UNDERWATER BIOMATERIALS FOR THE TREATMENT OF CORAL DISEASES AND CONSERVATION OF REEF BIODIVERSITY

Numerous factors endanger reefs and the environments related to them due to climate change, and diseases are setting the final point on their disappearance. Outbreaks with exponentially increasing frequency occur, related to rising seawater temperatures, pollution, and alteration of the ecosystems because of tourism and overfishing. To prevent reef destruction, intense restoration programs are undertaken to protect and rebuild reefs using artificial constructions to resemble the coral 3D structures and aquacultures to refurbish the dead areas of the reefs. However, corals, especially when freshly transplanted, tend to be more susceptible to diseases, and the mortality rate is high. To prevent reef desertification due to outbreaks, environmentally friendly solutions should be presented to preserve one of the most important ecosystems in the world. This doctoral project aimed at the development of eco-friendly solutions for the treatment of coral diseases, focusing on infection determined by bacteria of the Vibrio family, some of which are coral pathogens known to develop a virulent behavior at temperatures high enough to impair the coral immune system, and hence are highly infective and virulent, which could cause outbreaks. Moreover, a further goal was posed during this Ph.D.: avoiding the pollution of the environment. To do so, the obtained technologies were designed to be fully biodegradable, focusing also on the concept of underwater targeted drug delivery and, hence, preventing the spread of active molecules in the surrounding environment, such as antibiotics. The final achievements of these solutions were then further optimized, singularly isolating and improving each of the main features of the leading technology, focusing on the improvement of applicability of the technology underwater, in particular on the adhesivity and the sealing of the infection, and on the development of antibiotic-free alternatives for the treatment of bacterial-determined coral diseases.