Search publications of the members of the Royal Belgian institute of natural Sciences
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La détermination du sexe grâce à la méthode probabalistic diagnosis dans un environnement virtuel
- The hip bone is one of the most reliable indicators of sex in the human body due to the fact it is the most dimorphic bone. Probabilistic Sex Diagnosis (developed by Murailet al., 2005) is a method based on a worldwide hip bone metrical database and relies on the actual physical bone for analysis. Sex is determined by comparing specific measurements taken from each specimen using sliding calipers and computing the probability of the specimens being female or male. In forensic science it is sometimes not possible to sex a body due to corpse decay or injury. Skeletinization and dissection of a body is a laborious process and desecrates the body. The current study aimed to see if it was possible to virtually utilise the DSP method to avoid this process. Forty-nine innominate bones of unknown sex were obtained from ULB. Bones were analysed by two researchers using the manual DSP method and a good correlation was found between researchers. CT scans of available bones were analysed to obtain three-dimensional (3D) virtual models using a commercially available software (Amira, www.amiravis.com). Available models were imported into a customized software programme called lhpFusionBox (developed at ULB from the MAF open-source library). lhpFusionBox is an advanced musculo-skeletal software which includes many operations relevant to Biomechanics. It also enables distances to be measured via virtually- palpated bony landmarks. DSP measurements were then obtained from the located bony landmarks. There was 100% accuracy between the manual and virtual DSP analysis. To further test the method 30 virtual bones of known sex were analysed (researchers had no prior knowledge of sex before analysis). There was found to be a 97% accuracy rate with only one bone leading to a wrong determination. These
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Les Formations du Devonien inférieur du Massif de la Vesdre, de la fenêtre de Theux et du synclinorium de Dinant (Belgique, France)
- The authors describe twenty-one Lower Devonian formations from the Vesdre Massif, the Theux Window and the Dinant Synclinorium, in Belgium and France. This work is combined with the geological remapping prograrn of Wallonia (scale 1/25 000). Seventeen of these formations (Fépin, Mondrepuis, Oignies, St-Hubert, Mirwart, La Roche, Pesche, Vireux, Chooz, Hierges, Fooz, Solières, Wépion, Burnot, Marteau, Bois d'Ausse and Acoz) are weIl known frorn the standard literature on the Lower Devonian of the Ardennes and are revised. The Villé and Nonceveux Formations have been introduced more recently, respectively in 1982 and 1992. The Pèrnelle and Hampteau Formations are new. Each formation is presented in a file giving a brief historical account, location of the reference sections, lithology, limits and thickness at the stratotype, lateral variations, age and eventual uses. Furthermore, each formation is documented by the location of the outcrops on a portion of the relevant topographic map (scale 1/10 000) and by a cross-section or stratigraphic log of the stratotype or other reference sections. Résumé Ce travail rassemble les descriptions de vingt-et-une formations caractérisant le Dévonien inférieur du Massif de la Vesdre, de la Fenêtre de Theux et du Synclinorium de Dinant, en Belgique et en France. Il s'intègre dans le cadre du programme de renouvellement des cartes géologiques de Wallonie à 1/25000. Dix-sept de ces formations (Fépin, Mondrepuis, Oignies, St-Hubert, Mirwart, La Roche, Pesche, Vireux, Chooz, Hierges, Fooz, Solières, Wépion, Burnot, Marteau, Bois d'Ausse et Acoz) sont bien connues dans la littérature classique du Dévonien inférieur de l'Ardenne et font l'objet d'une révision. Les Formations de Villé et Nonceveux sont moins familières, ayant été introduites respectivement en 1982 et 1992. Les Formations de Pèrnelle et de Hampteau sont nouvelles. Chaque formation est présentée dans une fiche comprenant un bref historique, la localisation des sites de référence, la lithologie, les limites et l'épaisseur au stratotype ou dans les sites de référence, les variations latérales, l'âge et les usages éventuels. En outre, chaque formation est documentée par un extrait de carte topographique à 1/10 000 localisant les affleurements cités et par une coupe ou une colonne stratigraphique du stratotype ou d'autres sites de référence. Samenvatting ln dit werk worden éénentwintig Onder-Devoon formaties beschreven uit het Vesder Massief, het Venster van Theux en het Synclinorium van Dinant, in België en Frankrijk. Het is in overeenstemming met het programma voor de hernieuwing van de geologische kaarten van Wallonië (schaal, 1/25000). Zeventien van deze formaties (Fépin, Mondrepuis, Oignies, St-Hubert, Mirwart, La Roche, Pesche, Vireux, Chooz, Hierges, Fooz, Solières, Wépion, Burnot, Marteau, Bois d' Ausse en Acoz) zijn goed gekend uit de klassieke Onder-Devoon litteratuur van de Ardennen en hun definitie wordt herzien. De Formaties van Villé en Nonceveux zijn minder gebruikelijk, zij werden meer recent ingevoerd, in 1982 en 1992. De Formaties van Pèrnelle en Hampteau zijn nieuw. Voor iedere formatie worden volgende gegevens verstrekt : een bondige historiek, lokalisatie van de referentie ontsluitingen, de lithologie, de grenzen en dikte in het stratotype of in andere referentiepunten, de laterale variaties, de ouderdorn en het eventueel gebruik. Iedere formatie wordt bovendien gedocumenteerd met een detail van de topografische kaart (schaal, 1/10000) met lokalisatie van de vermelde ontsluitingen en met een profiel of een stratigrafische kolom van het stratotype of andere referentiepunten.
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Economics of single chain EOR projects
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A GIS-based methodology for creating 3D geological models in sedimentary environment: application to the subcrop of Brussels
- In order to meet the requirements established by the European Directive (2006/118/EC) on the groundwater protection, the Geological Survey of Belgium (GSB) has started a new Geographic Information System (GIS) project called Hydrobrux. The aim is to create a thorough three-dimensional geological model of the subcrop of Brussels. The latter will be used to produce a hydrogeological model of the Brussels Formation aquifer composed of sands and covering 126 km2 in the eastern part of the Brussels-Capital Region and subsequent deeper aquifers (Palaeocene and Upper Cretaceous). The GIS 3D model is built by superposition of interpolated surfaces, which represent the top surface of each modelled geological layers. Eleven top surfaces are generated independently and are based on the interpolation of 5169 points. This high density of information is provided by 2426 boreholes, water wells, outcrops, cone penetration tests (CPT) and other sources of stratigraphic data that were collected and structured in a relational database under Microsoft Access. The data were exported to ArcGIS for the geostatistics (2D mapping) and validation parts and subsequently to ArcScene for the construction and the visualisation of the 3D model.
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Is CCS a feasible option in developing countries? Presenting CCS as a realistic choice for Kazakhstan
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Les reptiles marins du Toarcien (Jurassique inférieur) belgo-luxembourgeois
- Deze samenvatting is niet beschikbaar in het Nederlands. Résumé Les affleurements toarciens (Jurassique Inférieur) de Belgique et, surtout, du Grand-Duché de Luxembourg ont livré de nombreux fossiles de reptiles marins Ichthyosauria, Thalattosuchia et Plesiosauria. Leur bon état de conservation permet, dans de nombreux cas, une détermination spécifique et la description de caractères anatomiques mal connus chez ces animaux. L'étude des ichthyosaures a nécessité une révision systématique du genre Stenopterygius. Une synthèse paléogéographique des reptiles marins toarciens est proposée. Des différences quantitatives importantes ont été observées dans la composition des faunes de reptiles marins découvertes dans la région du Württemberg (Allemagne), du Yorkshire (Angleterre) et du Luxembourg. Cette dernière faune se caractérise par une nette prédominance de formes bien adaptées à la vie en pleine mer. Abstract Toarcian (Lower Jurassic) outcrops have yielded many marine reptiles Ichthyosauria, Thalattosuchia and Plesiosauria in Belgiurn and, principally, in Grand Duchy of Luxemburg. Their preservation allows a determination at a specific level as also the description of badly known anatomical characters. The study of ichthyosaurs required a systematic revision of the genus Stenopterygius. A palaeogeographical synthesis of Toarcian marine reptiles is proposed. Important quantitative differences can be observed in the composition of marine reptiles' faunae from Württemberg (Germany), Yorkshire (England) and Luxemburg. This latter fauna is characterized by a predominance of animal weIl adapted for the life in open sea.
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Etude sédimentologique de la Grande Brèche viséenne("V3a") du Bassin de Namur - Dinant
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L'intrusion de la Helle (Hautes-Fagnes, Belgique) et la minéralisation cupro-molybdenifère associée: synthèse bibliographique, données des sondages et interprétation globale
- The Helle intrusion is located in the eastern part of Belgium and was discovered by the end of last century. Geochronology (U-Pb isotopic ratios ofzircon) indicates that the magma emplacement took place between Silurian and Lower Devonian (minimum age of emplacement: around 381 ± 16 Ma). Previous studies have shown that the Helle intrusion is a sill structure with most of its outcropping rocks characterized by a petrographic composition of quartz-diorite (tonalite). The low degree of thermic metamorphism related to the intrusion is reflected by a very thin aureole of hornfels. The rather large zone of pyritic rocks surrounding the igneous rocks was probably generated by an extensive hydrothermal (mainly a sulphidization) episod possibly contemporary of the thermic metamorphism phase. Finally, a main episode of regional metamorphism contemporary of the variscan orogeny induced a metamorphism of low-grade (ACF : paragenesis prehnite-chlorite-epidote) in the igneous rocks of la Helle. In 1976-1977, at the initiative of Union Minière S.A., the concealed magmatic rocks were recognized by four drillings down to a depth of approximately 100 m. The Belgian Geological Survey supervised the study. Results are included in the present memoir divided into 3 parts. The first part is devoted to a bibliographic synthesis of the geology and the mineralization of the Helle area. In a second part, results of lithological and petrographical observations are presented. The study under the microscope emphasizes a large variation of petrographic composition ranging from diorites to granodiorites and monzodiorites. Mineralogic variations seem to be related to mechanisms of magmatic differentiation (mainly fractional crystallization) but also to a complex post-magmatic hydrothermal alteration process, which mainly affected the superficial area of the intrusion. That zone is characterized by a secondary K-feldspar occurrence. The hydrothermal alteration also produced silicification and partial albitization with the development of a network of veinlets (locally mineralized) in the magmatic and surrounding Revinian metaquartzopelitic rocks. In this part, lithogeochemical logs of metallic elements are shown. A three dimensional reconstruction of the intrusion indicates that the structure corresponds to a laccolitic sill-shaped of: ± 500 m of NE-SW length, 125 m of maximal thickness and 30° SE dip. Small dykes are also connected to the main sill. The third part concerns the petrological and metallogenical interpretations. The primary mineralization is mainly formed by sulphide components (chalcopyrite, bornite, molybdenite). The average Cu and Mo content of the igneous rock is low (Cu = 0,17 % ; Mo = 0,02 %). The low metal stock of the intrusion (Cu: ± 35 000 tons; Mo: ± 4 000 tons) is the consequence of a reduced volume of mineralized rock as weIl as common low metal contents. Metallogenically, this type of mineralization can be compared to the porphyry copper model although some important differences appear. The difficulty to distinguish the various concentric patterns of alteration suggests the smash of the alteration zones and is probably due to the small size of the intrusion. Résumé L'intrusion de la Helle, située dans l'Est de la Belgique (Hautes Fagnes), a été découverte à la fin du XIXème siècle. Des études antérieures ont établi qu'il s'agit d'un sill présentant une composition de diorite quartzique, ou, plus restrictivement, de tonalite. A cette intrusion, sont associés, d'une part un faible métamorphisme se traduisant par une ceinture pluridécimétrique de cornéennes et, d'autre part, un dynamométamorphisme caractérisé par une auréole plurihectométrique de schistes tachetés. En outre, une minéralisation cupro-molybdénifère est également présente. Une datation radiométrique par la méthode U-Pb sur zircon attribue à cette intrusion un âge minimum de mise en place vers 381 ± 16 Ma, c'est à dire silurien ou dévonien inférieur. Enfin, un métamorphisme régional contemporain de l'orogenèse varisque, a donné naissance à une paragenèse A CF (préhnite - chlorite - épidote) de faible degré. En 1976-1977, l'Union Minière a financé 4 sondages dans le but de préciser la forme de l'intrusion et son potentiel minier. Ils ont été confiés au Service géologique de Belgique qui en a supervisé l'étude dont les résultats sont présentés dans le présent mémoire divisé en 3 parties. Dans une première partie, on effectue une synthèse bibliographique sur la géologie et la minéralisation de la région de la Helle. Dans une deuxième partie, on présente les résultats des descriptions lithologiques détaillées et des observations pétrographiques consacrées aux sondages. Les observations diascopiques soulignent une importante variation de la composition minéralogique, caractérisée par une gamme de roches allant de la diorite à la diorite quartzique et de la monzodiorite à la granodiorite éventuellement quartzique. Les variations minéralogiques semblent associées à des mécanismes de différenciation magmatique (principalement la cristallisation fractionnée), mais aussi à un processus hydrothermal post-magmatique complexe qui a principalement affecté la partie superficielle de la colonne magmatique actuellement dégagée par l'érosion. Cette zone est marquée par l'occurrence de feldspath potassique. L'altération hydrothermale a également produit une silicification et une albitisation partielle avec développement d'un réseau de veinules/veines localement minéralisées dans la roche magmatique et l'encaissant quartzopélitique revinien. Dans cette partie, on précise également les variations lithogéochimiques des roches ignées pour les éléments métalliques et la géométrie en trois dimensions de l'intrusion. Il s'agit d'un silllaccolitique d'environ 500 m d'extension NE-SW, épais en son centre de 125 m maximum, plongeant à 30° vers le SE, duquel se dégagent des petits dykes. Une troisième partie est consacrée aux interprétations pétrologiques et métallogéniques. On peut établir un certain parallélisme qualitatif entre l'intrusion faiblement minéralisée de la Helle et un porphyre cuprifère classique. Bien qu'à la Helle, la plupart des zones d'altération hydrothermale soient mélangées et donc quasi indiscernables, la variation spatiale du feldspath potassique semble suggérer la présence d'un début d'altération potassique dans les secteurs périphériques de l'intrusion. Le télescopage des différentes zones d'altération est probablement du à la petite dimension de l'intrusion. Comme les teneurs sont également faibles (en moyenne: Cu = O,17 % ; Mo = 0,02 %), le stock métal estimé en première approximation (Cu: environ 35 000 tonnes; Mo: environ 4 000 tonnes) est également très modeste. Samenvatting De intrusie van de Helle, gelegen in het oosten van België (Hoge Venen), werd ontdekt op het einde van de XIXste eeuw. Vroegere studiën hebben aangetoond dat het om een sill gaat, met de samenstelling van kwartsdioriet of strikter genomen uit tonaliet. Aan deze intrusie is enerzijds een zwak metamorfisme geassocieerd dat zich vertaald door een gordel van verscheidene dm hoornrots, anderzijds een dynamometamorfisme, gekenmerkt door een aureool van verscheidene honderden m gedekte schisten. Daarnaast is eveneens een koper-molybdeen- mineralisatie aanwezig. Een radiometrische datering met de U-Pb-methode op zirkoon verleent die intrusie een minimum leeftijd van ontstaan rond 381 ± 16 Mj, d.w.z. Silurisch of Onder-Devoon. Tenslotte is door regionaal metamorfisme tijdens de varistische orogenese een zwake ACF-paragenese gevormd (prehniet-chloriet-epidoot). In 1976-1977, heeft Union Minière 4 boringen gefinancierd met de bedoeling de vorm van de intrusie en haar ontginbaarheid nauwkeurig te bepa1en. Ze werden toevertrouwd aan de Geologische Dienst van België die de studie begeleidde waarvan de resultaten voorgesteld worden in deze toelichtingen verdeeld in 3 delen. Een eerste deel bevat een bib1iographische synthese van de geologie en mineralisatie van de Hellestreek. Een tweede deel geeft de resultaten van de gedetailleerde lithologische beschrijvingen en de petrographische waarnemingen in de boringen. De diascopische waarnemingen wijzen op een belangrijke variatie van de mineralogische samenstelling, gekenmerkt door een gamma gesteenten gaande van dioriet naar kwartsdioriet en van monzodioriet naar eventueel kwartsgranodioriet. De mineralogische variaties blijken samen te gaan met magmatische differentiemechanismen (voornamelijk de gefractioneerde kristallisatie), maar ook met de ingewikkeld post-magmatisch hydrothermaal proces dat hoofdzakelijk heeft ingewerkt op het bovenste deel van de magmazui1 nu blootgelegd door erosie. Die zone wordt gekenmerkt door het voorkomen van ka1iumveldspaat. De hydrotherma1e verwering heeft eveneens geleid tot silicificatie en gedeeltelijke albitisatie, gepaard gaand met de vorming van een netwerk van gedeeltelijke aders/adertjes in het magmatische gesteente en de omgevende kwartsopelitische Reviniaan eenheden. In dit deel uiten zich ook duidelijk de lithogeochemische variaties van de stollingsgesteenten voor de metallische elementen en de driedimensionele geometrie van de intrusie. Het betreft een laccolitische sill met een omvang van ongeveer 500 m in de NO-ZW richting, in het midden maximum 125 m dik, 30° naar het ZO duikend, waarvan kleine dykes loskomen. Een derde deel is gewijd aan de petrologische en metallogenetische interpretaties. Men kan een zeker kwalitatief parallelisme vaststellen tussen de zwak gemineraliseerde intrusie van de Helle en een klassieke koperhoudende porfier. Hoewel in het geval van de Helle, de meeste hydrothermale verweringszones vermengd en dus vrijwel niet te onderscheiden zijn, blijkt de ruimtelijke variatie van kaliumveldspaat toch te wijzen op de aanwezigheid van een beginnende potassische verwering in de randzones van de intrusie. Het telescoperen van de verschillende verweringszones is waarschijnlijk toe te schrijven aan de geringe afmetingen van de intrusie. Daar de gehalten eveneens la ag zijn (gemiddeld : Cu = O,17%; Mo = 0,02%) wordt de metaalreserve in een eerste benadering (Cu ongeveer 35 000 ton; Mo: ongeveer 4000 ton) eveneens als zeer bescheiden aanzien.
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Le « Calcaire D’Etroeungt » dans les coupes historiques d’Etroeungt et d’Avesnelles (Avesnois, Nord, France).
- Le « Calcaire d’Etroeungt», extrême sommet du Famennien, reconnu historiquement par Gosselet, fait l’objet d’une représentation détaillée, avec positionnement des niveaux qui ont fourni des faunes, dans les coupes de la carrière du Parcq à Etroeungt, stratotype historique, et dans celle de la tranchée d’Avesnelles, proposée antérieurement comme parastratotype, car la série est incomplète dans la carrière du Parcq. Toutefois la recherche d’un nouveau parastratotype est indispensable car la limite supérieure est masquée dans la coupe de la tranchée d’Avesnelles qui par ailleurs s’avère être très pauvre en faune. The Uppermost Famennian “Etroeungt Limestone”, historically recognized by Gosselet, is the subject of a detailed presentation. Levels providing faunas are situated in the historic stratotype du Parcq quarry section at Etroeungt, and in the Avesnelles railway section, that has earlier been proposed as a parastratotype, because the sequence is incomplete in the du Parcq quarry. However, investigation for a new parastratotype is necessary because the upper limit is hidden in the Avesnelles railway section which also proves to be very poor in fauna.
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The Earliest Bats from Europe
- Chiroptera is one of the few modern mammal orders for which no fossil record has been associated with the Paleocene-Eocene Thermal Maximum that happened 55.8 million years ago. With the exception of complete skeletons from the early Middle Eocene of the Messel Formation in Germany and the late Early Eocene Green River Formation in Wyoming, all early bats are only represented by isolated elements, mainly teeth and fragmentary jaws, making the diversity and taxonomic affinities more difficult to establish. Here we revise all of the Early Eocene bats from Europe based on dental features, including digitally reconstructed teeth using micro-CT scanning technology of some complete skeletons. The diversity of European early bats is composed of the families Onychonycteridae, Icaronycteridae, Archaeonycteridae, Palaeochiropterygidae, and some of undetermined affinities. Dental features and synapomorphies of each family are characterized for the first time. The earliest bats are dated from the early Early Eocene and are all of small size with lower molars less than 1.3 mm in length. They are represented by: Eppsinycteris anglica from Abbey Wood, east London, England, an onychonycterid with reduced lower p4 and long molars; Archaeonycteris? praecursor from Silveirinha, Portugal, an archaeonycterid with long postcristid on wide lower molars; a new archaeonycterid genus and species from Meudon, North France with long trigonid and shorter postcristid on wide lower molars. These results indicate that the diversity of European Early Eocene bats is higher than previously recognized and that diversification began early in the Early Eocene.
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New primate postcrania from the Eraly Eocene of Vastan Mine, Gujarat, India
- The Cambay Formation at Vastan Mine in Gujarat yields the oldest fossil primates known from India. New age estimates suggest that the fossils date from approximately 54.5 Ma (early Ypresian), about 2 million years older than initially thought and comparable in age to early Wasatchian Wa-4 faunas from North America. The Vastan primate fauna comprises predominantly the asiadapine adapoids Marcgodinotius and Asiadapis. Two species of omomyid primates, Vastanomys gracilis and V. major, are much rarer, each known from a single dental specimen. In addition to primate dental remains, Vastan Mine has produced the best preserved early Eocene primate postcranial elements known from anywhere in the world. Here we present new limb bones, including humeri, ulnae, femora, tibiae, and a talus, from three of the recognized primate species. They include the first omomyid postcrania from India: two femora, a talus, and a potential proximal tibia. We also report additional asiadapine postcrania: a pristine femur of Marcgodinotius and the first complete tibia of Asiadapis. Five new humeri (two complete) consist of one asiadapine and four that lack specializations of either group, making allocation difficult. Two ulnae are attributed to indeterminate euprimates due to lack of adequate comparative material. The elements attributed to Vastanomys are more primitive than any other known omomyid postcrania and are only subtly different from those of asiadapines, in contrast to the more distinct postcranial bones of their middle and late Eocene relatives. The femora attributed to Vastanomys exhibit features suggestive of leaping behavior (cylindrical femoral heads, lateral condyle higher than medial, proximal position of the third trochanter), as in other omomyids. However, while the talus of Vastanomys resembles those of omomyids more than those of other primates, features such as the relatively short, medially angled neck, and oval rather than spherical head suggest that Vastanomys was not as specialized for leaping as younger omomyids. Although asiadapines have been described as close to notharctids in morphology, the relatively wider distal femur and symmetrical condyles of Marcgodinotius resemble adapids more than notharctids and may also reflect less leaping. The revised age of the fossils, together with the similarity in morphology of omomyid and asiadapine postcrania, suggests that the postcrania, like the teeth of the most primitive members of each family, are converging toward a common morphology as we approach the base of the Eocene.
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Prionus antonkozlovi n. sp. de Chine (Coleoptera, Cerambycidae, Prioninae)
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Biology and fisheries of the spotted flounder (Citharus linguatula) caught by multiple gears with partial spatiotemporal overlaps
- Obtaining data to study fish biology can be a challenge if a stock is fished by a variety of gears with different effort units and different selectivity, particularly if these gears only partially overlap in space and time. In this work, we attempted to study the biology of the spotted flounder Citharus linguatula in the Patraikos Gulf and the adjacent central Ionian Sea (eastern Mediterranean) and to evaluate the current fisheries management. We characterized age composition and growth, length-at-maturity, and catch-perunit- effort (CPUE) of spotted flounder from the catches of bottom trawls, gillnets and trammel nets for the period autumn 2013–2014. Variation of fish total length, gonadosomatic index, hepatosomatic index and condition factor was analyzed using generalized additive models (GAMs) with regard to sex, date, fishing gear and depth.We also modeled CPUE fluctuations of each gear by date, depth, longitude and latitude using GAMs. Fish age ranged from 1 to 5 years. A slightly allometric growth was documented with females attaining larger sizes than males. Length-at-maturity was 163mm for females and 169mm for males. The seasonal change of gonad maturity stages and the gonadosomatic index indicated spawning in late summerautumn. Changes in length frequencies indicated that recruitment to the fisheries occurred in late springearly winter in shallow depth (<40 m). The catch composition of trawls and the CPUE model results suggested that the selectivity of this gear should be regulated to reduce catching immature individuals of spotted flounder. The results further indicated that the seasonal trawl closure of the Patraikos Gulf contributes to reduce catching juveniles.
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A risk-based approach to cumulative effect assessments for marine management
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Monitoring en Modellering van het cohesieve sedimenttransport en evaluatie van de effecten op het mariene ecosysteem ten gevolge van bagger- en stortoperatie (MOMO). Activiteitsrapport 1 januari 2017 – 30 juni 2017
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Redescription of Cichlidogyrus tiberianus Paperna, 1960 and C. dossoui Douëllou, 1993 (Monogenea: Ancyrocephalidae), with special reference to the male copulatory organ
- The flatworms of the genus Cichlidogyrus Paperna, 1960 (Monogenea: Ancyrocephalidae) are gill parasites of freshwater fish, affecting predominantly the family Cichlidae. Cichlidogyrus tiberianus Paperna, 1960 and Cichlidogyrus dossoui Doue¨llou, 1993 are among the most widely distributed species of the genus, occurring in several African river basins and infecting many different host species, including the economically important Nile tilapia Oreochromis niloticus (Linnaeus) and redbreast tilapia Coptodon rendalli (Boulenger). Despite their wide distribution, C. tiberianus and C. dossoui have so far been studied only by light microscopy. In this paper they are redescribed on the basis of scanning electron microscopy of newly-collected material. The new material was obtained from redbreast tilapia caught in the Luapula River (D. R. Congo). The haptoral sclerites and genitalia are redescribed and illustrated in detail. Special attention is given to the complex morphology of the male copulatory organ.
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Capacity building for the Monitoring, Reporting and Verficiation (MRV) of biodiversity and ecosystem services in Africa
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Dusty baseline: the merit of museum collections in biological invasion studies
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Spatial and seasonal variation of biomineral suspended particulate matter properties in high-turbid nearshore and low-turbid offshore zones
- Suspended particulate matter (SPM) is abundant and essential in marine and coastal waters, and comprises a wide variety of biomineral particles, which are practically grouped into organic biomass and inorganic sediments. Such biomass and sediments interact with each other and build large biomineral aggregates via flocculation, therefore controlling the fate and transport of SPM in marine and coastal waters. Despite its importance, flocculation mediated by biomass-sediment interactions is not fully understood. Thus, the aim of this research was to explain biologically mediated flocculation and SPM dynamics in different locations and seasons in marine and coastal waters. Field measurement campaigns followed by physical and biochemical analyses had been carried out from 2004 to 2011 in the Belgian coastal area to investigate bio-mediated flocculation and SPM dynamics. Although SPM had the same mineralogical composition, it encountered different fates in the turbidity maximum zone (TMZ) and in the offshore zone (OSZ), regarding bio-mediated flocculation. SPM in the TMZ built sediment-enriched, dense, and settleable biomineral aggregates, whereas SPM in the OSZ composed biomass-enriched, less dense, and less settleable marine snow. Biological proliferation, such as an algal bloom, was also found to facilitate SPM in building biomass-enriched marine snow, even in the TMZ. In short, bio-mediated flocculation and SPM dynamics varied spatially and seasonally, owing to biomass-sediment interactions and bio-mediated flocculation.
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Benthic and fish aggregation inside an offshore wind farm: Which effects on the trophic web functioning?
- As part of the energy transition, the French government is planning the construction of three offshore wind farms in Normandy (Bay of Seine and eastern part of the English Channel, north-western France) in the next years. These offshore wind farms will be integrated into an ecosystem already facing multiple anthropogenic disturbances such as maritime transport, fisheries, oyster and mussel farming, and sediment dredging. Currently no integrated, ecosystem-based study on the effects of the construction and exploitation of offshore wind farms exists, where biological approaches generally focused on the conservation of some valuable species or groups of species. Complementary trophic web modelling tools were applied to the Bay of Seine ecosystem (to the 50 km2 area covered by the wind farm) to analyse the potential impacts of benthos and fish aggregation caused by the introduction of additional hard substrates from the piles and the turbine scour protections. An Ecopath ecosystem model composed of 37 compartments, from phytoplankton to seabirds, was built to describe the situation “before” the construction of the wind farm. Then, an Ecosim projection over 30 years was performed after increasing the biomass of targeted benthic and fish compartments. Ecological Network Analysis (ENA) indices were calculated for the two periods, “before” and “after”, to compare network functioning and the overall structural properties of the food web. Our main results showed (1) that the total ecosystem activity, the overall system omnivory (proportion of generalist feeders), and the recycling increased after the construction of the wind farm; (2) that higher trophic levels such as piscivorous fish species, marine mammals, and seabirds responded positively to the aggregation of biomass on piles and turbine scour protections; and (3) a change in keystone groups after the construction towards more structuring and dominant compartments. Nonetheless, these changes could be considered as limited impacts of the wind farm installation on this coastal trophic web structure and functioning.
