It’s a hybrid of two sea grass species that kept all the chromosomes of both mother and father, so continued with genetic diversity, researchers say:
Scientists at the University of Western Australia (UWA) got a fascinating surprise when, while attempting to study genetic differences between plants in a massive undersea meadow, their samples revealed that the “meadow” was in fact just one very old — and very large — organism.
According to The Guardian, this single Posidonia australis plant, more commonly known as ribbon weed, spans an astonishing 77 square miles of undersea land off the coast of western Australia’s Shark Bay. For perspective, that’s three times the size of Manhattan. Move over, trees! There’s a new — well, ~4,500 year old — giant in town.
Maggie Harrison, “Scientists discover world’s largest organism, chilling out under ocean” at Futurism (June 1, 2022)
It grows by rhizomes rather than reproducing in a conventional way.
Here’s another seagrass meadow, to give some sense of the environment.
Then there’s The Blob at the ParisZoo …