This Plant from a Single Seed Is Now 77 Sq Miles Wide & the World’s Largest

Some 4500 years ago, one seed from two different species of seagrass was lodged in a spot between today’s Shark Bay, off the coast of West Australia. 

Since it was relatively undisturbed by humans, scientists have now found that the seed has grown to be the biggest plant on the planet. It covers around 200 square miles or 20,000 rugby fields. 

It spreads on three times the size of Manhattan Island. 

Plant from a Single Seeds Is Now the Largest on the Planet

The species is Posidonia australis or a fiber-ball weed or ribbon weed. It commonly grows along the south coast of Australia. 

When scientists began searching for genetic variations in this weed throughout the bay, they were puzzled. 

The samples from locations 180 km apart from each other showed that there weren’t several specimens, but only one type of plant.

According to Dr. Martin Breed, an ecologist from Flinders University, they were stumped. 

Student researcher from the University of Western Australia, Jane Edgeloe, notes that around 18,000 genetic markers were tested while looking for variations that might have offered them the best specimens to use for restoration purposes.

Their discovery was different: they found that the same plant spread all around with rhizomes in the same manner that a lawn may spread from edges by sending runners. The 200 square kilometers of ribbon weed meadow seems to have grown from one seedling. 

A Pivotal Habitat for Numerous Marine Species 

The meadow is now a habitat for plenty of marine species like dolphins, dugongs, turtles, fish, and crabs. 

This plant’s rhizomes may grow up to 35 cm per year. Through this rate, the research authors estimate that the plant probably needed at least 4500 years to spread as much as it did.

A co-author of the research, Dr. Elizabeth Sinclair, notes that the original samples they took had 116 labels with GPS coordinates when they placed them in deep freeze for genetic sampling. 

The plant created large and dense meadows that in some places stretch as far as the eye can see in all directions. The plant’s ribbons are 10 cm long in some areas whereas they spread to a meter in other sections. 

Shark Bay conditions are tough and the plant found how to survive where there’s double salinity than in other areas in the bay. And, it can succeed in temperatures of the water as hot as 30 degrees C and as low as 15 degrees C.

The survival, according to Sinclair, may be a result of the chromosomes from the two parents and the genetic diversity. Rather than half genes from the mother and half from the dad, this seagrass has maintained it all. 

Although the plant doesn’t have sex, its long survival is still a puzzle for scientists. Namely, sexless plants usually have a lower genetic diversity which is needed when environmental change is in question. 

The Shark Bay ribbon weed is around 20,000 hectares and it’s larger than an Aspen tree in Utah which is often said to be the largest plant in the world.

Other seagrass species can live between 2000 and 100,000 years. Their pattern for growth is versatile and therefore, they have such an impressive lifespan. They grow towards nutritious areas to get their needed nutrients or grow away from stress.