A recent publication demonstrates that Mediterranean seagrass meadows contain genetically identical clones that have been found up to 15km apart. The findings suggest that these clones must be thousands, or even tens of thousands, of years old.
Posidonia oceanica is a seagrass that reproduces asexually, which in essence produces a colony of clones, these clones are shown by the research to be large and very old.
The researchers, led by Sophie Arnaud-Haond of the French Research Institute for Exploration of the Sea (IFREMER) and The University of the Algarve in Portugal and Carlos M. Duarte from the CSIC-IMEDEA in Spain, investigated seagrass meadows across 3500km (2175 miles) of the Mediterranean as part of their investigation. They found that not all the seagrass was genetically identical, but those that were genetically identical suggested both extreme size and age.
Seagrasses are the basis of essential coastal ecosystems but are waning worldwide, and P. oceanica meadows are declining at an estimated rate of about 5% per year. The research published via the open-access Journal PLoS ONE suggests that clones of that species have adapted to a broad range of environmental conditions, but the unprecedented rate of global climate change, together with the steep decline in seagrasses already observed for the past 20 years, are raising serious concerns about the continued survival of this long-lived species.
For further information, see the paper: Arnaud-Haond S, Duarte CM, Diaz-Almela E, Marbà N, Sintes T, et al. (2012) Implications of Extreme Life Span in Clonal Organisms: Millenary Clones in Meadows of the Threatened Seagrass Posidonia oceanica. PLoS ONE 7(2): e30454. doi:10.1371/journal.pone.0030454
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