English Channel (ECH) and the Southern Bight of the North Sea (SBNS) to estimate the present-day spatio-temporal distribution of air–sea CO2 fluxes, surface water partial pressure of CO2 (pCO2) and other components of the carbonate system (pH, saturation state of calcite (Xca) and of aragonite (Xar)), and the main drivers of their variability. Over the 1994–2004 period, air–sea CO2 fluxes show significant interannual variability, with oscillations between net annual CO2 sinks and sources. The inter annual variability of air–sea CO2 fluxes simulated in the SBNS is controlled primarily by river loads and changes of biological activities (net autotrophy in spring and early summer, and net heterotrophy in winter and autumn), while in areas less influenced by river inputs such as the ECH, the inter annual variations of air–sea CO2 fluxes are mainly due to changes in sea surface temperature and in near-surface wind strength and direction. In the ECH, the decrease of pH, of Xca and of Xar follows the one expected from the increase of atmospheric CO2 (ocean acidification), but the decrease of these quantities in the SBNS during the considered time period is faster than the one expected from ocean acidification alone. This seems to be related to a general pattern of decreasing nutrient river loads and net ecosystem production (NEP) in the SBNS. Annually, the combined effect of carbon and nutrient loads leads to an increase of the sink of CO2 in the ECH and the SBNS, but the impact of the river loads varies spatially and is stronger in river plumes and nearshore waters than in offshore waters. The impact of organic and inorganic carbon (C) inputs is mainly confined to the coast and generates a source of CO2 to the atmosphere and low pH, of Xca and of Xar values in estuarine plumes, while the impact of nutrient loads, highest than the effect of C inputs in coastal nearshore waters, also propagates offshore and, by stimulating primary production, drives a sink of atmospheric CO2 and higher values of pH, of Xca and of Xar. [less ▲]

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See detailIntegrated study of southern ocean biogeochemistry and climate interactions in the Anthropocene “BELCANTO III”. Final Report
Dehairs, F; Cavagna, AJ; Jacquet, S et al

Report (2011)

The overall objective of the BELCANTO III project was to conduct targeted process studies and develop new proxies to construct and validate a realistic 3D ice-ocean biogeochemical model for the area south ... [more ▼]

The overall objective of the BELCANTO III project was to conduct targeted process studies and develop new proxies to construct and validate a realistic 3D ice-ocean biogeochemical model for the area south of latitude 30°S, based on improved understanding of the different factors regulating interactions between the atmosphere, ocean circulation and biogeochemical cycles and on synthesis/collection of existing/new data sets. The specific objectives were: - to improve our understanding about the iron cycling, with focus on the significance of iron-organic matter interactions for iron bioavailability and the efficiency of the biological pump (WP1) - to quantify nutrient consumption, CO2 uptake and C-export by assessing seasonality and interannuality of nutrient (Si, N) uptake; reconstruct carbon uptake and export from the surface layer via a multi-proxy approach; provide a relevant data set for 3D-NEMO-SWAMCO model validation (WP2) - to characterise the biogenic particles exported from the surface to the twilight zone and study their fate by quantifying remineralisation rates (WP3) - to model biogeochemical cycles in the modern Southern Ocean including seaice biogeochemistry (WP4) - to estimate impact of future climate change in the Southern Ocean through process-studies and modelling approaches (WP5). [less ▲]

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See detailOverview of CO2 dynamics within sea ice
Delille, Bruno ULiege; Geilfus, Nicolas-Xavier ULiege; Vancoppenolle, M. et al

Conference (2011)

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See detailModeling present-day spatial and seasonal variability of carbon dioxide in surface waters of the Southern Bight of the North Sea
Gypens; Borges, Alberto ULiege; Lancelot, C et al

Conference (2009)

The 3D ecological MIRO&CO-CO2 model is used to describe the spatial and seasonal variations of air-sea CO2 exchanges in the English Channel and the Southern Bight of the North Sea receiving important ... [more ▼]

The 3D ecological MIRO&CO-CO2 model is used to describe the spatial and seasonal variations of air-sea CO2 exchanges in the English Channel and the Southern Bight of the North Sea receiving important nutrient and carbon river loads. Runs are performed for years 2003 and 2004 using actual sea water temperature, light, wind speed and river forcings. MIRO&CO-CO2 simulations show large spatial and seasonal variations of surface pCO2 (range 100 - 600 ppm). Significant under- (and over-) saturation are simulated in spring (and summer) due to the dominance of auto- (and heterotrophic) activities. The highest pCO2 values are simulated in the vicinity of river mouths. Similarly, the computed annual air-sea CO2 fluxes varies spatially, predicting sources of CO2 to the atmosphere near estuaries but moderate sinks (or neutral) in offshore waters. Sensitivity studies are further performed to estimate the contribution of organic and inorganic carbon and nutrient river loads on the air-sea CO2 flux simulated in the area. [less ▲]

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See detailEffect of eutrophication on air-sea CO2 fluxes in the coastal Southern North Sea: a model study of the past 50 years
Gypens, N.; Borges, Alberto ULiege; Lancelot, C.

in Global Change Biology (2009), 15(4), 1040-1056

The RIVERSTRAHLER model, an idealized biogeochemical model of the river system, has been coupled to MIRO-CO2, a complex biogeochemical model describing diatom and Phaeocystis blooms and carbon and ... [more ▼]

The RIVERSTRAHLER model, an idealized biogeochemical model of the river system, has been coupled to MIRO-CO2, a complex biogeochemical model describing diatom and Phaeocystis blooms and carbon and nutrient cycles in the marine domain, to assess the dual role of changing nutrient loads and increasing atmospheric CO2 as drivers of air–sea CO2 exchanges in the Southern North Sea with a focus on the Belgian coastal zone (BCZ). The whole area, submitted to the influence of two main rivers (Seine and Scheldt), is characterized by variable diatom and Phaeocystis colonies blooms which impact on the trophic status and air–sea CO2 fluxes of the coastal ecosystem. For this application, the MIRO-CO2 model is implemented in a 0D multibox frame covering the eutrophied Eastern English Channel and Southern North Sea and receiving loads from the rivers Seine and Scheldt. Model simulations are performed for the period between 1951 and 1998 using real forcing fields for sea surface temperature, wind speed and atmospheric CO2 and RIVERSTRAHLER simulations for river carbon and nutrient loads. Model results suggest that the BCZ shifted from a source of CO2 before 1970 (low eutrophication) towards a sink during the 1970–1990 period when anthropogenic DIN and P loads increased, stimulating C fixation by autotrophs. In agreement, a shift from net annual heterotrophy towards autotrophy in BCZ is simulated from 1980. The period after 1990 is characterized by a progressive decrease of P loads concomitant with a decrease of primary production and of the CO2 sink in the BCZ. At the end of the simulation period, the BCZ ecosystem is again net heterotroph and acts as a source of CO2 to the atmosphere. R-MIRO-CO2 scenarios testing the relative impact of temperature, wind speed, atmospheric CO2 and river loads variability on the simulated air–sea CO2 fluxes suggest that the trend in air–sea CO2 fluxes simulated between 1951 and 1998 in the BCZ was mainly controlled by the magnitude and the ratio of inorganic nutrient river loads. Quantitative nutrient changes control the level of primary production while qualitative changes modulate the relative contribution of diatoms and Phaeocystis to this flux and hence the sequestration of atmospheric CO2. [less ▲]

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See detailEstuarine controls on the coastal ocean sink of CO2: a reactive-transport modelling study
Gypens, N.; Arndt, S; Borges, Alberto ULiege et al

Poster (2008)

Coastal areas receiving carbon and nutrient inputs from land play a significant role in the global carbon cycle. Previous budget calculations show that both the magnitude and the direction of the air ... [more ▼]

Coastal areas receiving carbon and nutrient inputs from land play a significant role in the global carbon cycle. Previous budget calculations show that both the magnitude and the direction of the air-water CO2 fluxes in these areas are largely controlled by riverine nutrient and carbon loads. Before reaching the coastal sea, terrestrial nutrients and carbon (in organic and inorganic forms) are profoundly modified in the estuary changing the amount and form of carbon and nutrient delivered to the adjacent coastal zone. These transformation processes rely on the physical characteristics of the estuary and the anthropogenic loads. In order to investigate the effect of the estuarine biogeochemical filter, a two-dimensional, nested-grid hydrodynamic and reactive-transport model was developed to determine the quantitative significance of the Scheldt estuary on the fluxes of carbon to Belgian coastal waters. Seasonal evolution of the main biogeochemical components of the ecosystem was described by coupling the MIRO model and a description of the carbonate system within this reactive-transport model. Model simulations were carried out along the continuum of the Scheldt river, estuary and the Belgian coastal zone and validated with pCO2 data at different stations along the river- coastal continuum. Sensitivity tests are then used to investigate how inner estuarine processes and resulting fluxes to the sea may alter the trapping efficiency of CO2 in the Belgian coastal zone. [less ▲]

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See detailA model study of the evolution over the past 50 years of air-sea CO2 fluxes in the Belgian coastal zone (Southern Bight of the North Sea)
Gypens, N; Borges, Alberto ULiege; Lancelot, C

Poster (2008)

The coupled river-coastal sea model RIVERSTRAHLER-MIRO-CO2 (R-MIROCO2) is used to appraise how nutrient loads and increased atmospheric CO2 are affecting contemporary air-sea CO2 exchanges in the Belgian ... [more ▼]

The coupled river-coastal sea model RIVERSTRAHLER-MIRO-CO2 (R-MIROCO2) is used to appraise how nutrient loads and increased atmospheric CO2 are affecting contemporary air-sea CO2 exchanges in the Belgian coastal zone (BCZ) (Southern Bight of the North Sea). R-MIRO-CO2 results of the offline coupling between RIVERSTRAHLER C, N, P and Si river loads to the coastal zone constrained by meteorological conditions and human activity on the watershed and the MIRO-CO2 model of C, N, P, Si cycles in the coastal sea. For this application, the marine MIROCO2 model is implemented in a 0D multi-box frame covering the eutrophied Eastern English Channel and Southern North Sea and receiving loads by the river Seine and Scheldt. Model simulations are performed for the period between 1951 and 1998 using real forcing fields for sea surface temperature, wind speed and atmospheric CO2 and RIVERSTRAHLER simulations for river C and nutrient loads. Model simulations suggest that the BCZ shifted from a source of CO2 before 1970 (low eutrophication) towards a sink during the 1970-1990 period when anthropogenic N and P loads increased. The period after 1990 is characterized by a progressive decrease of P loads concomitant with a decrease of the CO2 sink. At the end of the simulation period, the area acts again as a source for atmospheric CO2. Additional simulations investigating the relative impact of temperature, wind speed, atmospheric CO2 and river loads variability (compared to 1951) on the simulated air-sea CO2 fluxes point these latter as drivers of the magnitude and the direction of the air-sea CO2 fluxes in the BCZ. [less ▲]

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See detailCO2 dynamics and related air-ice-sea gas transfer in spring pack and land fast sea ice
Delille, Bruno ULiege; Schoemann, V.; Lannuzel, D. et al

Poster (2007, March)

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See detailCarbon dioxide dynamics in Antarctic pack ice and related air-ice CO2 fluxes
Delille, Bruno ULiege; Trevena, A.; Schoemann, V. et al

Conference (2005, May)

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