Metaexoproteomics Reveals Microbial Behavior in the Ocean's Interior

Area of Science:

• Marine microbiology
• Metaproteomics
• Biogeochemistry

Background:

• The extracellular proteins (exoproteome) are vital for microbial life but poorly understood in marine settings.
• Understanding microbial exoproteomes is key to deciphering marine ecosystem functions.

Purpose of the Study:

• To characterize marine microbial exoprotein profiles across a water column in the South China Sea.
• To investigate depth-related variations in microbial community composition and ecological functions.

Main Methods:

• Utilized a metaproteomic approach to analyze exoproteins (10 kDa-0.2 μm).
• Examined samples from various depths within the South China Sea water column.

Main Results:

• Viruses, Alpha-, and Gammaproteobacteria were dominant exoprotein contributors.
• Microbial communities and their exoprotein functions showed significant vertical zonation.
• Transporters, proteolysis, ammonia oxidation, C1 metabolism, and sulfur DOM degradation were key vertically distributed processes.

Conclusions:

• Marine microbial exoproteomes exhibit distinct depth-dependent patterns.
• These findings provide insights into nutrient cycling, niche partitioning, and DOM remineralization by marine microbes.