Search publications of the members of the Royal Belgian institute of natural Sciences
-
Feather evolution in Pennaraptora
-
Integumentary Structures in Kulindadromeus zabaikalicus, a Basal Neornithischian Dinosaur from the Jurassic of Siberia
-
Data of feather recovering performance of birds and micro structure of pigeons’ feathers
-
First annotated draft genomes of nonmarine ostracods (Ostracoda, Crustacea) with different reproductive modes
- Ostracods are one of the oldest crustacean groups with an excellent fossil record and high importance for phylogenetic analyses but genome resources for this class are still lacking. We have successfully assembled and annotated the first reference genomes for three species of nonmarine ostracods; two with obligate sexual reproduction (Cyprideis torosa and Notodromas monacha) and the putative ancient asexual Darwinula stevensoni. This kind of genomic research has so far been impeded by the small size of most ostracods and the absence of genetic resources such as linkage maps or BAC libraries that were available for other crustaceans. For genome assembly, we used an Illumina-based sequencing technology, resulting in assemblies of similar sizes for the three species (335–382 Mb) and with scaffold numbers and their N50 (19–56 kb) in the same orders of magnitude. Gene annotations were guided by transcriptome data from each species. The three assemblies are relatively complete with BUSCO scores of 92–96. The number of predicted genes (13,771–17,776) is in the same range as Branchiopoda genomes but lower than in most malacostracan genomes. These three reference genomes from nonmarine ostracods provide the urgently needed basis to further develop ostracods as models for evolutionary and ecological research.
-
Effects of hydrocarbon extraction on freshwaters
-
On the first Belgian record of the Eifelian (Middle Devonian) ammonoid cephalopod Subanarcestes (Suborder Anarcestina)
- Ammonoid cephalopods are extremely rare in the Lower and Middle Devonian sedimentary rocks of Belgium, which contrasts with the neighboring sedimentary basins. However, searches in old collections and recent collecting efforts show that ammonoids do occur in these beds in Belgium, which allows to enlarge our knowledge of Lower and Middle Devonian ammonoid occurrences. Here, a record of the Eifelian (Middle Devonian) anarcestid ammonoid genus Subanarcestes is described for the first time from Belgium based on a specimen from the Jemelle Formation (Chavées Member). This specimen was collected more than a century ago by Eugène Maillieux at Trou Bodet near Couvin. It laid unrecognized as an ammonoid cephalopod for many decades in the collections of the Royal Belgian Institute of Natural Sciences, while being previously identified as Cryptoceras or ‘Nautilus’ fossil, which if correct, constituted Belgium’s oldest Nautilida fossil. Micro-CT imaging greatly helped in the taxonomic assignment of the specimen.
-
A Santonian record of the nautilid cephalopod Angulithes westphalicus (Schlüter, 1872) from the subsurface of the Campine, north-east Belgium, with comments on regional lithostratigraphic problems
- Newly recognised material of the Late Cretaceous nautilid Angulithes westphalicus is described from the subsurface of the eastern part of the Campine in north-east Belgium. This constitutes the first formal documentation of this genus and species from the Cretaceous of Belgium, having been identified amongst a large suite of fossils collected from the Voort Shafts I & II of the Zolder colliery during the first half of the twentieth century. The specimens originate from an interval of marine calcareous sand with a marly glauconiferous base, dated as late middle Santonian (Gonioteuthis westfalicagranulata belemnite Zone) and for which a deepening of the depositional environment is documented. Lithostratigraphically, the specimens occur within the Vaals Formation, within the upper part of the Asdonk Member or alternatively within the lower part of the Sonnisheide Member. The early Campanian age of the Asdonk Member suggested previously is refuted, the age of the Sonnisheide Member needs further study. The position of the siphuncle in A. westphalicus is illustrated for the first time; it is positioned closer to the venter than the dorsum, which confirms the close evolutionary relationship with Angulithes galea, which ranges from the upper Turonian to middle Coniacian in central Europe.
-
The fossil bivalve Angulus benedeni benedeni: a potential seasonally resolved stable isotope-based climate archive to investigate Pliocene temperatures in the southern North Sea basin
- Bivalves record seasonal environmental changes in their shells, making them excellent climate archives. However, not every bivalve can be used for this end. The shells have to grow fast enough so that micrometre- to millimetre-sampling can resolve sub-annual changes. Here, we investigate whether the bivalve Angulus benedeni benedeni is suitable as a climate archive. For this, we use ca. 3-million-year-old specimens from the Piacenzian collected from a temporary outcrop in the Port of Antwerp area (Belgium). The subspecies is common in Pliocene North Sea basin deposits, but its lineage dates back to the late Oligocene and has therefore great potential as a high-resolution archive. A detailed assessment of the preservation of the shell material by micro-X-ray fluorescence, X-ray diffraction, and electron backscatter diffraction reveals that it is pristine and not affected by diagenetic processes. Oxygen isotope analysis and microscopy indicate that the species had a longevity of up to a decade or more and, importantly, that it grew fast and large enough so that seasonally resolved records across multiple years were obtainable from it. Clumped isotope analysis revealed a mean annual temperature of 13.5 ± 3.8 ∘C. The subspecies likely experienced slower growth during winter and thus may not have recorded temperatures year-round. This reconstructed mean annual temperature is 3.5 ∘C warmer than the pre-industrial North Sea and in line with proxy and modelling data for this stratigraphic interval, further solidifying A. benedeni benedeni's use as a climate recorder. Our exploratory study thus reveals that Angulus benedeni benedeni fossils are indeed excellent climate archives, holding the potential to provide insight into the seasonality of several major climate events of the past ∼ 25 million years in northwestern Europe.
-
New data on the Devonian and Carboniferous Graptolithina (Dendroidea) from Belgium with notes on possible occurrences of Rhabdopleuridae in the Belgian Carboniferous
-
The LASUGEO project:monitoring LAnd SUbsidence caused by Groundwater exploitation through gEOdetic measurements.
- In the last decades, rapid urbanization, global climate change and uncontrolled anthropogenic transformations of the territory caused a relevant increase in geo-hazards events with huge economic and social consequences. The dramatic increase of these events with environmental degradation highlights the importance of improving ground monitoring and natural resources management with a continuous exchange of knowledge between the scientific community and authorities in charge of environmental risk management. Since the late 1990s, SAR (Synthetic Aperture Radar) data allow measuring slow-moving ground deformations. In the last decades, the use of spaceborne InSAR (Interferometric SAR) has increased significantly thanks to the availability of large-area coverage, millimetre precision, high spatial/temporal data resolution and good cost-benefit. For the last 3 decades, the development of Multi-Temporal Interferometric SAR techniques (MT-InSAR), commonly grouped into PSI-like (Persistent Scatterers Interferometry) and SBAS-like (Small BAseline Subset) algorithms, has changed the way radar images can be exploited for geohazard monitoring (natural gas extraction, mining activities, groundwater overexploitation, karst or landslides processes, etc.). Most of the subsidence bowls mapped by the PSI technique in Belgium have been related to strong fluctuations of an aquifer implying at the surface ground deformations (Declercq et al., 2017; 2021). Besides, the recent dry years are related to ground stability problems in large areas of Flanders. Land subsidence poses significant problems. The most affected regions lie on compressible loose sediments. Any change in the piezometric heads modifies the pore pressure, which may induce consolidation if the geological formations are compressible. Geomechanical aspects are fully coupled to groundwater flow equations. If groundwater levels and pressures are restored, a partial rebound (uplift) corresponding to the elastic part of the geological formations is observed. Consolidation and elastic rebound processes occur in confined and unconfined conditions. The most sensitive parts of the concerned aquifers contain clay, loam or peat lenses but consolidation may occur mostly in the underlying and overlying layers that are often less permeable and more compressible than the aquifer itself. In this case, it is largely a delayed process occurring as far as the pore pressure variation slowly propagates in the low permeability (aquitard) layers. We propose to confront the results of the PSinSAR technique data with hydrogeological groundwater models and two other geodetic techniques: GNSS and gravimetry. LASUGEO Geologica Belgica Meeting 2021, September 15-18, Tervuren, Belgium – Abstract Book, p. 75 focusses on ground deformations in different areas in Belgium: the deep aquifer system of western Flanders, the Tertiary aquifer system in Central Flanders, the Antwerp area, the Leuven area and the Brussels Region. The possible groundwater overexploitation needs to be established through a transient hydrogeological model considering all the stress factors applied to the aquifers. The estimated compaction in the subsiding bowls will be compared with 1D geomechanical model results. The latter will be performed using geotechnical effective stresses as deduced from the pore pressure distribution from the hydrogeological model (Dassargues et al., 1989). These different steps will be done by the partners of the LASUGEO project that are involved in the different case study areas.
-
Statistical imaging of the deformation over Belgium using multiple geodetic techniques.
- One of the challenges of geodesy is to characterize at the sub-millimeter level the vertical deformation of the ground in response to tectonic, anthropogenic, and climatic forcing. Reaching this level of accuracy is crucial to understand the deformation mechanisms acting in Belgium and it contributes to the mitigation of geo-hazards and the operational management of the territory. To address this challenge, the LASUGEO project, aiming at identifying ground deformation caused by groundwater exploitation, makes use of the observations of three independent geodetic techniques, namely: Global Navigation Satellite System (GNSS), Permanent Scatterers Interferometry Synthetic Aperture Radar (PS-InSAR), and repeated Absolute Gravity measurements (AG). Because GNSS, PS-InSAR, and AG provide independent measurements with different spatial and temporal resolutions, they are highly complementary. However, considering that each technique also comes with its own reference frames, accuracy, and source of biases, the optimal combination of these observations requires an appropriate statistical methodology. To estimate the deformation over Belgium, we performed a joint analysis of the GNSS position time series provided by the Nevada Geodetic Laboratory (Blewitt et al., 2018), the PS-InSAR time series processed at Geological Survey of Belgium (Declercq et al., 2021), and the AG measurement carried out by the Royal Observatory of Belgium (Van Camp et al., 2011). Our statistical analysis is divided in three steps: (1) trajectory modelling of each geodetic time series, that is, the model of the predictable motion (e.g., linear trend, periodic deformation, and instrumental discontinuities), (2) surface reconstruction of the subsidence/uplift rates from each technique, and (3) the comparison of the result of the different techniques. For each step, attention is paid to the realistic estimation of the model uncertainties, by accounting for the influence of the time correlated stochastic variability in the geodetic time series (Williams et al. 2003). We propose to describe the algorithms used and results obtained from the trajectory modelling and surface reconstruction of the subsidence/uplift rates. We show that, by combining a large number of observation, we are able to image vertical deformation at the 1.0 mm/yr level over Belgium (see Figure 1 for the GNSS imaging). We also discuss differences between GNSS, AG and PS-InSAR that could highlight the need to calibrate PS-InSAR relative estimates with GNSS and AG geocentric velocities.
-
Silurian solid bitumen from Huy: evidences for a petroleum system in Belgium
- The discovery of a bitumen bed within the Silurian Bonne Esperance Formation near the city of Huy (Belgium) is the first clear evidence for a petroleum system in Belgium. The studied section near the city of Huy (Belgium) is part of a larger structural unit called the Condroz inlier. This structural unit is a wedge of Ordovician to Silurian aged marine sediments which was thrusted up along the Midi detachment fault during the Hercynian orogeny and forming the Ardennes Massif (Adams & Vandenberghe, 1999). To understand the geological processes involved in the formation of the bitumen bed, the Bonne Esperance Formation was logged and 82 samples were collected for XRF chemostratigraphy, five samples were collected (Figure 1, pictures 1-5) for biostratigraphic purposes and one sample was taken from the bitumen itself. ICP-MS, TOC, Rock-Eval pyrolysis and Gamma-ray measurements are underway to quantify the source rock potential of the Bonne Esperance Formation. Preliminary XRF measurements already show that especially the lower part of the Bonne Esperance Formation is enriched in elements linked to anoxic conditions/enrichment of organic material, which indicates that the Bonne Esperance Formation itself is the likely candidate source rock for the bitumen. The sample from the bed which includes the bitumen has already been tested to confirm the nature of the bitumen material. The sample was crushed and heated in a vial and the released hydrocarbons were then ignited with a flame (Figure 1, picture 6C). The First occurrence of the graptolites of the Family Monograptidae was used to pinpoint the location of the Ordovician-Silurian boundary (Akidograptus Ascensus zone at sample 4) (Maletz, 2017). Given the current results and the ongoing analyses a picture emerges of the Silurian of the Condroz inlier as being Belgium’s first and to date only petroleum system.
-
Preliminary activities aimed to cluster EU cities by a geological point of view: The Urban Geo Footprint tool.
- This century is the “century of the cities”, where rapid urbanization and greater global connection present unprecedented urban challenges and concentrates risk in urban areas making them increasingly vulnerable (Coaffee & Lee, 2016). The need arises for urban planning must be asked to fully incorporate an understanding of the sub-surface into the deliberation/decision-making process (Howard, 1997). The Urban Geo Footprint (UGF) is classification tool being developed by a sub-group of the Urban Geology Expert Group of EuroGeoSurvey (UGEG) and it is based on a multidisciplinary effort in which different skills and expertise come into play. The main objective of this project is to set up a classification method to identify the main geological and anthropic features that influence city's resilience related to its geological setting. A tool is being developed in order to clustering cities according to their geological and climatic features and to understand why target urban contexts have different issues (e.g. climate change, floods), and thus to assess the cities’ geo-resilience. The UGF will help cities to understand what ‘economic’ and ‘social well-being’ benefits (i.e. in terms of ‘geological resilience’) could derive from urban planning associated with subsoil knowledge. The salient features required for this tool are: - It must be user-friendly and easy to use by scientists and non-scientists - It must be available at European level (and maybe, once is tested in Europe, it could be extended worldwide). The following main 5 drivers are defined in the tool: Geology, Climate, Geohazards, Geomorphology, Subsoil anthropic pressure. The assessment method of UGF tool will consist in testing it with data of different EU pilot-cities. The work in progress is developing a complex worksheet (which can be defined as the «UGF framework») with several quantitative parameters related to the 5 drivers mentioned above. All these parameters are going to be indexed (using scores) and weighted based on two levels of investigation: “basic” and “advanced”. The final result for each city is a general UGF score that will be the combination of all the drivers specific scores. Each tested city will be classified also by the weight of each driver in the calculation. Other objectives of the project are: - Contributing to develop a method for the comparison of data from different cities and update all existing database. - Improving the European collaboration and, therefore, the exchange of ideas on good practices to increase cities’ resilience. - Improving citizens' awareness of both the resources and the threats associated with geology.
-
Organic Matter Composition of Biomineral flocs and Its Influence on Suspended Particulate Matter Dynamics Along a Nearshore to Offshore Transect
- The seasonal variation in concentration of transparent exopolymer particles (TEPs), particulate organic carbon (POC) and particulate organic nitrogen (PON) were investigated together with floc size and the concentration of suspended particulate matter (SPM) along the cross-shore gradient, from the high turbid nearshore toward the low-turbid offshore waters in the Southern Bight of the North Sea. Our data demonstrate that biophysical flocculation cannot be explained by these heterogeneous parameters, but requires a distinction between a more reactive labile (“fresh”) and a less reactive refractory (“mineral-associated”) fraction. Based on all data, we separated the labile and mineral-associated POC, PON, and TEP using a semi-empirical model approach. The model's estimates of fresh and mineral-associated organic matter (OM) show that great parts of the POC, PON, and TEP are associated with suspended minerals, which are present in the water column throughout the year, whereas the occurrence of fresh TEP, POC, and PON is restricted to spring and summer months. In spite of a constantly high abundance of total TEP throughout the entire year, it is its fresh fraction that promotes the formation of larger and faster sinking biomineral flocs, thereby contributing to reducing the SPM concentration in the water column over spring and summer. Our results show that the different components of the SPM, such as minerals, extracellular OM and living organisms, form an integrated dynamic system with direct interactions and feedback controls.
-
Flocculation with heterogeneous composition in water environments: A review
- Flocculation is a key process for controlling the fate and transport of suspended particulate matter (SPM) in water environments and has received considerable attention in the field of water science (e.g., oceanography, limnology, and hydrology), remaining an active area of research. The research on flocculation has been conducted to elucidate the SPM dynamics and to diagnose various environmental issues. The flocculation, sedimentation, and transportation of SPM are closely linked to the compositional and structural properties of flocs. In fact, flocs are highly heterogeneous in terms of composition. However, the lack of comprehensive research on floc composition and structure has led to misconceptions regarding the temporal and spatial dynamics of SPM. This review summarizes the current understanding of the heterogeneous composition of flocs (e.g., minerals, organic matter, metals, microplastic, engineered nanoparticles) and its effect on their structure and on their fate and transport within aquatic environments. Furthermore, the effects of human activities (e.g., pollutant discharge, construction) on floc composition are discussed.
-
Tracking the source of lead of medieval glazed pottery of the Meuse valley (Belgium) through lead isotope analyses.
- Abstract Lead isotope analyses (by MC-ICP-MS) have been performed on lead-glazed pottery artefacts from several production and consumption sites in the Meuse basin (Belgium) spanning a long-time period from the 9th to the 16th century AD. Comparison of the lead isotope data of the glazes from three mosan workshops with those of galenas from Palaeozoic (Variscan) Pb-Zn deposits from both Belgium and Western Germany points to a common Pb source that we identify as the regional Pb deposits hosted in Dinantian limestones of the Ardenno-Rhenish Massif, more specifically in the Namur and Verviers synclines in Belgium and in the Aachen-Stolberg mining district in Germany. The overall similarity of isotopic compositions between the medieval artefacts and the Variscan galenas implies that the mosan medieval potters used accessible local Pb-Zn ores mined between Namur and Huy. On the consumption sites of Dinant, the slightly different isotopic compositions of some potteries suggest that other regional Pb sources were used to produce the glazes. A comparison with Roman lead objects discovered in north-western Europe (Northern Gaul) shows the very good correspondence of the Pb isotopic compositions with those of the Medieval artefacts which indicates a very long continuity of regional lead supply and consequently of lead ore mining. Keywords: Lead-glazed pottery; Middle Age; Lead isotope analysis; Lead ores; Sourcing; Mosan valley; Belgium
-
Complementarity of LA-ICP-MS and petrography in the analysis of Neolithic pottery from the Scheldt River valley, Belgium.
- Abstract This paper presents the results of laser ablation – inductively coupled plasma – mass spectrometry (LA-ICP-MS) analysis of the clay fraction in 70 Late Mesolithic and Early/Middle Neolithic pottery sherds from the Scheldt basin and 10 sampled sediments. The elemental concentration results were visualized using multivariate chemometric techniques and compared to the results of petrographic analysis of the same ceramics in order to investigate the complementarity of both approaches. In addition, the results for the pottery and sediments were compared for clay sourcing purposes. Overall, the elemental analysis was able to confirm part of the observations from the petrographic analysis. However, a large part of the ceramics clustering was driven by heterogeneity in the elemental composition that does not stem from differences in the clay source used. Furthermore, no conclusions could be drawn on the use of the sampled sediments for pottery production. Therefore, it is concluded that LA-ICP-MS analysis of the clay fraction in pottery can complement petrography, but petrographic analysis remains indispensable for clay sourcing of pottery from northern Belgium. Keywords: ceramic petrography, LA-ICP-MS, t-SNE, elemental analysis, Neolithic pottery, Belgium
-
Pavements et placages, l’ornementation du balnéaire privé de Warcq (Ardennes, France).
- Introduction: Une fouille préventive s’est déroulée aux lieux-dits « Simonelle » et « Sous le Chemin de Tournes » de la commune de Warcq. Cette commune se situe à trois kilomètres au nord-ouest de Charleville-Mézières, à la confluence de la Meuse, du ruisseau de This et de la Sormonne. Les opérations de terrain ont permis de mettre au jour les vestiges d’une partie d’une petite villa gallo-romaine constituée d’une cave, d’une cour ainsi que d’un balnéaire . Son occupation, qui s’étend du 1er au 4e siècle de notre ère, est caractérisée par de nombreux réaménagements pouvant être rassemblés en quatre grandes phases distinctes (fig. 1). Le secteur thermal est construit vers 130-150 de notre ère (phase 2) et forme l’aile occidentale de la villa. Vraisemblablement contraints par le bâti existant, les bâtisseurs ont opté pour un plan longitudinal où seule la natatio est en saillie. Il en découle un alignement des pièces et plus particulièrement celui du caldarium et du tepidarium dans celui du praefurnium. Sur près de deux siècles, cette partie de la villa a été soumise à des modifications architecturales dont l’agrandissement du frigidarium aux dépends de la cave (phase 3, fin 2e – début 3e siècle), puis l’ajout d’un apodyterium (phase 4, milieu 3e siècle ?). Dans son dernier état, l’ensemble thermal mesure environ 18 m de long pour 5 m de large offrant aux baigneurs un itinéraire rétrograde. L’accès se fait par le vestiaire dont aucun décor n’a été observé. Le secteur froid est une salle, presque carrée (3,40 m x 2,90 m). Elle comporte un bassin à immersion (natatio) à l’ouest et une banquette plaquée contre le mur oriental. On passe ensuite par le tepidarium, une salle rectangulaire (3,30 m x 1,90 m). Le parcours se poursuit par le caldarium. Cette pièce, aux mêmes dimensions que la précédente, est pourvue en sus d’une petite alcôve de 1,20 m de long sur 0,90 m de large dans laquelle est logé un bassin. Une seconde baignoire est flanquée contre le mur occidental (fig. 1). Ce balnéaire se distingue par l’utilisation de la pierre pour son apparat décoratif. Elle est employée aussi bien pour les pavements que pour les parois. Ce type de pratique reste méconnu et peu fréquent dans le sud de la Gaule belgique. L’ornementation des thermes sera abordée au travers de l’étude de ces décors et, dans un second temps, par la caractérisation et la provenance des roches utilisées. Il convient de mentionner que ces roches se distinguent des pierres de construction qui sont en calcaire gréseux coquillier de couleur jaune pâle à beige, attribuées à la Pierre de Romery, d’extraction locale. Ce matériau affleure à quelques kilomètres de Warcq. Ce travail résulte d’une collaboration entre archéologue, géologue, restauratrices et spécialiste des pavements, et fait suite à une intervention de dépose des pavements et des revêtements muraux mis au jour lors de la fouille.
-
Chimpanzees surviving in a fragmented high-altitude forest landscape of the Congolese Albertine Rift
-
Natuur- en landschapslezen
