While we admire the crystal-clear sea and picturesque coasts of the Adriatic, beneath the seemingly serene surface, dramas are unfolding that threaten the very foundations of this precious ecosystem. Pollution, unprecedented heatwaves, the silent invasion of foreign species, and increasingly frequent extreme weather events have become our reality. At the epicenter of the fight to preserve the health of the Adriatic are the scientists of the Ruđer Bošković Institute (RBI), whose dedicated work in laboratories and in the field is writing the future of our sea. Their research, stretching from Zagreb, through Šibenik to Rovinj, represents the first line of defense against threats that often remain invisible to the naked eye.

When the sea "rings": The threat of invisible tsunamis

Earthquakes are not the only cause of devastating waves. A little-known but extremely dangerous phenomenon are meteorological tsunamis, a phenomenon investigated by a team of scientists gathered around the GLOMETS project, led by Dr. Ivica Vilibić from the Division for Marine and Environmental Research (DMER) in Zagreb. These waves are not caused by ground shaking, but by sudden and extreme changes in the atmosphere – abrupt changes in air pressure and strong winds. We saw a global example of the power of such events in 2022, when the eruption of the Hunga Tonga-Hunga Ha'apai volcano on the other side of the world caused the sea to literally "ring" across the planet, including in the Adriatic. By analyzing this data, scientists are now developing advanced models that could predict and warn of such dangers, which are crucial for the safety of densely populated coastal areas. "These phenomena come from the air, and without an early warning system, their destructive power can be surprising and devastating," points out Dr. Vilibić, whose work directly contributes to protecting lives and property along the Adriatic coast.

Can the Adriatic breathe for the planet? An experiment that changes the rules of the game

In the peaceful bay of Martinska, not far from the beautiful Šibenik, where you can also find excellent accommodation, an experiment is taking place that could have global significance. As part of the international OAEPIIP project, scientists led by Dr. Jelena Godrijan are testing one of the most innovative methods of combating climate change – increasing sea alkalinity. In specially designed tanks filled with Adriatic water, the accelerated natural process of rock dissolution is simulated by adding alkaline substances. The goal is to increase the sea's capacity to absorb carbon dioxide (CO₂) from the atmosphere, thereby mitigating the greenhouse effect. However, the key to success lies in a delicate balance. "We want to be sure that this intervention will not harm marine life. Our primary task is to check how phytoplankton, the foundation of the marine food web, reacts to the changes," explains Dr. Godrijan. Every sample is carefully analyzed, and the results from Croatia are compared with data from 18 other locations around the world, making our country a key part of the first global network for testing this revolutionary climate technology.

The return of the lost forests: Rovinj scientists on a mission to restore the seabed

Once, dense "forests" of brown algae from the order Fucales were one of the most recognizable symbols of a healthy and productive Adriatic. These algae, a kind of lungs and shelters of the seabed, provided home and food for numerous marine organisms. However, decades of pollution, uncontrolled coastal urbanization, and rising sea temperatures have almost wiped them out from our areas. Scientists from the Center for Marine Research (CMR) in Rovinj, gathered in the REFINE project, are determined to reverse this negative trend. Their work includes detailed mapping of the remaining populations, studying their genetics and reproductive capabilities, and developing innovative restoration methods. Particularly significant is the effort to return the algae not only to their natural habitats but also to concreted parts of the coast, literally bringing life back to where human impact had almost destroyed it. This initiative not only restores biodiversity but also shows a path towards the coexistence of urban development and a healthy marine environment. The beautiful coast in the vicinity of Rovinj hides this silent, but crucial battle for life beneath its surface.

The silent invasion: The fight against unwanted inhabitants of the Adriatic

While some species are trying to return, others, unfortunately, arrive uninvited. Invasive species, such as the aggressive blue crab, the poisonous silver-cheeked toadfish, or tropical algae that suffocate native species, pose an increasing threat to the ecological balance of the Adriatic. They arrive in the ballast water of ships, as well as through other human activities, and in the new environment, without natural enemies, they spread at great speed. Through the ALIENA project, Croatian scientists, in collaboration with colleagues from Italy, are developing a joint system for monitoring, control, and early warning. "The sea knows no borders, and the same goes for invasive species. Only through joint, cross-border efforts can we effectively respond to this challenge," say the researchers. Educating the public and fishermen is a key part of the project, as rapid recognition and reporting of new species can prevent their spread and catastrophic consequences for the domestic ecosystem.

The future of oceanography: An autonomous explorer will sail the Adriatic

Monitoring the state of the sea with traditional methods, which involve expensive ships and numerous researchers, is demanding and limited. But the future brings a revolution. The BRIGANTINE project, coordinated by Dr. Mirta Smodlaka Tanković, head of the Center for Marine Research in Rovinj, is developing a smart, uncrewed vessel. This autonomous "mini oceanographer," equipped with state-of-the-art sensors, cameras, and smart algorithms, will be able to navigate the Adriatic independently, collecting key data in real time – from temperature and salinity to the presence and blooming of algae. "Imagine a tireless researcher sailing 24 hours a day, without the need for fuel or a human crew, sending us a continuous stream of information. This is the future of sea monitoring that allows us to react faster and more efficiently to all changes," says Dr. Smodlaka Tanković. This technology will place Croatia at the forefront of modern oceanographic research.

Invisible heroes: Microalgae as cleaners and energy factories

In the world of microscopic organisms lie solutions to some of the biggest environmental problems. This is precisely what the A3PhyCoTox project, led by Dr. Maria Blažina, proves. Her team is investigating the incredible ability of microalgae not only to survive in toxic industrial wastewater but also to actively purify it. These tiny algae feed on pollutants, simultaneously absorbing CO₂ from the atmosphere and producing biomass that can be converted into biofuel or other useful compounds. Through sophisticated laboratory tests and computer simulations, scientists are developing a new, environmentally friendly purification model that turns waste into a resource. "Algae are our silent, invisible allies. Their power of transformation and purification is immense, and it is up to us to learn how to harness it for a healthier planet," explains Dr. Blažina. This research opens the door to a circular economy where industry and the environment can coexist in synergy.

Yesterday's World Oceans Day (June 8) is a powerful reminder that caring for the sea is our shared responsibility. While the scientists of the Ruđer Bošković Institute work tirelessly to understand and protect the Adriatic, their work lays the foundation for a future in which we can enjoy the richness and beauty of our sea. From defending against invisible tsunamis to employing micro-algorithms for cleaning, these "guardians of the Adriatic" prove every day that knowledge is the most powerful tool for preserving the world that surrounds us.