...found the seagrass was between 12,000 and 200,000 years old and was most likely to be at least 100,000 years old. (http://www.telegraph.co.uk)
The original article has wording that's more precise (http://www.plosone.org/article/info:doi/10.1371/journal.pone.0030454):
...The scenario of a km-range spread achieved exclusively through clonal growth requires that the clones reach a minimum age of about 12,500 years. Applying the same estimates to the genets shared between the two pairs of meadows, located 7 km apart between Formentera and Ibiza and 15 km apart around a cape in Formentera (Fig. 3), yields a minimum age estimate between 80,000 and 200,000 years, projecting the origin of the clones well into the late Pleistocene.
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