Dead or Alive: Seagrasses Continue to Release Methane After Their Die-off

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 have now investigated what controls methane production and release from seagrass meadows.

Seagrasses cover shallow coastal regions of temperate and tropical seas worldwide. Seagrass meadows form the basis of an essential ecosystem that is home to numerous animals, including endangered species of sea turtles, seahorses, and fishes. They also protect the coasts from erosion and sequester millions of tons of carbon dioxide from the atmosphere every year. But seagrass meadows also emit greenhouse gases, especially methane, which has a much stronger effect on our climate than carbon dioxide.

Where Does the Methane Come From?

Sina Schorn and her colleagues from the Max Planck Institute for Marine Microbiology and Hydra Marine Sciences first investigated what the methane in the seagrass meadows is formed from. Seagrasses, like many terrestrial plants, form large peat deposits under the sediment surface. Terrestrial peats are known to release large amounts of methane from the decomposition of the organic material. Thus, the researchers expected that the mechanisms behind methane production are similar in seagrass meadows. However: The opposite was the case. "Here we experienced our first surprise," explains Schorn, the lead author of the study.

Read more at Max Planck Institute for Marine Microbiology

Photo Credit: Paul Asman and Jill Lenoble via Wikimedia Commons