by Alessandra Ressa
A surprising and significant scientific breakthrough has emerged from the underground waters of the Timavo River, thanks to a unique collaboration between the University of Trieste, the Adriatic Speleological Society (SAS), and the Trieste Museum of Natural History. Researchers have identified the DNA of Craspedacusta sowerbii, a freshwater jellyfish of Asian origin, within samples taken from the Luftloch cave — a recently discovered subterranean site by the SAS.
This tiny jellyfish, part of the Olindiidae family and native to China’s Yangtze River, is almost entirely translucent with a whitish hue. While equipped with around 400 tentacles, it poses no threat to humans.
The discovery stems from a project led by Dr. Chiara Manfrin, focusing on biodiversity monitoring in subterranean ecosystems using environmental DNA (eDNA) — a cutting-edge technique that detects traces of genetic material organisms leave behind in their environment. “By filtering the water,” explains Dr. Manfrin, “we can pick up fragments of DNA shed by living organisms, allowing us to identify even those species that are nearly impossible to spot directly.”
The DNA evidence points unmistakably to the presence of Craspedacusta sowerbii, an alien, non-native species that, while harmless to humans, is currently being studied for its impact on the fragile karst ecosystems. This finding supports previous observations made in 2016 that reported the species in the Slovenian section of the Reka-Timavo system — an account later validated in a scientific note from the Trieste Museum by Nicola Bressi and Andrea Colla.
The genetic confirmation was announced over the weekend at the SPELEO25 conference in Gorizia, organized by the Regional Speleological Federation and the Central Directorate for Environment, Energy, and Sustainable Development of the Friuli Venezia Giulia Region.
Marco Restaino, president of the Adriatic Speleological Society — which completed the full exploration of the Luftloch cave just over a year ago — praised Dr. Manfrin for her discovery. Alongside fellow explorer Raffaele Bruschi, Restaino had been the first to collect water samples from nearly 300 meters underground in the Timavo’s hidden flow, at the bottom of the Luftloch cave.
Massimo Zanetti, Director of the Regional Geological Service, highlighted the institutional importance of supporting speleological research: “Discoveries like this are only possible thanks to the ongoing support the Region offers to caving organizations. Friuli Venezia Giulia pays special attention to subterranean exploration and monitoring, which are vital for understanding and protecting our hidden water resources — a truly strategic asset for our territory.”
He went on to add, “Speleology opens new frontiers for environmental science and resource management. Data collected in such extreme environments enrich our knowledge and strengthen our ability to plan and protect against future challenges.”
This discovery not only sheds new light on the spread of alien species in the Karst’s delicate ecosystems, but also underscores the critical role that speleology and scientific research play in preserving underground biodiversity and managing the natural resources hidden beneath our feet.
