Hypersaline Microbial Mats of San Salvador Island, Bahamas

Anhydrophilic, halotolerant microbial mats of San Salvador Island, Bahamas.

Funding:  National Science Foundation (NSF) - Microbial Observatories Program; 2002-2008

PI: H. Paerl; Co-PIs: A. Decho, T. Steppe, J. Pinckney
 

The highly-hydrated EPS slime matrix of bacteria provides an adaptation to resist and survive extreme stressors such as desiccation (loss of water) and salinity fluctuations; processes that occur in both natural and artificial systems. Bacterial mats growing in hypersaline ponds in the Bahamas, typically receive intermittent rainfall followed by prolonged dry periods. The mats often go to near-complete dryness. However, bacteria in these mats can be revived from a dry, hardened state to an actively metabolizing state within hours after exposure to (rain) water. In a five-year project, funded by the Microbial Observatories Program at the National Science Foundation (NSF), we are collaborating with researchers at the Universities of North Carolina-Marine Institute to understand how the EPS matrix, secreted by these mats, may aid in the binding of ions and the conservation of water for cells. The results of this study will provide broader insight into how bacteria in nature, and pathogenic (disease-causing) bacteria in artificial systems, may survive extreme environmental conditions.

Fig. 1.  Light-microscopy cross-section of a hypersaline microbial mat from Salt Pond, San Salvador.  Note distinct layering (with depth) of microbial communities.
 

 

Fig. 2.  The mat surface (gold) has a dense array of 'Polymer towers'  that likely influence the mats overall resiliency to changing ionic conditions.