According to scientists, the largest living plant in the world has been identified in the shallow waters off the coast of Western Australia. Here is an underwater picture of seaweed in Shark Bay, Western Australia. (Rachel Austin)
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SHARK BAY, Australia – The world’s largest living plant has been identified in the shallow waters off the coast of Western Australia, scientists say.
Extensive seagrass, a flowering sea plant known as Posidonia australis, stretches for more than 112 miles in Shark Bay, a World Heritage-protected wilderness area, said Elizabeth Sinclair, principal investigator at the Institute. of Biological Sciences and Oceans. at the University of Western Australia.
This is the distance between San Diego and Los Angeles.
The plant is so large that it clones itself, creating genetically identical shoots. This process is an uncommon way of reproducing in the animal kingdom although it occurs under certain environmental conditions and occurs more frequently among some plants, fungi and bacteria.
“We are often asked how many different plants grow in a meadow of seagrass. Here we have used genetic tools to answer that,” said Sinclair, author of a study on seaweed published Tuesday afternoon in Proceedings of the Royal Society B.
“The answer definitely surprised us: just ONE! That’s all, only one plant has expanded more than 180 km in Shark Bay, making it the largest known plant on Earth,” he said in an email.
Sinclair and colleagues sampled 10 seagrass meadows in Shark Bay in 2012 and 2019. The research team also measured environmental conditions, including depth, temperature. of water and salinity.
“We’ve been studying cold-water seagrass in South Australia for a long time, to understand how much genetic diversity there is and how connected the meadows are,” Sinclair said.
Scientists were able to sequence the DNA from the seagrass samples, which revealed that it was a single plant.
“The plant has been able to continue to grow through vegetative growth, extending its rhizomes (stems) outwards, as a buffalo grass would do in your back garden, extending the runners outwards. L ‘The only difference is that the rhizomes of the seaweed are under a sandy seabed, so you don’t see them, just the shoots inside the water column, “he said.
What was even more interesting is that it has twice as many chromosomes as in other populations we had been studying. He has 40, not the usual 20.
–Elizabeth Sinclair, School of Biological Sciences and Institute of the Oceans
“What was even more interesting is that it has twice as many chromosomes as in other populations we’ve been studying. It has 40, not the usual 20,” he added.
Seaweeds inhabit the coasts and estuaries of the sea all over the world.
The study suggested that reproduction by cloning helped the seagrass meadow to adapt to habitat conditions that were more extreme than where the seagrass is usually found: saltier water, higher light levels and wide temperature fluctuations.
The seagrass meadow covered nearly 77 square miles or 49,000 acres, Sinclair said, larger than Brooklyn. This is a much larger area than the Pando Aspen tremors in Utah, which are often described as the largest plant in the world. The clone extends over 106 acres, consisting of more than 40,000 individual trees, according to the USDA Forest Service.
At about 4,500 years old, Shark Bay seagrass is ancient, but its age is not breaking records, the researchers said. A Posidonia oceanica plant discovered in the western Mediterranean spanning up to 9.3 miles may be over 100,000 years old.
“Individual seagrass clones can persist almost indefinitely if they are not disturbed, as they depend on the vegetative and horizontal expansion of the rhizome, rather than sexual reproduction,” Sinclair said.
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