Cable bacteria extend the impacts of elevated dissolved oxygen into anoxic sediments

Area of Science:

• Environmental microbiology
• Geochemistry
• Biogeochemistry

Background:

• Anoxic sediments exhibit significant biogeochemical responses to dissolved oxygen (DO) fluctuations, despite limited oxygen permeability.
• A mechanism bridging oxic and anoxic sediment layers remains largely unrecognized.

Purpose of the Study:

• To investigate the physicochemical and microbial responses of contaminated river sediments to artificially elevated DO (eDO).
• To elucidate the role of cable bacteria in mediating sediment responses to eDO.

Main Methods:

• Incubation of urban river sediments with eDO for 9 weeks.
• Analysis of physicochemical parameters and microbial diversity.
• Phylogenetic ecological network analyses.

Main Results:

• Elevated DO (eDO) in overlying water significantly altered sediment parameters and microbial diversity within the top 6 cm.
• Accelerated degradation of polycyclic aromatic hydrocarbons (PAHs) was observed.
• Increased presence and activity of cable bacteria correlated with these changes, enhancing microbial syntrophy and interspecific interactions.

Conclusions:

• Cable bacteria mediate the impacts of eDO in anaerobic sediments by altering physiochemical properties and reinforcing community interactions.
• Cable bacteria play a crucial ecological role in sediment environments, facilitating pollutant degradation and nutrient cycling.