Penn State University, University Park, Pennsylvania, USA.
Lawrence Berkeley National Laboratory, Berkely, California, USA.
J Phycol. 2023 Aug;59(4):698-711. doi: 10.1111/jpy.13340. Epub 2023 May 31.
The existence of widespread species with the capacity to endure diverse, or variable, environments are of importance to ecological and genetic research, and conservation. Such "ecological generalists" are more likely to have key adaptations that allow them to better tolerate the physiological challenges of rapid climate change. Reef-building corals are dependent on endosymbiotic dinoflagellates (Family: Symbiodiniaceae) for their survival and growth. While these symbionts are biologically diverse, certain genetic types appear to have broad geographic distributions and are mutualistic with various host species from multiple genera and families in the order Scleractinia that must acquire their symbionts through horizontal transmission. Despite the considerable ecological importance of putative host-generalist symbionts, they lack formal species descriptions. In this study, we used molecular, ecological, and morphological evidence to verify the existence of five new host-generalist species in the symbiodiniacean genus Cladocopium. Their geographic distribution and prevalence among host communities corresponds to prevailing environmental conditions at both regional and local scales. The influence that each species has on host physiology may partially explain regional differences in thermal sensitivities among coral communities. The potential increased prevalence of a generalist species that endures environmental instability is a consequential ecological response to warming oceans. Large-scale shifts in symbiont dominance could ensure reef coral persistence and productivity in the near term. Ultimately, these formal designations should advance scientific communication and generate informed research questions on the physiology and ecology of coral-dinoflagellate mutualisms.
具有耐受多样化或可变环境能力的广泛物种的存在对生态和遗传研究以及保护具有重要意义。这种“生态通才”更有可能具有关键的适应能力，使它们能够更好地耐受快速气候变化带来的生理挑战。造礁珊瑚依赖内共生的甲藻（科：Symbiodiniaceae）来生存和生长。虽然这些共生体具有生物多样性，但某些遗传类型似乎具有广泛的地理分布，并与来自 Scleractinia 目多个属和科的各种宿主物种互利共生，这些宿主必须通过水平传播来获得共生体。尽管假定的宿主广适共生体具有相当大的生态重要性，但它们缺乏正式的物种描述。在这项研究中，我们使用分子、生态和形态学证据来验证共生甲藻属 Cladocopium 中存在五种新的宿主广适共生体物种。它们的地理分布和在宿主群落中的流行程度与区域和局部尺度上的流行环境条件相对应。每个物种对宿主生理学的影响可能部分解释了珊瑚群落之间热敏感性的区域差异。对环境不稳定具有耐受性的广适物种的潜在增加流行是对变暖海洋的重要生态响应。共生体优势的大规模转变可以确保珊瑚礁在近期内的生存和生产力。最终，这些正式的指定应该促进关于珊瑚-甲藻共生关系的生理学和生态学的科学交流，并提出明智的研究问题。
