Population structure and physiological changes within a hot spring microbial mat community following disturbance

Area of Science:

• Microbiology
• Ecology
• Geochemistry

Background:

• Hot spring cyanobacterial mats are sensitive ecosystems.
• Disturbance can significantly impact microbial community structure and function.
• Understanding recovery dynamics is crucial for ecological restoration.

Purpose of the Study:

• To investigate the effects of physical disturbance on hot spring cyanobacterial mat communities.
• To analyze changes in microbial populations and physiological activities post-disturbance.
• To assess the recovery patterns of these ecosystems.

Main Methods:

• Physical removal of the top 3.0 mm of the cyanobacterial mat.
• Monitoring 16S rRNA-defined populations using denaturing gradient gel electrophoresis (DGGE).
• Measuring physiological activity via oxygen microelectrode analyses and 14CO2 incorporation.

Main Results:

• Colonization by previously absent cyanobacterial populations in disturbed areas.
• Persistence of absence for some pre-disturbance populations up to 40 days.
• Unexplained light-induced oxygen consumption in freshly exposed mat.
• Increased phototroph carbon partitioning into growth macromolecules.
• Bimodal vertical photosynthesis profiles and delayed respiration recovery.

Conclusions:

• Physical disturbance causes significant shifts in hot spring cyanobacterial mat composition and function.
• Recovery is complex, with differential colonization and delayed physiological restoration.
• The study highlights the resilience and vulnerability of these unique microbial ecosystems.