Publications des scientifiques de l'IRD

Bernard C., Escalas A., Villeriot N., Agogue H., Hugoni M., Duval C., Carré Claire, Got P., Sarazin G., Jezequel D., Leboulanger Christophe, Grossi V., Ader M., Troussellier M. (2019). Very low phytoplankton diversity in a tropical saline-alkaline lake, with co-dominance of Arthrospira fusiformis (Cyanobacteria) and Picocystis salinarum (Chlorophyta). Microbial Ecology, 78 (3), p. 603-617. ISSN 0095-3628.

Titre du document
Very low phytoplankton diversity in a tropical saline-alkaline lake, with co-dominance of Arthrospira fusiformis (Cyanobacteria) and Picocystis salinarum (Chlorophyta)
Année de publication
2019
Type de document
Article référencé dans le Web of Science WOS:000485929400006
Auteurs
Bernard C., Escalas A., Villeriot N., Agogue H., Hugoni M., Duval C., Carré Claire, Got P., Sarazin G., Jezequel D., Leboulanger Christophe, Grossi V., Ader M., Troussellier M.
Source
Microbial Ecology, 2019, 78 (3), p. 603-617 ISSN 0095-3628
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 mu g 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.
Plan de classement
Limnologie biologique / Océanographie biologique [034] ; Ecologie, systèmes aquatiques [036]
Description Géographique
OCEAN INDIEN ; MAYOTTE ; COMORES
Localisation
Fonds IRD [F B010077025]
Identifiant IRD
fdi:010077025
Contact