The sprawling seaweed, a flowering marine plant known as Posidonia australis, stretches for more than 112 miles (180 kilometers) in Shark Bay, a wilderness area protected as a World Heritage site, said Elizabeth Sinclair, a senior researcher in the College of Biology. Institute of Science and Oceanography, University of Western Australia.
That’s about the distance between San Diego and Los Angeles.
The plant is so large that it reproduces itself, creating genetically identical branches. This process is a rare method of reproduction in the animal kingdom although it does occur in certain environmental conditions and occurs more often among some plants, fungi and bacteria.
“The answer definitely surprised us – just one! That’s it, just one plant has expanded over 180 kilometers into Shark Bay, making it the largest known plant on Earth,” she said by email.
Sinclair and her colleagues sampled 10 sites across the Shark Bay seagrass meadow range in 2012 and 2019. The research team also measured environmental conditions including depth, water temperature and salinity.
“We’ve been studying cold-water seaweeds in South Australia for a while, to understand how much genetic diversity they are and how closely related the meadows are,” Sinclair said.
Scientists managed to sequence the DNA of seaweed samples, which He revealed that it was a single plant.
“The plant was able to continue to grow through vegetative growth – extending its rhizomes (root stems) outward – the way a buffalo grass could be in your back garden, extending outwards. The only difference is that the seaweed roots lie under a sand bed. The sea so you don’t see it, just sprouts inside the water column.”
“The most interesting thing is that it has twice as many chromosomes as the other populations we were studying. It has 40 chromosomes, not the usual 20,” she added.
Seaweeds live in seacoasts and estuaries worldwide.
The study suggested that reproduction by cloning helped seagrass meadow adapt to habitat conditions Which were more extreme than where seaweed is usually found – more salty water, higher levels of light and large fluctuations in temperature.
“Seaweed clones may persist almost indefinitely if left undisturbed, because they depend on horizontal vegetative root expansion, rather than sexual reproduction,” Sinclair said.
