Search publications of the members of the Royal Belgian institute of natural Sciences
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La surexploitation des espèces sauvages menace des milliards d’humains
- La surexploitation d’espèces sauvages – animaux terrestres, poissons, algues, champignons, plantes ou encore arbres – menace le bien-être de milliards d’être humains, dévoile vendredi un rapport de l’Onu, qui donne des pistes pour un usage plus durable et met en valeur les savoirs des peuples autochtones.
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Ocean acidification modifies behaviour of shelf seabed macrofauna: A laboratory study on two ecosystem engineers, Abra alba and Lanice conchilega
- The feeding activity and burrow ventilation by benthic invertebrates importantly affect the biodiversity and functioning of seafloor sediments. Here we investigated how ocean acidification can modify these behavioural activities in two common and abundant macrofaunal ecosystem engineering species in temperate continental shelf communities: the white furrow shell Abra alba and the sand mason Lanice conchilega. Using time-lapse imagery and sediment porewater hydraulic signatures we show that both species adapt their behaviour in response to predicted future pH conditions (-0.3 units). During a three-week laboratory experiment, A. alba reduced the duration per feeding event when suspension and deposit feeding (by 86 and 53%, respectively), and almost completely ceased suspension feeding under reduced seawater pH in comparison to ambient seawater pH (pH ~ 8.2). This behavioural change reduces the intake of low pH water during feeding and respiration. L. conchilega increased its piston-pumping frequency by 30 and 52%, respectively, after one and two weeks of exposure to future pH conditions (-0.3 units) relative to ambient conditions. This change in irrigation activity suggests higher metabolic demands under low seawater pH, and also extended low water column pH conditions deeper into the seafloor. Because the distribution of other populations depends on the physicochemical setting by our focal species, we argue that the demonstrated behavioural plasticity will likely have cascading effects on seafloor diversity and functioning, highlighting the complexity of how ocean acidification, and climate change in general, will affect seafloor ecology.
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Review of Muricanthus Swainson, 1840 and some Recent species assigned to Hexaplex s.s. Perry, 1810, Hexaplex (Trunculariopsis) Cossmann, 1921 and Phyllonotus Swainson, 1833
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Catypnes marazziorum sp. nov. (Coleoptera: Cerambycidae: Prioninae) from Papua New Guinea
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Integration of landscape genomics, provenance trials and association mapping identifies genetic components underlying cold hardiness adaptation for coastal Douglas-fir (Pseudotsuga menziesii var. menziesii)
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Effect of aggregate extraction on MSFD descriptor 7 (hydrographic condition) in the Hinder Banks area (Belgian Continental Shelf).
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Changes in bottom shear stress, due to aggregate extraction in the area of the Hinder Banks (Belgian Continental Shelf)
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Including the observed effect of microbiological activities in a flocculation model
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Remote sensing of suspended particulate matter concentration, inter-comparison with surface buoy and tripod lander data
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Detection of shipwrecks in ocean colour satellite imagery
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The impact of disposal of fine grained sediments from maintenance dredging works on SPM concentration and fluid mud in and outside the harbor of Zeebrugge
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Changes in bottom shear stress, due to aggregate extraction in the area of the Hinder Banks (Belgian Continental Shelf)
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Quantitative clay mineralogy as provenance indicator for the recent muds located at the marine limit of influence of the Scheldt estuary
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BICEpS Annual report 2018 – Reinforcing Belgian ICES People
- 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 70 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. 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 2018 presents the genesis and first 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 demarche leading to the creation of the BICEpS community and activities conducted in 2018. The report contains the list of Belgian ICES members in 2018 with their membership to the different ICES working groups, and the results of the first BICEpS Colloquium organised on 14 November 2018 and hosted by RBINS in Brussels (outcome of a participatory discussion on the future of BICEpS, 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/BICEpS-2018-Colloquium-Presentations.pdf
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Polydictya lanternflies of Java: New species, taxonomy and identification key (Hemiptera: Fulgoromorpha: Fulgoridae)
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Case 3826 – Propappus Michaelsen, 1905 and Propappidae Coates, 1986 (Annelida, Clitellata): proposed conservation by suppression of Propappus Seeley, 1888 (Vertebrata, Reptilia)
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Productivity and Change in Fish and Squid in the Southern Ocean
- Southern Ocean ecosystems are globally important and vulnerable to global drivers of change, yet they remain challenging to study. Fish and squid make up a significant portion of the biomass within the Southern Ocean, filling key roles in food webs from forage to mid-trophic species and top predators. They comprise a diverse array of species uniquely adapted to the extreme habitats of the region. Adaptations such as antifreeze glycoproteins, lipid-retention, extended larval phases, delayed senescence, and energy-conserving life strategies equip Antarctic fish and squid to withstand the dark winters and yearlong subzero temperatures experienced in much of the Southern Ocean. In addition to krill exploitation, the comparatively high commercial value of Antarctic fish, particularly the lucrative toothfish, drives fisheries interests, which has included illegal fishing. Uncertainty about the population dynamics of target species and ecosystem structure and function more broadly has necessitated a precautionary, ecosystem approach to managing these stocks and enabling the recovery of depleted species. Fisheries currently remain the major local driver of change in Southern Ocean fish productivity, but global climate change presents an even greater challenge to assessing future changes. Parts of the Southern Ocean are experiencing ocean-warming, such as the West Antarctic Peninsula, while other areas, such as the Ross Sea shelf, have undergone cooling in recent years. These trends are expected to result in a redistribution of species based on their tolerances to different temperature regimes. Climate variability may impair the migratory response of these species to environmental change, while imposing increased pressures on recruitment. Fisheries and climate change, coupled with related local and global drivers such as pollution and sea ice change, have the potential to produce synergistic impacts that compound the risks to Antarctic fish and squid species. The uncertainty surrounding how different species will respond to these challenges, given their varying life histories, environmental dependencies, and resiliencies, necessitates regular assessment to inform conservation and management decisions. Urgent attention is needed to determine whether the current management strategies are suitably precautionary to achieve conservation objectives in light of the impending changes to the ecosystem.
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Noble gases in micrometeorites from the Transantarctic Mountains
- The bulk of extraterrestrial matter currently accreted by the Earth is in the form of micrometeorites (MMs) and interplanetary dust particles (IDPs), thus they may have collectively made a substantial contribution to the volatile inventory of the Earth and the other terrestrial planets. We have performed a complete noble gas study, accompanied by a complete petrographic characterization, of MMs from the Transantarctic Mountain (TAM) collection in the size range ∼300 to ∼1000 µm that fell over an extended time period during the last ∼1 Ma. Our noble gas study includes krypton and xenon, which have been largely missing in previous work. Helium and neon are dominated by a solar component, with generally lower abundance in scoriaceous MMs than in unmelted ones, and also generally lower in abundance than in previously studied MMs, which may be explained by the larger particle size (surface/volume ratio) of the MMs we studied. Considering an enhanced MM flux in the early Solar System, such MMs may have supplied a significant fraction of Earth’s neon. A number of MMs have kept what was probably their pre-terrestrial He/Ne ratio, from which we infer that the observed solar component is retained in a tiny surface region not affected by atmospheric entry. The abundances of (volume-correlated) heavier gases are similar to what was found in previous studies of smaller MMs. While Ar contains both solar and “planetary” contributions, the heavy noble gases (Kr, Xe) generally show “planetary” patterns but are often also compromised by terrestrial contamination as evidenced by an enhanced Kr/Xe ratio. Kr and Xe in a subset of scoriaceous MMs are dominated by isotopically fractionated air, possibly acquired during the passage through Earth’s ionosphere. Those not obviously affected by air show isotopic ratios similar to primitive meteorites (the Q component), thus primordial heavy gases supplied to the Earth by MMs are likely as those found in macroscopic meteorites. There is no evidence for the presence of a “cometary” Xe component as identified in the coma of comet 67P/Churyumov-Gerasimenko, hence a cometary source for a significant fraction of MMs in the studied size range is unlikely. Cosmogenic helium, neon and argon were detected in several cases. Cosmic ray exposure ages were calculated based on cosmogenic 21Ne in combination with the Poynting-Robertson effect, but depend on assumptions about atmospheric entry loss. Still, several cases are consistent with an origin from the asteroid belt (even assuming no loss) and one scoriaceous MM (#45b.17) would have to originate from beyond Jupiter. In at least two cases, including #45b.17, the isotopic composition of cosmogenic Ne appears to be inconsistent with predominant production in small particles free-floating in space, however; much of the irradiation of these MMs may have occurred when they were part of larger parent bodies.
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Micrometeorites from the Sør Rondane Mountains, Antarctica
- Micrometeorites are dust-sized (i.e., 10 to 2000 µm in size) extraterrestrial particles reaching the Earth’s surface [1]. We report the discovery of hundreds of micrometeorites during the 2017-2018 BELAM (Belgian Antarctic Meteorites) expedition that took place in the south to south-east area up to 40 km away from the Belgian Princess Elisabeth Station (71°57Ļ00ļS; 23°20Ļ49ļE). Two types of micrometeorite traps were targeted on the glacially eroded tops of Vengen, Walnumfjellet, Widerøfjellet, Svindland and Smalegga Mountains, consisting of 1/ seven samples of soils that have potentially been exposed for long periods of times (up to several Ma), similarly to samples collected in the Atacama Desert [2] and 2/ five samples of wind catchment areas, such as the base of large boulders or within cracks. The lee-sides of three lateral and supraglacial moraines were also sampled, totalling eleven samples. In all cases, the sampled material, weighing 80 kg, consisted of moderately sorted finegrained rock detritus. Preliminary results suggest that the distribution of micrometeorites varies according to the type of trap, with glacial moraines exhibiting the lowest concentrations, followed by wind-catchment areas and soils from the top of the glacially eroded summits of mountains. Samples exposed on the border of the Sør Rondane Mountains with the Antarctic Plateau exhibit concentrations one order of magnitude greater than in moraines. Similarly to the Larkman Nunatak micrometeorite collection [3], the micrometeorite accumulation mechanism in moraine and wind-catchment areas seems to be mainly controlled by wind. Conversely, direct infall of micrometeorites may contribute significantly as an accumulation mechanism in exposed soil samples, as evidenced by the presence of large micrometeorites (>400 µm in size). Thus, this new collection, comprising various sampling site types, may serve as the basis to understand micrometeorite distribution patterns in Antarctica.
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Petrographic and geochemical characterization of a chondrule-like object preserved in an Antarctic micrometeorite
- We report the discovery of a pristine chondrule-like object in a scoriaceous meteorite recovered from the Sør Rondane Mountains, East Antarctica. A preliminary study using a JEOL JSM-IT 300 scanning electron microscope, coupled to an energy dispersive spectrometer (SEM-EDS), at the Vrije Universiteit Brussel indicates that i) the chondrulelike object has a minimum diameter size of ~187 µm, which is broadly analoguous to chondrules found in CM, CO, H and EH chondrites [1]; ii) the chondrule-like object displays a radial pyroxene texture and is readily delineated from the surrounding micrometeorite ground mass. This is emphasized by the presence of microscopic olivine and magnetite crystals at the outer edge of the chondrule-like object. This suggests that it served as a nucleation point for crystallization of secondary mineral phases during atmospheric deceleration and heating. Hence, this object likely represents an original feature of the micrometeoroid; iii) the mineralogical content of the chondrule-like object is mainly composed of low-Ca pyroxene with interstitial glass, some smaller nodules of FeNi metal and a local cluster of chromite grains. The surrounding micrometeorite material displays a micro-porphyritic olivine texture which contains a single nodule of Fe sulfide, vesicles, and a number of relict mineral grains that survived atmospheric entry. The latter are predominantly composed of forsterite-rich olivine, although several relict grains of low-Ca pyroxene (i.e., enstatite-rich end-members) are observed as well. The objective of this study is twofold: i) analyze the major element and triple-oxygen isotope composition of the chondrule-like object, and the relict mineral phases to specify the nature of the precursor material, and ii) discuss the overall rarity of chondrules in micrometeorites.
