Measurement of Near-Bed sediment load, particle size, settling velocity and turbulence from a multi-frequency acoustic backscatter instrument

Some of the work described is supported by funding from the European Union’s Horizon 2020 research and innovation program under Grant agreement No 101000825 — NAUTILOS

Continuous monitoring of suspended sediment in rivers by use of new methods

Traditional sampling methods are restrictive for spatial and temporal monitoring of suspended sediment in river. Application of these methods is simple but labour intensive to collect and process. For this reason, the use of new technological methods has recently gained importance. These methods are commonly based on the scattering of sound or light in water. Acoustic methods involve propagating sound at around the Megahertz frequency range through the water column. Short bursts of high frequency sound are transmitted from a transducer and directed towards the measurement water sample. Sediment in suspension will scatter a part of this sound back to the transducer. Another method, laser scattering, directs a laser beam through the sample of water where particles in suspension will scatter, absorb and reflect the beam. The scattered laser beam is received by a ring detector that allows measurement of the scattering angle of the beam. Particle size and volumetric concentration can be calculated from knowledge of this angle. In addition to these methods, optical turbidimeters supply an estimate for suspended sediment concentration through measuring either the backscatter of the light or the attenuation of a light beam passing through a water sample. In this paper, these methods were presented and advantages and limitations of each were given for comparison

LES NOUVELLES TECHNOLOGIES AMÉLIORENT NOTRE COMPRÉHENSION DES CHANGEMENTS DANS L'ENVIRONNEMENT MARIN

International audienceExisting European observation tools and services have the potential to take advantage of cutting-edge technologies to obtain a wide range of data at a much higher spatial resolution and temporal regularity and duration. The EU-funded NAUTILOS project will develop a new generation of sensors and samplers for physical, chemical, and biological essential ocean variables in addition to micro-and nano-plastics. The project will improve our understanding of environmental variations and anthropogenic impacts connected with aquaculture, fi sheries, and marine litter. The project will integrate recently advanced marine technologies into different observing platforms and deploy them through innovative and cost-effective methods in a wide range of key environmental settings and EU policy-related applications. The project aims to complement and expand existing European observation instruments and services and further enable and democratise the monitoring of the marine environment for both traditional and non-traditional data users.Les outils et services d'observation européens existants ont le potentiel de tirer parti des technologies de pointe pour obtenir un large éventail de données à une résolution spatiale et une régularité temporelle et une durée beaucoup plus élevées. Le projet NAUTILOS, financé par l'UE, développera une nouvelle génération de capteurs et d'échantillonneurs pour les variables océaniques essentielles physiques, chimiques et biologiques, en plus des micro- et nano-plastiques. Le projet améliorera notre compréhension des variations environnementales et des impacts anthropiques liés à l'aquaculture, aux pêcheries et aux déchets marins. Le projet intégrera des technologies marines récemment avancées dans différentes plateformes d'observation et les déploiera par le biais de méthodes innovantes et rentables dans un large éventail de contextes environnementaux clés et d'applications liées aux politiques de l'UE. Le projet vise à compléter et à étendre les instruments et services d'observation européens existants et à permettre et démocratiser davantage la surveillance de l'environnement marin pour les utilisateurs de données traditionnels et non traditionnels

Is global warming affecting cave temperatures? Experimental and model data from a paradigmatic case study

This research focuses on the mechanisms that transfer the variations in surface atmospheric temperature into caves to evaluate whether they record the warming trend of recent decades. As a study case, we use the data from a hall in Postojna Cave (Slovenia), which was monitored from 2009 to 2013. The low-frequency thermal variability of this cave chamber is dominated by the conduction of heat from the surface through the bedrock. We implemented a thermal conduction model that reproduces low-frequency thermal gradients similar to those measured in the cave. At the 37 m depth of this chamber, the model confirms that the bedrock is already recording the local expression of global warming with a delay of 20–25 years, and predicts a cave warming during the coming decades with a mean rate of 0.015 ± 0.004 C year−1. However, because of the transfer of surface atmosphere thermal variability depends on the duration of the oscillations, the thermal anomalies with periods 7–15 years in duration have delay times \u3c10 years at the studied hall. The inter-annual variability of the surface atmospheric temperature is recorded in this cave hall, although due to the different delay and amplitude attenuation that depends on the duration of the anomalies, the cave temperature signal differs significantly from that at the surface. As the depth of the cave is a major factor in thermal conduction, this is a principal control on whether or not a cave has already recorded the onset of global warming

Genomic reconstruction of the SARS-CoV-2 epidemic in England

AbstractThe evolution of the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) virus leads to new variants that warrant timely epidemiological characterization. Here we use the dense genomic surveillance data generated by the COVID-19 Genomics UK Consortium to reconstruct the dynamics of 71 different lineages in each of 315 English local authorities between September 2020 and June 2021. This analysis reveals a series of subepidemics that peaked in early autumn 2020, followed by a jump in transmissibility of the B.1.1.7/Alpha lineage. The Alpha variant grew when other lineages declined during the second national lockdown and regionally tiered restrictions between November and December 2020. A third more stringent national lockdown suppressed the Alpha variant and eliminated nearly all other lineages in early 2021. Yet a series of variants (most of which contained the spike E484K mutation) defied these trends and persisted at moderately increasing proportions. However, by accounting for sustained introductions, we found that the transmissibility of these variants is unlikely to have exceeded the transmissibility of the Alpha variant. Finally, B.1.617.2/Delta was repeatedly introduced in England and grew rapidly in early summer 2021, constituting approximately 98% of sampled SARS-CoV-2 genomes on 26 June 2021.</jats:p