# Variations in deep-sea microbial composition and assembly mechanisms under different culture strategies

## TL;DR

This study explores how different cultivation methods affect deep-sea microbial communities, showing that high-pressure conditions better preserve their diversity and interactions.

## Contribution

The study reveals that high-pressure oligotrophic cultivation preserves deep-sea microbial diversity and community structure more effectively than atmospheric methods.

## Key findings

- High-pressure cultivation captured 44–55% of microbial diversity, significantly more than atmospheric cultivation.
- High-pressure conditions preserved complex microbial networks with cooperative interactions, resembling in situ communities.
- Deterministic assembly processes were stronger under high-pressure conditions, though stochastic processes still dominated.

## Abstract

Deep-sea sediments harbor diverse microbial resources with immense biotechnological potential. Cultivating of these microorganisms is essential for studying their physicochemical properties, ecological functions, and resource development but remains a significant challenge. This study investigated the effects of different cultivation conditions on microbial diversity, community composition, coexistence patterns, and assembly processes from Yap Trench sediments (4,159–6,682 m depth). Results indicated that 44–55% of the microbial diversity was captured from the original sediments under high-pressure cultivation conditions, significantly higher than the 6–18% obtained under atmospheric pressure. Communities cultivated under high-pressure oligotrophic conditions closely resembled in situ microbiota, forming complex co-occurrence networks with high modularity and predominantly positive interactions, indicative of cooperative relationships enhancing community stability. However, serial subculturing and atmospheric cultivation favored pressure-tolerant groups like Proteobacteria. The deterministic processes (particularly heterogeneous selection) of community assembly were enhanced under high-pressure conditions, despite stochastic processes remaining the dominant mechanism. These findings highlight the adaptive responses of deep-sea microbial communities to extreme environmental pressures and underscore the importance of simulating high-pressure oligotrophic conditions for enriching diverse microbial groups. This study advances our understanding of deep-sea microbiology and provides a framework for exploring microbial functions and resources in extreme environments.