Palma.—A team of scientists with the Spanish National Research Council (Consejo Superior de Investigaciones Científicas - CSIC) has found a 100'000-year-old clonal colony of ‘posidonia oceanica', an endangered seagrass, off the coast of Formentera.

The results of their findings, published in the latest edition of PLoS ONE magazine makes this species, commonly known as Neptune Grass or Mediterranean tapeweed, the longest-living in the biosphere.

Posidonia, a marine plant belonging to the Angiosperms family, displays “clonal” growth, based on the constant division of its meristematic tissue (where new cells are produced) and rhizomes, which connect to form new plants. This arrangement of the rhizomes eventually forms a mat; the surface contains the active parts of the plant, whereas the centre is a dense network of roots and decomposing stems.

Cloning
The study shows that clonal organisms, that make up over 50% of the primary production in the biosphere “have been systematically underestimated in publications” and urged greater investigation into the prolongation of life associated with cloning and its possible ecological and evolutionary implications.

Scientists have now discovered that rhizomes slowly take over the space around them until they stretch across areas measuring several kilometres, producing millions of plants from the same single clone and forming underwater meadows.

CSIC investigator Carlos Duarte explained that “the process is slow because the stems are a centimetre in diameter and the leaves can reach lengths of up to a metre. Furthermore, the Posidonia genome is very conservative and resistent to mutations”. “In areas with little in the way of nutrients, like the Mediterranean Sea, growth will be even slower, roots will be even longer and leaves will be longer and slimmer to increase efficiency”, he added.