Ecological Assembly Processes Are Coordinated between Bacterial and Viral Communities in Fractured Shale Ecosystems

Area of Science:

• Microbial Ecology
• Viral Ecology
• Deep Subsurface Ecosystems

Background:

• Interactions between viral and microbial communities are crucial but poorly understood.
• Deep subsurface hydraulically fractured shale ecosystems offer a unique, closed environment to study community assembly.
• Hypersaline conditions in these environments are expected to drive microbial community homogeneity.

Purpose of the Study:

• To investigate viral and microbial community assembly processes in deep subsurface shale ecosystems.
• To determine the relationship between ecological drivers acting on viruses and their hosts.
• To understand the balance of ecological dynamics necessary for microbial community persistence.

Main Methods:

• Metagenomic analysis of time-resolved produced fluid samples from two wells.
• Tracking viral and host dynamics over time.
• Utilizing a combined null modeling approach to analyze community assembly processes.

Main Results:

• Microbial community assembly is influenced by viral predation, counterbalancing homogeneous selection from hypersalinity.
• Viral community assembly is partly driven by homogeneous selection, alongside undominated processes.
• A significant relationship exists between the assembly processes of viral and microbial communities, despite differing selective pressures.

Conclusions:

• Viral predation plays a critical role in shaping microbial community structure in these ecosystems.
• Coordinated ecological assembly processes between viruses and microbes are essential for long-term microbial community persistence.
• This study provides insights into metacommunity development across trophic levels in deep subsurface environments.