Dept. of Marine Sciences, University of Gothenburg, Carl Skottbergs Gata 22B, 405 30, Gothenburg, Sweden.
Scripps Institution of Oceanography, 9500 Gilman Drive, Mail Code 0227, La Jolla, CA, 92093, USA.
Sci Rep. 2020 Jul 29;10(1):12774. doi: 10.1038/s41598-020-68613-y.
Wood submerged in saline and oxygenated marine waters worldwide is efficiently degraded by crustaceans and molluscs. Nevertheless, in the cold coastal waters of the Antarctic, these degraders seem to be absent and no evidence of other wood-degrading organisms has been reported so far. Here we examine long-term exposed anthropogenic wood material (Douglas Fir) collected at the seafloor close to McMurdo station, Antarctica. We used light and scanning electron microscopy and demonstrate that two types of specialized lignocellulolytic microbes-soft rot fungi and tunnelling bacteria-are active and degrade wood in this extreme environment. Fungal decay dominates and hyphae penetrate the outer 2-4 mm of the wood surface. Decay rates observed are about two orders of magnitude lower than normal. The fungi and bacteria, as well as their respective cavities and tunnels, are slightly smaller than normal, which might represent an adaptation to the extreme cold environment. Our results establish that there is ongoing wood degradation also in the Antarctic, albeit at a vastly reduced rate compared to warmer environments. Historical shipwrecks resting on the seafloor are most likely still in good condition, although surface details such as wood carvings, tool marks, and paint slowly disintegrate due to microbial decay.
在世界范围内，浸没在含盐和含氧海水中的木材会被甲壳类动物和软体动物有效地降解。然而，在南极寒冷的沿海水域，这些降解者似乎不存在，到目前为止，没有报告其他木材降解生物的证据。在这里，我们研究了在南极麦克默多站附近海底采集的长期暴露的人为木材材料（花旗松）。我们使用了光学显微镜和扫描电子显微镜，并证明了两种类型的专门木质纤维素分解微生物——软腐真菌和隧道细菌——在这种极端环境中是活跃的，并能降解木材。真菌分解占主导地位，菌丝穿透木材表面的外 2-4 毫米。观察到的腐朽速度比正常情况低两个数量级。真菌和细菌，以及它们各自的腔和隧道，都比正常情况略小，这可能代表对极寒环境的适应。我们的研究结果表明，即使在南极，木材也在不断降解，尽管与温暖的环境相比，其降解速度要低得多。躺在海底的历史沉船很可能仍处于良好状态，尽管由于微生物的分解，表面细节，如木雕、工具痕迹和油漆会慢慢解体。
