Contrasting diversity patterns between microeukaryotic and prokaryotic communities in cold-seep sediments

Area of Science:

• Marine microbial ecology
• Deep-sea ecosystems
• Biodiversity research

Background:

• Cold seeps are recognized as biodiversity hotspots, yet microbial diversity, especially microeukaryotes, is poorly quantified.
• Understanding the active microbial communities within cold seeps is crucial for comprehending ecosystem dynamics.

Purpose of the Study:

• To investigate the diversity and activity of prokaryotes and microeukaryotes in Haima cold seep sediments.
• To compare DNA (total community) and RNA (active community) signatures to differentiate between dormant and active taxa.
• To identify key active microbial groups influencing cold seep ecosystems.

Main Methods:

• Analysis of both DNA and RNA extracted from Haima cold seep sediments in the northern South China Sea.
• Comparative analysis of prokaryotic and microeukaryotic community composition and diversity.
• Assessment of the differences between whole community (DNA) and active community (RNA) to infer microbial activity.

Main Results:

• Prokaryotic diversity was lower in seep sediments compared to non-seep areas, suggesting homogeneous selection.
• Microeukaryotic diversity was higher in seep sediments, indicating less environmental selection and higher richness.
• A larger DNA-RNA compositional difference was observed in microeukaryotes, highlighting a significant number of inactive taxa.
• Active microeukaryotes, including Breviatea, Labyrinthulomycetes, and Apicomplexa, were sensitive to environmental factors and play vital roles.

Conclusions:

• Prokaryotic and microeukaryotic communities exhibit distinct diversity patterns and regulatory mechanisms in cold seeps.
• Active microeukaryotes are more responsive to environmental factors and are crucial for cold seep ecosystem functions.
• This study enhances understanding of microbial ecology in deep-sea extreme environments.