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See detailDensity variations and their influence on carbon stocks: case-study on two Biosphere Reserves in the Democratic Republic of Congo
De Ridder, Maaike; de Haulleville, Thalès ULg; Kearsley, Elizabeth et al

Poster (2014, April 28)

It is commonly acknowledged that allometric equations for aboveground biomass and carbon stock estimates are improved significantly if density is included as a variable. However, not much attention is ... [more ▼]

It is commonly acknowledged that allometric equations for aboveground biomass and carbon stock estimates are improved significantly if density is included as a variable. However, not much attention is given to this variable in terms of exact, measured values and density profiles from pith to bark. Most published case-studies obtain density values from literature sources or databases, this way using large ranges of density values and possible causing significant errors in carbon stock estimates. The use of one single fixed value for density is also not recommended if carbon stock increments are estimated. Therefore, our objective is to measure and analyze a large number of tree species occurring in two Biosphere Reserves (Luki and Yangambi). Nevertheless, the diversity of tree species in these tropical forests is too high to perform this kind of detailed analysis on all tree species (> 200/ha). Therefore, we focus on the most frequently encountered tree species with high abundance (trees/ha) and dominance (basal area/ha) for this study. Increment cores were scanned with a helical X-ray protocol to obtain density profiles from pith to bark. This way, we aim at dividing the tree species with a distinct type of density profile into separate groups. If, e.g., slopes in density values from pith to bark remain stable over larger samples of one tree species, this slope could also be used to correct for errors in carbon (increment) estimates, caused by density values from simplified density measurements or density values from literature. In summary, this is most likely the first study in the Congo Basin that focuses on density patterns in order to check their influence on carbon stocks and differences in carbon stocking based on species composition (density profiles ∼ temperament of tree species). [less ▲]

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See detailApplication of multi-scale variography for inferring the spatial variability of the hydraulic conductivity of a sandy aquifer
Rogiers, Bart; Vienken, Thomas; Gedeon, M et al

Poster (2014, April 28)

In the framework of the disposal of short-lived low- and intermediate-level radioactive waste in a near-surface disposal facility in Dessel (Belgium), extensive characterization of the hydraulic ... [more ▼]

In the framework of the disposal of short-lived low- and intermediate-level radioactive waste in a near-surface disposal facility in Dessel (Belgium), extensive characterization of the hydraulic conductivity (K) in the shallow Neogene aquifer has been performed at a regional scale. In the last few years the small-scale heterogeneity has been additionally characterized by outcrop analogue, hydraulic direct push, and borehole core air permeameter studies. The gathered data now include a) more than 350 hydraulic conductivity measurements on samples from 8 cored boreholes, mostly reaching depths of 50 m and data at 2 m intervals, b) more than 5000 air permeability measurements on the same borehole cores, c) more than 250 cone penetration tests (CPTs) with depths down to 40 m and data at 2 cm intervals, d) over 100 dissipation tests performed during the CPT campaigns, e) 17 direct push injections loggings, 6 hydraulic profiling tool logs, and 6 direct push slug tests, f) several hundreds of air permeability measurements on outcrop analogues of the aquifer sediments, and g) numerous grain size analyses. The current study aims to quantify the heterogeneity of K from the centimetre- to the kilometre-scale and to check the compatibility of the spatial variability revealed by the different datasets. This is achieved through gathering all K values (either direct measurements, calibrated relative K values, or K estimates from secondary data), and the use of variography to quantify spatial variability in terms of two-points geostatistics. The results are discussed, and the main differences between the different data sources are explained. In a final step, different multi-scale variogram models are proposed for capturing the main characteristics of multi-scale variability within the shallow Neogene aquifer in Belgium. [less ▲]

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See detailThe age of river-transported carbon: new data from African catchments and a global perspective
Marwick, TR; Tamooh, F; Teodoru, C et al

Conference (2014, April 27)

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See detailInorganic and organic carbon spatial variability in the Congo River during high waters (December 2013)
Borges, Alberto ULg; Bouillon, S; Teodoru, C et al

Poster (2014, April 27)

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See detailEutrophication counteracts ocean acidification effects on DMS emissions
Gypens, N; Borges, Alberto ULg

Poster (2014, April 27)

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See detailTemporal variability and spatial distribution of suspended matter and organic C pool in the Zambezi River
Teodoru, C; Bouillon, S; Borges, Alberto ULg et al

Poster (2014, April 27)

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See detailTemporal variability and spatial dynamics of CO2 and CH4 concentrations and fluxes in the Zambezi River system
Teodoru, C; Borges, Alberto ULg; bouillon, S et al

Conference (2014, April 27)

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See detailDrivers on carbon dioxide emissions from the Scheldt river basin
Gypens, N; Passy, P; Garnier, J et al

Poster (2014, April 27)

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See detailAnaerobic methane oxidation in two tropical freshwater systems
Roland, Fleur ULg; Darchambeau, François ULg; Crowe, SA et al

Poster (2014, April 27)

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See detailProduction of dissolved organic matter by phytoplankton and its uptake by heterotrophic prokaryotes in large tropical lakes
Morana, C; Sarmento, H; Descy, J-P et al

Poster (2014, April 27)

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