Adlafia langebertalotii sp. nov. (Bacillariophyceae), une diatomée nouvelle du Grand-Duché de Luxembourg à la morphologie proche d'A. suchlandtii comb. nov.

International audienceAdlafia langebertalotii Monnier et Ector est une nouvelle espèce de diatomée pennée naviculoïde, décrite des rivières du Grand-Duché de Luxembourg. Elle est morphologiquement proche de Navicula suchlandtii Hustedt, mais elle diffère clairement de cette dernière par ses stries plus serrées. Navicula suchlandtii avait été combinée par le passé avec Adlafia Lange-Bertalot, mais cette combinaison s'avère invalide. Elle est maintenant validement combinée en Adlafia suchlandtii (Hustedt) Monnier et Ector. A. langebertalotii est une diatomée rhéophile, présente surtout dans des petits cours d'eau dont les eaux sont peu minéralisées et caractérisées par un faible niveau de pollution organique. Adlafia est comparé à d'autres genres de petites diatomées naviculoïdes à la morphologie similaire : Encyonopsis Krammer, Eolimna Lange-Bertalot et Schiller, Kobayasiella Lange-Bertalot et Mayamaea Lange-Bertalot

Enhanced AoA estimation and localization through transmitter precoder design

10.1007/s10776-012-0186-0International Journal of Wireless Information Networks194315-325IJWN

Conditions de référence pour les cours d'eau méditerrannéens d'Europe

International audienceThe present report describes a three-step approach that was used to characterize and define thresholds for the Least Disturbed Condition in Mediterranean streams of four different types, regarding organic pollution and nutrients, hydrological and morphological alterations, and land use. For this purpose, a common database composed of national reference sites (929 records) from seven countries, sampled for invertebrates, diatoms and macrophytes was used. The analyses of reference sites showed that small (catchment b100 km2) siliceous and non-siliceous streams were mainly affected by channelization, bank alteration and hydropeaking. Medium-sized siliceous rivers were the most affected by stressors: 25–43% of the samples showed at least slight alterations regarding channelization, connectivity, upstream dam influence, hydropeaking and degradation of riparian vegetation. Temporary streams were the least affected by hydromorphological changes, but they were nevertheless affected by alterations in riparian vegetation. There were no major differences between all permanent stream types regarding water quality, but temporary streams showed lower values for oxygenation (DO) and wider ranges for other variables, such as nitrates. A lower threshold value for DO (60%) was determined for this stream type and can be attributed to the streams' natural characteristics. For all other river types, common limits were found for the remaining variables (ammonium, nitrate, phosphate, total P, % of artificial areas, % of intensive and extensive agriculture, % of semi-natural areas in the catchment)

The recovery of European freshwater biodiversity has come to a halt

Owing to a long history of anthropogenic pressures, freshwater ecosystems are among the most vulnerable to biodiversity loss(1). Mitigation measures, including wastewater treatment and hydromorphological restoration, have aimed to improve environmental quality and foster the recovery of freshwater biodiversity(2). Here, using 1,816 time series of freshwater invertebrate communities collected across 22 European countries between 1968 and 2020, we quantified temporal trends in taxonomic and functional diversity and their responses to environmental pressures and gradients. We observed overall increases in taxon richness (0.73% per year), functional richness (2.4% per year) and abundance (1.17% per year). However, these increases primarily occurred before the 2010s, and have since plateaued. Freshwater communities downstream of dams, urban areas and cropland were less likely to experience recovery. Communities at sites with faster rates of warming had fewer gains in taxon richness, functional richness and abundance. Although biodiversity gains in the 1990s and 2000s probably reflect the effectiveness of water-quality improvements and restoration projects, the decelerating trajectory in the 2010s suggests that the current measures offer diminishing returns. Given new and persistent pressures on freshwater ecosystems, including emerging pollutants, climate change and the spread of invasive species, we call for additional mitigation to revive the recovery of freshwater biodiversity