Diversity, ecology and distribution of benthic diatoms in thermo-mineral springs in Auvergne (France) and Sardinia (Italy)

Giuseppina G Lai; Aude Beauger; Carlos E Wetzel; Bachisio M Padedda; Olivier Voldoire; Antonella Lugliè; Elisabeth Allain; Luc Ector

doi:10.7717/peerj.7238

Diversity, ecology and distribution of benthic diatoms in thermo-mineral springs in Auvergne (France) and Sardinia (Italy)

PeerJ. 2019 Jul 15:7:e7238. doi: 10.7717/peerj.7238. eCollection 2019.

Authors

Giuseppina G Lai¹, Aude Beauger², Carlos E Wetzel³, Bachisio M Padedda¹, Olivier Voldoire², Antonella Lugliè¹, Elisabeth Allain², Luc Ector³

Affiliations

¹ Department of Architecture, Design and Urban Planning, University of Sassari, Sassari, Italy.
² CNRS, GEOLAB, University Clermont Auvergne, Clermont-Ferrand, France.
³ Environmental Research and Innovation Department (ERIN), Luxembourg Institute of Science and Technology (LIST), Belvaux, Luxembourg.

Abstract

This study investigated and compared the diatom flora from thermo-mineral springs in Auvergne (France) and Sardinia (Italy). Samples were collected from rock/cobbles and fine sediments in 16 springs between January 2015 and March 2017. A total of 207 taxa (59 genera) were found. Multivariate analyses revealed significant differences in species composition and abundance among diatom assemblages both within each geographic region and between Auvergne and Sardinia (global R = 0.516; p = 0.002), suggesting the importance of local and climatic factors in species distribution. Based on abundance and common occurrence in multiple sites, some taxa can be considered more representative of springs in each region: Crenotia thermalis for Auvergne and Lemnicola exigua, Nitzschia amphibia, N. inconspicua and Rhopalodia operculata for Sardinia. pH, conductivity and HCO₃ ^- were the most significant environmental variables for diatom assemblages. Our results highlight the high heterogeneity of these spring systems. Future taxonomic insights can be useful to define the identity of some abundant and dominant taxa not identified at the species level in this study. Their identification is a crucial step for a more precise ecological characterization and comparison of these peculiar spring systems.

Keywords: Auvergne; Bacillariophyceae; Biodiversity; Extreme conditions; Sardinia; Springs; Thermo-mineral waters.

Grants and funding

This study was funded by a research grant of University of Sassari for the PhD project “Ecological surveys for the valorization of spring environments of Sardinia: implications for their fruition and environmental protection” and by funds for the project “DIATOMS” (LIST - Luxembourg Institute of Science and Technology). External funding for a part of this research was provided in the framework of the project CRP -79058 “The thermal system in Sardinia. A new project on the natural, cultural and historical landscapes” (Sardinia Region, Regional Promotion with Law No 7/2007 - Promotion of Scientific Research and Technological Innovation in Sardinia). There was no additional external funding received for this study. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.