Clements Cody S, Burns Andrew S, Stewart Frank J, Hay Mark E
Aquatic Chemical Ecology Center, and Center for Microbial Dynamics and Infection, School of Biological Sciences, Georgia Institute of Technology, 950 Atlantic Drive, Atlanta, GA, 30332-0230, USA.
NIAID Microbiome Program, National Institute of Allergy and Infectious Disease, National Institutes of Health, Bethesda, MD, 20892, USA.
Anim Microbiome. 2020 Nov 16;2(1):42. doi: 10.1186/s42523-020-00061-5.
Impacts of biotic stressors, such as consumers, on coral microbiomes have gained attention as corals decline worldwide. Corallivore feeding can alter coral microbiomes in ways that contribute to dysbiosis, but feeding strategies are diverse - complicating generalizations about the nature of consumer impacts on coral microbiomes.
In field experiments, feeding by Coralliophila violacea, a parasitic snail that suppresses coral growth, altered the microbiome of its host, Porites cylindrica, but these impacts were spatially constrained. Alterations in microbial community composition and variability were largely restricted to snail feeding scars; basal or distal areas ~ 1.5 cm or 6-8 cm away, respectively, were largely unaltered. Feeding scars were enriched in taxa common to stressed corals (e.g. Flavobacteriaceae, Rhodobacteraceae) and depauperate in putative beneficial symbionts (e.g. Endozoicomonadaceae) compared to locations that lacked feeding.
Previous studies that assessed consumer impacts on coral microbiomes suggested that feeding disrupts microbial communities, potentially leading to dysbiosis, but those studies involved mobile corallivores that move across and among numerous individual hosts. Sedentary parasites like C. violacea that spend long intervals with individual hosts and are dependent on hosts for food and shelter may minimize damage to host microbiomes to assure continued host health and thus exploitation. More mobile consumers that forage across numerous hosts should not experience these constraints. Thus, stability or disruption of microbiomes on attacked corals may vary based on the foraging strategy of coral consumers.
随着全球范围内珊瑚数量的减少，诸如消费者等生物应激源对珊瑚微生物群的影响受到了关注。珊瑚食性动物的摄食会以导致生态失调的方式改变珊瑚微生物群，但摄食策略多种多样，这使得对消费者对珊瑚微生物群影响性质的概括变得复杂。
在野外实验中，抑制珊瑚生长的寄生蜗牛紫珊瑚螺（Coralliophila violacea）的摄食改变了其宿主柱形珊瑚（Porites cylindrica）的微生物群，但这些影响在空间上受到限制。微生物群落组成和变异性的改变主要局限于蜗牛的摄食伤痕处；分别距离摄食伤痕约1.5厘米或6 - 8厘米的基部或远端区域基本未受影响。与没有摄食的区域相比，摄食伤痕处富含受胁迫珊瑚常见的分类群（如黄杆菌科、红杆菌科），而假定的有益共生体（如内共生单胞菌科）则较少。
先前评估消费者对珊瑚微生物群影响的研究表明，摄食会破坏微生物群落，可能导致生态失调，但这些研究涉及在众多个体宿主之间移动的移动性珊瑚食性动物。像紫珊瑚螺这样久坐不动的寄生虫，长时间与单个宿主相处，并且依赖宿主获取食物和庇护所，可能会将对宿主微生物群的损害降至最低，以确保宿主持续健康从而得以寄生。在众多宿主间觅食的移动性更强的消费者不应受到这些限制。因此，受攻击珊瑚上微生物群的稳定性或破坏程度可能因珊瑚消费者的觅食策略而异。
