Temporal Evolution of Diatoms in a Temporary Pond Situated in the Massif du Sancy Mountains (Massif Central, France) and Description of a New Pinnularia Species

Aude Beauger,Luc Ector,Olivier Voldoire,Carlos E Wetzel,Bart Van De Vijver,Elisabeth Allain

doi:10.3390/d12100367

Abstract

A floristic survey was performed on a temporary pond, “Laqui du Seignavoux”, situated in the Mont-Dore massif of the French Massif Central, between 2017 and 2019. Except in 2017, each year, we performed four sampling campaigns from April/May to December. Water samples and diatoms were collected. The temporary pond evolved from a poorly mineralized ecosystem due to snow, inducing oligotrophic and oligosaprobic water, well oxygenated in spring, to a more mineralized, less oxygenated, eutrophic–hypereutrophic, and polysaprobic environment in summer. This change in abiotic conditions was found to be linked to the presence of cattle, beginning in May, that trample and excrete in the pond, leading to higher ammonium and nitrate concentrations. During this period, the dominant species were Pinnularia sp., Nitzschia palea, and Nitzschia palea var. tenuirostris. In spring and winter, different species of Eunotia dominated the community such as Eunotia pseudogroenlandica. Finally, light microscopy (LM) and scanning electron microscopy (SEM) observations on a new species of the genus Pinnularia from the temporary pond are presented and the ecological preferences are discussed.

Highlights

IntroductionLake and pond basins are formed by various glacial, tectonic, volcanic, and even episodic (e.g., occasional landslides) processes; specific information on the geomorphologic origins of small lake and pond basins in high-elevation regions is rather limited despite the fact that basin morphology can control the size of water bodies, their spatial distribution pattern, catchment area, etc. [1]
Lake and pond basins are formed by various glacial, tectonic, volcanic, and even episodic processes; specific information on the geomorphologic origins of small lake and pond basins in high-elevation regions is rather limited despite the fact that basin morphology can control the size of water bodies, their spatial distribution pattern, catchment area, etc. [1]
This analysis grouped, in the right part of the first factorial plan, the samples taken in April and December 2018 together with the samples taken in May, October, and November

Summary

Introduction

Lake and pond basins are formed by various glacial, tectonic, volcanic, and even episodic (e.g., occasional landslides) processes; specific information on the geomorphologic origins of small lake and pond basins in high-elevation regions is rather limited despite the fact that basin morphology can control the size of water bodies, their spatial distribution pattern, catchment area, etc. [1]. A few studies investigated the diatom diversity in pools in different mountains all around the world, such as in Japan and the Alpine, Pyrenean, Bulgarian, and Mediterranean massifs [11,12,13,14,15,16,17]. These studies focused on the environmental factors controlling benthic diatom diversity using taxonomic and ecological characterization. At present, no studies have been conducted for this type of pond in the French Massif Central

Methods

Results

Discussion

Conclusion