Scientists at the University of Gothenburg have made a groundbreaking discovery in the Baltic Sea, identifying a giant clone of the bladderwrack seaweed (Fucus vesiculosus) that stretches for more than 500 km along the coast. This might be the largest known clone organism on Earth. 

Overview photo 

Bladderwrack in the Baltic Sea 

Bladderwrack is the dominant seaweed species in the brackish waters of the Baltic Sea, one of the few that tolerate low salinity. It forms extensive underwater forests, reaching depths of up to 10 meters, providing habitat for fish, fry, snails and crustaceans. The presence of this seaweed is crucial to the Baltic ecosystem. 

Through DNA analysis, scientists have discovered that a small, bushy form of the seaweed, previously thought to be a separate species, is actually a clone of the bladderwrack seaweed. This clone has spread for more than 500 kilometers along the coast, from Öregrund to near Umeå, through fragmentation of the original female plant and its transport by ocean currents. This makes it potentially the largest clone of any organism in the world. 

Threats of low genetic variability 

The clone consists of millions of individuals, but the lack of genetic variability could pose a threat in the face of environmental changes such as warming and declining salinity in the Baltic Sea. Low genetic diversity limits the population’s ability to adapt, which could affect the species’ survival under changing conditions. 

“The Baltic Sea is entering a period of warmer and probably less saline water. Under the new conditions, all species must try to adapt in order to survive. This also applies to the important bladderwrack,” says Prof. Kerstin Johannesson, co-author of the publication in Molecular Ecology. 

In 2022, Australian scientists discovered a marine plant stretching 180 kilometers in Shark Bay, believed to be the largest known specimen of this kind before the discovery in the Baltic Sea. However, the clone of the bladderwrack seaweed, stretching more than 500 km, surpasses that find in size. 

New seaweed species off the coast of Estonia 

Researchers have also discovered a new species of seaweed off the coast of Estonia. This species, although morphologically similar to the bladderwrack seaweed, has both male and female specimens, and reproduces only sexually, which distinguishes it from its cloning counterpart from the Gulf of Bothnia. 

The discovery of the giant clone of the bladderwrack seaweed underscores the importance of research on genetic diversity and species adaptation in the face of climate change. Understanding the mechanisms of reproduction and adaptation of these seaweeds is crucial to protecting the Baltic Sea ecosystem. 

 Sources:  nauka.wiara.pl, dzienniknaukowy.pl, naukawposlce.pl