References of "Remacle, Jean"
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See detailElevated atmospheric CO2 in open top chambers increases net nitrification and potential denitrification
Carnol, Monique ULg; Hogenboom, L.; Jach, M. E. et al

in Global Change Biology (2002), 8

The control of soil nitrogen (N) availability under elevated atmospheric CO2 is central to predicting changes in ecosystem carbon (C) storage and primary productivity. The effects of elevated CO2 on ... [more ▼]

The control of soil nitrogen (N) availability under elevated atmospheric CO2 is central to predicting changes in ecosystem carbon (C) storage and primary productivity. The effects of elevated CO2 on belowground processes have so far attracted limited research and they are assumed to be controlled by indirect effects through changes in plant physiology and chemistry. In this study, we investigated the effects of a 4-year exposure to elevated CO2 (ambient + 400 mumol mol(-1) ) in open top chambers under Scots pine (Pinus sylvestris L) seedlings on soil microbial processes of nitrification and denitrification. Potential denitrification (DP) and potential N-2 O emissions were significantly higher in soils from the elevated CO2 treatment, probably regulated indirectly by the changes in soil conditions (increased pH, C availability and NO3 (-) production). Net N mineralization was mainly accounted for by nitrate production. Nitrate production was significantly larger for soil from the elevated CO2 treatment in the field when incubated in the laboratory under elevated CO2 (increase of 100%), but there was no effect when incubated under ambient CO2 . Net nitrate production of the soil originating from the ambient CO2 treatment in the field was not influenced by laboratory incubation conditions. These results indicate that a direct effect of elevated atmospheric CO2 on soil microbial processes might take place. We hypothesize that physiological adaptation or selection of nitrifiers could occur under elevated CO2 through higher soil CO2 concentrations. Alternatively, lower microbial NH4 assimilation under elevated CO2 might explain the higher net nitrification. We conclude that elevated atmospheric CO2 has a major direct effect on the soil microbial processes of nitrification and denitrification despite generally higher soil CO2 concentrations compared to atmospheric concentrations. [less ▲]

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See detailRt-Pcr-Elosa Tests On Pooled Sample Units For The Detection Of Virus Y In Potato Tubers
Chandelier, Anne; Dubois, Nathalie ULg; Baelen, Frédéric et al

in Journal of Virological Methods (2001), 91(2), 99-108

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See detailImpact of dolomite lime on the ground vegetation and on potential net N transformations in Norway spruce (Picea Abies (L.) Karst.) and sessile oak (Quercus Petraea (Matt.) Lieb.) stands in the Belgian Ardenne
Duliere, J.-F.; Carnol, Monique ULg; Dalem, S. et al

in Annals of Forest Science : a Multidisciplinary and International Journal (1999), 56

The impact of dolomite lime (5 T·ha-1) on the ground vegetation and on potential net nitrogen (N) transformations was investigated in two Belgian forest ecosystems. Norway spruce (Picea abies (L.) Karst ... [more ▼]

The impact of dolomite lime (5 T·ha-1) on the ground vegetation and on potential net nitrogen (N) transformations was investigated in two Belgian forest ecosystems. Norway spruce (Picea abies (L.) Karst.) and sessile oak (Quercus petraea (Matt.) Lieb.) stands were situated in the Haute Ardenne (east Belgium) on acid-brown soil. The herb-layer floristic richness increased during the 2 years following liming, with the appearance of light and N-demanding species, which are also found in clear-cut areas or on road verges. Mosses reacted rapidly, showing a decrease acidophilous-dominant species and the establishment of some ruderal species. Six months after liming, the pH was significantly increased in the organic horizon of both stands and in the organomineral horizon of the oak stand. Soils originating from the two stands showed distinct responses in net NO3- production to the dolomite lime treatment. In the organic layer of the Quercus soil, net NH4+ production was decreased, NO3- production increased, and total N mineralisation remained unchanged. In the organomineral layer, NO3 - production was increased. In the Picea soil, NO3 - production was decreased in the organomineral soil layer. These results indicate the possibility of differences in the control of the N transformation processes occurring in the two sites. [less ▲]

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See detailHypoxia-induced activation of HIF-1: role of HIF-1alpha-Hsp90 interaction.
Minet, E.; Mottet, Denis ULg; Michel, G. et al

in FEBS Letters (1999), 460(2), 251-6

The protein chaperone heat shock protein 90 (Hsp90) is a major regulator of different transcription factors such as MyoD, a basic helix loop helix (bHLH) protein, and the bHLH-Per-aryl hydrocarbon nuclear ... [more ▼]

The protein chaperone heat shock protein 90 (Hsp90) is a major regulator of different transcription factors such as MyoD, a basic helix loop helix (bHLH) protein, and the bHLH-Per-aryl hydrocarbon nuclear translocator (ARNT)-Sim (PAS) factors Sim and aryl hydrocarbon receptor (Ahr). The transcription factor hypoxia-inducible factor-1alpha (HIF-1alpha), involved in the response to hypoxia, also belongs to the bHLH-PAS family. This work was aimed to investigate the putative role of Hsp90 in HIF-1 activation by hypoxia. Using a EGFP-HIF-1alpha fusion protein, co-immunoprecipitation experiments evidenced that the chimeric protein expressed in COS-7 cells interacts with Hsp90 in normoxia but not in hypoxia. We also demonstrated that Hsp90 interacts with the bHLH-PAS domain of HIF-1alpha. Moreover, Hsp90 is not co-translocated with HIF-1alpha into the nucleus. At last, we showed that Hsp90 activity is essential for HIF-1 activation in hypoxia since it is inhibited in the presence of geldanamycin. These results indicate that Hsp90 is a major regulator in HIF-1alpha activation. [less ▲]

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See detailAmendement de bassins versants dans les Ardennes belges: effets sur l'eau de percolation et l'eau à l'exutoire
Carnol, Monique ULg; Piret, André ULg; Requier, Marie-Christine ULg et al

in Santé et Biodiversité en Forêt Wallonne - Acte des Colloques (1998)

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See detailComparaison des peuplements de diatomées épilithiques de ruisseaux acides en milieu forestier soumis à un amendement de dolomie (Massif Ardennais, Belgique)
Loncin, Anne; Leclercq, Louis ULg; Carnol, Monique ULg et al

in Annales de Limnologie (1998), 34(1), 13-22

Three to five years following application of dolomite (calcium magnesium carbonate) on some forest catchments in the belgian area of the Ardenne, epilithic diatoms were sampled in two streams running on ... [more ▼]

Three to five years following application of dolomite (calcium magnesium carbonate) on some forest catchments in the belgian area of the Ardenne, epilithic diatoms were sampled in two streams running on treated sites and in two streams running on untreated sites in order to evaluate the possible changes in the algal population. Typical acid water assemblages with Eunotia were observed. The dominant species was Eunotia exigua often found with E. rhomboidea or E. bilunaris. In the present study, no influence of the treatment can be demonstrated using these bioindicators. [less ▲]

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See detailWatershed Liming in the Belgian Ardennes : Effects on soil solution and streamwater chemistry
Carnol, Monique ULg; Hambuckers, Alain ULg; Remacle, Jean ULg

Conference (1997, June)

Forest liming has received increased attention in the 1980s, when unusual needle yellowing and fall were observed in large parts of Europe and North America. This ‘new forest decline’ has been attributed ... [more ▼]

Forest liming has received increased attention in the 1980s, when unusual needle yellowing and fall were observed in large parts of Europe and North America. This ‘new forest decline’ has been attributed to several causes acting individually or synergetically, amongst which were acidification, N saturation and nutritional imbalances. This time, liming did not aim at increased productivity, but as a counteracting measure to the soil acidification and to remove nutritional imbalances. The Belgian Ardennes were not exempt from this phenomena and symptoms of forest dieback were reported in 1983 by Weissen (Weissen et al.,1983). Soils are naturally poor in magnesium and the observed dieback was supposed to be the consequence of increased pollution exacerbating the deficiency in magnesium. A reduction in productivity and financial losses were predicted. Liming was suggested for prevention and correction, however possible side effects, in particular on soil solution (tree nutrition) and stream water chemistry (drinking water) needed to be evaluated. In this paper, we present results from a case study in four Picea abies watersheds in southern Belgium. The paired watersheds of approximately 80 ha were situated in the ‘Haute Ardenne’ and in the ‘Ardenne occidentale’ regions, on acid brown soils. One watershed of each pair was limed with 3 T/ha of fine ground dolomite ((Ca,Mg)CO3) 55/40 and 200 kg/ha K2SO4 in 1992 and 1993, respectively. Rainfall, throughfall and monolith lysimeter soil solution were analysed at monthly intervals, and runoff chemistry at two-weekly intervals (volume-weighed reconstructed daily samples). Time series intervention analysis was used as a tool to detect statistically significant changes in stream water chemistry due to the liming event, and fluxes were calculated to evaluate losses of the applied dolomitic lime to the catchment stream. Dolomite dissolution distinctively affected streamwater chemistry in the watershed situated in the Hautes Ardennes (Waroneu). Magnesium concentrations increased immediately after liming, most likely due to surface runoff. Four years after liming, concentrations were still higher than prior to liming. However, the proportions of magnesium lost were relatively low compared to the dose applied. Calcium concentrations did not change after liming in either catchment, nor did the concentrations of the major cations and anions measured. In the monolith lysimeters, magnesium concentrations increased immediately after liming under the organic horizons, and one year after liming under the mineral horizons. Calcium concentrations increased only three years after the application of lime under the organic and mineral horizons. These results led to the conclusions that for the soils under study and the doses applied, a major part of the lime was retained by the soil system, and that consequences on water chemistry were minor. [less ▲]

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See detailIS THE PRESENCE OF MESOTROPHIC PLANT-COMMUNITIES IN THE PEAT-BOGS OF HAUTES-FAGNES (BELGIUM) CONNECTED WITH TONALITE INTRUSIONS IN THE REVINIAN LAYERS
Hambuckers, Alain ULg; Schumacker, René ULg; Remacle, Jean ULg et al

in Belgian Journal of Botany (1995), 128(1), 48-56

Within the Hautes-Fagnes Nature Reserve (Belgium) acidic and oligotrophic biotopes are developing on very acidified stony silt raised bogs. However, they are locally dominated by mesotrophic species ... [more ▼]

Within the Hautes-Fagnes Nature Reserve (Belgium) acidic and oligotrophic biotopes are developing on very acidified stony silt raised bogs. However, they are locally dominated by mesotrophic species. Based on the fact that there are several outcrops of tonalite in the region and particularly one in the Nature Reserve, a hypothesis to explain these singularities of the vegetation implies discontinuities of the bedrock provoked by intrusions of this magmatic rock in the Revinian layer covering the region. Seventeen plots containing Phragmites australis were examined and vegetation was described. Silt and soil water were sampled and analyzed for mineral contents in 15 sites. The differences of mineral composition between the P. australis plots and their surrounding environment confirmed the more mesotrophic characteristics of these plots (i.e. higher pH, higher Ca and Mg contents, lower Al content). However, the lower Zn, Pb and Fe contents would lead to reject the hypothesis of intrusions of tonalite since these elements are more abundant in the tonalite and its mineralization than in the Revinian rock. Nevertheless, the overall ecological conditions of the examined plots and the differences of plant species composition suggested that the observed chemical environment could be evoked for explaining the distribution of the mesotrophic species in the oligotrophic environment of the Nature Reserve. Consequently, an alternative hypothesis is proposed. [less ▲]

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See detailRELATIVE IMPORTANCE OF FACTORS CONTROLLING THE LEACHING AND UPTAKE OF INORGANIC-IONS IN THE CANOPY OF A SPRUCE FOREST
Hambuckers, Alain ULg; Remacle, Jean ULg

in Biogeochemistry (1993), 23(2), 99-117

Sequential sampling of precipitation under mature spruce trees and time-series analysis of the data were performed in order to assess, in natural conditions, the relative importance of different factors ... [more ▼]

Sequential sampling of precipitation under mature spruce trees and time-series analysis of the data were performed in order to assess, in natural conditions, the relative importance of different factors that could influence the leaching and uptake of inorganic ions in the canopy. Eleven rain events were analyzed in order to estimate how external factors, rain intensity, H+, and ionic concentration of the incident rain influence the ionic throughfall concentrations and the net throughfall fluxes. The results led to the conclusion that leaching or uptake mostly occur by diffusion. The influence of the open rain acidity was not conclusive; however, it was shown that the tested external factors only controlled a few percent of the variation of the data. By contrast, the autocorrelation of the data always explained a large portion of the variance. lt could result from the gradual changes in the course time of internal factors related to the exchange system including waxes, cuticles, apoplast and xylem sap. These constituents were known to control the exchange at the canopy surface and to be sensitive to the plant physiology and environmental conditions. [less ▲]

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See detailNUTRITIONAL-STATUS OF DECLINING SPRUCE (PICEA-ABIES (L) KARST) - EFFECT OF SOIL ORGANIC-MATTER TURNOVER RATE
Hambuckers, Alain ULg; Remacle, Jean ULg

in Water, Air & Soil Pollution (1991), 59(1-2), 95-106

Foliar analysis was undertaken in two plots of Picea abies (L.) Karst., located in a watershed of Haute Ardenne, Belgium, in order to estimate the decline of the trees. Apart from a general Mg deficiency ... [more ▼]

Foliar analysis was undertaken in two plots of Picea abies (L.) Karst., located in a watershed of Haute Ardenne, Belgium, in order to estimate the decline of the trees. Apart from a general Mg deficiency, the concentrations of the needles were in the same range as those determined in other European stands. Comparisons between healthy and declining trees within each plot revealed a general pattern of decline similar to that observed elsewhere in Western Europe. This was shown as lower Ca, Mg, Zn concentrations and water content and higher N and P concentrations of the needles collected from declining trees. It is concluded that this decline could be due to N over fertilization by the atmospheric deposition. The difference of decline between the two plots was attributed to the turnover rate of the soil organic layer which was less intensive in the most damaged plot. [less ▲]

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See detailA Decennial Control Of N-Cycle In The Belgian Ardenne Forest Ecosystems
Weissen, F.; Hambuckers, Alain ULg; Vanpraag, Hj. et al

in Plant and Soil (1990), 128(1),

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