Search publications of the members of the Royal Belgian institute of natural Sciences
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Étude multidisciplinaire du contenu de reliquaires attribués au cardinal Jacques de Vitry (XII-XIIIe siècle ap. J.-C.)
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« Les saints ont la parole » : l’anthropologie biologique et les reliques.
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Increased food availability at offshore wind farms affects trophic ecology of plaice Pleuronectes platessa
- Offshore wind farms (OWFs) and their associated cables, foundations and scour protection are often constructed in soft- sediment environments. This introduction of hard substrate has been shown to have similar effects as artificial reefs by providing food resources and offering increased habitat complexity, thereby aggregating fish around the turbines and foundations. However, as most studies have focused their efforts on fish species that are typically associated with reef structures, knowledge on how soft sediment species are affected by OWFs is still largely lacking. In this study, we analysed the trophic ecology and condition of plaice, a flatfish species of commercial interest, in relation to a Belgian OWF. The combination of a stomach and intestine content analysis with the use of biomarkers (i.e. fatty acids and stable isotopes) identified a clear shift in diet with increased occurrences of typical hard-substrate prey species for fish in the vicinity of the foundations and this both on the short and the long term. Despite some condition indices suggesting that the hard substrate provides increased food availability, no clear increases of overall plaice condition or fecundity were found. Samples from within the wind farm, however, contained larger fish and had a higher abundance of females compared to control areas, potentially indicating a refuge effect caused by the cessation of fisheries activities within the OWF. These results suggest that soft-sediment species can potentially benefit from the presence of an OWF, which could lead to fish production. However, more research is still needed to further elucidate the behavioral ecology of plaice within OWFs to make inferences on how they can impact fish populations on a larger spatial scale.
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Structurally stable but functionally disrupted marine microbial communities under a future climate change scenario: Potential importance for nitrous oxide emissions
- The blue mussel Mytilus edulis is a widespread and abundant bivalve species along the North Sea with high economic and ecological importance as an engineer species. The shell of mussels is intensively colonized by microbial organisms that can produce significant quantities of nitrous oxide (N2O), a potent greenhouse gas. To characterize the impacts of climate change on the composition, structure and functioning of microbial biofilms on the shell surface of M. edulis, we experimentally exposed them to orthogonal combinations of increased seawater temperature (20 vs. 23 ◦ C) and decreased pH (8.0 vs. 7.7) for six weeks. We used amplicon sequencing of the 16S rRNA gene to characterize the alpha and beta diversity of microbial communities on the mussel shell. The functioning of microbial biofilms was assessed by measuring aerobic respiration and nitrogen emission rates. We did not report any significant impacts of climate change treatments on the diversity of mussel microbiomes nor on the structure of these communities. Lowered pH and increased temperature had antagonistic effects on the functioning of microbial communities with decreased aerobic respiration and N2O emission rates of microbial
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Developing expert scientific consensus on the environmental and societal effects of marine artificial structures prior to decommissioning
- Thousands of artificial (‘human-made ’ ) structures are present in the marine environment, many at or approaching end-of-life and requiring urgent decisions regarding their decommissioning. No consensus has been reached on which decommissioning option(s) result in optimal environmental and societal outcomes, in part, owing to a paucity of evidence from real-world decommissioning case studies. To address this significant chal- lenge, we asked a worldwide panel of scientists to provide their expert opinion. They were asked to identify and characterise the ecosystem effects of artificial structures in the sea, their causes and consequences, and to identify which, if any, should be retained following decommissioning. Experts considered that most of the pressures driving ecological and societal effects from marine artificial structures (MAS) were of medium severity, occur frequently, and are dependent on spatial scale with local-scale effects of greater magnitude than regional effects. The duration of many effects following decommissioning were considered to be relatively short, in the order of days. Overall, environmental effects of structures were considered marginally undesirable, while societal effects marginally desirable. Experts therefore indicated that any decision to leave MAS in place at end-of-life to be more beneficial to society than the natural environment. However, some individual environmental effects were considered desirable and worthy of retention, especially in certain geographic locations, where structures can support improved trophic linkages, increases in tourism, habitat provision, and population size, and provide stability in population dynamics. The expert analysis consensus that the effects of MAS are both negative and positive for the environment and society, gives no strong support for policy change whether removal or retention is favoured until further empirical evidence is available to justify change to the status quo. The combination of desirable and undesirable effects associated with MAS present a significant challenge for policy- and decision- makers in their justification to implement decommissioning options. Decisions may need to be decided on a case-by-case basis accounting for the trade-off in costs and benefits at a local level.
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The underwater soundscape of the North Sea
- As awareness on the impact of anthropogenic underwater noise on marine life grows, underwater noise mea- surement programs are needed to determine the current status of marine areas and monitor long-term trends. The Joint Monitoring Programme for Ambient Noise in the North Sea (JOMOPANS) collaborative project was funded by the EU Interreg to collect a unique dataset of underwater noise levels at 19 sites across the North Sea, spanning many different countries and covering the period from 2019 to 2020. The ambient noise from this dataset has been characterised and compared - setting a benchmark for future measurements in the North Sea area. By identifying clusters with similar sound characteristics in three broadband frequency bands (25 – 160 Hz, 0.2 – 1.6 kHz, and 2 – 10 kHz), geographical areas that are similarly affected by sound have been identified. The measured underwater sound levels show a persistent and spatially uniform correlation with wind speed at high frequencies (above 1 kHz) and a correlation with the distance from ships at mid and high frequencies (between 40 Hz and 4 kHz). Correlation with ocean current velocity at low frequencies (up to 200 Hz), which are sus- ceptible to nonacoustic contamination by flow noise, was also evaluated. These correlations were evaluated and simplified linear scaling laws for wind and current speeds were derived. The presented dataset provides a baseline for underwater noise measurements in the North Sea and shows that spatial variability of the dominant sound sources must be considered to predict the impact of noise reduction measures.
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Specific initial training standards are needed to dive for science in Europe, Occupational vs . Citizen Science Diving
- Today, collaboration between scienti fi c research and civil society is growing signi fi cantly. The general public ’ s curiosity drives it to engage with the scienti fi c process and culture and in the search for solutions to complex issues (economic, social, health, environmental, cultural, educational, or ethical). Clari fi cation is needed to differentiate between occupational scienti fi c activity and citizen-based science. They do not require the same scienti fi c and technical skills despite using similar equipment and their legal and administrative frameworks being totally different. The confusion created by the indiscriminate use of the same term “ scienti fi c diving ” to refer to different training courses and activities compromises the quality of existing occupational standards and, ultimately, has a negative impact on the safety of the activity at work. A clear de fi nition of Citizen Scienti fi c Diving and Occupational Scienti fi c Diving makes it possible to differentiate between the objectives and target groups of these two activities and their legal framework. There is a need to establish an accepted and shared standard in the occupational fi eld and to ensure the mobility of scientists. A long process undertaken by a motivated scienti fi c community (late 1980s-2000s) led to the establishment of European initial training standards for Occupational Scienti fi c Diving through the ESDP-European Scienti fi c Diving Panel ( fi rstly under the aegis of the European Marine Board, now of the MARS-European marine stations network). The quality and general acceptance of these standards by a large part of the European scienti fi c community have already adopted them in the occupational health and safety legislation of seven European countries (Belgium, Finland, France, Germany, Norway, Sweden, and the UK in 2023). Adopting them in other countries ’ health and safety legislation is still desirable. This will increase their recognition, acceptance and use for the bene fi t of scienti fi c work. Building bridges between academic science and non-academic citizen science is possible and this is done by developing coherent projects that produce results that bene fi t both science and society. While distinguishing between the two, as an added value, this approach could better guide the recreational diving training sector in developing a new market.
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Spiraaltjes op het strand en onderste boven in de oceaan: de Posthoorninktvis Spirula spirula weet iedereen te verbazen
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Observations on the Pliocene sediments exposed at Antwerp International Airport (Northern Belgium) constrains the stratigraphic position of the Broechem fauna
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Applying micro-CT imaging in the study of fossil sepiids and nautilids (Cephalopoda): examples from the Eocene of Belgium
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Graptolieten uit Lompret!
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Twee nautilusfossielen gevonden in de Donkerstraat in Leuven!
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The Upper Miocene Deurne Member of the Diest Formation revisted: unexpected results from the study of a large temporary outcrop near Antwerp International Airport, Belgium
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The internal division of the Pliocene Lillo Formation: correlation between Cone Penetration Tests and lithostratigraphic type sections
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Investigating the co-occurrence of Neanderthals and modern humans in Belgium through direct radiocarbon dating of bone implements
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Variability in ostracod communities (Crustacea, Ostracoda) in connected and isolated tropical floodplain lakes
- Floodplains mostly consist of primary and secondary riverbeds, connecting channels and lakes that are either isolated from rivers and channels for most of the year, or lakes that are connected to rivers and channels for most (or all) of the year. We hypothesize that the differences in invertebrate communities, as calculated by beta-diversities, will be higher in isolated than in connected lakes. We use ostracod communities in the pleuston of the floating macrophyte Eichhornia crassipes in the Upper Paraná River floodplain to test this hypothesis. We have observed significant differences in species composition between the two types of lakes. However, although beta diversity values are indeed slightly higher in isolated than in connected lakes, these differences are not significant. This lack of clear effect of isolation on beta diversity could be owing to the fact that the period of isolation since the last homogenizing flood pulse had not been long enough, or because differences in degree of isolation become altogether insignificant in periods of low water flow.
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On the affinity of Isocypridinae and Herpetocypridinae, with redescriptions of four species of Ilyodromus Sars, 1894 (Crustacea, Ostracoda)
- In previous studies, the high degree of similarity of some species of Ilyodromus Sars, 1894 (Herpetocypridinae) to species of another subfamily (Isocypridinae) was noted, calling for a revision of their systematic placement. Here, the systematics of Ilyodromus Sars, 1894 are revised within this context by redescribing four species and comparing these to other genera of Herpetocypridinae and Isocypridinae. Material for the four redescribed species (I. amplicolis De Deckker, 1981, I. dikrus De Deckker, 1981, I. candonites De Deckker, 1981, and I. williamsi (McKenzie, 1966)) was obtained from Museum Victoria and recollected topotypes. It was found that most genera within Isocypridinae share morphological characters that are diagnostic of the subfamily Herpetocypridinae. On these grounds, the transfer of Isocypridinae to the rank of Tribe Isocypridini Rome, 1965 of subfamily Herpetocypridinae Kaufmann, 1900 is proposed here to account for the present understanding of morphological similarity.
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Patterns of genetic divergence in the Ilyodromus amplicolis lineage (Crustacea, Ostracoda), with descriptions of three new species
- In this study, 13 previously recorded populations of Ilyodromus amplicolis De Deckker, 1981 from temporary aquatic habitats in Western Australia were scanned for undescribed species diversity using morphological and molecular systematics techniques. The study found congruent morphological and molecular evidence for three species that are new to science, all of which are formally described here (I. armacutis n. sp., I. sensaddito n. sp. and I. hiatus n. sp.). The findings shed light on the potential for further undescribed diversity in the genus Ilyodromus Sars, 1894.
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New data on the sedimentary processes and timing of the initial inundation of Lower Khuzestan (SW Iran) by the Persian Gulf
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NiphNet: a self-governing environmental monitoring network
- A high-precision and low-cost temperature and humidity logging device, called Niphargus and originally intended for environmental monitoring in caves, was developed at the Geological Survey of Belgium (Burlet et al., 2015). The Niphargus is designed as a standalone logger, with data to be retrieved manually whenever needed. This allows for a very small and simple electronic design, low power consumption and flexible placement. There are, however, a number of disadvantages for specific applications. For example, there is no feedback possible on malfunction or battery lifetime. To avoid loss of data during long-term measurement campaigns, regular inspection and data retrieval are necessary. Apart from the inconvenience, this manipulation also causes disturbance in the measurements. A new version of the Niphargus was therefore developed, including a wireless Digi XBee DigiMesh module. These modules communicate on a 868 MHz radio frequency, in a self-governing mesh network (Fig. 1). In such a network, every device is able to communicate to any other device within range. For data transmission, the most optimal pathway is chosen between transmitter and receiver. As such, in case of a single device malfunction, the connection between the other nodes can still be guaranteed. In case of the NiphNet, the receiving end includes a single-board computer with cellular network connectivity, from which data is uploaded to a cloud repository. From there, live monitoring data can be displayed online, downloaded and processed. A first successful test was conducted with a NiphNet of 5 devices in waterproof containers (Fig. 2) and online display at the GeoEnergy Test Bed in Nottingham, UK, in March 2018. Current and future efforts focus on the enclosure design and the automation of data readout over the network. There is a large array of possible applications. For environmental monitoring in caves, the individual nodes can ensure data transmission from a network of environmental sensors inside the cave to a station outside, allowing for continuous access to measurements and minimising the need for regular field inspection. This is currently being installed in the caves of Han. The geological storage of CO2 requires long-term monitoring to establish a baseline and detect leakage from the reservoir, both below and above ground. Such monitoring activities need to be maintained for several decades, and therefore need to be low effort and low cost. Near the surface, temperature is expected to be a good proxy for CO2 leakage when a network is set-up that can detect temperature anomalies in the range of 0.01°C. This is possible with a network of shallow buried Niphargus nodes. Then, wireless access to thesedevices is not only a matter of long-term and maintenance-free coverage of a large area. Detection of small temperature differences depends on not disturbing the shallow subsurface, and therefore on being able to download the data remotely.
