Land-use type temporarily affects active pond community structure but not gene expression patterns

Area of Science:

• Ecology
• Environmental Microbiology
• Freshwater Science

Background:

• Intensive agriculture and land-use changes threaten biodiversity and ecosystem functions in small water bodies.
• Kettle holes (KH) are representative of numerous small, glacial-origin standing water bodies globally.
• Long-term agricultural practices may lead to biodiversity homogenization in these ecosystems.

Purpose of the Study:

• To investigate the impact of land-use type on active microbial communities (bacteria, archaea, eukaryotes) in kettle holes.
• To compare responses of community structure and gene expression to land-use variations.
• To understand the drivers of functional changes in kettle hole microbial communities.

Main Methods:

• Landscape-scale metatranscriptomics was employed on 67 kettle holes in a German agricultural landscape.
• Sampling was conducted during spring crop fertilization and one month later.
• Community structure and gene expression patterns were analyzed in relation to land-use type and time.

Main Results:

• Land-use type significantly affected active microbial community structure during spring fertilization, particularly for eukaryotes, but this effect diminished later.
• No significant differences in gene expression patterns were observed across land-use types or between sampling times, indicating functional redundancy.
• Variability in gene expression was strongly correlated with active bacterial and eukaryotic community structures.

Conclusions:

• Surrounding landscape influences cause temporary shifts in microbial community activity within kettle holes.
• Even homogenized communities in kettle holes remain responsive to land management practices.
• These findings are crucial for developing sustainable management and restoration strategies for agricultural freshwater ecosystems.