Fig. 6

The severe erosion cell structures of archaeological woods from Nanhai No. 1 shipwreck. a Active secondary bacterial degraders (arrow) in cells (Sample 10, TEM). b Bacteria (arrow) decomposed the black erosion residue into granular (Sample 10, TEM). c The pits of tracheid encroached by a large number of bacteria (arrow) (Sample 10, SEM). d Cells only supported by the middle lamella but still in neat arrangement, secondary cell wall has been separated from the medium lamella (arrow) (Sample 17, TEM)