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Microbial Life in Playa-Lake Sediments: Adapted Structure, Plastic Function to Extreme Water Activity Variations
Judit Boadella1, Andrea Butturini2, Anna Doménech-Pascual3
1GRECO, Institute of Aquatic Ecology, University of Girona, Av. Mª Aurèlia Capmany, 69, 17003, Girona, Spain. judit.boadella@udg.edu.
Microbial Ecology
|November 9, 2024
Summary
Biofilms in drying saline lakes show resilience. Reduced water availability impacts function more than structure, with microbes adapting to harsh, hypersaline conditions.
Area of Science:
- Microbial Ecology
- Environmental Science
- Limnology
Background:
- Saline shallow lakes in arid regions face frequent drying, causing salinity and water availability fluctuations.
- Limited research exists on how salinity and drought affect biofilms in hypersaline lake ecosystems.
Purpose of the Study:
- To investigate changes in playa-lake sediment biofilms during drying events.
- To understand the impact of reduced water activity on biofilm structure and function.
Main Methods:
- Sediment samples collected from surface and subsurface at different hydrological periods (wet, retraction, dry).
- Water activity (aw) decreased from 0.99 to 0.72.
- Assessed structural and functional variables of biofilms.
Main Results:
- Reduced water activity (aw) had a greater impact on biofilm function than structure.
- Respiration and hydrolytic enzyme activity decreased with lower aw, while phenol oxidase and prokaryote biomass increased.
- Surface biofilms showed more pronounced shifts, likely due to more extreme conditions.
Conclusions:
- Biofilms exhibit high resistance and resilience to hypersalinity and drought.
- Microbial adaptation involves changes in extracellular polymeric substances and carotenoids for protection.
- Functional shifts favor resistant prokaryotes and nutrient acquisition from recalcitrant compounds.
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