Australian scientists sequenced the DNA of samples of the giant seagrass, Posidonia oceanic, from 40 underwater meadows in an area spanning more than 2,000 miles, from Spain to Cyprus. It's big, it's old and it lives under the sea and now an international research collaboration with The University of Western Australia's Ocean's Institute has confirmed an ancient seagrass to hold the secrets of the oldest living organism on earth.
The analysis, published in the journal PLos ONE, found the seagrass was between 12,000 and 200,000 years old and was most likely to be at least 100,000 years old. This is far older than the current known oldest species, a Tasmanian plant that is believed to be 43,000 years old.
Prof Carlos Duarte, from the University of Western Australia, said the seagrass has been able to reach such old age because it can reproduce asexually and generate clones of itself. Organisms that can only reproduce sexually are inevitably lost at each generation, he added.
"They are continually producing new branches," he told The Daily Telegraph. "They spread very slowly and cover a very large area giving them more area to mine resources. They can then store nutrients within their very large branches during bad conditions for growth."
The researchers note that:
... estimates from field studies and models of the clonal growth of P. oceanica, we estimated these large clones to be hundreds to thousands of years old, suggesting the evolution of general purpose genotypes with large phenotypic plasticity in this species. These results, obtained combining genetics, demography and model-based calculations, question present knowledge and understanding of the spreading capacity and life span of plant clones.
The separate patches of seagrass in the Mediterranean span almost 10 miles and weigh more than 6,000 tons.
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