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| Desmit, X.; Thieu, V.; Billen, G.; Campuzano, F.; Duliere, V.; Garnier, J.; Lassaletta, L.; Menesguen, Alain; Neves, R.; Pinto, L.; Silvestre, M.; Sobrinho, J. L.; Lacroix, G.. |
| Marine eutrophication in the North-East Atlantic (NEA) strongly relies on nutrient enrichment at the river outlets, which is linked to human activities and land use in the watersheds. The question is whether human society can reduce its nutrient emissions by changing land use without compromising food security. A new version of Riverstrahler model (pyNuts-Riverstrahler) was designed to estimate the point and diffuse nutrient emissions (N, P, Si) to the rivers depending on land use in the watersheds across a large domain (Western Europe agro-food systems, waste water treatment). The loads from the river model have been used as inputs to three marine ecological models (PCOMS, ECO-MARS3D, MIRO&CO) covering together a large part of the NEA from the Iberian... |
| Tipo: Text |
Palavras-chave: North-East Atlantic; Eutrophication; Model scenarios; Land-sea continuum; Land use; Pristine; Management support. |
| Ano: 2018 |
URL: http://archimer.ifremer.fr/doc/00438/55007/56426.pdf |
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| Billen, G.. |
| Nitrification and repartition of nitrifying bacteria were investigated in the autoepuration zone of the Scheldt estuary. Measurements of vertical profiles of nitrate and nitrite concentrations in the interstitial water of sediments show that nitrification in sediments is very low, implying that most of the nitrate and nitrate production occurs in the water of the river itself. Nitrifying bacteria, probably of terrestrial origin, are present throughout the water along a longitudinal profile of the estuary, with a regular decrease in numbers downstream. However, nitrification occurs only in a zone of favourable oxidation-reduction conditions, which coincides with the thermodynamic stability fields of nitrate and nitrite with respect to ammonium. |
| Tipo: Info:eu-repo/semantics/article |
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| Ano: 1975 |
URL: http://www.vliz.be/nl/open-marien-archief?module=ref&refid=3502 |
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| Vanderborght, J.P.; Billen, G.. |
| Vertical concentration profiles of nitrate in interstitial water of sediment in the Sluice Dock at Ostend (Belgium) commonly show a maximum in nitrate concentration at a few centimeters depth where sediments are sandy and poor in organic matter, while in muddy and organic-rich sediments, nitrate is lower in interstitial water than in the overlying water and decreases rapidly with depth. Direct measurements of the activity of autotrophic nitrifying bacteria in the sediments show nitrification in the upper few centimeters of sandy sediments but not in muddy sediments. A mathematical model is proposed to analyze quantitatively these experimental results, taking into account nitrification, denitrification, diffusion, and sedimentation. Seasonal variations of... |
| Tipo: Info:eu-repo/semantics/article |
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| Ano: 1975 |
URL: http://www.vliz.be/nl/open-marien-archief?module=ref&refid=3524 |
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| Joiris, C.R.; Billen, G.; Lancelot, MH.; Daro, M.H.; Mommaerts, J.-P.; Bertels, A.; Bossicart, M.; Nijs, J.; Hecq, J.H.. |
| The various biological compartments of the Belgian coastal zone of the North Sea were studied since 1971. The synthesis of available data on carbon cycling includes phytoplankton biomass and activities (particulate and dissolved primary production, respiration) , zooplankton biomass and activities (grazing, respiration) and planktonic and benthic microbial heterotrophic activities. These various carbon flux estimates allow the development of an overall budget of carbon cycling. This budget shows the importance of microbial (planktonic and benthic) heterotrophs versus zooplankton in the utilization of primary production. Comparison with literature data suggests that this could be a general feature of coastal, as opposed to open sea ecosystems. |
| Tipo: Info:eu-repo/semantics/article |
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| Ano: 1982 |
URL: http://www.vliz.be/nl/open-marien-archief?module=ref&refid=6908 |
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| Billen, G.; Joiris, C.R.; Wijnant, J.; Gillain, G.. |
| Concentrations and utilization rates of alanine, aspartate, lysine, glucose, glycollic, acetic and lactic acids have been determined on 6 occasions at least, during a full seasonal cycle in the water column of 3 stations (Scheldt estuary, coastal North Sea and English Channel) with greatly differing biological characteristics. No significant differences in substrate concentration could be detected between the 3 stations, although the rate of utilization of all substrates differed greatly, decreasing in the order estuarine > coastal > open sea environment. This apparent paradox is explained by aid of a simple model showing that the steady state concentration of a particular substrate is independent of its rate of production (and thus of consumption)... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Organic compounds ANE; Belgium; Belgian Coast ANE; English Channel Belgium; Zeeschelde. |
| Ano: 1980 |
URL: http://www.vliz.be/nl/open-marien-archief?module=ref&refid=6912 |
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| Benoit, M.; Garnier, J.; Billen, G.; Mercier, B.; Azougui, A.. |
| A great challenge to science is to elucidate how agriculture can feed the increasing world population without damaging the environment, while preserving other resources such as freshwater. In the Seine basin, characterised by intensive agriculture, most of surface and underground water is contaminated by nitrate. Conventional agriculture has regularly increased the use of industrial fertilisers since the WWII, leading to high nitrogen leaching, as shown by lysimeters or suction cup measurements. Such measurements are very scarce for other agricultural systems such as organic farming (Hansen et al. 2000; Haas et al. 2002; Mondelaers et al. 2009). The goal of our study is to investigate nitrogen leaching from organic agriculture, taking into account complete... |
| Tipo: Conference paper, poster, etc. |
Palavras-chave: Nutrient turnover; Air and water emissions. |
| Ano: 2013 |
URL: http://orgprints.org/24518/1/24518.pdf |
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| Anglade, J.; Billen, G.; Garnier, J.. |
| This work suggests that Soil Surface Balance is a robust indicator to compare the performances of organic agriculture with those of conventional agriculture, even strictly following the rules of rational and optimised application of fertilisers. The results of long term nitrogen budget calculation brought us to seriously reconsider the relevance of the need to increase crop yields, and more broadly to reconsider cropping patterns and production systems. In terms of policy levers for mitigating nitrogen contamination of water resources, only the shift to organic farming provides a possible way to reconcile agricultural production and water quality. Further, this view points out the need for specific measures to encourage more mixed farming approach to... |
| Tipo: Conference paper, poster, etc. |
Palavras-chave: Air and water emissions; Farm nutrient management. |
| Ano: 2013 |
URL: http://orgprints.org/24519/1/24519.pdf |
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