16S and 18S sequences from the epiphytic biofilm on leaves of Enhalus acroides

Seagrass meadows are a crucial component of tropical marine reef ecosystems. The seagrass plants are colonized by a multitude of epiphytic organisms that contribute to determining the ecological role of seagrasses. To better understand how environmental changes like ocean acidification might affect epiphytic assemblages, the microbial community composition of the epiphytic biofilm of Enhalus acroides was investigated at a natural CO2 vent in Papua New Guinea using molecular fingerprinting and next generation sequencing of 16S and 18S rRNA genes. Both bacterial and eukaryotic epiphytes formed distinct communities at the CO2-impacted site compared to the control site. This site-related CO2 effect was also visible in the succession pattern of microbial epiphytes. We further found an increased abundance of bacterial types associated with coral diseases at the CO2-impacted site (Fusobacteria, Thalassomonas) whereas eukaryotes such as certain crustose coralline algae commonly related to healthy reefs were less diverse. These trends in the epiphytic community of E. acroides suggest a potential role of seagrasses as vectors of coral pathogens and may support previous predictions of a decrease in reef health and prevalence of diseases under future ocean acidification scenarios.

海草床是热带珊瑚礁生态系统中至关重要的组成部分。海草植物被众多附生生物所侵染，这些生物共同决定了海草在生态系统中的角色。为了更好地理解环境变化，如海洋酸化可能对附生生物群落产生的影响，研究人员在巴布亚新几内亚的一个天然CO2喷口处，利用分子指纹技术和16S、18S rRNA基因的下一代测序技术，对海藻类植物Enhalus acroides的附生生物膜中的微生物群落组成进行了调查。与对照位点相比，受CO2影响的位点形成了独特的细菌和真核附生生物群落。这一与位点相关的CO2效应也体现在微生物附生生物的演替模式中。研究还发现，在受CO2影响的位点，与珊瑚疾病相关的细菌类型（如梭杆菌、蓝藻）的丰度增加，而与健康珊瑚礁密切相关的某些石珊瑚藻类等真核生物的多样性较低。这些趋势表明，海草可能作为珊瑚病原体的传播媒介，并可能支持先前关于未来海洋酸化情景下珊瑚礁健康下降和疾病普遍性增加的预测。