During a survey done on the mineral springs in the French Massif Central region, a new Chamaepinnularia species (Bacillariophyceae) was found and is hereby described: Chamaepinnularia salina Beauger, C.E.Wetzel, Allain & Ector sp. nov. This new small species, with valves linear with almost parallel margins, is formally described using light and scanning electron microscopy. The central area is rectangular, forming a rather broad fascia and the raphe is straight, filiform located on an elevated sternum. Virgae between striae are developed. The ecological preferences of Chamaepinnularia salina are presented. This species is mainly in mineral springs with Na-K-HCO3 water type.

Although a strong link between viruses and prokaryotes is commonly known to exist in aquatic systems, few studies have investigated their relationship in spring waters. In the French Massif Central, certain springs are known to exhibit varying levels of naturally occurring radioactivity. Therefore, the aim of this study was to examine the standing stock of viruses together with prokaryotes, and determine the potential environmental factors influencing them in springs characterized by contrasted radioactivity gradient. Among the investigated 15 spring habitats, flow cytometry analyses indicated that both viral (VA) and prokaryotic abundances (PA) varied by an order of magnitude accompanied by virus-toprokaryote ratio ranging between 8 and 144.2. Significant differences in VA was evident among springs where low abundances (mean ± SD: 21.3 ± 7.0 x 10 7 VLP l -1 ) corresponded to high (mean ± SD: 1911 ± 814.0 nGy.h -1 ) gamma (γ) dose radiation ( 222 Rn) and vice versa.Adverse effect of water radioactivity ( 222 Rn) on VA could perhaps corroborate our hypothesis of drastic effect of ionizing radiations on viruses, which might explain for lack of significant relationship between PA and VA. In such a scenario of prevailing low VA, the adopted phage life strategies could define their existence in these specialized ecosystems.

Diatoms colonised most aquatic ecosystems on earth from marine to freshwater ones, and also the springs containing a fairly large and poorly known diversity of diatoms.While investigations on the influence of substrates on diatom assemblages in rivers are relatively well documented, few studies have been done for mineral springs. The purpose of this study was to analyse if the type of substrate on which diatoms grow, influences diatom assemblage's ecological metrics (i.e. species richness, diversity and evenness) and diatom composition. During 18 months, two minerals springs of Auvergne (France), La Montagne and Mariol were sampled monthly, both epilithic and epipelic diatom communities. A total of 201 taxa were found. Data analysis showed that location (i.e. environmental variables of a site) explained significantly higher portions of variability of diatom composition than substrate. However, substrate have a role in the species abundances as much as the location.