Co-dynamics of Symbiodiniaceae and bacterial populations during the first year of symbiosis with Acropora tenuis juveniles

Fourteen colonies of A. tenuis were collected from Geoffrey Bay, Magnetic Island and transported to the National Sea Simulator Facility (SeaSim) at the Australian Institute of Marine Sciences (AIMS). Corals were maintained in outside aquaria prior to the spawning eventOnce larvae were competent to settle (7 days postspawning) preconditioned terracotta tiles crustose coralline algae (CCA) were introduced to induce settlement. Larvae were left to settle for 11 days. Settlement on each tile was assessed visually, and tiles containing juveniles were strung onto stainless steel rods in groups of 15 separated by PVC spacers.Nineteen days postspawning, 240 tiles, each with 40–200 juveniles, were transported to Magnetic Island and deployed at two sites at Magnetic Island (Geoffrey Bay and Nelly Bay) respectively, at a depth of approximately 6.Fluorescent microscopy was used to confirm the absence of Symbiodiniaceae cells prior to field deployment. Juveniles were sampled from tiles on the 19th of each month from 8:30 to 10:30 a.m. where conditions allowed, where between 6 and 17 juveniles were photographed at each time point. As juveniles began to present more complex branching patterns, 3D modelling was then employed to capture the geometries and estimate surface area. Surface area measurements were matched with Symbiodiniaceae cell counts and DNA extractions for each juvenile. The age of juveniles at each sampling time point was as follows:T1 – 40 daysT2 – 71 daysT3 – 11 daysT4 – 129 daysT5 – 167 daysT6 – 194 daysT7 – 316 daysT8 – 380 daysSee Quigley et al (2020) for full details.

从磁岛杰弗里湾采集了14株A. tenuis珊瑚，转运至澳大利亚海洋科学研究所（Australian Institute of Marine Sciences, AIMS）的国家海洋模拟设施（National Sea Simulator Facility, SeaSim）。实验前，珊瑚被饲养于室外水族箱中。待幼虫具备附着能力（产卵后7天）时，投放预附着了结壳珊瑚藻（crustose coralline algae, CCA）的陶土瓦片以诱导幼虫附着。随后让幼虫附着11天，通过目视评估每块瓦片的附着情况，将携带幼体的瓦片以15片为一组串在不锈钢杆上，组间用聚氯乙烯（PVC）垫片分隔。产卵后19天，将240块各携带40~200株幼体的瓦片运回磁岛，分别部署于磁岛的两处海域（杰弗里湾与内莉湾），部署水深约6米。野外部署前，通过荧光显微镜确认样本未携带虫黄藻科（Symbiodiniaceae）细胞。若环境条件允许，于每月19日上午8:30至10:30从瓦片上采集幼体，每次采样选取6~17株幼体进行拍照。随着幼体逐渐形成更为复杂的分枝形态，采用三维建模技术获取其几何结构并估算表面积。针对每株幼体，将表面积测量结果与虫黄藻细胞计数、DNA提取结果进行关联分析。各采样时间点对应的幼体日龄如下：T1——40天；T2——71天；T3——11天；T4——129天；T5——167天；T6——194天；T7——316天；T8——380天。完整实验细节请参阅Quigley等人（2020）的研究。