Analysis of biological adhesion and biomineralization products on the Yangtze Estuary II shipwreck

Biological deposition is commonly observed on wooden shipwrecks. This study employs analytical techniques, including optical microscopy (OM), scanning electron microscope equipped with an energy dispersive spectrometer (SEM-EDS), X-ray diffraction (XRD) and Fourier infrared transform spectroscopy (FTIR), to investigate the microscopic morphology and structural composition of barnacles and their adhesion to the wooden surface of the Yangtze Estuary II shipwreck. Results indicate that microorganisms like diatoms and Trichoderma spp. were present at the interface between the barnacles and the wooden surface. These microorganisms played a crucial role in the formation of SiO₂, CaHPO₄•2(H₂O), FeO(OH) and CaCO₃. Specifically, the bio-mineralized cell walls of diatoms and their cellular contents, including polyphosphates, provided the necessary Si and P for SiO₂ and CaHPO₄•2(H₂O), respectively. Furthermore, during their metabolic processes, diatoms and Trichoderma spp. supply dissolved Fe ions, which contribute to the formation of FeO(OH) on the wooden surface. This study elucidates four types of bio-mineralized products resulting from microbial activity on the salvaged wooden shipwreck.