Planktonic microbial communities from microbialite-bearing lakes sampled along a salinity-alkalinity gradient

Area of Science:

• Environmental microbiology
• Aquatic ecology
• Biogeochemistry

Background:

• Continental freshwater systems face threats from climate change and human activities, leading to evaporation and salinization.
• The impact of salinization on microbial communities and their role in biogeochemical cycles remains largely unknown.

Purpose of the Study:

• To investigate how microbial communities in lakes change along a salinity-alkalinity gradient.
• To identify the key environmental drivers shaping these microbial communities.

Main Methods:

• A space-for-time substitution approach was used, sampling 12 lakes across a salinity gradient in the Trans-Mexican Volcanic Belt.
• 16S/18S rRNA gene metabarcoding was applied to analyze prokaryotic and eukaryotic microbial communities in different cell-size fractions.

Main Results:

• Salinity-alkalinity parameters were the primary drivers of microbial community structure, more so than trophic status, depth, or season.
• Microbialites, where present, harbored distinct microbial communities compared to planktonic communities.
• Most lakes along the evaporation trend showed active microbialite formation.

Conclusions:

• Climate change and anthropogenic water use significantly impact microbial communities in inland waters.
• Changes in microbial communities due to salinization could alter essential ecosystem functions.