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Characterization of Aquatic Biofilms with Flow Cytometry
Published on: June 6, 2018
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Light availability affects stream biofilm bacterial community composition and function, but not diversity.
Karoline Wagner1,2, Katharina Besemer1,3, Nancy R Burns1,2
1Department of Limnology and Oceanography, University of Vienna, Vienna, Austria.
Environmental Microbiology
|May 28, 2015
Summary
Stream light levels significantly impact biofilm structure and function. Higher light boosts multifunctionality, while lower light increases phenol oxidase activity, altering microbial reliance on organic matter.
Area of Science:
- Aquatic Ecology
- Microbial Ecology
- Biogeochemistry
Background:
- Stream light availability is influenced by riparian vegetation and water quality.
- Light is a critical factor affecting stream biofilm structure and function.
- Biofilms play a key role in stream ecosystem processes.
Purpose of the Study:
- To investigate the effects of varying light intensities on stream biofilm structure and function.
- To assess how light gradients influence bacterial community composition and extracellular enzyme activities.
Main Methods:
- Biofilm microcosms were established under a gradient of light intensities (5–152 µmol photons s⁻¹ m⁻²).
- Bacterial community composition was analyzed using 454-pyrosequencing.
- Extracellular enzyme activities and community respiration were measured.
Main Results:
- Bacterial community composition shifted significantly along the light gradient, but alpha diversity remained unchanged.
- Biofilm multifunctionality, assessed via extracellular enzymes, was highest under high light conditions.
- Phenol oxidase activity was higher under low light, suggesting a shift in microbial substrate utilization.
Conclusions:
- Light availability is a key driver of stream biofilm structure and function.
- Changes in light regimes can alter microbial community composition and metabolic pathways.
- These alterations in biofilms can significantly impact nutrient cycling and overall stream ecosystem processes.
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