The bacterial decay of waterlogged archeological wood (WAW, hard pine spp.) taken from Daebudo shipwreck No. 2, which was buried in the intertidal zone in the mid-west coast (Yellow sea) of South Korea approximately 800 years ago, was investigated. The maximum moisture content of the outer parts (approx. 3 cm of depth) of WAW was approximately 4.2 times higher than that of undegraded reference pine wood. ATR-FTIR and solid-state 13C-NMR analysis indicated a relative increase of the lignin concentration in WAW caused by the degradation of cellulose and hemicelluloses across the board studied (31-cm-wide and 14.5-cm-thick board). Micromorphological studies also revealed that bacterial degradation was progressed to a depth of 15 cm (vertically 7.3 cm) from the surface, which is the innermost part of the board. Erosion bacteria (EB) were identified as the main degraders of WAW. Degradation by tunneling bacteria (TB) was occasionally detected. Decay resistance to bacterial attacks in WAW varied between cell types and between cell wall regions. Axial tracheids showed less resistance than ray tracheids, ray parenchyma cells, and axial intercellular canal cells, including strand tracheids, subsidiary parenchyma cells, and epithelial cells. Decay resistance was higher in ray tracheids and strand tracheids than in ray parenchyma cells and subsidiary parenchyma-/epithelial cells, respectively. Bordered- and cross-field pit membranes and the initial pit borders showed higher decay resistance than the tracheid cell walls. Overall, the S2 layer of the axial tracheids showed the weakest resistance to bacterial attacks.

The radiocarbon dating laboratory in the Institute of Marine Science at the University of Alaska was established in the fall of 1968 and became operational a year later. Most of the samples examined have been from Alaska and consist largely of wood and peat.

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Bacterial decay in compression wood (CW) tracheids of waterlogged archaeological wood (WAW) was investigated using light microscopy, confocal laser scanning microscopy, transmission electron microscopy (TEM), and TEM immunogold labeling. Erosion bacteria were identified as the main degraders, and the extent of cell wall degradation differed depending on the severity of CW tracheids (mild vs. severe). Mild CW tracheids showed preferential decay in the inner S2 layer, with the locally degraded and/or fragmented S3 layer remaining. In contrast, severe CW tracheids revealed gradual degradation of the cell wall from the erosion progressing from exposed faces of the cell wall as decay progressed. The overall decay was more extensive in mild than in severe CW tracheids, and degradation of the highly lignified outer S2 layer (S2L) was only detected in mild CW tracheids. TEM immunogold labeling of 1,4-β-galactan, homogalacturonan (HG), heteroxylan, and heteromannan epitopes showed that there was no preferential degradation of pectins and hemicelluloses by action of diffusible enzymes and/or agents through the un-decayed cell wall during bacterial decay, in both mild and severe CW tracheids. Inter-CW tracheid bordered pit membranes showed higher decay resistance than CW tracheid walls. Degradation of HG and heteromannan epitopes was suppressed in pit membranes.

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