The application of three-dimensional tomography and chemical mapping by soft X-ray microscopy to fungi spore on wood from the Nanhai No. 1 shipwreck

Microorganisms will induce biodeterioration and destruction to ancient wooden cultural heritages. The “Nanhai No. 1” shipwreck sank off at the Southern Song dynasty (1127∼1279 CE) and was salvaged to land in December 2007. After the wreck was salvaged from the seawater and stored in the museum, it was found that fungal hyphae appeared on the hull in certain places. Further examination revealed that the fungal infection tended to appear in areas enriched with sulfur and iron compounds. Therefore, analyzing the formation and germination of fungi in waterlogged archeological wood and whether it is related to inorganic compounds is a question that needs to be addressed in the conservation of marine shipwrecks. Here, based on synchrotron radiation technology, integrating X-ray absorption fine structures with full-field transmission X-ray microscope to analyze the iron component and demonstrate its distribution within a single spore, which probably traces the interaction between inorganic elements with cell and subcellular constituents. In conclusion, the results demonstrate soft X-ray tomographic generating 3-D reconstructions associated with chemical mapping of whole spore and illustrate the power and potential ability of synchrotron radiation-based techniques to study cultural heritage and its conservation application.