Hydrologic History Regulates Microbial Biofilm Diversity and Ecosystem Function.

Area of Science:

• Ecology
• Microbiology
• Environmental Science

Background:

• Aquatic biofilms are crucial but understudied in northern peatlands.
• Expanding aquatic habitats in peatlands necessitate understanding biofilm roles.
• Hydrologic history is a key factor influencing these ecosystems.

Purpose of the Study:

• To investigate the influence of hydrologic history on aquatic biofilm diversity.
• To identify functional genes within biofilms under varying water table conditions.
• To understand how simulated drought and flooding affect peatland biofilm communities.

Main Methods:

• Long-term water table manipulation simulating drought and flooding.
• Metabarcoding and metagenomic analyses to assess eukaryotic algae, cyanobacteria, bacteria, and fungi.
• Analysis of functional genes related to wet-dry transitional states.

Main Results:

• Historical flooding, not drought, broadly altered biofilm composition and functional genes.
• Changes were primarily in the relative abundance of taxa and genes, not presence/absence.
• Genes associated with carbon metabolism and nitrogen cycling were significantly affected by flooding.

Conclusions:

• Hydrologic history regulates the species membership and associated functional genes in aquatic biofilms.
• Water chemistry and interspecific interactions modify the relative abundance and functional potential of biofilm communities.
• Understanding these dynamics is crucial for peatland ecosystem processes in changing environments.