World's oldest living organism - a nine-mile-wide seagrass meadow dating back hundreds of thousands of years



When it comes to living to a ripe old age – nothing on Earth comes close to seagrass, with some meadows in the Mediterranean reaching hundreds of thousands of years old.

A team of scientists from the University of Algarve in Portugal believe that one nine-mile-wide stretch of Posidonia Oceanica could be 200,000 years old, which would mean it began its life when humans first emerged in the late Pleistocene era.

This particular patch of seagrass lies off the Spanish island of Formentera, with the researchers calculating its age with the help of DNA testing.

Posidonia oceanica: This seagrass can live for hundreds of thousands of years, say scientists

Seagrasses fan out by creating genetically identical clones of themselves.

Co-author Sophie Arnaud-Haond from the French Research Institute for the exploration of the Sea, told the BBC: ‘They can reproduce sexually through flowering and recombination of male and female genomes, or clonally through the exact replication of the genome of an individual forming a new plant module through clonal growth.’

The ancient seagrass was found near the island of Formentera

The meadows of P oceanica have grown so old and vast because, as the team write in journal PLoS One, they lack any native competitors or predators.

Its longevity also comes from its ability to adapt – when it began life the sea temperature would have been 10 to 15C lower than it is today.