Brackish diatom species (Bacillariophyta) from rivers of Rhin-Meuse basin in France

ABSTRACT

The French part of the Rhin-Meuse basin is quite heterogeneous due to the broad variability in pH and conductivity ranges of its rivers and streams. Parts of the basin are characterized by the presence of typical natural or anthropogenically induced brackish environments, showing a typical diatom flora. Since many brackish diatom species observed in these particular environments are often only poorly illustrated in literature used for biomonitoring, the present paper tends to fill this gap in our knowledge. Therefore, we illustrate in this work a large number of brackish taxa such as Cyclotella scaldensis, Skeletonema potamos, Thalassiosira gessneri, T. lacustris, T. weissflogii, Achnanthes secretitaeniata, Bacillaria paxillifera, Berkeleya rutilans, Entomoneis paludosa, Halamphora coffeaeformis, Haslea spicula, Nitzschia amplectens, N. aurariae, N. frequens, N. inconspicua and N. thermaloides. Additionally, one new species, Tabularia massenana sp. nov. is described based on detailed LM and SEM observations.

KEYWORDS:

• Brackish waters
• diatoms
• new species
• rivers
• scanning electron microscopy
• Tabularia
• taxonomy
• morphology

Acknowledgments

The results of this paper have been presented during the 37ème Colloque de l’Association des Diatomistes de Langue Française (ADLaF), 11–14 September 2018 in Meise, Belgium. We gratefully acknowledge Dr. David M. Williams (Department of Botany, The Natural History Museum, London, United Kingdom) for sharing information about Kützing material. We also acknowledge Dr. Mark Edlund (Science Museum of Minnesota, Saint Paul, United States of America) for sharing information about the genus Conticribra suppression. Finally, we thank two anonymous reviewers for their time and valuable comments.

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Funding

Funding for this research was partly provided in the framework of the project DIATOMS (LIST – Luxembourg Institute of Science and Technology).

Notes on contributors

David Heudre

David Heudre: sample collection, identification of diatom species, LM photos, plates, physicochemical data treatment and writing of the article.

Carlos E. Wetzel

Carlos E. Wetzel: SEM photos, discussion of results and development of the manuscript.

Bart Van de Vijver

Bart Van de Vijver: investigation of Haslea spicula type material from Van Heurck collection (Meise Botanic Garden, Belgium), discussion of results, editing of the manuscript.

Laura Moreau

Laura Moreau: sample collection, map editing and development of the manuscript.

Luc Ector

Luc Ector: Provision of literature, identification of diatom species, discussion of results, development, revision and editing of the manuscript.