Microbial biofilm community dynamics in five lowland streams

Area of Science:

• Ecology
• Microbiology
• Environmental Science

Background:

• Stream biofilms are crucial for global nutrient cycling.
• Previous research often overlooked the simultaneous dynamics of prokaryotic and eukaryotic communities within biofilms.
• Understanding the full diversity of biofilm communities is essential for ecological assessments.

Purpose of the Study:

• To investigate the community composition and diversity of both prokaryotic and eukaryotic organisms in stream biofilms.
• To explore the influence of hydrological and physico-chemical factors on biofilm dynamics.
• To identify key drivers of variation in stream biofilm communities.

Main Methods:

• Artificial substrates were incubated in five Danish lowland streams with varying conditions.
• Community composition and diversity of prokaryotes and eukaryotes were analyzed.
• Network analysis was employed to reveal trophic and non-trophic interactions.

Main Results:

• Specific phyla (Gammaproteobacteria, Bacteroidetes, Cercozoa) dominated both prokaryotic and eukaryotic communities.
• Prokaryotic and eukaryotic diversity exhibited synchronous temporal peaks in July and January.
• Hydrological and physico-chemical variables explained significant community variation, but a substantial portion remained unexplained.

Conclusions:

• Stream biofilm communities harbor a core set of dominant prokaryotic and eukaryotic taxa.
• Environmental factors significantly shape biofilm community structure, but biological interactions are also critical.
• A multitrophic level perspective, considering trophic and non-trophic interactions, is necessary for a comprehensive understanding of stream biofilms.