Effect of salinity on temporal and spatial dynamics of ammonia-oxidising bacteria from intertidal freshwater sediment

• Published in: FEMS microbiology ecology 2005-08, Vol.53 (3), p.359-368
• Main Authors: Coci, Manuela, Riechmann, Daniela, Bodelier, Paul L.E., Stefani, Stefania, Zwart, Gabriel, Laanbroek, Hendrikus J.
• Format: Article
• Language: English
• Subjects: Ammonia; Ammonia - metabolism; Ammonia-oxidising bacteria; Bacteria; Bacteria - classification; Bacteria - genetics; Bacteria - isolation & purification; Bacteriology; Biological and medical sciences; Brackish; Communities; Community composition; Composition; Differentiation; DNA, Bacterial - analysis; DNA, Bacterial - genetics; Ecology; Electrophoresis; Electrophoresis - methods; Flooding; Floods; Fresh water; Fresh Water - chemistry; Fresh Water - microbiology; Freshwater; Freshwater sediment; Functional groups; Fundamental and applied biological sciences. Psychology; Gel electrophoresis; Geologic Sediments - chemistry; Geologic Sediments - microbiology; Marine; Microbiology; Microcosms; Miscellaneous; Niche differentiation; Nitrosomonas; Nitrosomonas marina; Nitrosomonas oligotropha; Oxidation-Reduction; Phylogeny; Polymerase Chain Reaction; Rivers; RNA, Ribosomal, 16S - genetics; Salinity; Salinity effects; Salt stress; Sediments; Sequence Analysis, DNA; Sodium Chloride - pharmacology; Spatial and temporal community change; Steering; Time Factors
• ISSN: 0168-6496; 1574-6941
• DOI: 10.1016/j.femsec.2005.01.016

Temporal and spatial dynamics within an ammonia-oxidising community from intertidal, freshwater sediments were studied in microcosms simulating flooding twice a day with fresh, brackish and marine waters. The microcosms had been filled with the upper 5 cm of intertidal freshwater sediment from the river Scheldt. Changes in community composition were examined by denaturing gradient gel electrophoresis of amplified DNA from the community. In the first week of incubation the initially present members of the Nitrosomonas oligotropha lineage were replaced by other members of the same lineage in the top layer of the sediment subjected to flooding with freshwater. Prolonged incubation extended niche differentiation to a depth of 5 cm. In the microcosms flooded with saline media, the initially present members of the N. oligotropha lineage were replaced by strains belonging to the Nitrosomonas marina lineage, but only in the top 1 cm. Shift in community composition occurred earlier in the marine microcosms than in the brackish microcosms and was slower than the change in the freshwater microcosms. Irrespective of the nature of the flooding medium, shifts in community composition were always consistent among replicate microcosms. We conclude that salinity is an important steering factor in niche differentiation among ammonia-oxidising bacteria and also that changes within the community of this functional group of bacteria may occur at different rates.