Seagrass meadows play an important role in the marine carbon cycle and our climate. On the one hand, they sequester carbon dioxide from the atmosphere and store it underground, on the other hand, they emit the potent greenhouse gas methane. Researchers at the Max Planck Institute for Marine Microbiology in Bremen, Germany, have now investigated what controls methane production and release from seagrass meadows. They now present their results in the journal Proceedings of the National Academy of Sciences (PNAS).