Abstract：
Ships\' ballast water and sediments have long been linked to the global transport and expansion of invasive species and thus have become a hot research topic and administrative challenge in the past decades. The relevant concerns, however, have been mainly about the ocean-to-ocean invasion and sampling practices have been almost exclusively conducted onboard. We examined and compared the dinoflagellate cysts assemblages in 49 sediment samples collected from ballast tanks of international and domestic routes ships, washing basins associated with a ship-repair yard, Jiangyin Port (PS), and the nearby area of Yangtze River (YR) during 2017-2018. A total of 43 dinoflagellates were fully identified to species level by metabarcoding, single-cyst PCR-based sequencing, cyst germination and phylogenetic analyses, including 12 species never reported from waters of China, 14 HABs-causing, 9 toxic, and 10 not strictly marine species. Our metabarcoding and single-cyst sequencing also detected many OTUs and cysts of dinoflagellates that could not be fully identified, indicating ballast tank sediments being a risky repository of currently unrecognizable invasive species. Particularly important, 10 brackish and fresh water species of dinoflagellate cysts (such as Tyrannodinium edax) were detected from the transoceanic ships, indicating these species may function as alien species potentially invading the inland rivers and adjacent lakes if these ships conduct deballast and other practices in fresh waterbodies. Significantly higher numbers of reads and OTUs of dinoflagellates in the ballast tanks and washing basins than that in PS and YR indicate a risk of releasing cysts by ships and the associated ship-repair yards to the surrounding waters. Phylogenetic analyses revealed high intra-species genetic diversity for multiple cyst species from different ballast tanks. Our work provides novel insights into the risk of bio-invasion to fresh waters conveyed in ship\'s ballast tank sediments and washing basins of shipyards.
摘要：
船舶压载水和沉积物长期以来一直与入侵物种的全球运输和扩张有关，因此在过去几十年中已成为热门的研究课题和管理挑战。相关关注,然而,主要是关于海洋对海洋的入侵，采样实践几乎完全是在船上进行的。我们检查并比较了从国际和国内航线船舶压载舱收集的49个沉积物样品中的鞭毛藻囊肿组合，与修船场相关的洗涤池，江阴港(PS),以及2017-2018年长江（YR）附近地区。总共有43个鞭毛藻被完全鉴定到物种水平，基于单囊肿PCR的测序，囊肿萌发和系统发育分析，包括12个从未从中国水域报告的物种，导致14例HAB，9有毒，和10个不严格的海洋物种。我们的元转录编码和单囊肿测序还检测到许多无法完全识别的OTU和鞭毛藻囊肿，表明压载舱沉积物是目前无法识别的入侵物种的危险储存库。尤其重要的是,从越洋船只中检测到10种微咸和淡水的鞭毛藻囊肿（例如Tyrannodiniumedax），表明如果这些船只在淡水体内进行deballast和其他做法，这些物种可能会作为外来物种入侵内陆河流和邻近的湖泊。压载舱和洗涤盆中鞭毛藻的读数和OTU数量明显高于PS和YR，这表明船舶和相关的修船场将囊肿释放到周围水域的风险。系统发育分析显示，来自不同压载舱的多个囊肿物种的物种内遗传多样性很高。我们的工作为生物入侵在船舶压载舱沉积物和造船厂洗涤盆中输送的淡水的风险提供了新的见解。
