Finite element modelling of the Scheldt estuary and the adjacent Belgian/Dutch coastal zone with application to the transport of fecal bacteria

A fundamental problem in coastal modelling is the need to simultaneously consider large- and small-scale processes, especially when local dynamics or local environmental issues are of interest. The approach widely resorted to is based on a nesting strategy by which coarse grid large scale model provide boundary conditions to force fine resolution local models. This is probably the best solution for finite difference methods, needing structured grids. However, the use of structured grids leads to a marked lack of flexibility in the spatial resolution. Another solution is to take advantage of the potential of the more modern finite element methods, which allow the use of unstructured grids in which the mesh size may vary over a wide spectrum. With these methods only one model is required to describe both the larger and the smaller scales.Such a model is use herein, namely the Second-generation Louvain-la-Neuve Ice-ocean Model (SLIM, http://www.climate.be/SLIM). For one of its first realistic applications, the Scheldt Estuary area is studied. The hydrodynamics is primarily forced by the tide and the neatest way to take it into account is to fix it at the shelf break. This results in a multi-scale problem since the domain boundary lies at the shelf break, and covers about 1000km of the North Sea and 60km of the actual estuary, and ends with a 100km long section of the Scheldt River until Ghent where the river is not more than 50 m wide.Two-dimensional elements are used to simulate the hydrodynamics from the shelf break to Antwerp (80km upstream of the mouth) and one-dimensional elements for the riverine part between Antwerp and Ghent.For first application we consider the transport of faecal bacteria (Escherichia coli) which is an important water quality indicator.The model will be described in detail and the simulation results will be discussed. This modelling exercise actually falls within the framework of the interdisciplinary project TIMOTHY (http://www.climate.be/TIMOTHY) dedicated to the modelling of ecological indicators in the Scheldt area

Terrestrialization in the Ordovician

This contribution reviews the evidence for terrestrial organisms during the Ordovician (microbial, land plant, fungal, animal) and for the nature of the terrestrial biota. The evidence regarding the origin and early diversification of land plants combines information from both fossils and living organisms. Extant plants can be utilized in: (1) phylogenetic analyses to provide evidence for the nature of the algal–land plant transition and the characteristics of the most basal land plants; (2) evolutionary developmental biology studies of the characters that enabled the invasion of the land; (3) molecular clock analysis to provide evidence regarding timing of the origin and diversification of land plants. We conclude that the Ordovician was a critical period during the terrestrialization of planet Earth that witnessed the transition from a microbial terrestrial biota to one dominated by a vegetation of the most basal land plants

Spectrometric Monitoring of Atmospheric Carbon Tetrafluoride (CF4) Above the Jungfraujoch Station Since 1989: Evidence of Continued Increase But at a Slowing Rate

The long-term evolution of the vertical column abundance of carbon tetrafluoride (CF4) above the high-altitude Jungfraujoch station (Swiss Alps, 46.5 ° N, 8.0 ° E, 3580 ma.s.l.) has been derived from the spectrometric analysis of Fourier transform infrared solar spectra recorded at that site between 1989 and 2012. The investigation is based on a multi-microwindow approach, two encompassing pairs of absorption lines belonging to the R-branch of the strong ν3 band of CF4 centered at 1283 cm-1, and two additional ones to optimally account for weak but overlapping HNO3 interferences. The analysis reveals a steady accumulation of the very long-lived CF4 above the Jungfraujoch at mean rates of (1.38 ± 0.11) x 1013 molec cm-2 yr-1 from 1989 to 1997, and (0.98 +/- 0.02) x 1013 molec cm-2 yr-1 from 1998 to 2012, which correspond to linear growth rates of 1.71 ± 0.14 and 1.04 ± 0.02% yr-1 respectively referenced to 1989 and 1998. Related global CF4 anthropogenic emissions required to sustain these mean increases correspond to 15.8 ±1.3 and 11.1 ± 0.2 Gg yr-1 over the above specified time intervals. Findings reported here are compared and discussed with respect to relevant northern mid-latitude results obtained remotely from space and balloons as well as in situ at the ground, including new gas chromatography mass spectrometry measurements performed at the Jungfraujoch since 2010

The Ordovician of France and neighbouring areas of Belgium and Germany

The Ordovician successions of France and neighbouring areas of Belgium and Germany are reviewed and correlated based on international chronostratigraphic and regional biostratigraphic charts. The same three megasequences related to the rift, drift and docking of Avalonia with Baltica can be tracked in Belgium and neighbouring areas (Brabant Massif and Ardenne inliers), western (Rhenish Massif) and northeastern Germany (Rügen). The remaining investigated areas were part of Gondwana in the Ordovician. The Armorican Massif shares with the Iberian Peninsula a Furongian–Early Ordovician gap (Toledanian or Norman gap), and a continuous Mid–Late Ordovician shelf sedimentation. The Occitan Domain (Montagne Noire and Mouthoumet massifs), eastern Pyrenees and northwestern Corsica share with southwestern Sardinia continuous shelf sedimentation in the Early Ordovician, and a Mid Ordovician ‘Sardic gap’. In the Ordovician, the Maures Massif probably belonged to the same Sardo-Occitan domain. The Vosges and Schwarzwald massifs display compa-rable, poorly preserved Ordovician successions, suggesting affinities with the Teplá-Barrandian and/or Molda-nubian zones of Central Europe.This paper is a contribution to the International Geoscience Programme (IGCP) projects 653 "The onset of the Great Ordovician Biodiversification Event" and 735 “Rocks and the Rise of Ordovician Life: Filling knowledge gaps in the Early Palaeozoic Biodiversification". The authors are particularly grateful to Annalisa Ferretti, David A.T. Harper and Petr Kraft for their careful and constructive reviews, comments and suggestions, which greatly improved the quality and relevance of the paper

A factor analysis approach to modelling the early diversification of terrestrial vegetation

peer reviewedData from a new comprehensive macrofossil-based compilation of early plant genera are analyzed via a Q-mode factor analysis. This compilation ranges from the Silurian to the earliest Carboniferous and illustrates the key vegetation changes that took place during the configuration of early terrestrial ecosystems. Results reveal that four factors can be used to explain more than 90% of the variance in the data. These factors are interpreted as the major phases of the early land plant evolution: a first Eotracheophytic flora (Silurian-Lochkovian) dominated by basal eutracheophytes and rhyniophytoids, an early Eophytic Flora (Early Devonian) dominated by zosterophylls, a transitional late Eophytic Flora (Middle Devonian-earliest Carboniferous) dominated by lycopsids and cladoxylopsids, and finally, the earliest phase of the Palaeophytic Flora (Late Devonian-earliest Carboniferous) dominated by the first seed plants. These floras present different but complementary diversity patterns, which help us to understand the overall trajectory of changes in plant diversity. Results further show how the maximum peaks of diversity appear linked to the rise of each new flora but, interestingly, these diversifications are not associated with any exponential declines of the previously dominant one. This new four-phase diversification model reflects the early steps of Earth's greening

The emergence of international food safety standards and guidelines: understanding the current landscape through a historical approach

Following the Second World War, the Food and Agriculture Organization (FAO) and the World Health Organization (WHO) teamed up to construct an International Codex Alimentarius (or 'food code') which emerged in 1963. The Codex Committee on Food Hygiene (CCFH) was charged with the task of developing microbial hygiene standards, although it found itself embroiled in debate with the WHO over the nature these standards should take. The WHO was increasingly relying upon the input of biometricians and especially the International Commission on Microbial Specifications for Foods (ICMSF) which had developed statistical sampling plans for determining the microbial counts in the final end products. The CCFH, however, was initially more focused on a qualitative approach which looked at the entire food production system and developed codes of practice as well as more descriptive end-product specifications which the WHO argued were 'not scientifically correct'. Drawing upon historical archival material (correspondence and reports) from the WHO and FAO, this article examines this debate over microbial hygiene standards and suggests that there are many lessons from history which could shed light upon current debates and efforts in international food safety management systems and approaches

Colonial palynomorphs from the Upper Ordovician of north-eastern Iran : ‘thalli’, coenobial Chlorophyceae (Hydrodictyaceae) or cyanobacteria?

This study documents ‘colonial’ palynomorphs from the Upper Ordovician Ghelli Formation of north-eastern Iran. The aggregates of organic-walled microfossils come from the Katian Armoricochitina nigerica–Ancyrochitina merga chitinozoan biozones of this formation. The ‘colonial’ microfossils can be classified as acritarchs and/or cryptospores, but they cannot be attributed to a particular biological group. Some specimens resemble ‘thalli’ of putative spores, such as Grododowon orthogonalis Strother 2017. Other clusters may suggest an affinity to green algal groups, in particular to colonial chlorophyceaen algae, most probably belonging to Hydrodictyaceae. Some specimens also show morphological similarities with cyanobacterial groups. There is so far no evidence to relate these ‘colonial’ palynomorphs to primitive land plants, but we hypothesise that they were possibly produced by ancient green algal lineages with some kind of subaerial existence