4,500-Year-Old Seagrass Is World's Largest Plant That Can Clone Itself to Reproduce, Researchers Claim

Researchers from Flinders University and The University of Western Australia discovered that the ancient seagrass in the UNESCO World Heritage Site of Shark Bay could be the largest plant in the world, stretching across 180 kilometers (112 miles).

The 4,500-year-old seagrass is called Poseidon's ribbon weed or Posidonia australis. Study co-author Elizabeth Sinclair told Alice Klein of New Scientist that it is the largest known example of a clone in any environment on Earth.

(Photo : Unsplash/Benjamin L. Jones)
4,500-Year-Old Seagrass is World's Largest Plant That Can Clone Itself, Researchers Claim

World's Largest Plant Can Clone Itself

The researchers took some samples of the seagrass shoots from across Shark Bay and studied 18,000 genetic markers to test how many different plants grow in the UNESCO World Heritage Site. But they were shocked to see that the plant generated a single "fingerprint."

The authors wrote in The Conversation that one single parent had expanded over 180 kilometers, which is a result they were not expecting. They believe that after the area had been flooded about 8,500 years ago, the seagrass grew into the newly submerged areas.

Aside from their unusual gigantic size, the team also found that it has a unique genetic make-up. While most seagrasses inherit half of each parent's genes, Poseidon's ribbon has the condition called polyploidy, in which it carries the entire genome of a parent. Moreover, the seagrass also appears to be a hybrid of two species, indicating they are a clone of older organisms like a turtlegrass from 6,000 years ago.

Sinclair said in a statement that polyploid plants are often seen in habitats with extreme environmental conditions and are often sterile but can still grow when left alone, which is just the characteristic of the seagrass in Shark Bay. The ancient seagrass appears resilient after experiencing a wide range of temperatures and being subjected to a lot of environmental stress, like the heatwave in 2010 and 2011.

Researchers added that they were amazed at the findings that the seagrass does not seem to reproduce sexually. In places such as this, it could only mean that species that successfully reproduce, do so through cloning themselves rapidly and repeatedly to better adapt than those species that reproduce sexually.

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The Important Role of Seagrass in the Ecosystem

According to the Smithsonian Ocean, seagrasses are often dubbed - the foundation of plant species or ecosystem engineers because of their ability to modify their surroundings to create unique habitats for many species.

Aside from making coastal habitats suitable for themselves, seagrasses have other important roles in the ecosystem that provide ecological functions and a variety of services for humans.

They have been around for at least 10,000 years and humans have used them as fertilizers, insulation for houses, to weave furniture, thatch rooks, make bandages, and sometimes to fill mattresses or car seats. However, their role in the ocean as providers of native habitat perhaps is the biggest benefit for humans and the ocean.

Biologist Marlene Jahnke from the University of Gothenburg said that seagrasses help purify water and are one of the biggest carbon sinks and host many species that are important to protect. One hectare of seagrass could be worth over $19,000 per year, which makes them the most valuable ecosystem on the planet.