Search publications of the members of the Royal Belgian institute of natural Sciences
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DNA barcoding and male genital morphology reveal six cryptic species in the West Palearctic bee complex Seladonia smaragdula (Vachal, 1895) (Hymenoptera: Apoidea: Halictidae)
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Benthic foraminiferal and isotopic patterns during the Early Eocene Climatic Optimum (Aktulagay section, Kazakhstan).
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Eocene hyperthermals in the North Sea Basin: a Belgian Ypresian perspective.
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Kaart van het gebruik van de Belgische zeegebieden - Carte de l'usage des espaces marins belges
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Seasonal variation in concentration, size and settling velocity of muddy marine flocs in the benthic boundary layer
- Suspended Particulate Matter (SPM) concentration profiles of the lowest 2 m of the water column and particle size distribution at 2 m above the bed were measured in a coastal turbidity maximum area (southern North Sea) during more than 700 days between 2006 and 2013. The long-term data series of SPM concentration, floc size, and settling velocity have been ensemble averaged according to tidal range, alongshore residual flow direction, and season, in order to investigate the seasonal SPM dynamics and its relation with physical and biological processes. The data show that the SPM is more concentrated in the near-bed layer in summer, whereas in winter, the SPM is better mixed throughout the water column. The decrease of the SPM concentration in the water column during summer is compensated by a higher near- bed concentration indicating that a significant part of the SPM remains in the area during summer rather than being advected out of it. The opposite seasonality between near-bed layer and water column has to our knowledge not yet been presented in literature. Physical effects such as wave heights, wind climate, or storms have a weak correlation with the observed seasonality. The argument to favor microbial activity as main driver of the seasonality lies in the observed variations in floc size and settling velocity. On average, the flocs are larger and thus settling velocities higher in summer than winter.
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Seasonality of floc strength in the southern North Sea
- The suspended particulate matter (SPM) concentration in the high turbidity zones of the south- ern North Sea is inversely correlated with chlorophyll (Chl) concentration. During winter, SPM concentration is high and Chl concentration is low and vice versa during summer. This seasonality has often been associated with the seasonal pattern in wind forcing. However, the decrease in SPM concentration corresponds well with the spring algal bloom. Does the decrease of SPM concentration caused by changing wind conditions cause the start of algae bloom, or does the algae bloom decrease SPM concentrations through enhanced floccula- tion and deposition? To answer the question, measurements from 2011 of particle size distribution (PSD), SPM, and Chl concentrations from the southern North Sea have been analyzed. The results indicate that the frequency of occurrence of macroflocs has a seasonal signal, while seasonality has little impact upon floc size. The data from a highly turbid coastal zone suggest that the maximum size of the macroflocs is controlled by turbulence and the available flocculation time during a tidal cycle, but the strength of the macroflocs is con- trolled by the availability of sticky organic substances associated with enhanced primary production during spring and summer. The results highlight the shift from mainly microflocs and flocculi in winter toward more muddy marine snow with larger amounts of macroflocs in spring and summer. The macroflocs will reduce the SPM concentrations in the turbidity maximum area as they settle faster. Consequently, the SPM concen- tration decreases and the light condition increases in the surface layer enhancing algae growth further.
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In situ observations of turbidity plumes at on offshore wind farm
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Lifestyle and Ice: The Relationship between Ecological Specialization and Response to Pleistocene Climate Change
- Major climatic changes in the Pleistocene had significant effects on marine organisms and the environments in which they lived. The presence of divergent patterns of demographic history even among phylogenetically closely-related species sharing climatic changes raises questions as to the respective influence of species-specific traits on population struc- ture. In this work we tested whether the lifestyle of Antarctic notothenioid benthic and pelagic fish species from the Southern Ocean influenced the concerted population response to Pleistocene climatic fluctuations. This was done by a comparative analysis of sequence variation at the cyt b and S7 loci in nine newly sequenced and four re-analysed species. We found that all species underwent more or less intensive changes in population size but we also found consistent differences between demographic histories of pelagic and benthic species. Contemporary pelagic populations are significantly more genetically diverse and bear traces of older demographic expansions than less diverse benthic species that show evidence of more recent population expansions. Our findings suggest that the life- styles of different species have strong influences on their responses to the same environ- mental events. Our data, in conjunction with previous studies showing a constant diversification tempo of these species during the Pleistocene, support the hypothesis that Pleistocene glaciations had a smaller effect on pelagic species than on benthic species whose survival may have relied upon ephemeral refugia in shallow shelf waters. These find- ings suggest that the interaction between lifestyle and environmental changes should be considered in genetic analyses.
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Baggeren en storten
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Dredging and dumping
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Modellering van een alternatieve stortstrategie voor de onderhoudsbaggerwerken in de voorhaven van Zeebrugge
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Field Data on the Little Known and, Endangered Lepilemur Mittermeieri
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Dispersion and deposition of sediment plumes, resulting from intensive marine aggregate extraction
- Marine aggregate extraction activities, using small (2.500m3) to large (> 10.000m3) trailer suction hopper dredgers, pressurize quasi-continuous the marine ecosystem of the Belgian part of the North Sea. Since the concession zones are within a Habitat Directive Area, or nearby, potential near- and far-field impacts need investigation. Results indicated that, after 2-yrs of intensive extraction along the far offshore coarse-grained sandbanks, some fining trend was observed in the upper seabed. In the Habitat Directive area, mud enrichment has been observed over 3 consecutive years. Hitherto, no direct link can be made with the extraction activities, though the area is further monitored to assess changes in seafloor integrity.
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Apport de l'analyse pollinique du contenu ruminal dans le diagnostic de certaines intoxications végétales chez les ruminants. Examen d'un cas.
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Study of fossil feathers using infrared spectroscopy and imagery.
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The primitive ornithischian dinosaur Kulindadromeus from the Jurassic of Siberia and the origin of feathers
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Taphonomy of the Late Jurassic Kulinda Lake
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Paléoenvironnement tardiglaciaire et holocène des lacs de Pelléautier et Siguret (Hautes Alpes, France). II: Les macrorestes.
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L'analyse des végétaux conservés dans les dépôts tourbeux.
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L'analyse des macrorestes végétaux.
