References of "Borges, Alberto"
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See detailThe ecology of Lake Kivu: a puzzle solved?
Darchambeau, François ULg; Sarmento, Hugo; Isumbisho, Mwapu et al

Conference (2010, January 14)

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See detailOceanic CO2 sink: the contribution of the marine cryosphere
Delille, Bruno ULg; Vancoppenolle, M.; Tilbrook, B. et al

Conference (2010)

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See detailEvaluation of sinks and sources of CO2 in the global coastal ocean using a spatially-explicit typology of estuaries and continental shelves
Laruelle, Goulven G; Durr, Hans H; Slomp, Caroline P et al

in Geophysical Research Letters (2010), 37

The exchange of CO2 between the atmosphere and the global coastal ocean was evaluated from a compilation of air-water CO2 fluxes scaled using a spatially-explicit global typology of inner estuaries ... [more ▼]

The exchange of CO2 between the atmosphere and the global coastal ocean was evaluated from a compilation of air-water CO2 fluxes scaled using a spatially-explicit global typology of inner estuaries (excluding outer estuaries such as large river deltas) and continental shelves. The computed emission of CO2 to the atmosphere from estuaries (+0.27 +/- 0.23 PgC yr(-1)) is similar to 26% to similar to 55% lower than previous estimates while the sink of atmospheric CO2 over continental shelf seas (-0.21 +/- 0.36 PgC yr(-1)) is at the low end of the range of previous estimates (-0.22 to -1.00 PgC yr(-1)). The air-sea CO2 flux per surface area over continental shelf seas (-0.7 +/- 1.2 molC m(-2) yr(-1)) is the double of the value in the open ocean based on the most recent CO2 climatology. The largest uncertainty of scaling approaches remains in the availability of CO2 data to describe the spatial variability, and to capture relevant temporal scales of variability. Citation: Laruelle, G. G., H. H. Durr, C. P. Slomp, and A. V. Borges (2010), Evaluation of sinks and sources of CO2 in the global coastal ocean using a spatially-explicit typology of estuaries and continental shelves, Geophys. Res. Lett., 37, L15607, doi:10.1029/2010GL043691. [less ▲]

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See detailSpatiotemporal variations of fCO(2) in the North Sea
Omar, A. M.; Olsen, A.; Johannessen, T. et al

in Ocean Science (2010), 6(1), 77-89

Data from two Voluntary Observing Ship (VOS) (2005-2007) augmented with data subsets from ten cruises (1987-2005) were used to investigate the spatiotemporal variations of the CO2 fugacity in seawater ... [more ▼]

Data from two Voluntary Observing Ship (VOS) (2005-2007) augmented with data subsets from ten cruises (1987-2005) were used to investigate the spatiotemporal variations of the CO2 fugacity in seawater (fCO(2)(sw)) in the North Sea at seasonal and inter-annual time scales. The observed seasonal fCO(2)(sw) variations were related to variations in sea surface temperature (SST), biology plus mixing, and air-sea CO2 exchange. Over the study period, the seasonal amplitude in fCO(2)(sw) induced by SST changes was 0.4-0.75 times those resulting from variations in biology plus mixing. Along a meridional transect, fCO(2)(sw) normally decreased northwards (-12 mu atm per degree latitude), but the gradient disappeared/reversed during spring as a consequence of an enhanced seasonal amplitude of fCO(2)(sw) in southern parts of the North Sea. Along a zonal transect, a weak gradient (-0.8 mu atm per degree longitude) was observed in the annual mean fCO(2)(sw). Annually and averaged over the study area, surface waters of the North Sea were CO2 undersaturated and, thus, a sink of atmospheric CO2. However, during summer, surface waters in the region 55.5-54.5 degrees N were CO2 supersaturated and, hence, a source for atmospheric CO2. Comparison of fCO(2)(sw) data acquired within two 1 degrees x1 degrees regions in the northern and southern North Sea during different years (1987, 2001, 2002, and 2005-2007) revealed large interannual variations, especially during spring and summer when year-to-year fCO(2)(sw) differences (approximate to 160-200 mu atm) approached seasonal changes (approximate to 200-250 mu atm). The springtime variations resulted from changes in magnitude and timing of the phytoplankton bloom, whereas changes in SST, wind speed and total alkalinity may have contributed to the summertime interannual fCO(2)(sw) differences. The lowest interannual variation (10-50 mu atm) was observed during fall and early winter. Comparison with data reported in October 1967 suggests that the fCO(2)(sw) growth rate in the central North Sea was similar to that in the atmosphere. [less ▲]

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See detailCarbonate chemistry in the coastal zone responds more strongly to eutrophication than to ocean acidification
Borges, Alberto ULg; Gypens, N.

in Limnology & Oceanography (2010), 55(1), 346-353

The accumulation of anthropogenic CO2 in the ocean has altered carbonate chemistry in surface waters since preindustrial times and is expected to continue to do so in the coming centuries. Changes in ... [more ▼]

The accumulation of anthropogenic CO2 in the ocean has altered carbonate chemistry in surface waters since preindustrial times and is expected to continue to do so in the coming centuries. Changes in carbonate chemistry can modify the rates and fates of marine primary production and calcification. These modifications can in turn lead to feedback on increasing atmospheric CO2. We show, using a numerical model, that in highly productive nearshore coastal marine environments, the effect of eutrophication on carbon cycling can counter the effect of ocean acidification on the carbonate chemistry of surface waters. Also, changes in river nutrient delivery due to management regulation policies can lead to stronger changes in carbonate chemistry than ocean acidification. Whether antagonistic or synergistic, the response of carbonate chemistry to changes of nutrient delivery to the coastal zone (increase or decrease, respectively) is stronger than ocean acidification. [less ▲]

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See detailBenthic remineralisation in the Northeast European Continental margin (Northern Biscay Bay)
Suykens, K.; Schmidt, S.; Delille, Bruno ULg et al

Poster (2010)

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See detailNitrogen and carbon cycling in the North Sea and exchange with the North Atlantic-A model study, Part II: Carbon budget and fluxes
Kuhn, Wilfried; Paetsch, Johannes; Thomas, Helmuth et al

in Continental Shelf Research (2010), 30(16), 1701-1716

The 3-d coupled physical-biogeochemical model ECOHAM (version 3) was applied to the Northwest-European Shelf (47 degrees 41'-63 degrees 53'N, 15 degrees 5'W-13 degrees 55'E) for the years 1993-1996 ... [more ▼]

The 3-d coupled physical-biogeochemical model ECOHAM (version 3) was applied to the Northwest-European Shelf (47 degrees 41'-63 degrees 53'N, 15 degrees 5'W-13 degrees 55'E) for the years 1993-1996. Carbon fluxes were calculated for the years 1995 and 1996 for the inner shelf region, the North Sea (511,725 km(2)). This period was chosen because it corresponds to a shift from a very high winter-time North Atlantic Oscillation Index (NAOI) in 1994/1995, to an extremely low one in 1995/1996, with consequences for the North Sea physics and biogeochemistry. During the first half of 1996, the observed mean SST was about 1 degrees C lower than in 1995; in the southern part of the North Sea the difference was even larger (up to 3 degrees C). Due to a different wind regime, the normally prevailing anti-clockwise circulation, as found in winter 1995, was replaced by more complicated circulation patterns in winter 1996. Decreased precipitation over the drainage area of the continental rivers led to a reduction in the total (inorganic and organic) riverine carbon load to the North Sea from 476 Gmol C yr(-1) in 1995 to 340 Gmol C yr(-1) in 1996. In addition, the North Sea took up 503 Gmol C yr(-1) of CO2 from the atmosphere. According to our calculations, the North Sea was a sink for atmospheric CO2, at a rate of 0.98 mol C m(-2) yr(-1), for both years. The North Sea is divided into two sub-systems: the shallow southern North Sea (SNS; 190,765 km(2)) and the deeper northern North Sea (NNS; 320,960 km2). According to our findings the SNS is a net-autotrophic system (net ecosystem production NEP > 0) but released CO2 to the atmosphere: 159 Gmol C yr(-1) in 1995 and 59 Gmol C yr(-1) in 1996. There, the temperature-driven release of CO2 outcompetes the biological CO2 drawdown. In the NNS, where respiratory processes prevail (NEP < 0), 662 and 562 Gmol C yr(-1) were taken up from the atmosphere in 1995 and 1996. respectively. Stratification separates the productive, upper layer from the deeper layers of the water column where respiration/remineralization takes place. Duration and stability of the stratification are determined by the meteorological conditions, in relation to the NAO. Our results suggest that this mechanism controlling the nutrient supply to the upper layer in the northern and central North Sea has a larger impact on the carbon fluxes than changes in lateral transport due to NAOI variations. The North Sea as a whole imports organic carbon and exports inorganic carbon across the outer boundaries, and was found to be net-heterotrophic, more markedly in 1996 than in 1995. (C) 2010 Elsevier Ltd. All rights reserved. [less ▲]

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See detailDissolved inorganic carbon dynamics and air-sea carbon dioxide fluxes during coccolithophore blooms in the northwest European continental margin (northern Bay of Biscay)
Suykens, Kim; Delille, Bruno ULg; Chou, Lei et al

in Global Biogeochemical Cycles (2010), 24

We report a data set of dissolved inorganic carbon (DIC) obtained during three cruises in the northern Bay of Biscay carried out in June 2006, May 2007, and May 2008. During these cruises, blooms of the ... [more ▼]

We report a data set of dissolved inorganic carbon (DIC) obtained during three cruises in the northern Bay of Biscay carried out in June 2006, May 2007, and May 2008. During these cruises, blooms of the coccolithophore Emiliania huxleyi occurred, as indicated by patches of high reflectance on remote sensing images, phytoplankton pigment signatures, and microscopic examinations. Total alkalinity showed a nonconservative behavior as a function of salinity due to the cumulative effect of net community calcification (NCC) on seawater carbonate chemistry during bloom development. The cumulative effect of NCC and net community production (NCP) on DIC and the partial pressure of CO2 (pCO(2)) were evaluated. The decrease of DIC (and increase of pCO(2)) due to NCC was overwhelmingly lower than the decrease of DIC (and decrease of pCO(2)) due to NCP (NCC: NCP << 1). During the cruises, the northern Bay of Biscay acted as a sink of atmospheric CO2 (on average similar to-9.7 mmol C m(-2) d(-1) for the three cruises). The overall effect of NCC in decreasing the CO2 sink during the cruises was low (on average similar to 12% of total air-sea CO2 flux). If this is a general feature in naturally occurring phytoplankton blooms in the North Atlantic Ocean (where blooms of coccolithophores are the most intense and recurrent), and in the global ocean, then the potential feedback on increasing atmospheric CO2 of the projected decrease of pelagic calcification due to thermodynamic CO2 "production" from calcification is probably minor compared to potential feedbacks related to changes of NCP. [less ▲]

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See detailSeasonal variability of methane in the rivers and lagoons of Ivory Coast (West Africa)
Kone, Y. J. M.; Abril, G.; Delille, Bruno ULg et al

in Biogeochemistry (2010), 100(1-3), 21-37

We report a data-set of dissolved methane (CH4) in three rivers (Como,, Bia and Tano,) and five lagoons (Grand-Lahou, Ebri,, Potou, Aby and Tendo) of Ivory Coast (West Africa), during the four main ... [more ▼]

We report a data-set of dissolved methane (CH4) in three rivers (Como,, Bia and Tano,) and five lagoons (Grand-Lahou, Ebri,, Potou, Aby and Tendo) of Ivory Coast (West Africa), during the four main climatic seasons (high dry season, high rainy season, low dry season and low rainy season). The surface waters of the three rivers were over-saturated in CH4 with respect to atmospheric equilibrium (2221-38719%), and the seasonal variability of CH4 seemed to be largely controlled by dilution during the flooding period. The strong correlation of CH4 concentrations with the partial pressure of CO2 (pCO(2)) and dissolved silicate (DSi) confirm the dominance of a continental sources (from soils) for both CO2 and CH4 in these rivers. Diffusive air-water CH4 fluxes ranged between 25 and 1187 mu mol m(-2) day(-1), and annual integrated values were 288 +/- A 107, 155 +/- A 38, and 241 +/- A 91 mu mol m(-2) day(-1) in the Como,, Bia and Tano, rivers, respectively. In the five lagoons, surface waters were also over-saturated in CH4 (ranging from 1496 to 51843%). Diffusive air-water CH4 fluxes ranged between 20 and 2403 mu mol m(-2) day(-1), and annual integrated values were 78 +/- A 34, 338 +/- A 217, 227 +/- A 79, 330 +/- A 153 and 326 +/- A 181 mu mol m(-2) day(-1) in the Grand-Lahou, Ebri,, Potou, Aby and Tendo lagoons, respectively. The largest CH4 over-saturations were observed in the Tendo and Aby lagoons that are permanently stratified systems (unlike the other three lagoons), leading to anoxic bottom waters favorable for a large CH4 production. In addition, these two stratified lagoons showed low pCO(2) values due to high primary production, which suggests an efficient transfer of organic matter across the pycnocline. As a result, the stratified Tendo and Aby lagoons were respectively, a low source of CO2 to the atmosphere and a sink of atmospheric CO2 while the other three well-mixed lagoons were strong sources of CO2 to the atmosphere but less over-saturated in CH4. [less ▲]

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See detailDecadal changes of carbon dioxide in the Scheldt estuary
Borges, Alberto ULg; Middelburg, J. J.

Poster (2010)

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See detailCarbon dioxide and methane dynamics in estuaries
Borges, Alberto ULg; Abril, G.

Conference (2010)

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See detailEstimating pCO2 from remote sensing in the Belgian Coastal Zone
Borges, Alberto ULg; Ruddick, K.; Lacroix, G. et al

in ESA Living Planet Symposium : 28 June - 2 July 2010, Bergen, Norway (2010)

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See detailDecadal changes of carbon dioxide in the Scheldt estuary
Borges, Alberto ULg; Middelburg, J. J.

Poster (2010)

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