A recently released voxel model quantifying aggregate resources of the Belgian part of the North Sea includes lithological properties of all Quaternary sediments and modelling-related uncertainty. As the underlying borehole data come from various sources and cover a long time-span, data-related uncertainties should be accounted for as well. Applying a tiered data-uncertainty assessment to a composite lithology dataset with uniform, standardized lithological descriptions and rigorously completed metadata fields, uncertainties were qualified and quantified for positioning, sampling and vintage. The uncertainty on horizontal positioning combines navigational errors, on-board and off-deck offsets and underwater drift. Sampling-gear uncertainty evaluates the suitability of each instrument in terms of its efficiency of sediment yield per lithological class. Vintage uncertainty provides a likelihood of temporal change since the moment of sampling, using the mobility of fine-scale bedforms as an indicator. For each uncertainty component, quality flags from 1 (very uncertain) to 5 (very certain) were defined and converted into corresponding uncertainty percentages meeting the input requirements of the voxel model. Obviously, an uncertainty-based data selection procedure, aimed at improving the confidence of data products, reduces data density. Whether or not this density reduction is detrimental to the spatial coverage of data products, will depend on their intended use. At the very least, demonstrable reductions in spatial coverage will help to highlight the need for future data acquisition and to optimize survey plans. By opening up our subsurface model with associated data uncertainties in a public decision support application, policy makers and other end users are better able to visualize overall confidence and identify areas with insufficient coverage meeting their needs. Having to work with a borehole dataset that is increasingly limited with depth below the seabed, engineering geologists and geospatial analysts in particular will profit from a better visualization of datarelated uncertainty.
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RBINS Staff Publications 2020
Caecilians are elongate, limbless and annulated amphibians that, with the exception of one aquatic family, all have an at least partly fossorial lifestyle. It has been suggested that caecilian evolution resulted in sturdy and compact skulls with fused bones and tight sutures, as an adaptation to their head-first burrowing habits. However, although their cranial osteology is well described, relationships between form and function remain poorly understood. In the present study, we explored the relationship between cranial shape and in vivo burrowing forces. Using micro-computed tomography (µCT) data, we performed 3D geometric morphometrics to explore whether cranial and mandibular shapes reflected patterns that might be associated with maximal push forces. The results highlight important differences in maximal push forces, with the aquatic Typhlonectes producing a lower force for a given size compared with other species. Despite substantial differences in head morphology across species, no relationship between overall skull shape and push force could be detected. Although a strong phylogenetic signal may partly obscure the results, our conclusions confirm previous studies using biomechanical models and suggest that differences in the degree of fossoriality do not appear to be driving the evolution of head shape.
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RBINS Staff Publications 2021
