Enormous Underwater Organism Discovered in the Baltic Sea

A remarkable underwater ecosystem has been identified in the Baltic Sea, consisting of a massive expanse of marine plants that stretches for hundreds of kilometers. Researchers from the University of Gothenburg in Sweden have uncovered what may be the world's largest clonal organism.

The study commenced with DNA sampling of the native bladder wrack, initially aimed at understanding the species' adaptation to climate change and the resulting increase in sea temperatures. However, findings revealed that this bushy seaweed, previously classified as a distinct species, is actually a clone.

Bladder wrack is the predominant type of algae in the Baltic Sea, thriving in its low-salinity environment. This unique organism reproduces through a method that is different from typical sexual reproduction. While bladder wrack has both male and female plants that can create new individuals through fertilization, the colossal organism developed through an alternative process. The clonal structure originated by dispersing fragments of a single original female plant via ocean currents, leading to the growth of new seaweed individuals.

Extending over 500 kilometers along the coast of the Bothnian Sea, which lies between Sweden and Finland, this extraordinary organism stretches from Öregrund to the southern region of Umeå. Researchers have proposed that this may represent the largest clonal organism on the planet, likening it to a "super female."

As the dominant algae species in the Baltic Sea, bladder wrack forms dense forests that provide crucial habitat for various marine life, including fish larvae, snails, and crustaceans, while larger fish find refuge within these kelp forests. This mega-clonal structure serves as a vital ecosystem. However, the future of this organism is under threat.

The reliance on clonal reproduction limits genetic diversity, which is essential for adaptation to changing environmental conditions. Experts warn that without consistent sexual reproduction, the organism's genetic pool may stagnate, jeopardizing its survival.

Climate change poses a significant risk to this expansive organism. Projections suggest that by the end of the century, the Baltic Sea could warm by as much as six degrees Celsius. Such changes could critically endanger the bladder wrack populations, particularly in the northern and eastern regions of the sea, leading to potential catastrophic consequences for the local ecosystem.

Researchers emphasize that the absence of genetic variation within the clonal population severely diminishes its resilience against environmental shifts. If climate change continues to escalate, the survival of this extensive clonal organism and the habitats it supports could be gravely compromised.