Sediment microbial assemblage structure is modified by marine polychaete gut passage.

Area of Science:

• Marine ecology
• Microbial ecology
• Biogeochemistry

Background:

• Invertebrate bioturbation influences sediment microbial structure.
• Limited research exists on the impact of sediment ingestion and gut passage by deposit feeders.

Purpose of the Study:

• To investigate the effect of gut passage through Hediste diversicolor on bacterial and archaeal assemblages.
• To assess the impact on nitrogen cycling taxa abundance.

Main Methods:

• High-throughput sequencing
• Quantitative PCR (qPCR)
• Analysis of microbial communities in sediment, polychaete gut, and burrow walls.

Main Results:

• H. diversicolor's digestive tract harbors unique, transient microbial communities that shift towards sediment-like assemblages during gut passage.
• Distinct microbial taxa were enriched in the hindgut and burrow walls, suggesting influence on local sediment communities.
• Unique ammonia-oxidizing archaeal taxa were identified in the hindgut.
• External polychaete surfaces hosted distinct microbial assemblages, indicating a role in microbial transport.

Conclusions:

• Sediment ingestion and gut passage by deposit feeders play a crucial role in regulating sediment microbial communities.
• Marine invertebrates act as vectors for microbial transport, influencing biogeochemical processes.
• The hindgut serves as a reservoir for specific microbial taxa, impacting local sediment composition.