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See detailCarbon dioxide dynamics in rivers and coastal waters of the ABig Island@ of Hawaii, USA, during baseline and heavy rain condition
Paquay, F. S.; Mackenzie, F. T.; Borges, Alberto ULg

in Aquatic Geochemistry (2007), 13(1), 1-18

The distributions of the partial pressure of carbon dioxide (pCO2) and total alkalinity (TA) were examined for a 6-month period in the Wailuku and Wailoa rivers and coastal waters of Hilo Bay on the west ... [more ▼]

The distributions of the partial pressure of carbon dioxide (pCO2) and total alkalinity (TA) were examined for a 6-month period in the Wailuku and Wailoa rivers and coastal waters of Hilo Bay on the west coast of the Island of Hawaii, USA. Main results for the largest and turbulent Wailuku River show in the watershed an oversaturation in CO2 with respect to atmospheric equilibrium and a CO2 undersaturation in the estuary. In the Wailoa river-estuary system, extremely high pCO2 values ranging from 1500 to 10500 ppm were measured with significant shifts in pCO2 from drought to flood period. In the two rivers, water residence time, groundwater inputs and occasional flood events are the predominant drivers of the spatial and temporal patterns in the distribution of pCO2. In Hilo Bay, CO2 oversaturation dominates and the bay was a source of CO2 to the atmosphere during the study period. TA is conservative along the salinity gradient, indicating calcification in the bay is not a significant source of CO2 to the atmosphere. [less ▲]

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See detailCarbon dioxide dynamics in the tropical Ebrié lagoon (Ivory Coast)
Koné, Y. J. M.; Delille, Bruno ULg; Borges, Alberto ULg

Poster (2007)

Detailed reference viewed: 11 (1 ULg)
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See detailCarbon Dioxide Emission from European Estuaries
Frankignoulle, Michel; Abril, Gwenaël; Borges, Alberto ULg et al

in Science (1998), 282(5388), 434-6

The partial pressure of carbon dioxide (pCO2) in surface waters and related atmospheric exchanges were measured in nine European estuaries. Averaged fluxes over the entire estuaries are usually in the ... [more ▼]

The partial pressure of carbon dioxide (pCO2) in surface waters and related atmospheric exchanges were measured in nine European estuaries. Averaged fluxes over the entire estuaries are usually in the range of 0.1 to 0.5 mole of CO2 per square meter per day. For wide estuaries, net daily fluxes to the atmosphere amount to several hundred tons of carbon (up to 790 tons of carbon per day in the Scheldt estuary). European estuaries emit between 30 and 60 million tons of carbon per year to the atmosphere, representing 5 to 10% of present anthropogenic CO2 emissions for Western Europe. [less ▲]

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See detailCarbon dioxide fluxes from a degraded Woodland in West Arica and their responses to main environmental factors
Ago, Expédit Evariste ULg; Serça, Dominique; Agbossou, Euloge Kossi et al

in Carbon Balance and Management (2015), 10

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See detailCarbon dioxide fluxes in Lake Kivu
Borges, Alberto ULg; Delille, Bruno ULg; Descy, Jean-Pierre et al

Conference (2007, June 12)

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See detailCarbon dioxide in cave air and soil air in some karstic areas of Belgium
Ek, Camille ULg

in Geologica Belgica (2014)

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See detailCarbon dioxide in cave atmospheres. New results in Belgium and comparison with some other countries.
Ek, Camille ULg; Gewelt, Michel

in Earth Surface Processes & Landforms (1985), 10

More than 600 measurements of the carbon dioxide content of cave air in Belgium lead up to the conclusion that the main factors of its distribution are: (1) a flow originating from the biomass and ... [more ▼]

More than 600 measurements of the carbon dioxide content of cave air in Belgium lead up to the conclusion that the main factors of its distribution are: (1) a flow originating from the biomass and diffusing in the soil and the voids of bedrock; (2) a trend, discernible in very still air only, to go down by density; (3) in some caves, draughts caused, for instance, by a swift underground stream. Results in Belgium are compared with published and unpublished data from other countries, showing that CO2 is often less abundant in cold climate caves and in caves of semi-arid regions (influence of the biomass). Special attention is paid to human contamination during analyses: the influence of people passing through the cave nearby the operator, but also the influence of the operator himself, are discussed, and the use of special precautions (including a CO2-absorbing mask) in defined critical situations is stressed. [less ▲]

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See detailCarbon dioxide in cave atmospheres: new results in Belgium and comparison with some other countries
Ek, Camille ULg; Gewelt, Michel

in Earth Surface Processes & Landforms (1985), 10

More than 600 measurements of carbon dioxide in cave air in Belgium lead to the conclusion that the main factors of its distribution are: (1) a flow originating from the biomass and diffusing in the soil ... [more ▼]

More than 600 measurements of carbon dioxide in cave air in Belgium lead to the conclusion that the main factors of its distribution are: (1) a flow originating from the biomass and diffusing in the soil and the voids of bedrock; (2) a trend to go down by density; (3) in some caves, draughts caused, for instance, by a swift underground stream. Results in Belgium are compared to other countries. l'usage d'un masque absorbant le CO2Special attention is paid to human contamination and the use of a CO2-absorbing mask in defined situations is stressed. [less ▲]

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See detailCarbon dioxide in European coastal waters
Borges, Alberto ULg; Schiettecatte, L. S.; Abril, Gwenaël et al

in Estuarine Coastal & Shelf Science (2006), 70(3), 375-387

We compiled from literature annually integrated air-water fluxes of carbon dioxide (CO2) computed from field measurements, in 20 coastal European environments that were gathered into 3 main ecosystems ... [more ▼]

We compiled from literature annually integrated air-water fluxes of carbon dioxide (CO2) computed from field measurements, in 20 coastal European environments that were gathered into 3 main ecosystems: inner estuaries, upwelling continental shelves and non-upwelling continental shelves. The comparison of annual cycles of the partial pressure of CO2 (pCO(2)) in 5 contrasting continental shelves provided insights into the biogeochemical drivers of the CO2 fluxes. The latter were also investigated by comparing CO2 fluxes to net ecosystem (NEP) and net community production (NCP) in 3 contrasted coastal ecosystems. Air-water CO2 fluxes were scaled at European regional level and compared to fluxes of atmospheric CO2 in other aquatic and terrestrial compartments. Continental shelves are significant sinks for atmospheric CO2 at an average rate of -1.9 molC m(-2) yr(-1) that scaled at European level corresponds to an absorption of atmospheric CO2 of -68.1 TgC yr(-1). This sink is equivalent to the one reported for the terrestrial biosphere of -66.1 TgC yr(-1), based on carbon-stock change models. Estuaries are significant sources of CO2 to the atmosphere at an average rate of 49.9 molC m(-2) yr(-1) that is higher than the CO2 emission to the atmosphere from rivers, streams and lakes. The scaled emission of CO2 to the atmosphere from inner estuaries of about 67.0 TgC yr(-1) would almost fully balance the sink of atmospheric CO2 computed for continental shelves. However, the scaled emission of CO2 from estuaries to the atmosphere is inconsistent with the potential emission of CO2 based on the fate of river organic carbon during estuarine transit. This discrepancy is most probably due to the poorly constrained surface area estimate of inner estuaries. (c) 2006 Elsevier Ltd. All rights reserved. [less ▲]

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See detailCarbon dioxide in European coastal waters
Borges, Alberto ULg; Schiettecatte, L.-S.; Abril, G. et al

Poster (2007, March)

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See detailCarbon dioxide in European coastal waters
Borges, Alberto ULg; Schiettecatte, L.-S.; Abril, G. et al

Poster (2006)

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See detailCarbon dioxide in European coastal waters
Borges, Alberto ULg; Schiettecatte, L.-S.; Abril, G. et al

Poster (2007)

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See detailCarbon dioxide of the air of shallow caves in mountainous areas
Ek, Camille ULg

in International Symposium on the Problems of Karst Study in Mountainous Countries (1987)

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See detailCarbon dioxide transfer at the ice-sea and air-ice interfaces: a step towards the end of a long-lived paradigm ?
Delille, Bruno ULg; Trevena, A.; Lannuzel, D. et al

Poster (2004, March 05)

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See detailCarbon dioxide, a cheap bio-sourced building block for cyclic carbonates and non-isocyanate polyurethanes
Gennen, Sandro ULg; Alves, Margot ULg; Tassaing, Thierry et al

Poster (2015, May 03)

Due to concerns about global warming combined with the decrease of fossil resources, new carbon feedstocks that are abundant, renewable, non-toxic, inexpensive and environmentally friendly must be ... [more ▼]

Due to concerns about global warming combined with the decrease of fossil resources, new carbon feedstocks that are abundant, renewable, non-toxic, inexpensive and environmentally friendly must be explored to produce chemicals. Besides the valorization of bio-based raw materials, the chemical transformation of carbon dioxide into added-value products has gained interest in both academia and industry. To date, the chemical fixation of CO2 onto epoxides with the formation of cyclic carbonates is one of the most promising ways to valorize CO2 at an industrial scale. Indeed, cyclic carbonates find applications as electrolytes in lithium ion batteries, as aprotic polar solvents or as useful intermediates for polycarbonates. Cyclic carbonates also react with primary amines to produce 2-hydroxyethylurethane. This reaction can be extrapolated to the synthesis of non-isocyanate polyurethanes (NIPU) by polyaddition of bifunctional cyclic carbonates with diamines.5 This study aims (i) at developing a new highly efficient organocatalyst for the synthesis of cyclic carbonates under mild experimental conditions and (ii) their valorization as monomers to produce non-isocyanate polyurethanes. First, we have identified a bicomponent organocatalyst, composed of a judicious combination of an organocatalyst and an activator, for the very fast synthesis of cyclic carbonates from CO2 and epoxides under very mild reaction conditions. Kinetics of reactions were followed by online Raman spectroscopy measurements under pressure. NMR titrations were realized to evidence the mechanism of activation of this novel organocatalytic system that will be discussed in detail in this talk. The second objective relies on the development of new efficient organocatalysts for the synthesis of high molar masses NIPUs in short reaction times. Organic compounds interacting with the cyclic carbonate by hydrogen bonding were identified and their catalytic activity was demonstrated for model compounds. [less ▲]

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See detailCarbon dynamics and CO2 air-sea exchanges in the eutrophicated coastal waters of the Southern Bight of the North Sea: a modelling study
Gypens, N.; Lancelot, Christiane; Borges, Alberto ULg

in Biogeosciences (2004), 1(2), 147-157

A description of the carbonate system has been incorporated in the MIRO biogeochemical model to investigate the contribution of diatom and Phaeocystis blooms to the seasonal dynamics of air-sea CO2 ... [more ▼]

A description of the carbonate system has been incorporated in the MIRO biogeochemical model to investigate the contribution of diatom and Phaeocystis blooms to the seasonal dynamics of air-sea CO2 exchanges in the Eastern Channel and Southern Bight of the North Sea, with focus on the eutrophied Belgian coastal waters. For this application, the model was implemented in a simplified three-box representation of the hydrodynamics with the open ocean boundary box ‘Western English Channel’ (WCH) and the ‘French Coastal Zone’ (FCZ) and ‘Belgian Coastal Zone’ (BCZ) boxes receiving carbon and nutrients from the rivers Seine and Scheldt, respectively. Results were obtained by running the model for the 1996–1999 period. The simulated partial pressures of CO2 (pCO2) were successfully compared with data recorded over the same period in the central BCZ at station 330 (51 26.050 N; 002 48.500 E). Budget calculations based on model simulations of carbon flow rates indicated for BCZ a low annual sink of atmospheric CO2 (−0.17 mol C m−2 y−1). On the opposite, surface water pCO2 in WCH was estimated to be at annual equilibrium with respect to atmospheric CO2. The relative contribution of biological, chemical and physical processes to the modelled seasonal variability of pCO2 in BCZ was further explored by running model scenarios with separate closures of biological activities and/or river inputs of carbon. The suppression of biological processes reversed direction of the CO2 flux in BCZ that became, on an annual scale, a significant source for atmospheric CO2 (+0.53mol C m−2 y−1). Overall biological activity had a stronger influence on the modelled seasonal cycle of pCO2 than temperature. Especially Phaeocystis colonies which growth in spring were associated with an important sink of atmospheric CO2 that counteracted the temperature-driven increase of pCO2 at this period of the year. However, river inputs of organic and inorganic carbon were shown to increase the surface water pCO2 and hence the emission of CO2 to the atmosphere. Same calculations conducted in WCH, showed that temperature was the main factor controlling the seasonal pCO2 cycle in these open ocean waters. The effect of interannual variations of fresh water discharge (and related nutrient and carbon inputs), temperature and wind speed was further explored by running scenarios with forcing typical of two contrasted years (1996 and 1999). Based on these simulations, the model predicts significant variations in the intensity and direction of the annual air-sea CO2 flux. [less ▲]

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See detailCarbon dynamics in the highly eutrophicated Belgian Coastal Zone
Gypens, N.; Borges, Alberto ULg

in Current status of eutrophication in the Belgian coastal zone (2008)

Detailed reference viewed: 21 (0 ULg)
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See detailCarbon exchange in a Belgian grassland with cattle
Jerome, Elisabeth ULg; Beckers, Yves ULg; Bodson, Bernard ULg et al

Poster (2011, April 08)

Detailed reference viewed: 79 (21 ULg)
See detailCarbon fluxes and cycling in African Rivers
Bouillon, Steven; Tamooh, Frederick; Marwick, Trent et al

Conference (2010, October 04)

Detailed reference viewed: 18 (1 ULg)