Sorbonne Universités, UPMC Univ. Paris 6, CNRS, Laboratoire d'Ecogéochimie des Environnements Benthiques, Observatoire Océanologique, 66650, Banyuls-sur-Mer, France.
Université Laval, Département de Biologie, Québec, Canada.
Sci Rep. 2018 Jan 17;8(1):907. doi: 10.1038/s41598-017-17463-2.
Wood debris on the ocean floor harbor flourishing communities, which include invertebrate taxa thriving in sulfide-rich habitats belonging to hydrothermal vent and methane seep deep-sea lineages. The formation of sulfidic niches from digested wood material produced by woodborers has been known for a long time, but the temporal dynamics and sulfide ranges encountered on wood falls remains unknown. Here, we show that wood falls are converted into sulfidic hotpots, before the colonization by xylophagaid bivalves. Less than a month after immersion at a depth of 520 m in oxygenated seawater the sulfide concentration increased to millimolar levels inside immersed logs. From in situ experiments combining high-frequency chemical and video monitoring, we document the rapid development of a microbial sulfur biofilm at the surface of wood. These findings highlight the fact that sulfide is initially produced from the labile components of wood and supports chemosynthesis as an early pathway of energy transfer to deep-sea wood colonists, as suggested by recent aquarium studies. The study furthermore reveals that woodborers promote sulfide-oxidation at the periphery of their burrows, thus, not only facilitating the development of sulfidic zones in the surrounding of degraded wood falls, but also governing sulfur-cycling within the wood matrix.
海底的木屑中蕴藏着繁荣的生物群落，其中包括在富含硫化物的热液喷口和甲烷渗漏深海谱系栖息地中繁衍生息的无脊椎动物分类群。人们早就知道，食木生物分解木材产生的木屑会形成硫化小生境，但人们对木屑坠落形成的硫化小生境的时间动态和硫化范围仍不清楚。在这里，我们展示了在木甲贝类动物殖民之前，木屑会先转变成硫化热点。在 520 米深的含氧海水中浸泡不到一个月后，浸入原木内部的硫化物浓度增加到了毫摩尔水平。通过结合高频化学和视频监测的现场实验，我们记录了在木材表面快速形成微生物硫生物膜的过程。这些发现强调了一个事实，即硫化物最初是由木材的不稳定成分产生的，并支持化学生物合成作为深海木材殖民者早期能量转移的途径，这一点最近的水族馆研究也有所表明。该研究还表明，蛀木虫在其洞穴的外围促进了硫化物的氧化，因此，不仅促进了周围降解木屑坠落区硫化物区的形成，而且控制了木材基质内的硫循环。
