Saha Mahasweta, Ferguson Robert M W, Dove Shawn, Künzel Sven, Meichssner Rafael, Neulinger Sven C, Petersen Finn Ole, Weinberger Florian
Benthic Ecology, GEOMAR Helmholtz Centre for Ocean Research, Kiel, Germany.
The School of Life Sciences, University of Essex, Colchester, United Kingdom.
Front Microbiol. 2020 Jan 15;10:2870. doi: 10.3389/fmicb.2019.02870. eCollection 2019.
The establishment of epibacterial communities is fundamental to seaweed health and fitness, in modulating ecological interactions and may also facilitate adaptation to new environments. Abiotic factors like salinity can determine bacterial abundance, growth and community composition. However, influence of salinity as a driver of epibacterial community composition (until species level) has not been investigated for seaweeds and especially under long time scales. We also do not know how abiotic stressors may influence the 'core' bacterial species of seaweeds. Following an initial (immediately after field collection) sampling of epibacterial community of an invasive red seaweed , we conducted a long term mesocosm experiment for 5 months, to examine the influence of three different salinities (low, medium and high) at two different time points (3 months after start of experiment and 5 months, i.e., at the end of experiment) on the epibacterial community richness and composition of . Metagenomic sequencing showed that epibacterial communities changed significantly according to salinity and time points sampled. Epibacterial richness was significantly different between low and high salinities at both time points. Epibacterial richness also varied significantly between 3 months (after start of experiment) and 5 months (end of experiment) within low, medium and high salinity level. Irrespective of salinity levels and time points sampled 727 taxa consistently appeared in all samples hinting at the presence of core bacterial species on the surface of the alga. Our results indicate that both salinity and time can be major driving forces in structuring epibacterial communities of seaweeds with respect to richness and β-diversity. We highlight the necessity of conducting long term experiments allowing us to detect and understand epibacterial succession over time on seaweeds.
附生细菌群落的建立对于海藻的健康和适应性至关重要，它能调节生态相互作用，还可能促进对新环境的适应。盐度等非生物因素可以决定细菌的丰度、生长和群落组成。然而，盐度作为附生细菌群落组成（直至物种水平）驱动因素的影响，尚未针对海藻进行研究，尤其是在长时间尺度下。我们也不知道非生物应激源如何影响海藻的“核心”细菌物种。在对一种入侵红海藻的附生细菌群落进行初始（野外采集后立即进行）采样后，我们进行了为期5个月的长期中宇宙实验，以研究在两个不同时间点（实验开始后3个月和5个月，即实验结束时）三种不同盐度（低、中、高）对该海藻附生细菌群落丰富度和组成的影响。宏基因组测序表明，附生细菌群落根据盐度和采样时间点发生了显著变化。在两个时间点，低盐度和高盐度之间的附生细菌丰富度存在显著差异。在低、中、高盐度水平内，实验开始后3个月和5个月（实验结束时）之间的附生细菌丰富度也有显著变化。无论盐度水平和采样时间点如何，727个分类单元始终出现在所有样本中，这暗示了藻类表面存在核心细菌物种。我们的结果表明，盐度和时间在构建海藻附生细菌群落的丰富度和β多样性方面都可能是主要驱动力。我们强调进行长期实验的必要性，以便我们能够检测和理解海藻上附生细菌随时间的演替。
