Data from: Symbiont community and host genetic structure of the brain coral Platygyra verweyi, at the outlet of a nuclear power plant and adjacent areas

In the context of rising seawater temperatures associated with climate change, the issue of whether coral holobionts deal with this challenge by shuffling their associations with stress- and/or heat-tolerant Symbiodinium, by generating heat-resistant host genotypes, or both is important for coral survival. In the present study, the composition of communities of the endosymbiont Symbiodinium and the population genetics of the coral host Platygyra verweyi were examined in a reef impacted by hot water discharged from the outlet of a nuclear power plant in operation in Kenting, Southern Taiwan since 1984. The water at this site is 2.0-3.0 ºC warmer than adjacent reefs in summer, which have an average seawater temperature of 29.0 ºC. The data were compared with those for the same species at other sites within 12 km of the outlet site. Platygyra verwyei was associated with one or both of Symbiodinium types C3 (heat sensitive) and D1a (heat tolerant) at all sites with the latter being the dominant at the nuclear power plant outlet. The proportion of C3 in populations increased gradually with increasing distance from the hot-water discharge. Genetic analysis of the Platygyra verweyi host using mitochondrial and nuclear markers showed no genetic differentiation among sites. Changes in the composition of Symbiodinium types associated with P. verweyi among closely located sites in Kenting suggested that this coral might have acclimatized to the constant thermal stress by selective association with heat-tolerant Symbiodinium types, whereas the role of the host in adaptation was inconclusive.在气候变化引发海水温度上升的背景下，珊瑚共生体（coral holobionts）能否通过调整与耐胁迫和/或耐热共生虫黄藻（Symbiodinium）的共生关系、产生耐热宿主基因型，或是二者协同作用来应对这一挑战，对珊瑚的生存至关重要。本研究针对中国台湾南部垦丁地区自1984年起投入运营的某核电站出水口排放热水所影响的珊瑚礁，开展了两项分析：其一为该礁区内共生虫黄藻（Symbiodinium）的群落组成，其二为珊瑚宿主韦氏扁脑珊瑚（Platygyra verweyi）的群体遗传学特征。该区域夏季海水温度较周边平均水温为29.0℃的相邻礁区高出2.0~3.0℃。研究将上述采样点的相关数据，与出水口周边12公里范围内其他同物种种群的采样数据进行了对比分析。结果显示，韦氏扁脑珊瑚（Platygyra verweyi）在所有采样点均与C3（热敏感型）和D1a（耐热型）两种共生虫黄藻中的一种或两种形成共生关系；其中在核电站出水口处，耐热型的D1a为优势共生类群。随着距离热水排放口的距离逐渐增加，C3型共生虫黄藻在种群中的占比亦逐步升高。研究团队利用线粒体及核分子标记对韦氏扁脑珊瑚宿主开展群体遗传分析，结果显示各采样点间的宿主种群并无显著遗传分化。垦丁地区邻近采样点间，韦氏扁脑珊瑚所关联的共生虫黄藻类群组成存在差异，这表明该珊瑚或可通过选择性与耐热型共生虫黄藻类群建立共生关系，以适应持续存在的热胁迫；但宿主自身在该适应过程中所发挥的作用仍未明确。