Search publications of the members of the Royal Belgian institute of natural Sciences
- Sediment analyses of ST1407, ST1807 and ST1909
- Effecten van mariene aggregaatextractie op zeebodemintegriteit en hydrografische condities. Nieuwe inzichten en ontwikkelingen.
- Analysis of oceanographic profiles taken during RV Belgica campaign ST2019/09
- Le service géologique de Belgique contribue au développement du géotourisme
- 33 million year old Myotis (Chiroptera, Vespertilionidae) and the rapid global radiation of modern bats
- The bat genus Myotis is represented by 120+ living species and 40+ extinct species and is found on every continent except Antarctica. The time of divergence of Myotis has been contentious as has the time and place of origin of its encompassing group the Vespertilionidae, the most diverse (450+ species) and widely distributed extant bat family. Fossil Myotis species are common, especially in Europe, beginning in the Miocene but earlier records are poor. Recent study of new specimens from the Belgian early Oligocene locality of Boutersem reveals the presence of a relatively large vespertilionid. Morphological comparison and phylogenetic analysis confirms that the new, large form can be confidently assigned to the genus Myotis, making this record the earliest known for that taxon and extending the temporal range of this extant genus to over 33 million years. This suggests that previously published molecular divergence dates for crown myotines (Myotis) are too young by at least 7 million years. Additionally, examination of first fossil appearance data of 1,011 extant placental mammal genera indicates that only 13 first occurred in the middle to late Paleogene (48 to 33 million years ago) and of these, six represent bats, including Myotis. Paleogene members of both major suborders of Chiroptera (Yangochiroptera and Yinpterochiroptera) include extant genera indicating early establishment of successful and long-term adaptive strategies as bats underwent an explosive radiation near the beginning of the Early Eocene Climatic Optimum in the Old World. A second bat adaptive radiation in the New World began coincident with the Mid-Miocene Climatic Optimum.
- Estimating body size in early primates: The case of Archicebus and Teilhardina
- Obtaining accurate estimations of the body mass of fossil primates has always been a subject of interest in paleoanthropology because mass is an important determinant for so many other aspects of biology, ecology, and life history. This paper focuses on the issues involved in attempting to reconstruct the mass of two early Eocene haplorhine primates, Teilhardina and Archicebus, which pose particular problems due to their small size and temporal and phylogenetic distance from extant primates. In addition to a ranking of variables from more to less useful, the effect of using models of varying taxonomic and size compositions is examined. Phylogenetic correction is also applied to the primate database. Our results indicate that the choice of variable is more critical than the choice of model. The more reliable variables are the mediolateral breadth across the femoral condyles and the area of the calcaneocuboid facet of the calcaneus. These variables suggest a body mass of 39 g (range 33e46 g) for Archicebus and 48 g (range 44 e56 g) for Teilhardina. The width of the distal femur is found to be the most consistent estimator across models of various composition and techniques. The effect of phylogenetic correction is small but the choice of branch length assumption affects point estimates for the fossils. The majority of variables and models predict the body mass of Archicebus and Teilhardina to be in the range of the smaller extant mouse lemurs, as expected.
- Changes in chlorophyll concentration and phenology in the North Sea in relation to de‐eutrophication and sea surface warming
- At least two major drivers of phytoplankton production have changed in recent decades in the North Sea: sea surface temperature (SST) has increased by ~ 1.6°C between 1988 and 2014, and the nitrogen and phosphorus loads from surrounding rivers have decreased from the mid‐1980s onward, following reduction policies. Long time series spanning four decades (1975–2015) of nutrients, chlorophyll (Chl), and pH measurements in the Southern and Central North Sea were analyzed to assess the impact of both the warming and the de‐eutrophication trends on Chl. The de‐eutrophication process, detectable in the reduction of nutrient river loads to the sea, caused a decrease of nutrient concentrations in coastal waters under riverine influence. A decline in annual mean Chl was observed at 11 out of 18 sampling sites (coastal and offshore) in the period 1988–2016. Also, a shift in Chl phenology was observed around 2000, with spring bloom formation occurring earlier in the year. A long time series of pH in the Southern North Sea showed an increase until the mid‐1980s followed by a rapid decrease, suggesting changes in phytoplankton production that would support the observed changes in Chl. Linear correlations, however, did not reveal significant relationships between Chl variability and winter nutrients or SST at the sampling sites. We propose that the observed changes in Chl (annual or seasonal) around 2000 are a response of phytoplankton dynamics to multiple stressors, directly or indirectly influenced by de‐eutrophication and climate warming.
- Salinity predicts the distribution of chlorophyll a spring peak in the southern North Sea continental waters
- In the North Sea, the coastal waters of Belgium and The Netherlands regularly exhibit intense spring phytoplankton blooms where species such as Phaeocystis recurrently form a potential ecological nuisance. In the Belgian and Dutch continental shelves (BCS and DCS), we observe a direct correlation between the chlorophyll a spring maximum (Chlmax) and the nutrients (DIN and DIP) available for the bloom. As the nutrients are themselves strongly correlated with salinity, a rationale is developed to predict Chlmax from winter salinity. The proposed rationale is first tested in a theoretical case with a 3D-biogeochemical model (3D-MIRO&CO). The method is then applied to independent sets of in situ observations over 20 years in the BCS and the DCS, and to continuous FerryBox data in April 2008. Linear regressions explain the relationships between winter nutrients and winter salinity (R2 = 0.88 to 0.97 with model results, and R2 = 0.83 to 0.96 with in situ data). The relationship between Chlmax and the available nutrients across the salinity gradient is also explained by yearly linear regressions (R2 = 0.82 to 0.94 with model results, and R2 = 0.46 to 0.98 with in situ data). Empirical ‘DIP requirement’ and ‘DIN requirement’ for the spring biomass bloom formation are derived from the latter relationships. They depend i.a. on the losses from phytoplankton during the spring bloom formation, and therefore show some interannual variability (8–12% for DIP and 13–20% for DIN). The ratio between nutrient requirements allows predicting in winter which nutrient will eventually limit the spring biomass bloom along the salinity gradient. DIP will generally be limiting in the coastal zone, whereas DIN will generally be limiting offshore, the switch occurring typically at salinity 33.5 in the BCS and 33.6 in the DCS. N reduction should be prioritized to limit Phaeocystis in the coastal zone, with target winter DIN:DIP ratios below 34.4 molN molP−1 in the BCS, or 28.6 molN molP− 1 in the DCS.
- Marine phytoplankton community composition data from the Belgian part of the North Sea, 1968–2010
- The Belgian Phytoplankton Database (BPD) is a comprehensive data collection comprising quantitative phytoplankton cell counts from multiple research projects conducted since 1968. The collection is focused on the Belgian part of the North Sea, but also includes data from the French and the Dutch part of the North Sea. The database includes almost 300 unique sampling locations and more than 3,000 sampling events resulting in more than 86,000 phytoplankton cell count records. The dataset covers two periods: 1968 to 1978 and 1994 to 2010. The BPD can be accessed online and provides high quality phytoplankton count data. The species taxonomy is updated, and the count values are quality checked and standardized. Important metadata like sampling date, sampling location, sampling depth and methodology is provided and standardized. Additionally, associated abiotic data and biovolume values are available. The dataset allows to conduct analyses of long-term temporal and spatial trends in phytoplankton community structure in the southern part of the North Sea, including changes in phytoplankton phenology and seasonality.
- Signature patterns of chlorophyll a variability in the Greater North Sea
- The greater North Sea comprises a high diversity of marine systems within a relatively small geographical area: shallow and well-mixed systems, stratified systems, continental shelf, margin and deep ocean. Across these systems, different seasonal and interannual patterns of chlorophyll a (Chl) variability may be observed. Characteristic features of the Chl dynamics are used to identify typical areas across the studied domain. Remote sensing observation of Chl (ENVISAT-MERIS) offers a comprehensive picture of the spatial dynamic of surface phytoplankton biomass over almost a decade (2003-2011). The Cloern and Jassby (2010) method of Chl signal decomposition was applied to every pixel separating the Chl signal into four components: 1) the grand mean, 2) the interannual, 3) the seasonal and 4) the residual components for the considered 9-years period. The method assumes no trend a priori over the considered period and the standard deviations for each component are compared in a relative fashion to describe the local dynamics of Chl. The pixel-wise calculated components are represented in individual maps to depict the spatial patterns of chlorophyll a variability and outline areas of high or low seasonal and interannual variability. Subsequently the decomposed Chl signal is used in a K-means cluster analysis to classify areas in the greater North Sea. These areas correspond to different categories of Chl dynamics for the considered period 2003-2011, providing a governance tool for policy makers. It is also shown how these areas directly reflect physical features of the sea, suggesting invariant structure of phytoplankton dynamics.
- Description of the long-term (1991–2005) temporal and spatial distribution of phytoplankton carbon biomass in the Dutch North Sea
- Since the beginning of the 1990s phytoplankton species composition and abundance have been monitored at a high frequency (bi-weekly in the growing season and monthly in winter) at a number of fixed stations on the Dutch Continental Shelf, of which 18 are used in this study. Phytoplankton carbon biomass has been calculated from species-specific biovolume/cell data and summed over all species per functional group enumerated in the samples. The species are divided into four functional groups i.e. diatoms, flagellates, autotrophic and mixotrophic dinoflagellates and Phaeocystis spp. The total number of phytoplankton samples analysed up to and including 2005 is almost 4000. The annual mean phytoplankton biomass over all stations remained stable at around 145 mg C m−3. However, the phytoplankton composition has changed significantly, with increases in diatoms and dinoflagellates and compensating decreases in flagellates and Phaeocystis. With increasing distance from the shore, coinciding with a decrease in nutrient availability and increasing water depth, total phytoplankton biomass as well as the biomass of diatoms, flagellates and Phaeocystis spp. decreased. This pattern was not true for the dinoflagellates, which occurred at more or less the same biomass throughout the region. Stations near river mouths and in the Wadden Sea outlets had much higher phytoplankton biomass than stations further from freshwater discharges. The data, split in two periods (1991–1998) and (1999–2005) and averaged over the whole Dutch Continental Shelf, had been aggregated into seasonal biomass distributions. The seasonal phytoplankton biomass distribution was unimodal in both periods, with similar spring maxima of around 300 mg C m− 3. The spring maximum occurred one month earlier, in April, in the second period. Phaeocystis over the whole study period remained the dominant near-shore species as it has been since the first phytoplankton observations at the end of the 19th century.
- La chasse au mammouth à Yudinovo (plaine russe) ?
- Interdisciplinary investigation of early dogs and other carnivores from Eurasia
- Bioarchaeological research at the Natural History Museum in Brussels
- Bear bones with red ochre traces in the Belgian Upper Palaeolithic: comparison with the use of colours in ethnographic bear rituals.
- Red coloured cave bear bones: an indication of symbolic behaviour in the Upper Palaeolithic of Belgium
- Red coloured fossil bear bones: a possible indication of symbolic behaviour in the Upper Palaeolithic of Belgium
- The Pleniglacial cave bear from Goyet, Belgium
- The influence of climate on cub mortality and sexual segregation in Pleniglacial cave bear
- Taphonomy of mammoth remains from Belgium