It grows at the bottom of the strait that separates the islands of Ibiza and Formentera. herb more comprehensive and long-lasting of the planet: a vast meadow ocean of posidonia (an underwater seaweed) actually forms a single specimen with a minimum estimated 100,000 years of age and an extension and length of about eight kilometers. In fact, it is “the largest living organism ever documented” worldwide, according to an international team of scientists in 2006. CSIC, University of the Balearic Islands and other experts from Portugal, the Caribbean and the United States.
However, recently another study has declared it “the world’s largest and oldest plant”. Another different species found in Australiabut curiously sharing many similarities ocean of posidonia From Ibiza and Formentera. Moreover: it is actually a plant of the same genus. Posidonia australis.
Researchers from the University of Western Australia (UWA) discovered a meadow of this marine plant in Shark Bay in the west of the country. will be approximately 10 kilometers long, spread over an area of 180 square kilometers, As published in the scientific journal Proceedings of the Royal Society.
The scientists were studying the genetic diversity of Shark Bay seagrass meadows when they realized that these seagrass beds were actually made up of a single plant, or a ‘clone’ of the same seed.
The study’s lead author, Jane Edgeloe of UWA, explained in a statement that her team created a ‘fingerprint’ using 18,000 genetic markers to control diversity in this grassland: “The answer left us speechless: There was only one factory in Shark Bay, spread over 180 square kilometers, This makes it the largest known plant in the world,” he added.
To calculate the age of the sample, the scientists counted the estimated total area of the meadow in the area and divided it by the annual expansion range of the rhizome (15 to 35 centimeters per year). Like this, at least 4,500 years of age were obtained.
But despite the statement made by the Australian team, the world’s oldest vial plant is still the one located under the seabed of the Pitiusas Islands. Between Ibiza and Formentera there is a gigantic specimen of similar proportions to that in Australia, but much taller. Its 100,000 years far exceeds the 4,500 years of Posidonia australis.
posidonia of Ibiza and Formentera, “longest on the planet”
But how is it possible that when the Australian was young, it had expanded to reach the same surface as Ibiza in a much shorter time?
Oceanographer and posidonia expert Carlos Duarte offers the answer. Duarte, familiar with research at the University of Western Australia (he was director of the ocean institute for the past decade), explains that this is because: “Australian angiosperm species grow much faster than those in the Mediterranean”.
In every situation, The meadow between Ibiza and Formentera “is still the longest-lived plant on the planet,” he explains.
“This is not a Guinness Book of Records competition, but the new study confirms that marine angiosperms are the largest living organisms on the planet, as well as playing a fundamental role as carbon sinks,” says Duarte, who now works at the University. Saudi Arabia.
Across the entire Mediterranean, this marine native plant has about 50,000 square kilometers, and five percent of that surface is found in the Balearic Islands, meaning 2,000 to 3,000 square kilometers of underwater meadows.
However ocean of posidonia There may be a number of days. According to the University of the Balearic Islands, the annual loss of this species in the Mediterranean exceeds 5% due, among other reasons, to the ‘tropicalization’ this sea has been subjected to.where water temperatures rise even more than air temperatures, facilitating the expansion of large numbers of invasive alien species and weakening native ones.
In addition, it should be taken into account that Posidonia grows very slowly, at less than two centimeters per year, and also has low seed production, which, according to scientists, makes any loss it suffers practically irreversible. It takes centuries to heal.
“Champion in separating CO2 from atmosphere”
Professor Carlos Duarte underlined the extraordinary role these underwater meadows play in capturing CO2 from the atmosphere, to the point where this scientist describes the plant in question as “carbon sequestration champions in our biosphere.” “One hectare of Posidonia meadows in the Mediterranean seizes as much carbon as 15 hectares of Amazonian forest. and also non-combustible”, with reference to the fires to which the tropical forest in question is exposed.
The uncontrolled mooring of yachts on this meadow in summer feeds a tourist pressure that is incompatible with its conservation, while the warming of the waters as well as pollutant discharges from submarine outlets and ships put this very important species at risk. very deteriorating situation.
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