Spatial and temporal variability in a stratified hypersaline microbial mat community

• Published in: FEMS microbiology ecology 2009-04, Vol.68 (1), p.46-58
• Main Authors: Dillon, Jesse G, Miller, Scott, Bebout, Brad, Hullar, Meredith, Pinel, Nicolás, Stahl, David A
• Format: Article
• Language: English
• Subjects: Animal and plant ecology; Animal, plant and microbial ecology; Bacteroidetes - genetics; Bacteroidetes - growth & development; Beggiatoa; Biodiversity; Biological and medical sciences; Brackish water ecosystems; Chloroflexus; Chloroflexus - genetics; Chloroflexus - growth & development; Communities; Community composition; Community structure; Cyanobacteria; Cyanobacteria - genetics; Cyanobacteria - growth & development; Ecology; Fundamental and applied biological sciences. Psychology; Gene sequencing; Genes, rRNA; Guerrero Negro; hypersaline; Mats; Microbial ecology; microbial mat; Microbiology; Microcoleus; Microorganisms; migration; Photoperiod; Polymorphism, Restriction Fragment Length; Population distribution; RNA, Bacterial - genetics; RNA, Ribosomal, 16S - genetics; rRNA 16S; Sequence Analysis, DNA; Species diversity; Synecology; T-RFLP; Various environments (extraatmospheric space, air, water); Vertical orientation; Water Microbiology
• ISSN: 0168-6496; 1574-6941
• DOI: 10.1111/j.1574-6941.2009.00647.x

Hypersaline microbial mat communities have recently been shown to be more diverse than once thought. The variability in community composition of hypersaline mats, both in terms of spatial and temporal dimensions, is still poorly understood. Because this information is essential to understanding the complex biotic and abiotic interactions within these communities, terminal restriction fragment analysis and 16S rRNA gene sequencing were used to characterize the near-surface community of a hypersaline microbial mat in Guerrero Negro, Mexico. Core samples were analyzed to assay community variability over large regional scales (centimeter to kilometer) and to track depth-related changes in population distribution at 250-μm intervals over a diel period. Significant changes in total species diversity were observed at increasing distances across the mat surface; however, key species (e.g. Microcoleus sp.) were identified throughout the mat. The vertical position and abundance of >50% of the 60 peaks detected varied dramatically over a diel cycle, including Beggiatoa sp., cyanobacteria, Chloroflexus sp., Halochromatium sp., Bacteroidetes sp. and several as-yet-identified bacteria. Many of these migrations correlated strongly with diel changes in redox conditions within the mat, contributing to strong day-night community structure differences.