Shallow‐water coral reef ecosystems, particularly those already impaired by anthropogenic pressures, may be highly sensitive to disturbances from natural catastrophic events, such as volcanic eruptions. Explosive volcanic eruptions expel large quantities of silicate ash particles into the atmosphere, which can disperse across millions of square kilometres and deposit into coral reef ecosystems. Following heavy ash deposition, mass mortality of reef biota is expected, but little is known about the recovery of post‐burial reef ecosystems. Reef regeneration depends partly upon the capacity of the ash deposit to be colonised by waterborne bacterial communities and may be influenced to an unknown extent by the physiochemical properties of the ash substrate itself. To determine the potential for volcanic ash to support pioneer bacterial colonisation, we exposed five well‐characterised volcanic and coral reef substrates to a marine aquarium under low light conditions for 3 months: volcanic ash, synthetic volcanic glass, carbonate reef sand, calcite sand and quartz sand. Multivariate statistical analysis of Automated Ribosomal Intergenic Spacer Analysis (ARISA) fingerprinting data demonstrates clear segregation of volcanic substrates from the quartz and coral reef substrates over 3 months of bacterial colonisation. Overall bacterial diversity showed shared and substrate‐specific bacterial communities; however, the volcanic ash substrate supported the most diverse bacterial community. These data suggest a significant influence of substrate properties (composition, granulometry and colour) on bacterial settlement. Our findings provide first insights into physicochemical controls on pioneer bacterial colonisation of volcanic ash and highlight the potential for volcanic ash deposits to support bacterial diversity in the aftermath of reef burial, on timescales that could permit cascading effects on larval settlement.

中文翻译：

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火山灰支持海洋中生态系统中多样化的细菌群落。

浅水珊瑚礁生态系统，特别是那些已经受到人为压力损害的生态系统，可能对火山爆发等自然灾害事件的干扰高度敏感。火山喷发将大量硅酸盐灰颗粒排放到大气中，这些颗粒可以分散到数百万平方公里的范围内并沉积到珊瑚礁生态系统中。大量火山灰沉积后，预计珊瑚礁生物群将大量死亡，但人们对埋藏后珊瑚礁生态系统的恢复知之甚少。珊瑚礁的再生部分取决于灰沉积物被水生细菌群落定殖的能力，并且可能在未知程度上受到灰基质本身的理化性质的影响。为了确定火山灰支持先锋细菌定殖的潜力，我们将五种特征良好的火山和珊瑚礁基质在弱光条件下暴露在海洋水族馆中 3 个月：火山灰、合成火山玻璃、碳酸盐礁砂、方解石砂和石英砂。自动核糖体基因间间隔分析 (ARISA) 指纹数据的多变量统计分析表明，在细菌定殖的 3 个月内，火山基质与石英和珊瑚礁基质明显分离。总体细菌多样性显示出共享的和底物特异性的细菌群落；然而，火山灰基质支持最多样化的细菌群落。这些数据表明底物特性（成分、粒度和颜色）对细菌沉降有显着影响。我们的研究结果为对火山灰中先驱细菌定植的物理化学控制提供了初步见解，并强调了火山灰沉积物在珊瑚礁埋藏后支持细菌多样性的潜力，在时间尺度上可能会对幼虫沉降产生连锁效应。