Search publications of the members of the Royal Belgian institute of natural Sciences
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Suspended Particulate Matter (SPM) mapping from MERIS imagery. Calibration of a regional algorithm for the Belgian coastal waters
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MERIS imagery of Belgian coastal waters: mapping of Suspended Particulate Matter and Chlorophyll-a
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Preliminary validation of MERIS water products for Belgian coastal waters
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Validation of MERIS water products for Belgian coastal waters: 2002-2003
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Suspended Particulate Matter Mapping From Multitemporal SeaWiFS Imagery Over The Southern North Sea (SEBAB Project)
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A model of diffuse attenuation of the downwelling irradiance for ecosystem models
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Calibration and validation of a generic multisensor algorithm for mapping of turbidity in coastal waters
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Spatio-temporal Dynamics of the Turbidity Maximum in the Belgian-Dutch Coastal Zone (51.5 N)
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Promoting best practices in ocean forecasting through an Operational Readiness Level
- Predicting the ocean state in a reliable and interoperable way, while ensuring high-quality products, requires forecasting systems that synergistically combine science-based methodologies with advanced technologies for timely, user-oriented solutions. Achieving this objective necessitates the adoption of best practices when implementing ocean forecasting services, resulting in the proper design of system components and the capacity to evolve through different levels of complexity. The vision of OceanPrediction Decade Collaborative Center, endorsed by the UN Decade of Ocean Science for Sustainable Development 2021-2030, is to support this challenge by developing a “predicted ocean based on a shared and coordinated global effort” and by working within a collaborative framework that encompasses worldwide expertise in ocean science and technology. To measure the capacity of ocean forecasting systems, the OceanPrediction Decade Collaborative Center proposes a novel approach based on the definition of an Operational Readiness Level (ORL). This approach is designed to guide and promote the adoption of best practices by qualifying and quantifying the overall operational status. Considering three identified operational categories - production, validation, and data dissemination - the proposed ORL is computed through a cumulative scoring system. This method is determined by fulfilling specific criteria, starting from a given base level and progressively advancing to higher levels. The goal of ORL and the computed scores per operational category is to support ocean forecasters in using and producing ocean data, information, and knowledge. This is achieved through systems that attain progressively higher levels of readiness, accessibility, and interoperability by adopting best practices that will be linked to the future design of standards and tools. This paper discusses examples of the application of this methodology, concluding on the advantages of its adoption as a reference tool to encourage and endorse services in joining common frameworks.
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Lessons from the calibration and sensitivity analysis of a fish larval transport model
- ABSTRACT: Numerous fish populations show strong year-to-year variations in recruitment. The early life stages play a crucial role in determining recruitment and dispersal patterns. A helpful tool to understand recruitment and dispersal involves simulations with a Lagrangian transport model, which results from the coupling between a hydrodynamic model and an individual-based model. Larval transport models require sound knowledge of the biological processes governing larval dispersal, and they may be highly sensitive to the parameters selected. Various assumptions about larval traits, behaviour and other model parameters can be tested by comparing simulation results with field data to identify the most sensitive parameters and to improve model calibration. This study shows that biological parameterization is more important than inter-annual variability in explaining the year-to-year differences in larval recruitment of common sole in the North Sea and the eastern English Channel. In contrast, year-to-year variability of connectivity leads to higher variability than changes in the biological parameters. The most influential parameters are pelagic larval duration, spawning period and mortality. Calibration over a 12 yr recruitment survey shows that a scenario with low mortality associated with a long larval duration and behaviour involving nycthemeral and tidal migration best reproduces the observations. This research provides insights into factors influencing fish dispersal and recruitment, suggesting a strategy for enhancing the accuracy of models in upcoming studies. The study supports the improvement of larval dispersal modelling by incorporating an easily applicable sensitivity analysis for both calibration and validation. Incorporating sensitivity analyses enhances larval dispersal models, providing performing tools that can contribute to informed fisheries management and understanding of recruitment variability.
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Intraskeletal histovariability, allometric growth patterns, and their functional implications in bird-like dinosaurs
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Fossil whale barnacles from the lower Pleistocene of Sicily shed light on the coeval Mediterranean cetacean fauna
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Responses of summer phytoplankton biomass to changes in top-down forcing: Insights from comparative modelling
- Abstract The present study describes the responses of summer phytoplankton biomass to changes in top-down forcing (expressed as zooplankton mortality) in three ecosystems (the North Sea, the Baltic Sea and the Nordic Seas) across different 3D ecosystem models. In each of the model set-ups, we applied the same changes in the magnitude of mortality (±20%) of the highest trophic zooplankton level (Z1). Model results showed overall dampened responses of phytoplankton relative to \Z1\ biomass. Phytoplankton responses varied depending on the food web structure and trophic coupling represented in the models. Hence, a priori model assumptions were found to influence cascades and pathways in model estimates and, thus, become highly relevant when examining ecosystem pressures such as fishing and climate change. Especially, the different roles and parameterizations of additional zooplankton groups grazed by Z1, and their importance for the outcome, emphasized the need for better calibration data. Spatial variability was high within each model indicating that physics (hydrodynamics and temperature) and nutrient dynamics also play vital roles for ecosystem responses to top-down effects. In conclusion, the model comparison indicated that changes in top-down forcing in combination with the modelled food-web structure affect summer phytoplankton biomass and, thereby, indirectly influence water quality of the systems.
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Deux millénaires d’occupations mésolithiques au bord de l’Escaut à Kerkhove (Belgique) : première approche palethnographique
- Résumé : La fouille récente du gisement alluvial de Kerkhove (Belgique), situé dans la vallée de l’Escaut, à une vingtaine de kilomètres de la frontière française, a permis de mettre au jour 17 locus mésolithiques. D’après les données typochronologiques et les datations absolues, ces locus datent non seulement du Mésolithique ancien, mais aussi du Mésolithique moyen et récent. La première phase d’occupation de la levée alluviale, datée du 11e et 10e millénaire avant le présent (cal BP), a clairement été la plus intensive. Elle correspond à un Mésolithique ancien caractérisé par des assemblages du « groupe de Chinru », dominés par les triangles et les pointes à base retouchée. La deuxième phase d’occupation, celle du Mésolithique moyen, compte trois locus et est caractérisée par de nombreuses lamelles étroites à bord abattu, et des pointes à retouche couvrante d’une part, et par une exploitation de matières premières siliceuses différentes d’autre part. La dernière phase d’occupation date du Mésolithique récent. Elle est représentée par un seul locus qui a livré de nombreux artefacts en grès-quartzite de Wommersom, quelques trapèzes et des lamelles plus régulières. Le principal intérêt du site de Kerkhove est la possibilité d’étudier tous les aspects de l’industrie lithique, mais également l’exploitation des matières premières siliceuses et des autres ressources naturelles dans une large perspective diachronique. En effet, hors vestiges lithiques, des quantités considérables de coquilles de noisettes carbonisées et de restes fauniques ont été récupérées. En plus de la présence d’ossements brûlés, des restes fauniques non brûlés sont également conservés, situation inédite pour le Mésolithique ancien, moyen et récent du nord de la Belgique. Ainsi, les ossements de sanglier et de chevreuil dominent les assemblages du Mésolithique ancien et sont associés à des restes d’animaux à fourrures, tandis que les contextes du Mésolithique moyen livrent des indices fréquents de consommation de poissons sur le site. Mots-clés : Mésolithique ancien, Mésolithique moyen, RMS, Mésolithique récent, faune, poisson, tracéologie lithique, analyse spatiale. Abstract: 17 Mesolithic artefact loci were discovered on an alluvial levee during recent excavations at the wetland site of Kerkhove, located in the Scheldt floodplain at about 20 km from the French border. On typochronological grounds, these artefact loci are mainly dated to the Early Mesolithic, already well known from previous large-scale excavations in the lower Scheldt basin, but also to the lesser known Middle and Late Mesolithic periods. The first occupation phase proved to be the most intense and lasted from the middle of the 11th to the middle of the 10th millennium cal BP, based on a series of 19 14C-dates on single entity charred hazelnut shells. At least 9 different artefact loci belonging to this period were documented, covering either small (< 40 m2) or rather large areas (> 100 m2). The microlith compositions of most of these clusters were dominated by triangles and points with retouched base, corresponding to the regional assemblage type of the « Chinru group ». The second occupation phase, the Middle Mesolithic, was harder to define spatially, due to its location on the western edge of the excavation area and to its partial admixture with Early Mesolithic artefacts at specific locations. Nevertheless, three distinct artefact loci were discovered, characterised by the presence of numerous small backed bladelets combined with occasional points with invasive retouch on the one hand and by a different exploitation of lithic raw material resources on the other hand. Besides these more traditional clusters, several discrete concentrations of armatures were located in the low-density areas to the west of the most important Middle Mesolithic occupation zone. Unfortunately, this Middle Mesolithic occupational phase could not be directly dated by ecofacts associated with the artefact loci. However, two dates on unburnt faunal remains recovered from the colluvial deposits on the slope of the levee, indicate that this Middle Mesolithic occupation could date to as early as the second part of the 10th millennium cal BP, at the very beginning of the Middle Mesolithic period. Finally, the last occupation of the site dates to the Late Mesolithic and is only represented by one artefact locus, that contained regular Wommersom quartzite and flint bladelets associated with a few trapezes. Unfortunately, no absolute dates were obtained for this cluster to corroborate and specify its chronological position. This being said, the Kerkhove site offers the advantage, compared to previously excavated sites, that it allows us to study evolutions in lithic typology, lithic technology, tool-uses and the exploitation of lithic raw materials and other types of natural resources from a multi-period perspective. Indeed, besides lithics, considerable amounts of carbonized hazelnut shells and faunal remains were recovered, the latter consisting not only of heavily burnt bone fragments but also numerous unburnt remains. This particular feature of the site is unprecedented within the Early to Late Mesolithic of northern Belgium and allows us for the first time to reconstruct the subsistence behaviour of the Mesolithic hunter-gatherers of the Scheldt basin. Furthermore, the detailed excavation methodology applied, allows for a high-resolution intra-site analysis including not only the spatially well-defined artefact loci but also the areas in between, characterized by the occurrence of small and a low-density artefact clusters. The most interesting preliminary results consist of the striking differences between the distinct occupations phases of the sites on several levels, from the general layout and spatial organisation, over site-function, raw material procurement to the exploitation of animal and plant resources. These differences are particularly outspoken when comparing the Early and Middle Mesolithic occupation of the site. The Early Mesolithic occupation appears homogeneous and is mainly characterised by the use of Scheldt flint, the systematic presence of carbonised hazelnut shells, the almost systematic presence of hearths in the clusters and the functional organisation of space, that doesn’t show contrasts between the individual clusters. Moreover, medium-sized mammals like wild boar and roe deer dominate these assemblages and they are to a lesser extent accompanied by fur-animals such as pine marten. By contrast, the layout and the general use of space of the Middle Mesolithic occupation seems to diverge completely from this picture. From this time onwards, Wommersom quartzite is imported and the use of the Scheldt flint is largely abandoned in favour of a grey-brown translucent and more fine-grained flint, probably indicating a change in the social territorial boundaries of the groups occupying the site of Kerkhove. Besides this, from a functional point of view, the clusters clearly contrast with one another and seem to form special activity areas, although it remains to be proven whether they are complementary special activity areas from one and the same larger campsite or if they are non-contemporaneous, individually functioning clusters. Furthermore, hearth features and carbonised hazelnut shells are completely absent from these artefact loci. Finally, in addition to the exploitation of wild boar, roe deer, red deer and fur animals, from the Middle Mesolithic onwards, we have indications for the consumption of freshwater fish at the site, in the form of burnt fish remains associated with the aforementioned discrete armature clusters. Keywords: Early Mesolithic, Middle Mesolithic, RMS, Late Mesolithic, faunal remains, fish, microwear-analysis, spatial analysis.
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Molecular detection and genomic characterisation of diverse hepaciviruses in African rodents
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Historical biogeography, systematics, and integrative taxonomy of the non‑Ethiopian speckled pelage brush‑furred rats (Lophuromys flavopunctatus group)
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First record of the cicadas genus Orientopsaltria Kato, 1944 (Hemiptera: Cicadidae) from Vietnam, with description of one new species
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A new species and first record of the cicada genus Sinotympana Lee, 2009 (Hemiptera: Cicadidae: Dundubiini) from Vietnam
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A profitability study of CO2-EOR and subsequent CO2 storage in the North Sea under low oil market prices
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Towards geological-economic modelling to improve evaluating policy instruments for geothermal energy – Case study for Belgium (Campine Basin)
