摘要
The toxic dinoflagellate Karenia mikimotoi frequently forms harmful algal blooms (HABs) and thus causes massive kills of fish and shellfish in worldwide coastal waters, which has led to intensive investigations on multiple facets of the species. Following our recent discovery of K. mikimotoi forming resting cyst, a very possible mechanism for the inoculation of blooms and geographic expansion for this and many other HABs-causing species, here we report our detection of K. mikimotoi resting cysts in 125 surface sediment samples collected from the coastal waters (covering a latitude range from 18.29°N to 39.85°N) and 3 sediment cores (accumulated in 70‒100 years) collected from the East China Sea where are adjacent to the frequent blooming areas of K. mikimotoi. Via applications of quantitative real-time PCR (LSU rDNA-targeted), species-specific fluorescence in situ hybridization (FISH), and nested-PCR-and-sequencing to both types of the sediment samples that were pretreated with sodium polytungstate solution (SPT), we demonstrated that 1) K. mikimotoi cysts are widely present in surface sediments of the China seas (Bohai Sea (BS), Yellow Sea (YS), East China Sea (ECS), and South China Sea (SCS)), 2) the abundance of cysts is generally low (0 to 33 cysts in 32 g wet sediment), with that in the ECS and the SCS being higher than that in the YS and the BS, and the highest abundance was observed in sites of the ECS (e.g., Ningde, Fujian province) where the blooms of the species occurred frequently, as quantified by both methods, and 3) the cysts of K. mikimotoi have been present in the sediments of the ECS since 1970s, a short time prior to the first recorded bloom of K. mikimotoi in the SCS at 1980s. Our results not only demonstrated the wide geographic distribution of resting cyst of K. mikimotoi along the coast of China, but also proved a 50 years preservation of the cysts in the sediments of coastal area prone to forming frequent blooms. We consider our results have provided critical insights into the mechanisms of frequent bloom outbreaks and global distribution of K. mikimotoi in general, and particularly into the historical origin of K. mikimotoi in China. Further investigations are suggested to focus on on-site surveys for the cyst production and germination rates.
摘要译文
毒性Dinoflagellate Karenia mikimotoi经常形成有害的藻类绽放（HAB），从而导致全球沿海水域的大规模杀死鱼类和贝类，这导致了对物种多个方面的密集调查。在我们最近发现K.Mikimotoi形成休息囊肿之后，为此和许多其他疾病的种植物种接种盛开和地理扩展的一种非常可能的机制，在这里我们报告了我们在125种表面沉积物样品中的K.Mikimotoi休息囊肿的检测从沿海水域收集（覆盖18.29°N至39.85°N）和3个沉积物核心（70-100岁），从东海收集，毗邻K.Mikimotoi的常旅店盛开区域。通过定量实时PCR（LSU RDNA靶向），物种特异性荧光原位杂交（鱼），并嵌套-PCR和测序与钠钼酸钠溶液预处理的沉积物样品的两种类型（SPT ），我们证明了1）K.Mikimotoi囊肿广泛存在于中国海洋的表面沉积物（渤海（BS），黄海（ys），东海（ECS）和南海（SCS））中， 2）囊肿的丰度通常是低（32g湿沉积物中的0至33囊肿），在ECS中，SCS高于Ys和BS中的SC，并且在地点观察到最高的丰度ECS（例如，宁DE，福建省）繁殖的盛开经常发生，用两种方法量化，3）K.Mikimotoi自20世纪70年代以来的沉积物中存在K.Mikimotoi的囊肿，在短时间内20世纪80年代，在SCS的第一个录制的K.Mikimotoi盛开。我们的结果不仅展示了中国海岸K.Mikimotoi休息的广泛地理分布，而且还证明了50年来保存沿海地区沉积物的囊肿，容易形成频繁的绽放。我们认为，我们的结果已经为常见的盛开爆发和K.Mikimotoi的全球分布的机制提供了重要的见解，特别是在中国K.Mikimotoi的历史起源。建议进一步调查专注于囊肿生产和萌发率的现场调查。
Yuyang Liu[a][b][c];Yunyan Deng[a][b][c];Lixia Shang[a][b][c];Liang Yi[d];Zhangxi Hu[a][b][c];Ying Zhong Tang[a][b][c]. Geographic distribution and historical presence of the resting cysts of Karenia mikimotoi in the seas of China[J]. Harmful Algae, 2021,109