Search publications of the members of the Royal Belgian institute of natural Sciences
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The Holocene palaeolake of Tayma – A key site for unravelling palaeoclimate, with implications for Neolithic incursions and “oasisation” on the northern Arabian Peninsula
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Die holozäne Feuchtphase auf der Arabischen Halbinsel und Implikationen für die Entstehung der Oasenkultur
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La conservation des holothuries aspidochirotes dans les eaux du littoral kenyan
- Les holothuries aspidochirotes (Échinodermes : Holothurides) font l’objet d’une pêche intensive dans les eaux du littoral kenyan et les stocks fondent comme neige au soleil. Afin de protéger et de gérer ces ressources naturelles, il convient d’élaborer des programmes de conservation et de gestion. Or, une telle entreprise nécessite la réalisation d’études rigoureuses et informatives dans différents domaines. Ce document s’attarde sur les cinq niveaux de compréhension nécessaires à l’élaboration d’un programme adapté à la conservation des holothuries en Afrique orientale.
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A 1500 years-record of North Atlantic storminess from the Shetland Islands (UK) – preliminary insights
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Holocene climate variability in the Near East and its impact on the history of civilization
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The process of oasisation in light of the new discovery of a surprisingly short early to mid-Holocene humid period in Northern Arabia
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A new species of Holothuria (Aspidochitotida, Holothuriidae) from Kenya
- A new species, Holothuria (Mertensiothuria) arenacava (Echinodermata, Holothuroidea) from the littoral waters of Kenya is described. This species is characterized by its sand-burrowing behaviour, its small tentacles, the variously developed tables, corpuscules, buttons, plates and rods in the tube feet, and by the smooth, spiny and knobbed rods in the tentacles.
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Historical storm frequency on the Shetland Islands (UK) – Insights from lake sediment cores and coastal wave modelling
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First application of a microfauna-based transfer function to reconstruct Holocene relative sea-level change in the southern North Sea
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Metagenomics of tsunami deposits: developments and challenges from a case study on the Shetland Islands (UK)
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Historical storm frequency on the Shetland Islands (UK) – Preliminary insights from lake sediment cores and coastal wave modelling
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Significance of boulder shape for the transport of boulders by tsunamis
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Historical records of storm frequency on the Shetland Islands (UK) – Preliminary insights from lake sediment cores and coastal wave modelling
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Active earth-surface processes following rainfall events in the southern Namib Desert – Insights from the Kaukausib catchment by means of remote sensing
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High-resolution facies analysis provides insights into sabkha formation in the Gulf of Salwa (Arabian Gulf)
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Sawflies containing toxic peptides
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Cranial morphology of Khirtharia inflata (Raoellidae, Artiodactyla)
- Raoellidae are extinct small-sized semiaquatic artiodactyls that are the closest relatives to crown clade Cetacea. They display morphological features showing the transition between terrestrial and aquatic lifestyles and therefore bring crucial information to understand the earliest steps of cetacean evolution. Raoellid cranial morphology, including the ear region and endocranial morphology, has been documented using cranial remains referred to Indohyus indirae from the Kalakot area, Jammu and Kashmir in India. The study of these specimens highlighted that several cetacean features are already present in raoellids. The previously available Indohyus material was very deformed, preventing access to quantitative data and leading to potential misinterpretations. We describe new undeformed cranial material from the Kalakot area, documenting another raoellid species, Khirtharia inflata. The new observations allow us to complete our knowledge of raoellid cranial morphology, including the original shape of the cranium and brain endocast and to confirm the specificities of raoellid morphology within Artiodactyla. We further provide the first quantitative data for the different brain components and show that Raoellidae had low encephalization and neocorticalization values, much lower than cetaceans and close to early diverging, primitive, dichobunoid artiodactyls. Reconstruction of the blood sinuses above the cerebellum supports the previous “intraosseous” hypothesis about the initial steps of the development of the caudal venous rete mirabile in cetaceans. The presence of several cetacean cranial features in Raoellidae, such as the peculiar shape of the frontal, the strong postorbital constriction, the periotic involucrum, or the elongation of the olfactory bulbs, questions the definition of the Cetacea clade.
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Novel Cardinium strains from non-marine ostracod (Crustacea) hosts
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Impact of macrofaunal activities on the biogeochemical cycling in anthropogenically disturbed sediment
- Marine coastal areas are important for the ecosystem functioning because they provide a wealth of goods and services. Hence, it is a major challenge nowadays to understand and predict how human activities will affect marine sediment communities, benthic biogeochemical cycling and the link between them. It is known that bioturbation activities affect the ecosystem functioning. In this study, we are going one step further by studying biogeochemical cycling in a range of natural sediment and disturbed sediment, and by assessing the contribution of macrofaunal activities (bioturbation and bio-irrigation) to the ecosystem cycling. We conducted closed-core incubations of sediment sampled along a gradient from fine to coarse sediments, including sediments subjected to fining. Nutrients and oxygen concentration were followed by sampling the overlying water every 2 hours. Bio- and physical irrigation has been quantified by adding a bromide tracer to the overlying water and following the decreasing concentration over time. At the end of the incubation, the sediment was sieved and the organisms retrieved to calculate the bioturbation potential of the community (BPc). With those data, we will estimate the total flux of degradable organic carbon deposited at the sediment surface, its degradation rate and transformation, and the nitrification/denitrification rates. The aim is to assess the effect of fining and the effect of bioturbation and bio irrigation on benthic ecosystem functioning. The research plan and the preliminary results will be reported.
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How do macrofaunal activities impact biogeochemical cycling in anthropogenically disturbed sediment?
- Marine coastal areas are important for ecosystem functioning because they provide a wealth of goods and services. Hence, it is a major challenge nowadays to understand and predict how human activities will affect marine sediment communities, benthic biogeochemical cycling and the link between them. In this study, we investigate biogeochemical fluxes and the contribution of macrofaunal activities (bioturbation and bio-irrigation) in sediment ranging from muddy to coarse, including two coarse sediment stations affected by human activity (installation of an offshore windfarm and aggregate extraction). For each station, we conducted triplicate closed-core incubations to measure oxygen, nutrients and DIC fluxes as well as bioirrigation rates by following the decreasing concentration of bromide in the water column over time. After the incubation, the macrofaunal community was identified and the bioturbation potential of the community calculated (BPc). Our results show the highest Sediment Community Oxygen Consumption (SCOC) in a fine sandy station inhabited by an abundant bioirrigating and bioturbating macrofaunal community and characterized by relatively high organic matter content. In the muddy station, the SCOC was 4 times lower and the DIC efflux much higher than the SCOC reflecting anaerobic mineralization processes happening in absence of bioirrigators. Within the coarse sediment stations characterized by poor organic matter content and inhabited by a limited macrofaunal community, the undisturbed station shows the highest irrigation rates associated with moderate SCOC and DIC efflux. In the disturbed stations, irrigation rate, SCOC and DIC efflux were low suggesting that physical disturbance decreases the efficiency of mineralization processes in coarse sediments. The overall results show that irrigation of the sediment affects biogeochemical cycling along a range of coastal sediments.
