Physiological status and microbial diversity assessment of microbial mats: The signature lipid biomarker approach

Abstract

Molecular fingerprinting using signature lipid biomarker (SLB) analysis and nucleic-acid-based techniques provides a quantitative and comprehensive method to assess the viable biomass, community composition and physiological status of microbial communities. Photosynthetic microbial mats are sedimentary structures composed primarily of different populations of bacteria in multilayered communities. Traditionally, microbial ecology studies of microbial mat communities have been incomplete because of the inability to identify and quantify all contributing populations. In fact, classical methods often revealed less than 1% of the microbial diversity. Examination of the lipid components of microbial mat samples allows a sensitive assessment of the in situ microbial community that is independent of the isolation and culture of certain microorganisms. Numerous studies based on SLB analysis of microbial mats have established a relationship between physiological activities, daily and seasonal processes and microniches within the mat. Expansion of the SLB approach and concomitant analysis of the nucleic acids derived from the lipid extraction provide a powerful tool for improving our understanding of complex microbial communities such as intertidal microbial mats.

Key Words:

• Lipid analysis
• Phospholipid fatty acids
• Poly-β-hydroxyalkanoates
• Ecophysiology
• Microbial mats