Polycyclic aromatic hydrocarbons in deep sea sediments: Microbe-pollutant interactions in a remote environment

Area of Science:

• Marine microbiology
• Environmental science
• Biogeochemistry

Background:

• Recalcitrant polycyclic aromatic hydrocarbons (PAHs) accumulate in deep sea sediments (DSSs).
• Current models oversimplify PAH fate in DSSs, assuming surface-like biodegradation.
• DSS conditions (high pressure, low temperature) significantly inhibit biodegradation.

Purpose of the Study:

• To review recent research on hydrocarbonoclastic bacteria in DSSs.
• To explore mechanisms of PAH degradation in deep sea environments.
• To discuss the impact of future climate scenarios (high CO2, UV) on PAH biodegradation.

Main Methods:

• Literature review of existing studies on DSS microbial communities.
• Analysis of genetic and metabolic adaptations of bacteria to psychro-peizophilic conditions.
• Discussion of theoretical challenges and future research directions.

Main Results:

• Deep sea sediment bacteria, primarily α- and γ-Proteobacteria, possess unique genes and pathways for PAH degradation.
• These bacteria exhibit adaptations to extreme DSS conditions.
• Existing biodegradation models for PAHs in DSSs are inadequate.

Conclusions:

• Bacterial communities in DSSs are adapted to degrade PAHs under extreme conditions.
• Future climate change may significantly impact PAH biodegradation in DSSs.
• Further research is needed to understand PAH fate in DSSs under changing environmental conditions.