Search publications of the members of the Royal Belgian institute of natural Sciences
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Normal growth, altered growth? Study of the relationship between harris lines and bone form within a post-medieval plague cemetery (Dendermonde, Belgium, 16th Century).
- Objectives Harris lines (HLs) are defined as transverse, mineralized lines associated with temporary growth arrest. In paleopathology, HLs are used to reconstruct health status of past populations. However, their etiology is still obscure. The aim of this article is to test the reliability of HLs as an arrested growth marker by investigating their incidence on human metrical parameters. Methods The study was performed on 69 individuals (28 adults, 41 subadults) from the Dendermonde plague cemetery (Belgium, 16th century). HLs were rated on distal femora and both ends of tibiae. Overall prevalence and age-at-formation of each detected lines were calculated. ANOVA analyses were conducted within subadult and adult samples to test if the presence of HLs did impact size and shape parameters of the individuals. Results At Dendermonde, 52% of the individuals had at least one HL. The age-at-formation was estimated between 5 and 9 years old for the subadults and between 10 and 14 years old for the adults. ANOVA analyses showed that the presence of HLs did not affect the size of the individuals. However, significant differences in shape parameters were highlighted by HL presence. Subadults with HLs displayed slighter shape parameters than the subadults without, whereas the adults with HLs had larger measurements than the adults without. Conclusions The results suggest that HLs can have a certain impact on shape parameters. The underlying causes can be various, especially for the early formed HLs. However, HLs deposited around puberty are more likely to be physiological lines reflecting hormonal secretions.
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The impact of gender, age, social status and spatial distribution on the ancient Easter Islanders’ diet.
- Abstract: Easter Island (or Rapa Nui), famous worldwide for its gigantic stone statues, is the most isolated inhabited island in the Pacific. Yet the history of its inhabitants has been far from peaceful: they have faced deforestation, slave raids, epidemics and colonialism. This paper aims to study the diet of the ancient Easter Islanders and focuses on dietary reconstruction through the analysis of human teeth and bones, more particularly, on the impact of gender, age, social status and spatial distribution. However, retrieving information on their dietary habits is difficult, due to the absence of written archives and the disappearance of most of the bearers of the indigenous culture during the slave raids and epidemics of the nineteenth century. Therefore our primary source of direct information are food remains (animal bones and plant remnants) and human bones. The individuals studied came from twenty sites, which date mainly from the seventeenth to the nineteenth centuries. The greater part had been buried in monuments (funerary stone platforms called ahu), or caves. These individuals are currently stored at the Royal Belgian Institute of Natural Sciences and the Father Sebastian Englert Anthropological Museum of Easter Island. Dietary reconstruction is based on stress indicators, dental microwear and stable carbon and nitrogen isotope analyses. Stress indicators are skeletal markers which reveal poor living conditions during growth. Two indicators were studied: dental enamel hypoplasia (localised defects in the tooth crown generally expressed in the form of horizontal depressions) and cribra orbitalia(porotic lesions in the bony orbital roof). Dental microwear is the study of the microscopic features that form on the teeth’s surfaces as a result of use. Their density, dimensions, and orientation are a direct result of diet. Stable isotope analyses are based on the fact that the isotopic composition of an individual’s tissues is determined by the proportion of the various foods consumed. Carbon and nitrogen stable isotope composition were analysed in the bone collagen. Dental microwear patterns indicated a large proportion of tubers in the Easter islanders’ diet. Additionally, the stable isotopes showed that, on average, one third of the dietary proteins were of marine origin and that children were breastfed until three years of age. Stress indicators suggest that infantile malnutrition was not severe. Our results also demonstrated gender disparity in access to food resources. Furthermore, the isotopic signatures clustered according to the place of burial (ahu), indicating family dietary specificities. Finally, our study revealed the influence of social status on food intake: individuals from Ahu Nau Nau, which is said to be the royal ahu, displayed the highest value of nitrogen and carbon isotopes and the lowest number of microwear features. A greater consumption of marine products may explain this distinction.
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La grotte de On révèle quelques secrets
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Het schrijn van de Z. Idesbald in de O.L.V.-Ter-Potterie: wie ligt er in de kist? (Koksijde-Brugge, W.-Vl)
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Etude d'impact des changements hydrodynamiques induits par une ferme d'aquaculture de moules offshore
- About 30 years ago, researchers of RBINS developed COHERENS (coupled hydrodynamical-ecological model for regional and shelf seas), a three-dimensional hydrodynamic model designed for a wide range of applications in coastal and shelf seas, estuaries, lakes and reservoirs. The main goal of this internship is to quantify the hydrographic changes (especially marine currents) induced by an offshore mussel aquaculture farm similar to the industrial project "Wesdiep Sea Farm", using the COHERENS model. The mussel aquaculture technique used in this project is known to disturb currents and turbulence in the water column. The goal of this internship is to implement the parameterisation of the impacts of the mussel droppers in the COHERENS hydrodynamic model as well as the addition of a new source term for turbulent kinetic energy production. Then, a sensitivity study will be carried out using the implementation made in a test case of a simplified mussel aquaculture farm. Note that in parallel to this report, a more complete report was produced for RBINS within the framework of this internship and the student has already been offered a contract of employment.
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Quantification of hydrodynamic changes induced by an offshore mussel aquaculture farm (Part 1)
- The goal of this end-of-studies internship proposed by the Royal Belgian Institute of Natural Sciences (RBINS) is the quantification of hydrodynamic changes (especially sea currents) induced by an offshore aquaculture farm similar to that of the industrial project “Westdiep Sea Farm”. The mussel aquaculture technique used in this project is known to disturb currents by, among other things, increasing the velocity of currents under the farm and significantly increasing the turbulence developing in the wake of the rigs. However, according to the knowledge of the RBINS, no study quantifies these disturbances. From an environmental point of view, an open question is whether or not these changes can modify the erosion/sedimentation pattern around the farm, leading, for example, to a risk of destabilization of the neighbouring sandbanks. First, the objective of this internship is to implement the parameterization of droppers impacts in the COHERENS hydrodynamic model. For this, a literature study will be carried out. Then, a sensitivity study will be conducted in order to use the implementation in a test case of a similar and simplified mussel farm. If time permits, the final objective would be to apply these different tests and simulations on the realistic case of the "Westdiep Sea Farm".
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Quantification of hydrodynamic changes induced by an offshore mussel aquaculture farm (SYMAPA)
- The goal of this numerical study is the quantification of hydrodynamic changes (especially sea currents) induced by an offshore aquaculture farm similar to that of the industrial project “Westdiep Sea Farm”. To do that, a parameterization of the impact of longlines and droppers on hydrodynamics has been included in the 3D COHERENS hydrodynamic model and the impact of several configurations of the aquaculture farm on currents and bottom shear stress has been estimated in a simplified test case. The mussel aquaculture technique of longlines used in this project is known to disturb currents by, among other things, increasing the velocity of currents under the farm and significantly increasing the turbulence developing in the wake of the rigs. From an environmental point of view, an open question is whether or not these changes can modify the erosion/sedimentation pattern around the farm, leading, for example, to a risk of destabilization of the neighbouring sandbanks. As part of the SYMAPA (Synergy between Mariculture & Passive Fisheries) project, the goal is to link current variations in and around the farm to the amount of food available for mussels attached to droppers. At the seabed, a link between hydrodynamic processes and modification of the sedimentation scheme may be considered following this report. This preliminary study can help lead to the final goal of determining the scope of the impact that the aquaculture farm may have on the ecosystems in the farm and on the benthos. Three major effects will be studied for three different farm designs: the impact on surface currents, the sinking of currents under the farm and the impact on bottom shear stress.
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Reviews and syntheses: A framework to observe, understand and project ecosystem response to environmental change in the East Antarctic Southern Ocean
- Abstract. Systematic long-term studies on ecosystem dynamics are largely lacking from the East Antarctic Southern Ocean, although it is well recognized that they are indispensable to identify the ecological impacts and risks of environmental change. Here, we present a framework for establishing a long-term cross-disciplinary study on decadal timescales. We argue that the eastern Weddell Sea and the adjacent sea to the east, off Dronning Maud Land, is a particularly well suited area for such a study, since it is based on findings from previous expeditions to this region. Moreover, since climate and environmental change have so far been comparatively muted in this area, as in the eastern Antarctic in general, a systematic long-term study of its environmental and ecological state can provide a baseline of the current situation, which will be important for an assessment of future changes from their very onset, with consistent and comparable time series data underpinning and testing models and their projections. By establishing an Integrated East Antarctic Marine Research (IEAMaR) observatory, long-term changes in ocean dynamics, geochemistry, biodiversity, and ecosystem functions and services will be systematically explored and mapped through regular autonomous and ship-based synoptic surveys. An associated long-term ecological research (LTER) programme, including experimental and modelling work, will allow for studying climate-driven ecosystem changes and interactions with impacts arising from other anthropogenic activities. This integrative approach will provide a level of long-term data availability and ecosystem understanding that are imperative to determine, understand, and project the consequences of climate change and support a sound science-informed management of future conservation efforts in the Southern Ocean.
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Cable Bacteria Activity Modulates Arsenic Release From Sediments in a Seasonally Hypoxic Marine Basin
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Assessing the impact of bioturbation on sedimentary isotopic records through numerical models
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Working Group on Fisheries Benthic Impact and Trade-offs (WGFBIT; outputs from 2021 meeting).
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Comparative ultrastructure of the spermatogenesis of three species of Poecilosclerida (Porifera, Demospongiae)
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Tropical Eastern Pacific Amphoriscidae Dendy, 1892 (Porifera: Calcarea: Calcaronea: Leucosolenida) from the Peruvian coast
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NUEVOS REGISTROS DE DEMOSPONGIAE (PORIFERA) PARA LA COSTA CENTRO-SUR DEL PERÚ
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INTEGRATIVE TAXONOMY OF SYMPATRIC SPECIES OF OSCARELLA VOSMAER, 1887 FROM THE CABO FRIO REGION, IN SOUTHEAST BRAZIL (PORIFERA, HOMOSCLEROMORPHA)
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PRIMER REGISTRO DE CIOCALYPTA BOWERBANK, 1862 (PORIFERA, DEMOSPONGIAE, SUBERITIDA, HALICHONDRIIDAE) EN EL PACÍFICO ESTE Y DESCRIPCIÓN DE UNA ESPECIE NUEVA
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IDENTIFICACIÓN PRELIMINAR DE LAS ESPECIES DE HYMENIACIDON (PORIFERA, DEMOSPONGIAE) DEL PERÚ
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ESPONJAS DE LA ISLA REY JORGE Y CERCANÍAS, ISLAS SHETLAND DEL SUR, ANTÁRTIDA
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NUEVAS ESPECIES DE SUBERITES NARDO, 1833 (PORIFERA, DEMOSPONGIAE, SUBERITIDA) DE LAS ISLAS ASIA, PACHACAMAC Y SAN LORENZO (PERÚ)
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Similar ecology, different morphology: Three new species of oral-mollusc shellers from Lake Edward
- Abstract Lake Edward, East Africa, harbours a largely understudied assemblage of haplochromine cichlids that displays a range of adaptions to various specialised trophic niches. In this system, we discovered specimens of Haplochromis with morphologies similar to those of oral-mollusc shellers from Lake Victoria. These morphologies are characterised by short oral jaws with stout teeth that are used either to crush molluscs or to grab the soft bodies of snails and wrench them out of their shells. A morphometric study on 47 specimens from Lake Edward revealed the presence of three new species with an oral-shelling morphology: Haplochromis concilians sp. nov., H. erutus sp. nov. and H. planus sp. nov. All three species are formally described. Stomach-content observations confirmed an opportunistic oral-shelling ecology for H. concilians sp. nov. and H. erutus sp. nov. Within H. planus sp. nov., only large specimens displayed a specialised oral-shelling morphology, but their stomachs were nearly empty, while small specimens consumed mainly Ostracoda and Hydrachnidia. Remarkably, the three species differed considerably in morphology from each other, but they each resembled oral-sheller species from Lake Victoria.
