Rapid ecosystem collapse and biofilter formation following seabed methane leakage

Area of Science:

• Marine biology
• Geochemistry
• Microbial ecology

Background:

• Subseafloor gas hydrates store vast methane globally.
• Perturbations can destabilize hydrates, leading to methane release.
• Deep-sea ecosystem responses to methane release are poorly understood.

Purpose of the Study:

• To monitor the in situ response of a seabed ecosystem to methane leakage from hydrate exploration.
• To understand the ecological and biogeochemical shifts following methane release.

Main Methods:

• Multi-year in situ monitoring of seabed ecosystems.
• Geochemical and omics analyses (metagenomics, metatranscriptomics).
• Benthic microbial and macrofaunal abundance and diversity assessments.

Main Results:

• Significant decline in benthic microbial and eukaryotic diversity within two years.
• Increase in microbial and macrofaunal abundance.
• Rapid ecosystem shift to a chemosynthetic system with co-existing aerobic and anaerobic methanotrophs.
• Recruitment of opportunistic polychaetes enhanced bioirrigation.
• High methane oxidation rates sustained by diverse electron acceptors.

Conclusions:

• Methane hydrate destabilization causes rapid native ecosystem collapse.
• An effective methane biofilter forms, consuming methane faster than previously estimated.
• Understanding these feedbacks is critical for predicting methane cycling and resource management.