References of "Borges, Alberto"
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See detailThe influence of biogeochemical processes on the pH dynamics in the seasonally hypoxic saline Lake Grevelingen
Hagens, M; Slomp, C; Meysman, F et al

Poster (2013, April 07)

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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 detailCarbon dioxide dynamics and fluxes in coastal waters influenced by river plumes
Cai, W.-J.; Chen, C.-T.A.; Borges, Alberto ULg

in Bianchi, TS; Allison, MA; Cai, WJ (Eds.) Biogeochemical Dynamics at Large River-Coastal Interfaces: Linkages with Global Climate Change (2013)

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See detailSeagrass production: linking individual, community and ecosystem carbon fluxes
Santos, R; Silva, J; Olivé, I et al

Conference (2013)

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See detailGeochemistry of continental rivers of the Virunga Volcanic Province, East Africa
Balagizi, C; Darchambeau, François ULg; Kasereka, M et al

Conference (2013)

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See detailModelling ocean acidification in marginal seas: the North Western European shelf case study
Artioli, Y; Blackford, JC; Butenschön, M et al

Conference (2013)

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See detailPhotoferrotrophy and Fe-cycling in a freshwater column
Llirós, M; Crowe, SA; García-Armisen, T et al

Conference (2013)

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See detailPhotoferrotrophy and Fe-cycling in a freshwater column
Llirós, M; Crowe, SA; García-Armisen, T et al

Poster (2013)

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See detailVariability of North Sea pH and CO2 in response to North Atlantic Oscillation forcing
Salt, L.A.; Thomas, H.; Prowe, A.E.F. et al

in Journal of Geophysical Research. Biogeosciences (2013), 118(1-9),

High biological activity causes a distinct seasonality of surface water pH in the North Sea, which is a strong sink for atmospheric CO 2 via an effective shelf pump. The intimate connection between the ... [more ▼]

High biological activity causes a distinct seasonality of surface water pH in the North Sea, which is a strong sink for atmospheric CO 2 via an effective shelf pump. The intimate connection between the North Sea and the North Atlantic Ocean suggests that the variability of the CO 2 system of the North Atlantic Ocean may, in part, be responsible for the observed variability of pH and CO 2 in the North Sea. In this work, we demonstrate the role of the North Atlantic Oscillation (NAO), the dominant climate mode for the North Atlantic, in governing this variability. Based on three extensive observational records covering the relevant levels of the NAO index, we provide evidence that the North Sea pH and CO 2 system strongly responds to external and internal expressions of the NAO. Under positive NAO, the higher rates of in fl ow of water from the North Atlantic Ocean and the Baltic out fl ow lead to a strengthened north-south biogeochemical divide. The limited mixing between the north and south leads to a steeper gradient in pH and partial pressure of CO 2 (pCO 2 ) between the two regions in the productive period. This is exacerbated further when coinciding with higher sea surface temperature, which concentrates the net community production in the north through shallower strati fi cation. These effects can be obscured by changing properties of the constituent North Sea water masses, which are also in fl uenced by NAO. Our results highlight the importance of examining interannual trends in the North Sea CO 2 system with consideration of the NAO state [less ▲]

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See detailDynamics of dissolved inorganic carbon and aquatic metabolism in the Tana River basin, Kenya
Tamooh, F.; Borges, Alberto ULg; Meysman, F. J. R. et al

in Biogeosciences (2013), 10(11), 6911-6928

A basin-wide study was conducted in the Tana River basin (Kenya) in February 2008 (dry season), September–November 2009 (wet season) and June– July 2010 (end of the wet season) to assess the dynamics and ... [more ▼]

A basin-wide study was conducted in the Tana River basin (Kenya) in February 2008 (dry season), September–November 2009 (wet season) and June– July 2010 (end of the wet season) to assess the dynamics and sources of dissolved inorganic carbon (DIC) as well as to quantify CO2 fluxes, community respiration (R), and primary production (P). Samples were collected along the altitudinal gradient (from 3600 to 8 m) in several headwater streams, reservoirs (Kamburu and Masinga), and the Tana River mainstream. DIC concentrations ranged from 0.2 to 4.8 mmol L−1, with exceptionally high values (3.5±1.6 mmol L−1) in Nyambene Hills tributaries. The wide range of 13CDIC values (−15.0 to −2.4 ‰) indicate variable sources of DIC, with headwater streams recording more positive signatures compared to the Tana River mainstream. With with only a few exceptions, the entire riverine network was supersaturated in CO2, implying the system is a net source of CO2 to the atmosphere. pCO2 values were generally higher in the lower Tana River mainstream compared to headwater tributaries, opposite to the pattern typically observed in other river networks. This was attributed to high suspended sediment in the Tana River mainstream fuelling in-stream community respiration and net heterotrophy. This was particularly evident during the 2009 wet season campaign (median pCO2 of 1432 ppm) compared to the 2010 end of the wet season (1002 ppm) and 2008 dry season(579 ppm). First-order estimates show that in-stream community respiration was responsible for the bulk of total CO2 evasion (77 to 114 %) in the Tana River mainstream, while in the tributaries, this could only account for 5 to 68% of total CO2 evasion. This suggests that CO2 evasion in the tributaries was to a substantial degree sustained by benthic mineralisation and/or lateral inputs of CO2-oversaturated groundwater. While sediment loads increased downstream and thus light availability decreased in the water column, both chlorophyll a (0.2 to 9.6 μg L−1) and primary production (0.004 to 7.38 μmol CL−1 h−1) increased consistently downstream. Diurnal fluctuations of biogeochemical processes were examined at three different sites along the river continuum (headwater, reservoir and mainstream), and were found to be substantial only in the headwater stream, moderate in the reservoir and not detectable in the Tana River mainstream. The pronounced diurnal fluctuations observed in the headwater stream were largely regulated by periphyton as deduced from the low chlorophyll a in the water column. [less ▲]

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See detailAnthropogenic perturbation of the carbon fluxes from land to ocean
Regnier; Friedlingstein, P.; Ciais, P. et al

in Nature Geoscience (2013)

A substantial amount of the atmospheric carbon taken up on land through photosynthesis and chemical weathering is transported laterally along the aquatic continuum from upland terrestrial ecosystems to ... [more ▼]

A substantial amount of the atmospheric carbon taken up on land through photosynthesis and chemical weathering is transported laterally along the aquatic continuum from upland terrestrial ecosystems to the ocean. So far, global carbon budget estimates have implicitly assumed that the transformation and lateral transport of carbon along this aquatic continuum has remained unchanged since pre-industrial times. A synthesis of published work reveals the magnitude of present-day lateral carbon fluxes from land to ocean, and the extent to which human activities have altered these fluxes. We show that anthropogenic perturbation may have increased the flux of carbon to inland waters by as much as 1.0 Pg C yr-1 since pre-industrial times, mainly owing to enhanced carbon export from soils. Most of this additional carbon input to upstream rivers is either emitted back to the atmosphere as carbon dioxide (~0.4 Pg C yr-1) or sequestered in sediments (~0.5 Pg C yr-1) along the continuum of freshwater bodies, estuaries and coastal waters, leaving only a perturbation carbon input of ~0.1 Pg C yr-1 to the open ocean. According to our analysis, terrestrial ecosystems store ~0.9 Pg C yr-1 at present, which is in agreement with results from forest inventories but significantly differs from the figure of 1.5 Pg C yr-1 previously estimated when ignoring changes in lateral carbon fluxes. We suggest that carbon fluxes along the land–ocean aquatic continuum need to be included in global carbon dioxide budgets. [less ▲]

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See detailCO2, CH4 and N2O dynamics and fluxes in the brackish Lake Grevelingen (The Netherlands)
Borges, Alberto ULg; Meysman, Filip; Harlay, Jérôme ULg

Poster (2013)

Lake Grevelingen in the South West Netherlands is a former estuary locked off from the sea by two dikes and a brackish lake since 1971 (salinities from 29 to 33 during our sampling). It is connected with ... [more ▼]

Lake Grevelingen in the South West Netherlands is a former estuary locked off from the sea by two dikes and a brackish lake since 1971 (salinities from 29 to 33 during our sampling). It is connected with the North Sea by sluices, has a surface area of 108 km2, a mean depth of 5.3 m, a maximum depth of 48 m, and about 60% of the area the depth is less than 5 m. In summer, anoxia occurs in bottom waters. From January 2012 to December 2012 a biogeochemical survey was conducted at monthly interval at a fixed station (35 m depth) at Den Osse. Here, we focus on the analysis of partial pressure of CO2, and concentrations of CH4 and N2O obtained throughout the water column. pCO2 followed a typical seasonal cycle for temperate coastal environments shifting from CO2 over-saturation in winter to spring CO2 under-saturation due to the spring phytoplankton bloom, and shifting back to over-saturation in fall. Unlike the adjacent Southern Bight of the North Sea and the adjacent Oosterschelde, CO2 under-saturation prevailed in summer in Lake Grevelingen. CH4 values were minimal in winter ( 20 nM) and as stratification developed during spring and summer a distinct maximum of CH4 (up to 730 nM) developed at the pycnocline (5 to 10 m). N2O showed little seasonal variations and only a very faint increase with depth, except in August when bottom waters became anoxic. At this time, N2O shown a maximum ( 22 nM) at the oxycline (probably related to enhanced N2O production by nitrification at low O2 concentrations), and decreased in the anoxic layer ( 3 nM) (probably related to denitrification). [less ▲]

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See detailSurface Ocean CO2 Atlas (SOCAT) gridded data products
Sabine, C. L. Br; Hankin, S. Br; Koyuk, H. Br et al

in Earth System Science Data (2013), 5(1), 145-153

As a response to public demand for a well-documented, quality controlled, publically available, global surface ocean carbon dioxide (CO2) data set, the international marine carbon science community ... [more ▼]

As a response to public demand for a well-documented, quality controlled, publically available, global surface ocean carbon dioxide (CO2) data set, the international marine carbon science community developed the Surface Ocean CO2 Atlas (SOCAT). The first SOCAT product is a collection of 6.3 million quality controlled surface CO2 data from the global oceans and coastal seas, spanning four decades (1968–2007). The SOCAT gridded data presented here is the second data product to come from the SOCAT project. Recognizing that some groups may have trouble working with millions of measurements, the SOCAT gridded product was generated to provide a robust, regularly spaced CO2 fugacity (fCO2) product with minimal spatial and temporal interpolation, which should be easier to work with for many applications. Gridded SOCAT is rich with information that has not been fully explored yet (e.g., regional differences in the seasonal cycles), but also contains biases and limitations that the user needs to recognize and address (e.g., local influences on values in some coastal regions). [less ▲]

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See detailA uniform, quality controlled Surface Ocean CO2 Atlas (SOCAT)
Pfeil, B. Br; Olsen, A. Br; Bakker, D. C. E. Br et al

in Earth System Science Data (2013), 5(1), 125-143

A well-documented, publicly available, global data set of surface ocean carbon dioxide (CO2) parameters has been called for by international groups for nearly two decades. The Surface Ocean CO2 Atlas ... [more ▼]

A well-documented, publicly available, global data set of surface ocean carbon dioxide (CO2) parameters has been called for by international groups for nearly two decades. The Surface Ocean CO2 Atlas (SOCAT) project was initiated by the international marine carbon science community in 2007 with the aim of providing a comprehensive, publicly available, regularly updated, global data set of marine surface CO2, which had been subject to quality control (QC). Many additional CO2 data, not yet made public via the Carbon Dioxide Information Analysis Center (CDIAC), were retrieved from data originators, public websites and other data centres. All data were put in a uniform format following a strict protocol. Quality control was carried out according to clearly defined criteria. Regional specialists performed the quality control, using state-of-the-art web-based tools, specially developed for accomplishing this global team effort. SOCAT version 1.5 was made public in September 2011 and holds 6.3 million quality controlled surface CO2 data points from the global oceans and coastal seas, spanning four decades (1968–2007). Three types of data products are available: individual cruise files, a merged complete data set and gridded products. With the rapid expansion of marine CO2 data collection and the importance of quantifying net global oceanic CO2 uptake and its changes, sustained data synthesis and data access are priorities. [less ▲]

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See detailEstablishing research strategies, methodologies and technologies to link genomics and proteomics to seagrass productivity, community metabolism, and ecosystem carbon fluxes
Mazzuca, Silvia; Bjork, M; Beer, S et al

in Frontiers in Plant Science (2013), 4(38), 1-19

A complete understanding of the mechanistic basis of marine ecosystem functioning is only possible through integrative and interdisciplinary research.This enables the prediction of change and possibly the ... [more ▼]

A complete understanding of the mechanistic basis of marine ecosystem functioning is only possible through integrative and interdisciplinary research.This enables the prediction of change and possibly the mitigation of the consequences of anthropogenic impacts. One major aim of the European Cooperation in Science and Technology (COST) Action ES0609 “Seagrasses productivity. From genes to ecosystem management,” is the calibration and synthesis of various methods and the development of innovative techniques and protocols for studying seagrass ecosystems. During 10 days, 20 researchers representing a range of disciplines (molecular biology, physiology, botany, ecology, oceanography, and underwa- ter acoustics) gathered at The Station de Recherches Sous-marines et Océanographiques (STARESO, Corsica) to study together the nearby Posidonia oceanica meadow. STARESO is located in an oligotrophic area classified as “pristine site” where environmental distur- bances caused by anthropogenic pressure are exceptionally low. The healthy P. oceanica meadow, which grows in front of the research station, colonizes the sea bottom from the surface to 37 m depth. During the study, genomic and proteomic approaches were integrated with ecophysiological and physical approaches with the aim of understanding changes in seagrass productivity and metabolism at different depths and along daily cycles. In this paper we report details on the approaches utilized and we forecast the potential of the data that will come from this synergistic approach not only for P. oceanica but for seagrasses in general. [less ▲]

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See detailThe BONUS-GoodHope IPY project: dynamics and biogeochemistry interactions in the Southern Ocean south off Africa
Speich, S.; Dehairs, F.; Sicre, M.-A. et al

Book published by EGU (2013)

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See detailParticle export during a bloom of Emiliania huxleyi in the North-West European continental margin
Schmidt, S.; Harlay, Jérôme ULg; Borges, Alberto ULg et al

in Journal of Marine Systems (2013), 109-110

Coccolithophores, the dominant pelagic calcifiers in the oceans, play a key role in the marine carbon cycle through calcification, primary production and carbon export, the main rivers of the biological ... [more ▼]

Coccolithophores, the dominant pelagic calcifiers in the oceans, play a key role in the marine carbon cycle through calcification, primary production and carbon export, the main rivers of the biological CO2 pump. In May 2002 a cruise was conducted on the outer shelf of the North West European continental margin, from the north Bay of Biscay to the Celtic Sea (47.0°-50.5°N, 5.0°-11.0°W), an area where massive blooms of Emiliania huxleyi are observed annually. Biogeochemical variables including primary production, calcification, partial pressure of CO2 (pCO2), chlorophyll-a (Chl-a), particle load, particulate organic and inorganic carbon (POC, PIC) and 234Th, were measured in surface waters to assess particle dynamic and carbon export in relation to the development of a coccolithophore bloom. We observed a marked northward decrease in Chl-a concentration and calcification rates: the bloom exhibited lower values and may less well developed in the Goban Spur area. The export fluxes of POC and PIC from the top 80 m, determined using the ratios of POC and PIC to 234Th of particles, ranged from 81 to 323 mgC m-2 d-1 and from 30 to 84 mgC m-2 d-1, respectively. The highest fluxes were observed in waters presenting a well-developed coccolithophore bloom, as shown by high reflectance of surface waters. This experiment confirms that the occurrence of coccolithophores promotes efficient export of organic and inorganic carbon on the North-West European margin. [less ▲]

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See detailLes eaux continentales comme sources de gaz à effet de serre vers l’atmosphère : étude pilote dans 4 cours d’eau en Wallonie
Borges, Alberto ULg

Scientific conference (2012, October 25)

Les eaux continentales (fleuves et lacs) sont d’importantes composantes des cycles globaux du carbone et de l’azote. Elles transportent du carbone et de l’azote organique et inorganique des écosystèmes ... [more ▼]

Les eaux continentales (fleuves et lacs) sont d’importantes composantes des cycles globaux du carbone et de l’azote. Elles transportent du carbone et de l’azote organique et inorganique des écosystèmes terrestres vers les océans. Cependant, ce transport n’est pas passif et les eaux continentales produisent, dégradent, stockent et échangent du carbone et de l’azote avec l’atmosphère. Ainsi, les eaux continentales émettent du dioxyde de carbone (CO2), du méthane (CH4) et du protoxyde d’azote (N2O) vers l’atmosphère. Le CO2, CH4 et N2O sont les principaux gaz à effet de serre (GES) anthropiques, et le N2O est en plus le plus important agent anthropique de destruction de la couche d’ozone. L’Unité d’Océanographie Chimique a mené une étude pilote dans quatre cours d’eau à proximité de la ville Liège (Meuse, Ourthe, Geer et Ruisseau du Blanc Gravier) qui ont été étudiés afin de décrire la dynamique du CO2, CH4 et N2O et d’en estimer les flux émis des eaux de surface vers l’atmosphère. Les conditions ainsi que les résultats de l’étude seront présentés lors de cet exposé. [less ▲]

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See detailVertical stratification and functional guilds in the bacterial community of Lake Kivu (East Africa)
Garcia-Armisen, T; Inceoglu, O; Llirós, M et al

Conference (2012, August 19)

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