Changes in Community Structure of Sediment Bacteria Along the Florida Coastal Everglades Marsh–Mangrove–Seagrass Salinity Gradient

• Published in: Microbial ecology 2010-02, Vol.59 (2), p.284-295
• Main Authors: Ikenaga, Makoto, Guevara, Rafael, Dean, Amanda L., Pisani, Cristina, Boyer, Joseph N.
• Format: Article
• Language: English
• Subjects: Bacteria; Bacteria - classification; Bacteria - genetics; Biodiversity; Biological and medical sciences; Biomedical and Life Sciences; Brackish; Chloroflexi; Cluster Analysis; Community structure; Cyanobacteria; Deoxyribonucleic acid; DNA; DNA, Bacterial - genetics; Ecology; Electrophoresis, Polyacrylamide Gel; ENVIRONMENTAL MICROBIOLOGY; Everglades; Florida; Fresh water; Fresh Water - microbiology; Fundamental and applied biological sciences. Psychology; Geoecology/Natural Processes; Geologic Sediments - microbiology; Life Sciences; Mangrove forests; Marine; Marine environment; Marshes; Microbial Ecology; Microbiology; Nature Conservation; Phosphorus - analysis; Phylogeny; Planctomycetes; Poaceae - microbiology; Polymerase Chain Reaction; Rhizophoraceae - microbiology; RNA, Ribosomal, 16S - genetics; rRNA genes; Salinity; Sediment samplers; Sediments; Sequence Alignment; Sequence Analysis, DNA; Sulfate reduction; Water Microbiology; Water Quality/Water Pollution; Wetlands
• ISSN: 0095-3628; 1432-184X
• DOI: 10.1007/s00248-009-9572-2

Community structure of sediment bacteria in the Everglades freshwater marsh, fringing mangrove forest, and Florida Bay seagrass meadows were described based on polymerase chain reaction-denaturing gradient gel electrophoresis (PCR-DGGE) patterns of 16S rRNA gene fragments and by sequencing analysis of DGGE bands. The DGGE patterns were correlated with the environmental variables by means of canonical correspondence analysis. There was no significant trend in the Shannon–Weiner index among the sediment samples along the salinity gradient. However, cluster analysis based on DGGE patterns revealed that the bacterial community structure differed according to sites. Not only were these salinity/vegetation regions distinct but the sediment bacteria communities were consistently different along the gradient from freshwater marsh, mangrove forest, eastern-central Florida Bay, and western Florida Bay. Actinobacteria- and Bacteroidetes/Chlorobi-like DNA sequences were amplified throughout all sampling sites. More Chloroflexi and members of candidate division WS3 were found in freshwater marsh and mangrove forest sites than in seagrass sites. The appearance of candidate division OP8-like DNA sequences in mangrove sites distinguished these communities from those of freshwater marsh. The seagrass sites were characterized by reduced presence of bands belonging to Chloroflexi with increased presence of those bands related to Cyanobacteria, γ-Proteobacteria, Spirochetes, and Planctomycetes. This included the sulfate-reducing bacteria, which are prevalent in marine environments. Clearly, bacterial communities in the sediment were different along the gradient, which can be explained mainly by the differences in salinity and total phosphorus.