Functional vertical connectivity of microbial communities in the ocean

Area of Science:

• Marine microbiology
• Oceanography
• Biogeochemistry

Background:

• Sinking particles are crucial for transporting microbes vertically in the ocean.
• Previous research confirmed phylogenetic connectivity, but functional connectivity remains understudied.

Purpose of the Study:

• To explore the functional vertical connectivity of microbial communities via sinking particles.
• To investigate protein and taxa profiles from surface to deep-sea environments.

Main Methods:

• Combined metaproteomic and 16S rRNA amplicon sequencing.
• Analysis of free-living and particle-attached microbial communities.
• Depth profiling from surface to 3000 m.

Main Results:

• Observed clear compositional and functional vertical connectivity throughout the water column.
• Identified key taxa including Oceanospirillales, Alteromonadales, and Rhodobacterales.
• Surface-derived microbes on particles showed increased expression of metabolism, organic matter processing, and stress response proteins in deep waters.

Conclusions:

• Sinking particles establish functional links between surface and deep-sea microbial communities.
• A significant portion of deep-sea microbes may originate from surface waters.
• These microbes play a substantial role in deep-sea biogeochemical cycles.