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First mammal species identified from the Upper Cretaceousof the Rusca Montana Basin (Transylvania, Romania)
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Multituberculate mammals are scarce in the Late Cretaceous of Europe, being recorded exclusively from the Maastrichtian terrestrial deposits of the Hateg and Transylvanian basins, in Romania. Moreover, they all belong to the endemic and primitive cimolodontan family Kogaionidae. Here, we report multituberculate teeth originating from the Maastrichtian fluviatile sediments of the Rusca Montana Basin (Occidental Carpathians, Poiana Rusca Mountains). This is the westernmost occurrence of these Cretaceous mammals in Romania. These teeth are assigned to Barbatodon oardaensis, the smallest Cretaceous kogaionid species. This study presents the first occurrence of this species outside the Metaliferi sedimentary area (southwestern Transylvania, Romania). The distribution of Romanian Maastrichtian kogaionids is also discussed.
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RBINS Staff Publications 2016
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Frasnian reef mounds in the Durbuy-Bomal area (eastern border of the Dinant Synclinorium, Belgium)
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RBINS Staff Publications 2022 OA
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The highly diversified rugose coral fauna from the Lower Givetian Meerbüsch quarry in the Eifel Hills (Germany).
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RBINS Staff Publications 2022 OA
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Late Devonian (Frasnian) phyllopod and phyllocarid crustaceanshields from Belgium reinterpreted as ammonoid anaptychi
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The taxonomic affinities of fossils from theFrasnian succession of Be lgium previously described asphyllopod and phyllocarid crustacean shields are discussed.The rediscovery of the holotype of Ellipsocaris dewalquei,the type species of the genus Ellipsocaris Woodward inDewalque, 1882, allows to end the discussion on the taxo-nomic assignation of the genus Ellipsocaris. It is removedfrom the phyllopod crustaceans as interpreted originally andconsidered here as an ammonoid anaptychus. Furthermore, itis considered to be a junior synonym of the genus SidetesGiebel, 1847. Similarly, Van Straelen’s (1933) lower to middleFrasnian record Spathiocaris chagrinensis Ruedemann, 1916,is also an ammonoid anaptychus. Although ammonoids canbe relatively frequent in some Frasnian horizons of Belgium,anaptychi remain particularly scarce and the attribution to thepresent material to peculiar ammonoid species is not possible.
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RBINS Staff Publications 2017
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A new Miocene baleen whale from Peru deciphers the dawn of cetotheriids
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RBINS Staff Publications 2017
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Latest Cretaceous storm-generated sea grass accumulations in the Maastrichtian type area, the Netherlands – preliminary observations
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RBINS Staff Publications 2019
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Publications
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Influence of Meteorological Variability on Primary Production Dynamics in the Ligurian Sea (NW Med Sea) with a 1D Hydrodynamic/Biological Model.
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In order to estimate the effects of the meteorological variability on the gross primary production in the Ligurian Sea (NW Mediterranean Sea), a coupling between a hydrodynamic model and a biological one is realized. The one-dimensional version of the GHER hydrodynamic model includes heat and momentum exchanges at the air–sea interface. It is coupled with a simple food-web model from the LEPM. A simulation performed with real meteorological data for the year 1985 reproduces reasonably the seasonal phytoplanktonic dynamics and the distribution between diatoms and flagellates. From this simulation, an annual gross primary production integrated over 200 m of 46.4 g C m−2 year−1 is computed which is representative of an oligotrophic environment. In order to estimate the relative effect on the gross primary production of the meteorological variability on the one hand and of the initial conditions on the other hand, several runs have been performed for the year 1985 with different conditions of light, wind intensity and nitrate initial quantity. The first simulations are performed with daily and monthly mean solar radiation and wind intensity. An averaging of wind intensity yields a decrease in the gross primary production and leads to unrealistic phytoplankton dynamics. It seems then necessary to take into account the 3-hourly variability of the wind intensity in order to simulate the phytoplankton dynamics with relatively good accuracy. On the other hand, an averaging of the solar radiation leads to an increase in the gross primary production. The following simulations are performed with an increase (decrease) in the solar radiation, the wind intensity or the nitrate initial quantity which are representative of the variability observed in a 5-year set of meteorological and hydrobiological data (1984–1988). An increase in the solar radiation is found to reduce the gross primary production, while an increase in the initial nitrate quantity or the wind intensity leads to a higher gross primary production, and the reverse. In the case of variations of the solar radiation (±2%), the simulations give an annual gross primary production integrated over 200 m included between 44.8 and 46.7 g C m−2 year−1, representing a variability of 4%. With the variations of the surface wind intensity (±10%), the runs carry to an annual gross primary production integrated over 200 m from 34.1 to 59.1 g C m−2 year−1, representing a variability of 54%. The variations of the initial nitrate concentration (±50%) lead to an annual gross primary production integrated over 200 m between 20.7 and 69.8 g C m−2 year−1 which represents a variability of 108%. An analysis of the relationship between the total gross primary production and the annual mean depth of the mixed layer has shown that the deeper the mixed layer is, the higher is the total annual gross primary production.
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Study of the oxygen budget of the Black Sea waters using a 3D coupled hydrodynamical-biogeochemical model.
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The ventilation of the Black Sea waters by physical and biogeochemical processes is investigated using the Geohydrodynamics and Environment Research (GHER) laboratory 3D coupled hydrodynamical–biogeochemical model. In particular, the penetration at depth of the winter mixing, the generation of unstable motions by frontal instabilities, the exchanges between the north-western shelf and the open sea along the shelf break, the primary production distribution, the generation of detritus and the resulting consumption of oxygen for their recycling are studied. The GHER 3D hydrodynamic model is used to simulate the Black Sea's general circulation and the associated synoptic and mesoscale structures. This model is coupled with a simple ecosystem model defined by a nitrogen cycle which is described by seven state variables: nitrate, ammonium, dissolved oxygen, phytoplankton, zooplankton, pelagic and benthic detritus. The model simulates the space–time variations of the biogeochemical state variables. In particular, the spatial variability of the phytoplankton biomass annual cycle, imparted by the horizontal and vertical variations of the physical and chemical properties of the water column, is clearly illustrated. For instance, on the north-western shelf, the seasonal variability of the circulation and in particular, the reversal of the surface current at the end of spring, has a strong influence on the transport of the rich nutrient Danube waters and, thus, on the repartition of the primary production. Furthermore, the results illustrate the seasonal and vertical variations of the dissolved oxygen concentration resulting (a) from its atmospheric and photosynthetic productions in the surface layer, (b) from its loss to the atmosphere in spring and summer and (c) from its consumption associated with the detritus decomposition, the ammonium oxidation during the nitrification process, as well as the oxidation of hydrogen sulfide. The simulated sea surface, phytoplankton fields are compared with satellite estimates of chlorophyll-a fields. Comparisons are made with seasonal mean pictures and snapshot images, illustrating the mesoscale motions of the main coastal current. In the central Black Sea and the Danube delta area, comparisons with available field data are also made. As a general rule, all these comparisons show a quite good qualitative agreement. In particular, at the surface, the simulated phytoplankton space–time distribution is in a good qualitative agreement with satellite observations. However, on a quantitative point of view, the model underestimates the bloom intensity especially in the Danube discharge area.
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Ecosystem model (MODECOGeL) of the Ligurian Sea revisited. Seasonal and interannual variability due to atmospheric forcing.
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A one-dimensional coupled hydrodynamical–biological model, MODèle d'ECOsystème du G.H.E.R. et du L.O.V. (MODECOGeL), of the water column is developed and applied to the Ligurian Sea (North Western Mediterranean). It is an extended and improved version of the model presented by Lacroix and Nival [J. Mar. Syst. 16 (1998) 23]. The hydrodynamic model is a 1D version of the 3D turbulent closure G.H.E.R. model, which takes into account momentum and heat surface fluxes computed from a real meteorological data set. The ecosystem model is defined by a nitrogen cycle described by 12 biological state variables including several plankton size classes and an explicit description of the bacterial loop. One data set coming from the FRONTAL missions is used to initialise and validate the model. To assess the impact of the interannual variability of the meteorological conditions on the ecosystem dynamics, the coupled model is run with 4-year real meteorological conditions (October 1984–September 1988). The model estimated percentages of the interannual variability of the annual mean biomass of phytoplankton, zooplankton and bacteria respectively of 31.0%, 16.2% and 16.3%. The contribution of the zooplankton related to the total plankton biomass (phytoplankton, zooplankton and bacteria) has been found to be the most sensitive to the meteorological conditions variations (21%), followed by the phytoplankton (12%) and finally, by the bacteria (5%). The model estimated percentages of interannual variability of the annual gross primary production, the annual mean f-ratio and the annual bacterial production respectively of 27.9%, 18.5% and 13.4% although the interannual variability of the real winds conditions is only of 11.3%. Due to the more windy and less sunny conditions prevailing during the years “1985–1986” and “1986–1987”, the annual primary production was found higher than during the years “1984–1985” and “1987–1988”. The bacterial production is always greater than the primary production, showing the importance of the bacteria in such an oligotrophic environment. On a seasonal scale, the highest interannual variability of the primary production and the f-ratio is found in spring like for the wind intensity.
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