By measuring the number of genetic mutations over time in underwater meadows that reproduce themselves endlessly, a team of researchers from the Universities of London, Davis (California), Kiel and Oldenburg (Germany) were able to determine the age of the ancestor of these plants with unprecedented precision.
“It’s the first reliable estimate of a clone’s age,” Thorsten Ruesch, the researcher who led the study published in June in the scientific journal Nature Ecology & Evolution, told AFP.
Using the “genetic clock” method, the researchers studied 20 eelgrass populations around the world before discovering, in the Finnish coastal waters of the Baltic Sea, the oldest known seagrass bed, at more than 1,403 years old.
Determining the age of plants provides data on the functioning of ecosystems and aging processes in the natural world, according to the researcher.
“It is interesting to understand how plants avoid the symptoms of aging over thousands of years,” said Roesch, a marine ecologist and evolutionary biologist at the GEOMAR Center at the University of Kiel in Germany, adding that this could provide insight into “how to manage aging in humans.”
He expected that this new method would in the future make it possible to discover the oldest aquatic plants, those that are “one hundred thousand years old or more.”
Eelweed populations reproduce through flowers, seeds, and roots in sediments, providing important marine habitats for other organisms and storing carbon dioxide in their stems and roots.
“It is the most important ecosystem in the Baltic Sea,” Roysch explained.
Despite its ability to survive, the eelgrass is an endangered species in the Baltic Sea, whose shallow, brackish waters surround Germany, Poland, Finland, Sweden, the Baltic states and Russia.
Nutrient pollution from sectors such as agriculture, combined with rising sea temperatures due to climate change, poses a major threat to eelgrass.
“60 percent of the eelgrass has become extinct over the last 100 years in the western Baltic Sea,” Ruesch noted.
