Microbial community dynamics in Mediterranean nutrient-enriched seawater mesocosms: changes in abundances, activity and composition.
FEMS Microbiol Ecol
; 34(3): 255-266, 2001 Jan.
Article
en En
| MEDLINE
| ID: mdl-11137605
Quantitative and qualitative changes in bacterial communities from the Mediterranean Sea were compared in duplicate batch mesocosms with or without addition of inorganic nutrients. Methods including traditional microbial ecology techniques, molecular biology and flow cytometry were combined to determine abundances, production, cell size, activity, culturability and taxonomic diversity of bacterial cells. Addition of nutrients and confinement resulted in an increase of bacterial densities which were rapidly controlled by protozoan grazing. Changes in bacterial activity and morphology were observed during the growth phase of bacteria and under grazing pressure. The proportion of medium-size and culturable cells increased during the growth phase. These cells were preferentially consumed by grazers resulting in a strong limitation of bacterial production. As a consequence of the grazing pressure, large cells were produced and contributed to the remaining bacterial productivity after grazing. Grazing had an effect on the taxonomic composition of bacterial communities by preferentially eliminating gamma-Proteobacteria, alpha-Proteobacteria were preserved. It seems that some species from the genera Ruegeria and Cytophaga may have developed defence strategies to escape predation.
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Colección:
01-internacional
Base de datos:
MEDLINE
Tipo de estudio:
Qualitative_research
Idioma:
En
Revista:
FEMS Microbiol Ecol
Año:
2001
Tipo del documento:
Article
Pais de publicación:
Reino Unido