The substrate, a key factor or not, to explain the species diversity of diatom communities in mineral springs

Abstract

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.

Biodiversity and Environmental Factors Structuring Diatom Assemblages of Mineral Saline Springs in the French Massif Central

“…Diatoms were sampled in relation to the dominant substrate observed for each spring (Table S1). As underlined by Baker et al [42], the substrate collected in springs was found to influence diatom community composition less than local environmental conditions. The sediments were recovered by scraping off the first few millimeters of mud directly within the vial, and the stones and travertine (a sedimentary rock) by brushing them with a toothbrush.…”

Diatom DNA metabarcoding to assess the effect of natural radioactivity in mineral springs on ASV of benthic diatom communities

“…1). Since it was earlier demonstrated that the substrate has little influence on benthic diatom composition in mineral springs (Baker, 2022), the biofilm was recovered and considered to be the dominant substrate, representative of each of the springs sampled. In some springs, biofilm was collected by scrubbing the upper surface of rocks over which water flowed with a clean toothbrush.…”