Mechanisms of diatom inhibition by a new antifouling biocide with broad-spectrum efficacy against bacteria, algae, and barnacles

Marine biofouling, the accumulation of microorganisms, algae, and invertebrates on submerged surfaces, poses significant challenges for maritime industries. This study introduces a new biocide specifically designed to combat marine biofouling and assesses its efficacy and underlying algicidal mechanisms. The results showed that the biocide LaPT, synthesized by combining the rare-earth element Lanthanum (La) with pyrithione (PT), exhibited not only remarkable antibacterial properties but also strong algicidal activity against diatom species Amphora sp. and Thalassiosira pseudonana . Long-term field tests conducted in Xiamen Port, confirmed the effectiveness of LaPT-coated panels in reducing barnacle infestation. Algicidal mechanistic investigations through physiological, transgenic, and transcriptomic analyses revealed that LaPT disrupts cell wall and membrane integrity, interferes with calcium-dependent processes, and inhibits photosynthesis and energy metabolism, leading to diatom cell death. This study demonstrates the LaPT's effectiveness in preventing biofouling and reveal its unique mechanism of action, offering a promising solution for managing marine biofouling.