Testing the light:nutrient hypothesis: Insights into biofilm structure and function using metatranscriptomics

Area of Science:

• Ecology
• Microbiology
• Biogeochemistry

Background:

• Aquatic biofilms harbor diverse microbial communities crucial for biogeochemical cycling.
• Microbial interactions within biofilms are vital for ecosystem processes, especially under resource limitation.
• Light availability is a key resource influencing both phototrophic and heterotrophic production in biofilms.

Discussion:

• This study investigated stream biofilm responses to varying light availability using microcosm experiments.
• Metatranscriptomics and biogeochemical rate estimations were integrated to link gene expression to ecosystem functions.
• The research examined impacts across three domains of life within the biofilm.

Key Insights:

• Under low light, diatoms and cyanobacteria increased photosynthetic activity to meet energy demands.
• Under high light, heterotrophic bacteria showed increased phosphorus metabolism and uptake.
• Biogeochemical functions in biofilms are driven by complex, multi-trophic microbial interactions.

Outlook:

• Understanding microbial feedbacks under resource gradients is crucial for stream ecosystem management.
• Further research can elucidate the specific roles of different taxa in biofilm functioning.
• This work highlights the importance of considering microbial community structure in biogeochemical models.