浑浊和沉积应力对珊瑚早期生命阶段的影响知之甚少,特别是在大西洋物种中。疏浚作业,海滩营养,和其他沿海建筑活动会增加附近珊瑚礁栖息地的沉积和浊度,并有可能对珊瑚幼虫的发育和变态产生负面影响,减少有性生殖的成功。在这项研究中,我们调查了受威胁的加勒比珊瑚物种Orbicellafaveolata的幼虫的表现,这些幼虫暴露于从佛罗里达州东南部的一个珊瑚礁地点收集的悬浮沉积物中,最近受到疏浚(迈阿密港)的影响,并将其与暴露于从近海收集的沉积物中的幼虫的性能进行比较,亲本殖民地的出生礁。在实验室实验中,我们测试了低剂量和高剂量的每一种沉积物是否会影响存活,结算,与无沉积物对照处理相比,珊瑚幼虫的呼吸。此外,我们用16SrRNA基因扩增子测序分析了实验中使用的沉积物,以评估港口沉积物与礁石沉积物中存在的微生物群落的差异,以及它们对珊瑚性能的潜在影响。总的来说,与对照处理相比,只有O.faveolata幼虫暴露于高剂量Port沉积物处理的存活率显着降低,表明对升高的悬浮沉积物的初始耐受性。然而,暴露后一周,与对照治疗相比,两种Port治疗(低剂量和高剂量)的沉降率显着降低,暗示着强烈的潜在影响。港口附近收集的沉积物也含有与珊瑚礁沉积物不同的微生物群落,细菌脱硫杆菌的相对丰度较高,这与珊瑚病有关。我们假设两种沉积物之间的微生物群落差异可能是解释观察到的幼虫性能差异的一个促成因素。一起,这些结果表明,与珊瑚礁沉积物相比,O.faveolata幼虫的定居成功和存活更容易因遇到港口入口沉积物而受到损害,对该物种在受影响地区的招募成功具有潜在的重要影响。
The effects of turbidity and sedimentation stress on early life stages of corals are poorly understood, particularly in Atlantic species. Dredging operations, beach nourishment, and other coastal construction activities can increase sedimentation and turbidity in nearby coral reef habitats and have the potential to negatively affect coral larval development and metamorphosis, reducing sexual reproduction success. In this study, we investigated the performance of larvae of the threatened Caribbean coral species Orbicella faveolata exposed to suspended sediments collected from a reef site in southeast Florida recently impacted by dredging (Port of Miami), and compared it to the performance of larvae exposed to sediments collected from the offshore, natal reef of the parent colonies. In a laboratory experiment, we tested whether low and high doses of each of these sediment types affected the survival, settlement, and respiration of coral larvae compared to a no-sediment control treatment. In addition, we analyzed the sediments used in the experiments with 16S rRNA gene amplicon sequencing to assess differences in the microbial communities present in the Port versus Reef sediments, and their potential impact on coral performance. Overall, only O. faveolata larvae exposed to the high-dose Port sediment treatment had significantly lower survival rates compared to the control treatment, suggesting an initial tolerance to elevated suspended sediments. However, significantly lower settlement rates were observed in both Port treatments (low- and high-dose) compared to the control treatment one week after exposure, suggesting strong latent effects. Sediments collected near the Port also contained different microbial communities than Reef sediments, and higher relative abundances of the bacteria Desulfobacterales, which has been associated with coral disease. We hypothesize that differences in microbial communities between the two sediments may be a contributing factor in explaining the observed differences in larval performance. Together, these results suggest that the settlement success and survival of O. faveolata larvae are more readily compromised by encountering port inlet sediments compared to reef sediments, with potentially important consequences for the recruitment success of this species in affected areas.