Light at the end of the tunnels? The origins of microbial bioerosion in mineralised collagen

摘要: Abstract Microbial bioerosion, in all its manifestations, is one of the major factors determining long-term survival archaeologically and environmentally important artefacts ecofacts made from mineralised collagen – bones, antler, teeth ivory. The bone diagenesis literature contains extensive descriptions different morphologies classifications microbial bioerosion microscopical focal destruction, Wedl tunnels, linear longitudinal, budded lamellate tunnelling, etc. but causative agents remain to be discovered. Palaeontologists are a similar situation when describing ichnofossils where classified by characteristic morphology only tentatively assigned specific causes. In archaeological tunnels have traditionally been ascribed fungi re-examination Wedl's original paper subsequent has shown that early specimens examined came aquatic environments euendolithic microflora (cyanobacteria or chlorophytes) might responsible. These microorganisms known tunnel into marine shells. Linear tunnelling bacteria. However, analyses using combination backscatter SEM (BSEM) mercury intrusion porosimetry (HgIP) bones excavated terrestrial soils suggest various described earlier researchers actually manifestations single architecture, differences arising inherent variability microstructure hydrology burial environment. An examination BSEM HgIP data also indicates bacteria responsible may spread through dead tissues expanding canalicular network (or dentinal tubules teeth) rather than creating new tunnels. Long-term field experiments de-fleshed cow now demonstrated bacterial develops over decades months as was previously thought, even warm tropical soils. This obvious implications for origin (soil versus endogenous gut bacteria) since were quickly isolated contents. Although no attempt here identify organism organisms tentative model proposed how cycles wetting drying, changes local dissolved oxygen levels, could lead common gram positive soil bacterium produce pattern seen exhumed bones. act way Staphylococcus aureus which proliferates living (causing osteomyelitis) infiltrating enlarging network.