Simulation and Investigation of Wood Degradation by Erosion Bacteria in Laboratory Experiments
J Gelbrich, E I Kretschmar, N Lamersdorf, H Militz
A Microcosm experiment was successfully set up to establish, monitor and manipulate bacterial wood degradation under low oxygen conditions. Sound pine sticks were placed in waterlogged sediment from a heavily decayed pine pile foundation site in Amsterdam. The system was subject to different gassing treatment regimes in order to investigate the role of oxygen in the bacterial degradation process of wood. In different treatments, microcosm head space was aerated with air, air + O2 or N2. As a fourth treatment the air aeration was combined with a vertical water circulation through the whole Microcosm. Some Microcosms were equipped with oxygen sensors (optodes) to measure the oxygen concentration during the experiment in different depths. Wood degradation was microscopically detected and a classification for low decay intensities was developed. It was found that bacterial wood degradation occurred in all treatments detectable after 150 days. The fastest rate of decay developed in 120 days and was most intense in the water circulated treatment. The used approach was successful in simulating bacterial wood degradation under reproducible laboratory conditions. The presented set up can be used as a base for further investigations regarding optimal living conditions of and preservation strategies against erosion bacteria.
Further investigations, especially long-term experiments, are necessary to understand the complex interaction of the bacterial wood degradation. Therefore, it is important to test preservation strategies in the laboratory before using it in the real environments, which will be possible with such an experimental design.