Search publications of the members of the Royal Belgian institute of natural Sciences
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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.
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Towards investigating the effect of fining and hardening of marine coastal areas on ecosystem functioning in the Belgian part of the North Sea (BPNS)
- Sediments and the inhabiting macrofauna play an important role in the functioning of coastal marine environments. Human activities in these environments result in two obvious pressures on the sediment: hardening from the installation of offshore wind farms (OWF) and fining in the vicinity of sand extraction sites and in OWF. This study is part of the FaCE-It project and aims at understanding the impacts of those pressures on biogeochemical cycling and on the food web structure. In order to understand benthic ecosystem functioning in different types of sediment, we will measure nutrient fluxes in closed-core incubations sampled along a gradient from fine to coarse sediments, including sediments subjected to fining. Bio- and physical irrigation will be quantified by adding a bromide tracer to the overlying water and following the decreasing concentration over time. With those data, we will estimate the total flux of degradable organic carbon deposited at the sediment surface, its degradation rate and transformation and assess the effect of bioturbation and bio irrigation on benthic ecosystem functioning. Along the same sediment gradient, we will study the macrobenthic food web using stable isotope analysis. Furthermore, the overall food web will be investigated at 3 stations characterized by fine sediment, coarse sediment and an OWF to compare the food web complexity in areas with and without OWFs. These data will finally be used to build a quantitative food web using linear inverse modelling (LIM). To constrain this model, individual respiration rate measurements and pulse chase experiments will be conducted. This combined approach will allow assessing the effect of fining and hardening of marine coastal areas on important ecological processes on the scale of the BPNS.
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An incredibly massive ancient whale skeleton reveals a new way to become a giant
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D3.3 Cumulative sediment dispersal mapping of seafloor-disturbing activities
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Kowieria alveoformis gen. nov. sp. nov., a new heterosporous lycophyte from the Latest Devonian of Southern Africa
