Microbial micropatches within microbial hotspots.

Area of Science:

• Microbiology
• Environmental Science
• Ecology

Background:

• Organism abundance and diversity display spatial heterogeneity, even at the sub-centimetre scale for microbes.
• Previous work identified distinct microbial hotspots, coldspots, and background regions at the 300 μl scale.
• This study investigates microbial distribution at the finer 1 μl scale within these previously defined regions.

Purpose of the Study:

• To characterize taxonomic micropatches within microbial hotspots, coldspots, and background regions at the 1 μl scale.
• To identify the specific genera driving heterogeneity at the microscale.
• To infer the ecological implications of these microscale structures.

Main Methods:

• Analysis of microbial taxonomic composition in 1 μl subsamples from 300 μl microscale regions.
• Identification of dominant genera within observed micropatches.
• Correlation of microbial associations with particle-associated lifestyles.

Main Results:

• Taxonomic heterogeneity was observed at the 1 μl scale, forming micropatches within larger microscale regions.
• Micropatches were most pronounced in hotspots and dominated by genera such as Pseudomonas and Bacteroides.
• These genera, often particle-associated, suggest the presence of sub-millimetre aggregates and aquatic polymer matrices.

Conclusions:

• Microscale microbial distributions are numerically and taxonomically heterogeneous, even at scales less than a millimetre.
• The identified micropatches suggest specific microenvironments are created or exploited by certain microbial groups.
• Microbial hotspots possess internal structure, potentially facilitating localized nutrient exchange and cellular interactions.