References of "Borges, Alberto"
     in
Bookmark and Share    
Full Text
See detailCarbon dioxide in European coastal waters
Borges, Alberto ULg; Schiettecatte, L.-S.; Abril, G. et al

Poster (2007)

Detailed reference viewed: 4 (0 ULg)
Full Text
Peer Reviewed
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 ▲]

Detailed reference viewed: 48 (8 ULg)
Full Text
Peer Reviewed
See detailAssessment of the processes controlling the seasonal variations of dissolved inorganic carbon in the North Sea
Bozec, Y.; Thomas, H.; Schiettecatte, L. S. et al

in Limnology & Oceanography (2006), 51(6), 27462762

We used a seasonal North Sea data set comprising dissolved inorganic carbon (DIC), partial pressure of CO2 (pCO2), and inorganic nutrients to assess the abiotic and biological processes governing the ... [more ▼]

We used a seasonal North Sea data set comprising dissolved inorganic carbon (DIC), partial pressure of CO2 (pCO2), and inorganic nutrients to assess the abiotic and biological processes governing the monthly variations of DIC. During winter, advection and air–sea exchange of CO2 control and increase the DIC content in the surface and deeper layers of the northern and central North Sea, with the atmosphere supplying CO2 on the order of 0.2 mol C m22 month21 to these areas. From February to July, net community production (NCP) controls the seasonal variations of DIC in the surface waters of the entire North Sea, with a net uptake ranging from 0.5 to 1.4 mol C m22 month21. During the August–December period, NCP controls the seasonal variations of DIC in the southern North Sea, with a net release ranging from 0.5 to 0.8 mol C m22 month21. Similarly, during the April–August period in the deeper layer of the northern North Sea, the NCP was the main factor controlling DIC concentrations, with a net release ranging from 0.5 to 5.5 mol C m22 month21. In the surface layer of the North Sea, NCP on the basis of DIC was 4.3 6 0.4 mol C m22 yr21, whereas, NCP on the basis of nitrate was 1.6 6 0.2 mol C m22 yr21. Under nutrient-depleted conditions, preferential recycling (extracellular) of nutrients and intracellular mechanisms occurred and were responsible for the non-Redfield uptake of DIC versus nitrate and phosphate. [less ▲]

Detailed reference viewed: 16 (2 ULg)
Full Text
Peer Reviewed
See detailOrganic carbon metabolism and carbonate dynamics in a Mediterranean seagrass (Posidonia oceanica) meadow
Barrón, Cristina; Duarte, Carlos M.; Frankignoulle, Michel et al

in Estuaries and Coasts (2006), 29(3), 417-426

in a Posidonia oceanica meadow and unvegetated sediments of Magalluf Bay (Mallorca Island, Spain) to determine gross primary production (GPP), community respiration (R), and net community production (NCP ... [more ▼]

in a Posidonia oceanica meadow and unvegetated sediments of Magalluf Bay (Mallorca Island, Spain) to determine gross primary production (GPP), community respiration (R), and net community production (NCP). From June 2001 to October 2002, we also measured fluxes of dissolved inorganic carbon (DIC) and total alkalinity (TAlk). The yearly integrated metabolic rates based on DO changes show that the P. oceanica communities are net autotrophic while the metabolic rates in the unvegetated benthic communities are nearly balanced. Higher calcium carbonate (CaCO3) cycling, both in terms of production and dissolution, was observed in P. oceanica communities than in unvegetated benthic communities. In the P. oceanica meadow, the annual release of CO2 from net CaCO3 production corresponds to almost half of the CO2 uptake by NCP based on DIC incubations. In unvegetated benthic communities, the annual uptake of CO2 from net CaCO3 dissolution almost fully compensates the CO2 release by NCP based on DIC incubations. CaCO3 dynamics is potentially a major factor in CO2 benthic fluxes in seagrass and carbonate-rich temperate coastal ecosystems. [less ▲]

Detailed reference viewed: 26 (5 ULg)
Full Text
Peer Reviewed
See detailTime series of the partial pressure of carbon dioxide (2001 2004) and preliminary inorganic carbon budget in the Scheldt plume (Belgian coast waters)
Schiettecatte, Laure-Sophie; Gazeau, Frédéric; Van der Zee, Claar et al

in Geochemistry, Geophysics, Geosystems (G3) (2006), 7(Q06009),

A 4-year time series (2001–2004) of the partial pressure of CO2 (pCO2) and air-sea CO2 fluxes is reported in the Scheldt estuarine plume. This system is oversaturated in CO2 with respect to the atmosphere ... [more ▼]

A 4-year time series (2001–2004) of the partial pressure of CO2 (pCO2) and air-sea CO2 fluxes is reported in the Scheldt estuarine plume. This system is oversaturated in CO2 with respect to the atmosphere, except during the spring phytoplanktonic bloom, and acts as a net source of CO2 to the atmosphere of 0.7 mol C m 2 yr 1 that represents 7 to 27% of the inner Scheldt estuary CO2 emission. Results also highlight that a high spatial and temporal coverage of the surface pCO2 in coastal ecosystems is crucial for reliable estimations of air-sea CO2 fluxes. The seasonal variations of pCO2 seem to be more dominated by biological activities (photosynthesis/respiration) than by temperature change. A stochiometrically linked C/P mass balance budget failed to provide net ecosystem production estimates consistent with the pCO2 dynamics in this area. It is hypothesized that this discrepancy is related to physiological characteristics of the dominant phytoplanktonic species (Phaeocystis sp.) within the studied area. On the basis of a preliminary dissolved inorganic carbon input/output budget, the annual emission of CO2 toward the atmosphere seems to be largely due to the outgassing of the inputs of CO2 from the inner Scheldt estuary, rather than due to organic carbon degradation. [less ▲]

Detailed reference viewed: 21 (3 ULg)
Full Text
See detailTime series of the partial pressure of carbon dioxide (2001 2004) and preliminary inorganic carbn budget in the Scheldt plume (Belgian coastal waters)
Schiettecatte, L.-S.; Gazeau, F.; van der Zee, C. et al

Poster (2006)

Detailed reference viewed: 1 (0 ULg)
Full Text
See detailCarbon dioxide in European coastal waters
Borges, Alberto ULg; Schiettecatte, L.-S.; Abril, G. et al

Poster (2006)

Detailed reference viewed: 2 (0 ULg)
Full Text
Peer Reviewed
See detailBudgeting sinks and sources of CO2 in the coastal ocean: Diversity of ecosystems counts
Borges, Alberto ULg; Delille, Bruno ULg; Frankignoulle, M.

in Geophysical Research Letters (2005), 32(14),

Air-water CO2 fluxes were up-scaled to take into account the latitudinal and ecosystem diversity of the coastal ocean, based on an exhaustive literature survey. Marginal seas at high and temperate ... [more ▼]

Air-water CO2 fluxes were up-scaled to take into account the latitudinal and ecosystem diversity of the coastal ocean, based on an exhaustive literature survey. Marginal seas at high and temperate latitudes act as sinks of CO2 from the atmosphere, in contrast to subtropical and tropical marginal seas that act as sources of CO2 to the atmosphere. Overall, marginal seas act as a strong sink of CO2 of about -0.45 Pg C yr(-1). This sink could be almost fully compensated by the emission of CO2 from the ensemble of near-shore coastal ecosystems of about 0.40 Pg C yr(-1). Although this value is subject to large uncertainty, it stresses the importance of the diversity of ecosystems, in particular near-shore systems, when integrating CO2 fluxes at global scale in the coastal ocean. [less ▲]

Detailed reference viewed: 440 (1 ULg)
Full Text
Peer Reviewed
See detailResponse of primary production and calcification to changes of pCO(2) during experimental blooms of the coccolithophorid Emiliania huxleyi
Delille, Bruno ULg; Harlay, Jérôme ULg; Zondervan, Ingrid et al

in Global Biogeochemical Cycles (2005), 19(2),

[1] Primary production and calcification in response to different partial pressures of CO2 (PCO2) ("glacial,'' "present,'' and "year 2100'' atmospheric CO2 concentrations) were investigated during a ... [more ▼]

[1] Primary production and calcification in response to different partial pressures of CO2 (PCO2) ("glacial,'' "present,'' and "year 2100'' atmospheric CO2 concentrations) were investigated during a mesocosm bloom dominated by the coccolithophorid Emiliania huxleyi. The day-to-day dynamics of net community production (NCP) and net community calcification (NCC) were assessed during the bloom development and decline by monitoring dissolved inorganic carbon (DIC) and total alkalinity ( TA), together with oxygen production and 14 C incorporation. When comparing year 2100 with glacial PCO2 conditions we observed: ( 1) no conspicuous change of net community productivity (NCPy); ( 2) a delay in the onset of calcification by 24 to 48 hours, reducing the duration of the calcifying phase in the course of the bloom; ( 3) a 40% decrease of NCC; and ( 4) enhanced loss of organic carbon from the water column. These results suggest a shift in the ratio of organic carbon to calcium carbonate production and vertical flux with rising atmospheric PCO2. [less ▲]

Detailed reference viewed: 227 (6 ULg)
Full Text
See detailDissolved Inorganic Carbon dynamics in the northern Bay of Biscay during a Coccolithophore bloom
Harlay, Jérôme ULg; van der Zee, Claar; Schiettecatte, Laure-Sophie et al

Poster (2005, May 02)

In the framework of the Belgian global change programme, we have developed a project devoted to the study of the inorganic carbon cycle in the Bay of Biscay where coccolithophore blooms occur frequently ... [more ▼]

In the framework of the Belgian global change programme, we have developed a project devoted to the study of the inorganic carbon cycle in the Bay of Biscay where coccolithophore blooms occur frequently. The study focuses on processes associated with the oceanic production and dissolution of calcium carbonate and related CO2 fluxes. Real time remote sensing allowed to localize the coccolithophore bloom that the R.V. Belgica visited in June 2004 during a multidisciplinary scientific cruise. We will present vertical profiles of pH, Talk, along with other parameters (salinity, temperature, chlorophyll a and phaeopigments) and 14C incorporation experiments. Inorganic carbon fluxes will be discussed in the photic zone, in correlation with the biological activity of phytoplankton (biological and carbonate pumps). [less ▲]

Detailed reference viewed: 1 (0 ULg)
Full Text
Peer Reviewed
See detailWhole-system metabolism and CO2 fluxes in a Mediterranean Bay dominated by seagrass beds (Palma Bay, NW Mediterranean)
Gazeau, Frédéric; Duarte, C. M.; Gattuso, Jean-Pierre et al

in Biogeosciences (2005), 2(1), 43-60

Planktonic and benthic incubations (bare and Posidonia oceanica vegetated sediments) were performed at monthly intervals from March 2001 to October 2002 in a seagrass vegetated area of the Bay of Palma ... [more ▼]

Planktonic and benthic incubations (bare and Posidonia oceanica vegetated sediments) were performed at monthly intervals from March 2001 to October 2002 in a seagrass vegetated area of the Bay of Palma (Mallorca, Spain). Results showed a contrast between the planktonic compartment, which was on average near metabolic balance (-4.6 +/- 5.9 mmol O-2 m(-2) d(-1)) and the benthic compartment, which was autotrophic (17.6 +/- 8.5 mmol O-2 m(-2) d(-1)). During two cruises in March and June 2002, planktonic and benthic incubations were performed at several stations in the bay to estimate the whole-system metabolism and to examine its relationship with partial pressure of CO2 (pCO(2)) and apparent oxygen utilisation (AOU) spatial patterns. Moreover, during the second cruise, when the residence time of water was long enough, net ecosystem production (NEP) estimates based on incubations were compared, over the Posidonia oceanica meadow, to rates derived from dissolved inorganic carbon (DIC) and oxygen (O-2) mass balance budgets. These budgets provided NEP estimates in fair agreement with those derived from direct metabolic estimates based on incubated samples over the Posidonia oceanica meadow. Whereas the seagrass community was autotrophic, the excess organic carbon production therein could only balance the planktonic heterotrophy in shallow waters relative to the maximum depth of the bay ( 55 m). This generated a horizontal gradient from autotrophic or balanced communities in the shallow seagrass-covered areas, to strongly heterotrophic communities in deeper areas of the bay. It seems therefore that, on an annual scale in the whole bay, the organic matter production by the Posidonia oceanica may not be sufficient to fully compensate the heterotrophy of the planktonic compartment, which may require external organic carbon inputs, most likely from land. [less ▲]

Detailed reference viewed: 65 (14 ULg)
See detailVariability of the gas transfer velocity of CO2 in a macrotidal estuary (The Scheldt)
Borges, Alberto ULg; Vanderborght, Jean-Pierre; Schiettecatte, Laure-Sophie et al

Poster (2005)

Detailed reference viewed: 6 (0 ULg)
See detailDiversity of Ecosystems and Coastal Ocean CO2 Fluxes
Borges, Alberto ULg

Conference (2005)

Detailed reference viewed: 1 (0 ULg)
See detailPreliminary results on the biogeochemistry in the Mekong estuary and delta (Vietnam)
Borges, Alberto ULg; Koné; Schiettecatte, L. S. et al

Poster (2005)

Detailed reference viewed: 7 (0 ULg)
Full Text
Peer Reviewed
See detailControls of the surface water partial pressure of CO2 in the North Sea
Thomas, H.; Bozec, Y.; de Baar, Hein J. W. et al

in Biogeosciences (2005), 2(4), 323-334

The seasonal variability of the partial pressure of CO2 (pCO2) has been investigated in the North Sea, a northwest European shelf sea. Based on a seasonal and high spatial resolution data set the main ... [more ▼]

The seasonal variability of the partial pressure of CO2 (pCO2) has been investigated in the North Sea, a northwest European shelf sea. Based on a seasonal and high spatial resolution data set the main controlling factors – biological processes and temperature - have been identified and quantified. In the central and northern parts being a CO2- sink all year round, the biological control dominates the temperature control. In the southern part, the temperature control dominates the biological control at an annual scale, since the shallow water column prevents stronger net-CO2 removal from the surface layer due to the absence of seasonal stratification. The consequence is a reversal of the CO2 seato- air flux during the spring bloom period, the only time, when CO2 is taken up from the atmosphere in the southern region. Net community production in the mixed layer has been estimated to 4mol Cm−2 yr−1 with higher values (4.3 mol Cm−2 yr−1) in the northern part and lower values in the southern part (2.6 mol Cm−2 yr−1). [less ▲]

Detailed reference viewed: 139 (1 ULg)
Full Text
Peer Reviewed
See detailPlanktonic and whole system metabolism in a nutrient rich estuary (the Scheldt estuary)
Gazeau, Frédéric; Gattuso, Jean-Pierre; Middelburg, Jack J. et al

in Estuaries (2005), 28(6), 868-883

Planktonic gross primary production (GPP), community respiration (CR), and nitrification (NIT) were measured monthly in the Scheldt estuary by the oxygen incubation method in 2003. No significant ... [more ▼]

Planktonic gross primary production (GPP), community respiration (CR), and nitrification (NIT) were measured monthly in the Scheldt estuary by the oxygen incubation method in 2003. No significant evolution of planktonic GPP was observed since the 1990s with high rates in the freshwater area (salinity 0; 97 6 65 mmol C m22 d21) decreasing seaward (22–37 mmol C m22 d21). A significant decrease of NIT was observed with regard to previous investigations although this process still represents up to 20% of total organic matter production in the inner estuary. Planktonic CR was highest in the inner estuary and seemed to be mainly controlled by external organic matter inputs. Planktonic net community production was negative most of the time in the estuary with values ranging from 2300 to 165 mmol C m22 d21. Whole estuary net ecosystem production (NEP) was investigated on an annual scale using the results mentioned above and published benthic metabolic rates. A NEP of 239 6 8 mmol C m22 d21 was estimated, which confirms the strong heterotrophic status of this highly nutrified estuary. NEP rates were computed from June to December 2003 to compare with results derived from the Land-Ocean Interaction in the Coastal Zone budgeting procedure applied to dissolved inorganic phosphorus and carbon (DIP and DIC). DIP budgets failed to provide realistic estimates in the inner estuary where abiotic processes account for more than 50% of the nonconservative DIP flux. DIC budgets predicted a much lower NEP than in situ incubations (2109 6 31 versus 242 6 9 mmol C m22 d21) although, as each approach is associated with several critical assumptions, the source of this discrepancy remains unclear. [less ▲]

Detailed reference viewed: 10 (2 ULg)
Full Text
Peer Reviewed
See detailDo we have enough pieces of the jigsaw to integrate CO2 fluxes in the Coastal Ocean ?
Borges, Alberto ULg

in Estuaries (2005), 28(1), 3-27

Annually integrated air-water CO2 flux data in 44 coastal environments were compiled from literature. Data were gathered in 8 major ecosystems (inner estuaries, outer estuaries, whole estuarine systems ... [more ▼]

Annually integrated air-water CO2 flux data in 44 coastal environments were compiled from literature. Data were gathered in 8 major ecosystems (inner estuaries, outer estuaries, whole estuarine systems, mangroves, salt marshes, coral reefs, upwelling systems, and open continental shelves), and up-scaled in the first attempt to integrate air-water CO2 fluxes over the coastal ocean (26 3 106 km2), taking into account its geographical and ecological diversity. Air-water CO2 fluxes were then up-scaled in global ocean (362 3 106 km2) using the present estimates for the coastal ocean and those from Takahashi et al. (2002) for the open ocean (336 3 106 km2). If estuaries and salt marshes are not taken into consideration in the up-scaling, the coastal ocean behaves as a sink for atmospheric CO2 (21.17 mol C m22 yr21) and the uptake of atmospheric CO2 by the global ocean increases by 24% (21.93 versus 21.56 Pg C yr21). The inclusion of the coastal ocean increases the estimates of CO2 uptake by the global ocean by 57% for high latitude areas (20.44 versus 20.28 Pg C yr21) and by 15% for temperate latitude areas (22.36 versus 22.06 Pg C yr21). At subtropical and tropical latitudes, the contribution from the coastal ocean increases the CO2 emission to the atmosphere from the global ocean by 13% (0.87 versus 0.77 Pg C yr21). If estuaries and salt marshes are taken into consideration in the upscaling, the coastal ocean behaves as a source for atmospheric CO2 (0.38 mol C m22 yr21) and the uptake of atmospheric CO2 from the global ocean decreases by 12% (21.44 versus 21.56 Pg C yr21). At high and subtropical and tropical latitudes, the coastal ocean behaves as a source for atmospheric CO2 but at temperate latitudes, it still behaves as a moderate CO2 sink. A rigorous up-scaling of air-water CO2 fluxes in the coastal ocean is hampered by the poorly constrained estimate of the surface area of inner estuaries. The present estimates clearly indicate the significance of this biogeochemically, highly active region of the biosphere in the global CO2 cycle. [less ▲]

Detailed reference viewed: 32 (1 ULg)