Department of Microbiology, Oregon State University, 226 Nash Hall, Corvallis, OR, 97331, USA.
Department of Ecology, Evolution and Marine Biology, University of California Santa Barbara, Santa Barbara, CA, 93106-9610, USA.
Sci Rep. 2019 May 2;9(1):6834. doi: 10.1038/s41598-019-43274-8.
Perturbations in natural systems generally are the combination of multiple interactions among individual stressors. However, methods to interpret the effects of interacting stressors remain challenging and are biased to identifying synergies which are prioritized in conservation. Therefore we conducted a multiple stressor experiment (no stress, single, double, triple) on the coral Pocillopora meandrina to evaluate how its microbiome changes compositionally with increasing levels of perturbation. We found that effects of nutrient enrichment, simulated predation, and increased temperature are antagonistic, rather than synergistic or additive, for a variety of microbial community diversity measures. Importantly, high temperature and scarring alone had the greatest effect on changing microbial community composition and diversity. Using differential abundance analysis, we found that the main effects of stressors increased the abundance of opportunistic taxa, and two-way interactions among stressors acted antagonistically on this increase, while three-way interactions acted synergistically. These data suggest that: (1) multiple statistical analyses should be conducted for a complete assessment of microbial community dynamics, (2) for some statistical metrics multiple stressors do not necessarily increase the disruption of microbiomes over single stressors in this coral species, and (3) the observed stressor-induced community dysbiosis is characterized by a proliferation of opportunists rather than a depletion of a proposed coral symbiont of the genus Endozoicomonas.
自然系统中的干扰通常是多个胁迫因子相互作用的组合。然而，解释相互作用的胁迫因子的影响的方法仍然具有挑战性，并且偏向于识别协同作用，这些协同作用在保护中被优先考虑。因此，我们对珊瑚 Pocillopora meandrina 进行了多胁迫实验（无胁迫、单胁迫、双胁迫、三胁迫），以评估其微生物组随干扰程度增加而在组成上发生的变化。我们发现，营养盐富集、模拟捕食和温度升高对各种微生物群落多样性指标的影响是拮抗的，而不是协同的或相加的。重要的是，高温和疤痕单独对改变微生物群落组成和多样性有最大的影响。使用差异丰度分析，我们发现胁迫因子的主要效应增加了机会主义分类群的丰度，而胁迫因子之间的双向相互作用对这种增加具有拮抗作用，而三向相互作用则具有协同作用。这些数据表明：(1) 应该进行多种统计分析，以全面评估微生物群落动态；(2) 对于某些统计指标，在这种珊瑚物种中，多个胁迫因子不一定会比单一胁迫因子增加对微生物组的破坏；(3) 观察到的胁迫诱导的群落失调表现为机会主义者的增殖，而不是提议的珊瑚共生菌属 Endozoicomonas 的消耗。
