Showing results 81 to 100 of 144
  Variability of the partial pressure of CO2 in the upper Scheldt estuary from 2003 to 2007Borges, Alberto  ; ; Commarieu, Marc-Vincent et alPoster (2008) Detailed reference viewed: 5 (1 ULg)Estimating pCO2 from remote sensing in the Case-II waters of the Belgian Coastal Zone – First results from the BELCOLOUR-II projectBorges, Alberto ; ; Commarieu, Marc-Vincent et alPoster (2008) Detailed reference viewed: 5 (0 ULg)Carbon dioxide dynamics in lake Kivu during the dry and wet seasonsBorges, Alberto ; Delille, Bruno ; et alPoster (2008) Detailed reference viewed: 6 (0 ULg)Benthic dissolved inorganic carbon dynamics in the Gulf of Biscay (June 2006 – May 2007); Delille, Bruno ; Borges, Alberto Poster (2008) Detailed reference viewed: 5 (1 ULg)Inter-annual variability of the carbon dioxide oceanic sink south of TasmaniaBorges, Alberto ; ; et alPoster (2008) Detailed reference viewed: 3 (1 ULg)Seasonal variability of CO2 fluxes in the tropical lagoons of Ivory Coast; ; et al Poster (2008) Detailed reference viewed: 5 (0 ULg)A dynamic model of an experimental bloom of coccolithophores Emiliania huxleyiJoassin, Pascal ; Borges, Alberto ; et alConference (2007, November 27) A dynamic model has been developed to represent biogeochemical events observed during an experimentally induced bloom of coccolithophores Emiliania huxleyi. This bloom occurred in a mesocosm experiment ... [more ▼] A dynamic model has been developed to represent biogeochemical events observed during an experimentally induced bloom of coccolithophores Emiliania huxleyi. This bloom occurred in a mesocosm experiment (Bergen 2001 experiment) during which ecosystem development was followed over a 23-days period through changes of the stocks of inorganic nutrients (nitrate, ammonium and phosphate), dissolved inorganic carbon and pCO2, O2 concentration, pigments, particulate organic carbon and nitrogen, dissolved organic carbon, the production of Transparent Exopolymeric Particles (TEP), primary production, alkalinity, calcification and particulate inorganic carbon. The dynamic model is based on unbalanced algal growth and balanced growth for bacteria as described in Van den Meersche et al. (2004). In addition, in order to adequately reproduce the observations, the model has been extended by including an explicit description of calcification, T.E.P production and an enhanced mortality due to viruses. This last process, based on a critical promiscuity between cellular hosts and viral agents, successfully contributed to reproduce the bloom extinction as observed in the mesocosm experiment. This model will be implemented in a coupled physical-biogeochemical model of the Black Sea ecosystem in the framework of the EU Sesame project and in the Gulf of Biscay in the frame of the Belgian PEACE project. [less ▲] Detailed reference viewed: 35 (1 ULg)Planktonic Archaea in Lake Kivu; Darchambeau, François ; et alConference (2007, September 02) Detailed reference viewed: 2 (2 ULg) Biogeochemistry of a late coccolithophorid bloom at the continental margin of the Bay of BiscayHarlay, Jérôme ; ; et alPoster (2007, July 02) Recent findings have led to growing concern regarding the impact of ocean acidification on marine calcifyers, but little is known about their biogeochemistry in natural (field) conditions (a major but ... [more ▼] Recent findings have led to growing concern regarding the impact of ocean acidification on marine calcifyers, but little is known about their biogeochemistry in natural (field) conditions (a major but overlooked pre-requisite for realistic modelling of the future evolution of marine C cycling in a high CO2 world). The changes that will undergo these species in the near future and the biological feedback to decreasing oceanic pH are still open to debate. Coccolithophores, among which Emiliania huxleyi (Ehux) is the most abundant and widespread species, are the dominant calcifying phytoplankton in the subpolar and temperate zones of the worlds oceans. Within the framework of the Climate and Atmosphere Belgian Federal Science Policy Office programme, the continental margin of the Northern Bay of Biscay (North Atlantic Ocean) was visited in June 2006 during a transdisciplinary investigation of a late-spring bloom dominated by Ehux. Remote sensing images, transmitted onboard on a daily basis, were of valuable significance to pinpoint the coccolithophorid bloom along the margin, and to sample stations with contrasted biogeochemical properties.We determined 14C-based primary production and calcification rates, as well as pelagic respiration rates (O2 incubations). The magnitude of the biological and carbonate carbon fluxes will be synthesized and discussed in the light of biogeochemical parameters, such as Transparent Exopolymer Particles (TEP), chlorophyll-a, particulate carbon concentrations, particle dynamics and particulate organic carbon export (deduced from 234Th fluxes). Additional information on the bloom biogeochemistry will be presented (activity of dissolved esterase enzymes and bacterial community structure) to emphasize the importance of coccolithophorid blooms in the contemporary carbon cycle. [less ▲] Detailed reference viewed: 25 (2 ULg)Biogas (CO2, O-2, dimethylsulfide) dynamics in spring Antarctic fast iceDelille, Bruno ; ; Borges, Alberto et alin Limnology and Oceanography (2007), 52(4), 1367-1379 We studied the temporal variations of CO2, O-2, and dimethylsulfide (DMS) concentrations within three environments (sea-ice brine, platelet ice-like layer, and underlying water) in the coastal area of ... [more ▼] We studied the temporal variations of CO2, O-2, and dimethylsulfide (DMS) concentrations within three environments (sea-ice brine, platelet ice-like layer, and underlying water) in the coastal area of Adelie Land, Antarctica, during spring 1999 before ice breakup. Temporal changes were different among the three environments, while similar temporal trends were observed within each environment at all stations. The underlying water was always undersaturated in O-2 (around 85%) and oversaturated in CO2 at the deepest stations. O-2 concentrations increased in sea-ice brine as it melted, reaching oversaturation up to 160% due to the primary production by the sea-ice algae community (chlorophyll a in the bottom ice reached concentrations up to 160 mu g L-1 of bulk ice). In parallel, DMS concentrations increased up to 60 nmol L-1 within sea- ice brine and the platelet ice- like layer. High biological activity consumed CO2 and promoted the decrease of partial pressure of CO2 (pCO(2)). In addition, melting of pure ice crystals and calcium carbonate (CaCO3) dissolution promoted the shift from a state of CO2 oversaturation to a state of marked CO2 undersaturation (pCO(2) < 30 dPa). On the whole, our results suggest that late spring land fast sea ice can potentially act as a sink of CO2 and a source of DMS for the neighbouring environments, i.e., the underlying water or/ and the atmosphere. [less ▲] Detailed reference viewed: 63 (2 ULg)Planktonic Archaea in Lake Kivu; Darchambeau, François ; et alConference (2007, June 12) Detailed reference viewed: 7 (3 ULg)Carbon dioxide fluxes in Lake KivuBorges, Alberto ; Delille, Bruno ; et alConference (2007, June 12) Detailed reference viewed: 1 (0 ULg)Dedication - Michel FrankignoulleBorges, Alberto ; Delille, Bruno in Journal of Marine Systems (2007), 66(1-4), 4-5 Detailed reference viewed: 168 (9 ULg)Spatial and temporal variation of bacterioplankton in a sub-Antarctic coastal area (Kerguelen Archipelago); ; Delille, Bruno in Journal of Marine Systems (2007), 68(3-4), 366-380 Bacterial abundance and production were measured monthly for one year along cross-shore transects in 3 sub-Antarctic fjords of the Kerguelen Archipelago (seven stations each). Mean values of the 3 most ... [more ▼] Bacterial abundance and production were measured monthly for one year along cross-shore transects in 3 sub-Antarctic fjords of the Kerguelen Archipelago (seven stations each). Mean values of the 3 most coastal (inside) and most offshore (outside) stations were used to describe the relationship between temperature, phytoplankton biomass, bacterial abundance and bacterial production over a one year annual cycle. The entire sampling protocol was repeated twice during each cruise: once at noon and once at midnight. Over the whole sampling period, the temperature ranged from 2.1 to 7.4 degrees C, while chlorophyll a concentrations varied by a factor of 10, and bacterial abundance and production varied by factors of 12 and 30, respectively. Within one day, all of these parameters sometimes varied by a factor of 4 between noon and midnight. A clear seasonality was observed for all of the parameters. However, while variations of phytoplankton and bacterial production paralleled those of temperature, bacterial abundance was low in midsummer and maximum in autumn. While no general pattern could be observed from the total data set, spatial gradients could interfere strongly with temporal changes. (C) 2007 Elsevier B.V All rights reserved. [less ▲] Detailed reference viewed: 18 (0 ULg)Carbon dioxide in European coastal watersBorges, Alberto ; ; et alPoster (2007) Detailed reference viewed: 1 (0 ULg)Preliminary results of continuous oxygen measurement above a Posidonia oceanica seagrass bed in the Bay of Calvi (Corsica); Champenois, Willy ; Delille, Bruno et alPoster (2007) Detailed reference viewed: 10 (2 ULg)Dissolved inorganic carbon dynamics in the Gulf of Biscay (June 2006); Delille, Bruno ; Borges, Alberto Poster (2007) Detailed reference viewed: 1 (0 ULg)8. Borges A.V., B. Tilbrook, N. Metzl & B. Delille, Inter-annual variability of the carbon dioxide oceanic sink south of TasmaniaBorges, Alberto ; ; et alConference (2007) Detailed reference viewed: 9 (2 ULg)Carbon dioxide dynamics in the tropical Ebrié lagoon (Ivory Coast); Delille, Bruno ; Borges, Alberto Poster (2007) Detailed reference viewed: 8 (0 ULg) |
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