Department of Biological and Environmental Sciences and Technologies, University of Salento, Lecce, Italy; Consorzio Nazionale Interuniversitario per le Scienze del Mare, CoNISMa, Piazzale Flaminio 9, 00196 Roma, Italy.
Consorzio Nazionale Interuniversitario per le Scienze del Mare, CoNISMa, Piazzale Flaminio 9, 00196 Roma, Italy; Integrative Marine Ecology, Stazione Zoologica Anton Dohrn, Villa Comunale, 80121 Napoli, Italy.
Sci Total Environ. 2019 Nov 20;692:305-318. doi: 10.1016/j.scitotenv.2019.07.155. Epub 2019 Jul 19.
Jellyfish represent an important component of marine food webs characterized by large fluctuations of population density, with the ability to abruptly form outbreaks, followed by rarity periods. In spite of considerable efforts to investigate how jellyfish populations are responding globally to anthropogenic change, available evidence still remains unclear. In the last 50 years, jellyfish are seemingly on the rise in a number of coastal areas, including the Mediterranean Sea, where jellyfish blooms periodically become an issue to marine and maritime human activities. Their impacts on marine organism welfare have been poorly quantified. The jellyfish, Rhizostoma pulmo, is an outbreak-forming scyphomedusa whose large populations spread across the Mediterranean, with increasing periodicity and variable abundance. Studies on cnidarian jellyfish suggested being important vectors of bacterial pathogens. In the present study, by combination of conventional culture-based methods and a high-throughput amplicon sequencing (HTS) approach, we characterized the diversity of the bacterial community associated with this jellyfish during their summer outbreak. Three distinct jellyfish compartments, namely umbrella, oral arms, and the mucus secretion obtained from whole specimens were screened for specifically associated microbiota. A total of 17 phyla, 30 classes, 73 orders, 146 families and 329 genera of microbial organisms were represented in R. pulmo samples with three major clades (i.e. Spiroplasma, Mycoplasma and Wolinella) representing over 90% of the retrieved total sequences. The taxonomic microbial inventory was then combined with metabolic profiling data obtained from the Biolog Eco-Plate system. Significant differences among the jellyfish compartments were detected in terms of bacterial abundance, diversity and metabolic utilization of 31 different carbon sources with the highest value of abundance and metabolic potential in the mucus secretion compared to the umbrella and oral arms. Results are discussed in the framework of the species ecology as well as the potential health hazard for marine organisms and humans.
水母是海洋食物网的重要组成部分，其种群密度波动较大，具有突然爆发的能力，随后会出现稀有期。尽管人们已经做出了相当大的努力来研究全球范围内水母种群对人为变化的反应，但现有的证据仍然不清楚。在过去的 50 年里，许多沿海地区的水母数量似乎都在增加，包括地中海，那里的水母爆发周期性地成为海洋和海洋人类活动的一个问题。它们对海洋生物福利的影响还没有被很好地量化。海月水母是一种形成群体的钵水母，其大量种群分布在地中海各地，周期性地增加，数量也不稳定。有关刺胞动物水母的研究表明，它们是细菌病原体的重要载体。在本研究中，我们结合传统的基于培养的方法和高通量扩增子测序（HTS）方法，在夏季暴发期间描述了与这种水母相关的细菌群落的多样性。我们对伞部、口腕部和整个标本的粘液分泌物这三个独特的水母部位进行了筛选，以寻找与之相关的特定微生物群。从 R. pulmo 样本中总共代表了 17 个门、30 个纲、73 个目、146 个科和 329 个属的微生物，其中三个主要的进化枝（即螺旋体、支原体和沃林氏菌）占所回收的总序列的 90%以上。然后，我们将分类学微生物目录与从 Biolog Eco-Plate 系统获得的代谢谱数据结合起来。在伞部、口腕部和粘液分泌部三个水母部位之间，在细菌丰度、多样性和 31 种不同碳源的代谢利用方面都存在显著差异，与伞部和口腕部相比，粘液分泌部的细菌丰度和代谢潜力最高。结果从物种生态学以及对海洋生物和人类的潜在健康危害两个方面进行了讨论。
