1. The microbial food web in the recently flooded sep reservoir: Diel fluctuations in bacterial biomass and metabolic activity in relation to phytoplankton and flagellate grazers
- Author
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Louis-B. Jugnia, J. Devaux, Rémy D. Tadonléké, Télesphore Sime-Ngando, Laboratoire Microorganismes : Génome et Environnement (LMGE), Université Blaise Pascal - Clermont-Ferrand 2 (UBP)-Centre National de la Recherche Scientifique (CNRS)-Université d'Auvergne - Clermont-Ferrand I (UdA), and Université Blaise Pascal - Clermont-Ferrand 2 (UBP)-Université d'Auvergne - Clermont-Ferrand I (UdA)-Centre National de la Recherche Scientifique (CNRS)
- Subjects
Bacterioplankton ,0106 biological sciences ,Puy-de-Dome ,Algae ,Microbial biomass ,Freshwater environment ,Trophic chain ,Soil Science ,Biology ,010603 evolutionary biology ,01 natural sciences ,Zooplankton ,Flood ,Auvergne ,Water column ,Phytoplankton ,Artificial lake ,Protozoa ,Diel vertical migration ,Ecology, Evolution, Behavior and Systematics ,Trophic level ,Biomass (ecology) ,Microbial food web ,Bacteria ,Ecology ,Trophic relation ,010604 marine biology & hydrobiology ,Flood(streams) ,Thallophyta ,Carbon cycle ,Biological productivity ,Europe ,Microbial activity ,13. Climate action ,Primary productivity ,Population density ,France ,[SDE.BE]Environmental Sciences/Biodiversity and Ecology - Abstract
International audience; The spatial distribution of the bacterial biomass and production and of potential heterotrophic activity (PHA) were measured every 4 h between 23 July (10:00 h) and 25 July (10:00 h) 1997 in a recently flooded oligo-mesotrophic reservoir (the Sep Reservoir, Puy-de-Dôme, France), in relation to temperature, the phytoplankton biomass and production, and the abundance of heterotrophic flagellates. The temperature varied slightly with time during the study, but the well-established thermal stratification agreed well with vertical distribution of the biological variables that were measured. Only the bacterial production and the PHA showed significant diel changes (t-test, p < 0.05), with maxima at 18:00 h and minima at 02:00 h. A significant positive relation was found between bacterial abundance and that of heterotrophic flagellates, which, rather than being an association related to the thermal stratification of the water column, was considered to reflect a trophic relation between these two communities. A carbon balance analysis suggested that at least 30% of the C from primary production measured during the sampling period was used by bacteria, and that 42% of this secondary production, or 6% of the primary production, would be used for the development of the heterotrophic flagellates present. We conclude that the bacterioplankton forms, at least occasionally, an important source of carbon for higher trophic levels, and reject the hypothesis that bacterial production in the Sep Reservoir depends exclusively on organic matter of allochthonous origin.
- Published
- 2000
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