ABSTRACT: The diversity of symbiotic dinoflagellate Symbiodiniaceae hosted by anthozoans is known to be driven by the environment where the hosts are found. This study examined how environmental variations (<1 to 100s m) can influence the diversity of Symbiodiniaceae within the zoantharian Palythoa tuberculosa. We monitored the dominant Symbiodiniaceae lineages within tagged P. tuberculosa colonies near the Hija River mouth and adjacent coastal reefs at Mizugama, Okinawa, Japan, between July 2016 and April 2018. Seven sites were chosen based on depth and distance from the river mouth, with 5 tagged colonies at each site. Water parameters of tidal pools (TPs) at the river mouth, especially temperature, were significantly different from other sites. Surprisingly, P. tuberculosa colonies at TPs were more resilient to bleaching during summers compared to colonies at other shallow sites. We observed different Cladocopium psbA^ncr lineages hosted by the tagged P. tuberculosa, with TPs colonies usually hosting one Cladocopium lineage (designated as lineage 4). Colonies from the deep sites and other shallow sites hosted mostly Cladocopium lineages 1 (generalist) and 2 (riverine specialist). Throughout the study period, the shallow colonies (included TPs) recorded higher rates of switching dominant Cladocopium lineages (mostly to lineage 1), whereas most deep colonies did not switch their dominant Cladocopium lineages. Our results show that Cladocopium lineage 1, previously reported as a generalist lineage in terms of environmental parameters, could also be an opportunist lineage during periods of host stress. Our study confirms that Cladocopium lineage flexibility likely helps the resilience of P. tuberculosa in such variable environments.

中文翻译：

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温度、盐度和深度对河口附近由 Palythoatuberculosa 寄宿的 Symbiodiniaceae 谱系的影响

摘要：已知由珊瑚虫寄宿的共生甲藻共生菌科的多样性是由发现寄主的环境驱动的。这项研究调查了环境变化（<1 到 100 米）如何影响 zoantharian Palythoa tuberculosa内共生科的多样性。2016 年 7 月至 2018 年 4 月期间，我们监测了日本冲绳县水龟市 Hija 河口附近带标记的结核杆菌菌落内的优势共生菌科谱系。 根据深度和距离河口的距离选择了七个地点，其中每个位点有 5 个标记的菌落。河口潮汐池（TPs）的水参数，特别是温度，与其他站点有显着差异。出奇，与其他浅水区的菌落相比，TP 的结核菌菌落在夏季对白化的抵抗力更强。我们观察到不同Cladocopium的psbA ^NCR由托管谱系标记P. tuberculosa，与茶多酚的菌落通常举办一个Cladocopium谱系（称为谱系4）。来自深层地点和其他浅层地点的殖民地主要栖息着 Cladocopium谱系 1（通才）和 2（河流专家）。在整个研究期间，浅层菌落（包括 TP）记录了较高的转换优势枝条属谱系（主要是谱系 1）的比率，而大多数深部菌落没有转换其优势枝条状属血统。我们的结果表明，先前在环境参数方面被报道为通才谱系的Cladocopium谱系 1 也可能是宿主压力期间的机会主义谱系。我们的研究证实Cladocopium血统的灵活性可能帮助的弹性P. tuberculosa在这样的环境变量。