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Bistability in the redox chemistry of sediments and oceans
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For most of Earth’s history, the ocean’s interior was pervasively anoxic and showed occasional shifts in ocean redox chemistry between iron-buffered and sulfide-buffered states. These redox transitions are most often explained by large changes in external inputs, such as a strongly altered delivery of iron and sulfate to the ocean, or major shifts in marine productivity. Here, we propose that redox shifts can also arise from small perturbations that are amplified by nonlinear positive feedbacks within the internal iron and sulfur cycling of the ocean. Combining observational evidence with biogeochemical modeling, we show that both sedimentary and aquatic systems display intrinsic iron–sulfur bistability, which is tightly linked to the formation of reduced iron–sulfide minerals. The possibility of tipping points in the redox state of sediments and oceans, which allow large and nonreversible geochemical shifts to arise from relatively small changes in organic carbon input, has important implications for the interpretation of the geological rock record and the causes and consequences of major evolutionary transitions in the history of Earth’s biosphere.
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Prospections sur la « villa gallo-romaine du Sart », au lieu-dit La Hamaide, à Hautrage (B).
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Hautrage, une commune belge appartenant à l’entité de Saint-Ghislain, se situe dans la partie occidentale de la province du Hainaut. Plusieurs découvertes archéologiques, la plupart anciennes et souvent mal documentées, sont mentionnées sur son territoire1 . 1. Historique des recherches, le site (J. DUFRASNES) La première mention de ce site archéologique apparaît dans HAUBOUDIN 1898, p. 80. L’auteur, un archéologue amateur très actif habitant Stambruges2 , note alors : Villa du Sart.- Un chemin, qui porte encore le nom de chemin d’El Ville3 , indique la Villa du Sart qui est proche. Le cimetière était la nécropole de cette villa4 . Des notes manuscrites datées de janvier 19415 et un inventaire réalisé à l’occasion de l’entrée d’une partie de la collection d’Edmond Haubourdin aux Musées royaux d’Art et d’Histoire de Bruxelles mentionnent du matériel susceptible de provenir de la villa de la Hamaide à Hautrage, c’est-à-dire de la « villa du Sart » (fig. 1). Cependant, aucun des écrits laissés par cet archéologue ne relate qu’il obtint du matériel archéologique de ce site par acquisition, par des fouilles ou des prospections. Edmond Haubourdin ajoute : « Diverticulum.- Le chemin qui traverse le chemin de fer à la station de la Hamaide porte, au cadastre d’Hautrage, le nom de chaussée romaine. Cette chaussée [dont l’actuelle rue des Bats, à 300 mètres à l’est du site, serait un tronçon selon l’auteur ndlr] passait près de la villa et se dirigeait vers Bavay, probablement vers Chièvres, par Villerot, Sirault et Neufmaison, où elle se confondait avec le diverticulum qui venait de Condé par Stambruges. La grande largeur de cette voie de communication accuse son origine romaine »6
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RBINS Staff Publications 2022
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Bistability in the redox chemistry of sediments and oceans
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For most of Earth’s history, the ocean’s interior was pervasively anoxic and showed occasional shifts in ocean redox chemistry between iron-buffered and sulfide-buffered states. These redox transitions are most often explained by large changes in external inputs, such as a strongly altered delivery of iron and sulfate to the ocean, or major shifts in marine productivity. Here, we propose that redox shifts can also arise from small perturbations that are amplified by nonlinear positive feedbacks within the internal iron and sulfur cycling of the ocean. Combining observational evidence with biogeochemical modeling, we show that both sedimentary and aquatic systems display intrinsic iron–sulfur bistability, which is tightly linked to the formation of reduced iron–sulfide minerals. The possibility of tipping points in the redox state of sediments and oceans, which allow large and nonreversible geochemical shifts to arise from relatively small changes in organic carbon input, has important implications for the interpretation of the geological rock record and the causes and consequences of major evolutionary transitions in the history of Earth’s biosphere
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RBINS Staff Publications 2020
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Cryptophyllium, the hidden leaf insects – descriptions of a new leaf insect genus and thirteen species from the former celebicum species group (Phasmatodea, Phylliidae)
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RBINS Staff Publications 2021
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BICEpS Annual report 2019 – Reinforcing Belgian ICES People
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The International Council for the Exploration of the Sea (ICES; French: Conseil International pour l'Exploration de la Mer, CIEM) is an intergovernmental marine science organization that brings together the efforts and knowledge of 20 Member States, bordering the North Atlantic and the Arctic Circumpolar Zone, on physical oceanography, marine ecosystems and fisheries management. Nowadays, more than 80 Belgian scientists are directly involved in the work of the 150 bodies and expert groups of ICES, which gather the expertise of more than 1500 scientists yearly, totalling up to 5000 scientists from over 700 marine institutes and organizations over the years. This important and often voluntary dedication of Belgian scientists to the work of ICES deserves more visibility among the Belgian scientific community itself and to policy makers.This is, among others, why the BICEpS initiative was launched in 2018. BICEpS general aim is to offer a platform to the Belgian ICES community to get to know each other, to improve collaboration and share information, and to promote ICES to the wider scientific community in Belgium. BICEpS Annual report 2019 presents the second year of activity of this initiative created to reinforce Belgian ICES people. The report targets marine scientists, marine managers and policy makers. It presents the results of the initiative so far. The report contains the list of Belgian ICES members in 2019 with their membership to the different ICES working groups, and the results of the second BICEpS Colloquium organised on 2 December 2019 and hosted by ILVO in Ghent (Summary of the sessions, abstracts of communications presented and list of participants). The abstracts of the colloquium are supplemented by a separate annex published online which assembles the PowerPoint presentations of the colloquium accessible at http://ices.dk/community/groups/Documents/BICEPS/BICEpS19-PPT-presentations.pdf This report is accessible on the ICES website at http://ices.dk/community/groups/Pages/BICEpS.aspx
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RBINS Staff Publications 2020
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Are petrous bones just a repository of ancient biomolecules? Investigating biosystematic signals in sheep petrous bones using 3D geometric morphometrics
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Over the last decade, the petrous bone (petrosum) has become the ultimate repository of ancient biomolecules, leading to a plea for a more ethical curation preventing the systematic destruction of this bioarchaeological archive. Here, we propose to explore the biosystematic signal encompassed in the biological form of 152 petrosa from modern populations of wild and domestic sheep landraces/breeds across Western Europe, South-Western Asia and Africa, using high resolution geometric morphometrics (GMM) and the latest development in 3D virtual morphology. We assessed the taxonomic signals among wild and domestic caprine species and sheep landraces. We also explored the effect of sexual dimorphism and ageing at the population scale. Finally, we assessed the influence of climatic factors across the geographic distribution of our dataset using Köppen-Geiger climate categories. We found that the 3D form of petrous bones can accurately separate wild and domestic caprine taxa and that it is not influenced by sexual dimorphism, post-natal ageing or horn bearing. Recent selective breeding has not induced sufficient diversification to allow accurate identification of the different landraces/breeds in sheep; however, both genetic distance and climatic differences across the current distribution in sheep landraces/breeds strongly contribute to petrosum intraspecific variation. Finally, human mediated dispersal of domestic sheep outside their Near Eastern cradle, especially towards Africa, have greatly contributed to the diversification of sheep petrous bone form and shape. We therefore highly recommend systematic 3D surface modelling of archaeological petrosa with preliminary GMM studies to help target and reduce destructive biomolecular studies.
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RBINS Staff Publications 2022
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The introduction of the European fallow deer to the northern provinces of the Roman Empire: a multi-proxy approach to the Herstal skeleton (Belgium)
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Many exotic animal species were introduced to Northern Europe during the Roman period, including fallow deer (Dama dama). To date, however, finds of fallow deer bones at archaeological sites in this region have been sporadic and disarticulated, leaving uncertainty over their origins. This article presents the first known articulated fallow deer skeleton from Roman North-western Europe. Osteological, ancient DNA, radiocarbon dating and stable isotope analyses confirm that the species was established in this region by the Roman period, probably originating from translocated, rather than native, Mediterranean populations. Clarifying the origins of fallow deer in North-western Europe is critical for understanding the dynamics of species exchange around the Roman Empire.
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RBINS Staff Publications 2020
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Digital restoration of the snout of Khirtharia inflata (Raoellidae, Artiodactyla) from the middle Eocene of northwest Himalaya
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In this work, we digitally restore the snout of the raoellid Khirtharia inflata from the Kalakot area (Rajouri District, Jammu & Kashmir, India). Raoellids are small, semiaquatic ungulates closely related to cetaceans. The specimen is fairly complete and preserves left and right maxillae, left premaxilla, and part of the anterior and jugal dentition. The digital restoration of this quite complete but deformed specimen of Khirtharia inflata is a welcome addition to the data available for raoellids and will be used to further the understanding of the origins of cetaceans.
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RBINS Staff Publications 2024 OA
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Endocranial anatomy and phylogenetic position of the crocodylian Eosuchus lerichei from the late Paleocene of northwestern Europe and potential adaptations for transoceanic dispersal in gavialoids
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Eosuchus lerichei is a gavialoid crocodylian from late Paleocene marine deposits of northwestern Europe, known from a skull and lower jaws, as well as postcrania. Its sister taxon relationship with the approximately contemporaneous species Eosuchus minor from the east coast of the USA has been explained through transoceanic dispersal, indicating a capability for salt excretion that is absent in extant gavialoids. However, there is currently no anatomical evidence to support marine adaptation in extinct gavialoids. Furthermore, the placement of Eosuchus within Gavialoidea is labile, with some analyses supporting affinities with the Late Cretaceous to early Paleogene “thoracosaurs.” Here we present novel data on the internal and external anatomy of the skull of E. lerichei that enables a revised diagnosis, with 6 autapormorphies identified for the genus and 10 features that enable differentiation of the species from Eosuchus minor. Our phylogenetic analyses recover Eosuchus as an early diverging gavialid gavialoid that is not part of the “thoracosaur” group. In addition to thickened semi-circular canal walls of the endosseous labyrinth and paratympanic sinus reduction, we identify potential osteological correlates for salt glands in the internal surface of the prefrontal and lacrimal bones of E. lerichei. These salt glands potentially provide anatomical evidence for the capability of transoceanic dispersal within Eosuchus, and we also identify them in the Late Cretaceous “thoracosaur” Portugalosuchus. Given that the earliest diverging and stratigraphically oldest gavialoids either have evidence for a nasal salt gland and/or have been recovered from marine deposits, this suggests the capacity for salt excretion might be ancestral for Gavialoidea. Mapping osteological and geological evidence for marine adaptation onto a phylogeny indicates that there was probably more than one independent loss/reduction in the capacity for salt excretion in gavialoids.
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RBINS Staff Publications 2024 OA
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The cranium and dentition of Khirtharia (Artiodactyla, Raoellidae): new data on a stem taxon to Cetacea
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Raoellid mammals are small artiodactyls from the Eocene of Asia, hypothesized to be closely related to stem Cetacea. Knowledge of the cranial and dental morphology of Raoellidae comes mostly from one species, Indohyus indirae. Here we describe new material of another raoellid genus, Khirtharia, based on material retrieved from the Kalakot area, Jammu and Kashmir. This new material, comprising an almost complete, lightly deformed cranium and a partial snout with associated partial mandible, greatly adds to our knowledge of raoellid morphology. It highlights the similarity of cranial characters with Indohyus, such as a long snout with raptorial incisors, a thick and narrow supraorbital region, a strong postorbital constriction, a triangular shaped braincase, and a thickened medial wall to the auditory bulla (involucrum). The new specimen is similar to Indohyus cranially but differs dentally in being more bunodont. The presence of these traits in two different raoellid genera suggests they may be present more broadly across Raoellidae. These characters are also observed in early cetaceans, highlighting the need to investigate their phylogenetic impact. Some cranial features support aquatic habits of members of this family.
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RBINS Staff Publications 2024 OA
