Search results

By the time the University of Liège was founded in 1817, geology was a young science and the geological composition of the country was being unveiled. The works of precursors such as Robert de Limbourg were about to inspire the first generation of Belgian geologists, among which Jean-Baptiste Julien d’Omalius d’Halloy is the most renowned. Geology was not taught at the University of Liège before 1818, when Henri-Maurice Gaëde was appointed. He taught geology, mineralogy and crystallography as well as anatomy and botany. He was followed by Armand Lévy in 1828, then again by Gaëde in 1830, Philippe-Adolphe Lesoinne in 1831, Charles-Philippe Davreux 1834 and Michel Gloesener in 1834. Except the mineralogist Lévy, none of them conducted any geology-based research. Nevertheless, geological knowledge, especially palaeontology, progressed due to the work of scientists such as Philippe-Charles Schmerling who described the first fossil human in 1830. Geology became a true research area at the university with the arrival of André Dumont in 1835. Before his appointment as professor, Dumont had already proved his mastery of geology by publishing his Description géologique de la province de Liége which earned him the golden medal of the Academy of Sciences and Arts of Brussels and a great reputation. He was the first to demonstrate the stratigraphic succession of the strata (geognosy) and to trace those strata on a map to show how they correlate. A great field geologist, Dumont was appointed by the Belgian Government to map the geology of the country, providing the first geological map of Belgium and neighbouring areas as a whole in 1849. At the same period (1846), Laurent-Guillaume de Koninck was appointed to teach palaeontology. His expertise on all groups of fossil animals drove him to produce an impressive number of monographic publications, on Belgian material but also on collections sent to him from all over the world. His Faune du Calcaire carbonifère de la Belgique – of which only the six first volumes were published before his death – is by itself the most exhaustive study of Carboniferous invertebrates ever published. De Koninck was in conflict with Dumont about the utility of fossils in geology, the latter being persuaded that they were too variable to have any significance. However, de Koninck’s palaeontological methods were indeed necessary and led to the development of biostratigraphy. Both Dumont and de Koninck received the Wollaston medal from the Geological Society of London for their work. Their successor Gustave Dewalque became – in 1857 – professor of geology and palaeontology and combined the scientific views of both his predecessors to produce very detailed and holistic research. His palaeontological work on the Jurassic fossils of S Belgium is most remarkable but his main achievement was his geological map of Belgium and surrounding areas, replacing Dumont’s with a much higher level of details. To make the reading of the map easier, Dewalque wrote his masterful Prodrome d’une description géologique de la Belgique (1868), which is no less than an encyclopaedia on geology of Belgium. His name is also inseparable from two major achievements in Belgium. Firstly the production of a detailed geological map at the 1/40,000 scale for which he achieved scientific posterity. Secondly he was the founding character of the Société géologique de Belgiquein 1874 and was also Secretary General of the society for 25 years. For his tremendous works, Dewalque received the prestigious Hayden medal from the Academy of Natural Sciences of Philadelphia in 1899. During his academic life, Dewalque progressively delegated his teaching to his young collaborators who eventually replaced him: Alfred Gilkinet for Palaeobotany, Julien Fraipont for Palaeontology, Adolphe Firket for Physical Geography, Guiseppe Cesàro for Mineralogy, and Max Lohest for General and Applied Geology. Alfred Gilkinet was one of the first palaeobotanists to embrace the theory of evolution and to recognise it among his fossils. He had a particular interest on Devonian fossil plants but also described material from the Paleogene. He was moreover a pharmacist and the institute of Pharmacy of the University bears his name. Julien Fraipont first entered the university at the laboratory of biology led by Edouard Van Beneden and published several papers on marine organisms for him. His work on Devonian crinoids was rewarded by the Société géologique de Belgiqueaward and de Koninck chose him to collaborate to his monography on Carboniferous bivalves. Fraipont published several papers on Palaeozoic fossils, the most remarkable being his work on the exquisitely-preserved echinoderms from the Marbre Noir de Denée. Furthermore, Fraipont was, with his colleague Lohest, a palaeoanthropologist and archaeologist and both were responsible for many discoveries in Quaternary cave deposits, including in Spy. Lohest was first a palaeontologist and published several contributions to the Palaeozoic fishes from Belgium, including a mandible identified by him as being from a fish but now interpreted as a rare Ichthyostega-like tetrapod. He then focused only on geology and applied geology after his major discoveries; such as the phosphate deposits in Hesbaye area, his prevision of the existence of coal measure in a deep basin in N Belgium, his interpretation of the metamorphism in Ardenne and description of the boudinage phenomenon. With Julien Fraipont and Marcel de Puydt, he discovered and described the human remains from the Spy cave – remains they interpreted as belonging to a species distinct from ours and that they attributed to the Neanderthal ‘race’. They demonstrated, for the first time in history, the co-occurrence of a fossil human species, Mousterian lithic industries and Pleistocene megafauna. Adolphe Firket mainly taught Physical Geography but was involved in the geological study of the Belgian coal measures and various mineral deposits. Guiseppe Cesàro was the true founder of mineralogy and crystallography in Belgium. His works on calcites and phosphates were very advanced despite that he was a self-taught man. They are still used as references today as are his works on crystallography. All those great names were part of the University and Belgian geology history, as men, scientists and professors. They left us a considerable heritage that needs to be rediscovered.

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.

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.

As disease regulation is a key ecosystem service, it is crucial that we better understand the role that restoring landscapes can play in reducing disease risks. Ongoing One Health studies suggest that declining biodiversity and increasing zoonotic pathogen spill-over risk are linked. Restoration processes normally aim at increasing species diversity, wherefore it is assumed that pathogens will be diluted in restored ecosystems, hence reducing the risk of zoonotic spillover. Nonetheless, the developing species composition during restorative processes will impact dilution-amplification effects. To estimate the threshold beyond which a restored ecosystem can be considered to have reached the pathogen dilution phase, it is crucial to characterise the communities of hosts, and the prevalence of pathogens, at the different stages of recovery of an ecosystem. Using interdisciplinary methods, this project has the dual aim of examining the amplification-dilution of zoonotic pathogens in a mangrove forest of the western Peninsular Malaysia, and to estimate the frequency and duration of exposure of local communities to this hazard, so as to best mitigate the risk of zoonotic pathogen spillover.

Major climatic changes in the Pleistocene had significant effects on marine organisms and the environments in which they lived. The presence of divergent patterns of demographic history even among phylogenetically closely-related species sharing climatic changes raises questions as to the respective influence of species-specific traits on population struc- ture. In this work we tested whether the lifestyle of Antarctic notothenioid benthic and pelagic fish species from the Southern Ocean influenced the concerted population response to Pleistocene climatic fluctuations. This was done by a comparative analysis of sequence variation at the cyt b and S7 loci in nine newly sequenced and four re-analysed species. We found that all species underwent more or less intensive changes in population size but we also found consistent differences between demographic histories of pelagic and benthic species. Contemporary pelagic populations are significantly more genetically diverse and bear traces of older demographic expansions than less diverse benthic species that show evidence of more recent population expansions. Our findings suggest that the life- styles of different species have strong influences on their responses to the same environ- mental events. Our data, in conjunction with previous studies showing a constant diversification tempo of these species during the Pleistocene, support the hypothesis that Pleistocene glaciations had a smaller effect on pelagic species than on benthic species whose survival may have relied upon ephemeral refugia in shallow shelf waters. These find- ings suggest that the interaction between lifestyle and environmental changes should be considered in genetic analyses.