Scientists discovered a massive clone specimen of seaweed a known as bladderwrack along the coast of Sweden, stretching some 310 miles.
Bladderwrack can propagate both sexually and asexually, and experts think this “super female” may be the largest clonal organism in the world.
The future of this sprawling life form is uncertain—its lack of genetic diversity could threaten its survival as the Baltic Sea warms due to climate change.
Life on Earth can (and does) take on an astonishing amount of different sizes and shapes. But few are quite as large as the clonal “super female” belonging to the genus Fucus. That’s because, according to a new study by scientists at the University of Gothenburg in Sweden, this incredible seaweed specimen stretches more than 300 miles along Sweden’s coast in the Baltic Sea. This likely makes this particularly impressive specimen of Fucus vesiculosus, also known as bladderwrack, the largest cloned organism in the world.
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Originally, scientists thought (via DNA sequencing) that this specimen was a different species of seaweed called narrow wrack, but closer examination showed that was instead a massive specimen of bladderwrack. Understanding these seaweed species is important, as they form dense kelp forests stretching down from the water’s surface to a depth of about 32 feet. This provides excellent habitats for a variety of species—including snails and crustaceans—and the health of these forests is a primary concern as the world warms due to climate change. Bladderwrack is also more tolerant of waters with low salinity, which is why it is so widespread throughout the Baltic.
“The Baltic Sea is entering a period of warmer and probably even fresher seawater,” Kerstin Johannesson, a co-lead author of the study on the giant bladderwrack published in the journal Molecular Ecology, said in a press statement. “In new conditions, all species must try to adapt in order to survive, including the important bladderwrack.”
While this specimen of F. vesiculosus formed asexually, bladderwrack typically propagates via sexual reproduction, as the females release gametes when the water is calm. Asexual reproduction of bladderwrack occurs mostly in the Baltic, likely spurred on by the water’s low salinity—though, some sexually-produced bladderwrack intermingle with this massive clone.
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“This clone comprises millions of individuals, and in some areas, it is completely dominant, while in other areas it grows alongside sexually propagated individuals of bladderwrack,” Ricardo Pereyra, a co-author of the study, said in a press statement. “We have found a few more large clones in the Baltic Sea, but the female clone off the Swedish Gulf of Bothnia is by far the largest clone—a real super female.”
Although this super female’s asexual survival mechanism has allowed it to propagate throughout the Baltic, it could also be the cause of its downfall. Compared to sexual reproduction, cloning limits genetic diversity, making the seaweed susceptible to climate impacts—it lacks the genetic diversity to adapt and survive, Johannesson explained.
For now, this seaweed super female is likely the largest known clonal organism in the world. And for the sake of the aquatic species that rely on it, long may it reign.
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Darren lives in Portland, has a cat, and writes/edits about sci-fi and how our world works. You can find his previous stuff at Gizmodo and Paste if you look hard enough.