Very Low Phytoplankton Diversity in a Tropical Saline-Alkaline Lake, with Co-dominance of Arthrospira fusiformis (Cyanobacteria) and Picocystis salinarum (Chlorophyta) - Université Claude Bernard Lyon 1 Accéder directement au contenu
Article Dans Une Revue Microbial ecology Année : 2019

Very Low Phytoplankton Diversity in a Tropical Saline-Alkaline Lake, with Co-dominance of Arthrospira fusiformis (Cyanobacteria) and Picocystis salinarum (Chlorophyta)

Hélène Agogué

Résumé

Lake Dziani Dzaha (Mayotte Island, Indian Ocean) is a tropical thalassohaline lake which geochemical and biological conditions make it a unique aquatic ecosystem considered as a modern analogue of Precambrian environments. In the present study, we focused on the diversity of phytoplanktonic communities, which produce very high and stable biomass (mean 2014-2015 = 652 ± 179 μg chlorophyll a L −1). As predicted by classical community ecology paradigms, and as observed in similar environments, a single species is expected to dominate the phytoplanktonic communities. To test this hypothesis, we sampled water column in the deepest part of the lake (18 m) during rainy and dry seasons for two consecutive years. Phytoplanktonic communities were characterized using a combination of metagenomic, microscopy-based and flow cytometry approaches, and we used statistical modeling to identify the environmental factors determining the abundance of dominant organisms. As hypothesized, the overall diversity of the phytoplanktonic communities was very low (15 OTUs), but we observed a co-dominance of two, and not only one, OTUs, viz., Arthrospira fusiformis (Cyanobacteria) and Picocystis salinarum (Chlorophyta). We observed a decrease in the abundance of these co-dominant taxa along the depth profile and identified the adverse environmental factors driving this decline. The functional traits measured on isolated strains of these two taxa (i.e., size, pigment composition, and concentration) are then compared and discussed to explain their capacity to cope with the extreme environmental conditions encountered in the aphotic, anoxic, and sulfidic layers of the water column of Lake Dziani Dzaha.
Fichier principal
Vignette du fichier
Bernard et al_2019_Very LowP hytoplankton Diversity Dziani.pdf (2.16 Mo) Télécharger le fichier
Origine : Publication financée par une institution
Loading...

Dates et versions

mnhn-02292401 , version 1 (19-09-2019)

Identifiants

Citer

Cécile Bernard, Arthur Escalas, Nicolas Villeriot, Hélène Agogué, Mylène Hugoni, et al.. Very Low Phytoplankton Diversity in a Tropical Saline-Alkaline Lake, with Co-dominance of Arthrospira fusiformis (Cyanobacteria) and Picocystis salinarum (Chlorophyta). Microbial ecology, 2019, 78 (3), pp.603-617. ⟨10.1007/s00248-019-01332-8⟩. ⟨mnhn-02292401⟩
184 Consultations
287 Téléchargements

Altmetric

Partager

Gmail Facebook X LinkedIn More