Unexpected marine life bloom creates rapid methane filter after South China Sea leak

In 2018 a drilling operation in the South China Sea unintentionally created a methane leak that produced a plume soaring more than a kilometre above the seafloor. The leak went unnoticed for a year, giving scientists a rare chance to observe natural remediation. Over the next six years, a team led by microbiologist Emil Ruff employed echo-sounders, underwater cameras, chemical sensors and DNA analysis to track changes.

By the end of the second year, anaerobic methanotrophic archaea and spionid and acrocirrid polychaete worms had established a dense, methane-eating “worm bed,” achieving degradation rates comparable to long-standing natural seeps. This rapid biofilter reduced the plume’s height from about 1,200 m to roughly 800 m. However, the swift colonisation came at the expense of the original benthic community, with microbial diversity dropping over 50 % near the source and more than 30 % at a 500-metre distance.