CAS Key Laboratory of Marine Ecology and Environmental Sciences, Institute of Oceanology, Chinese Academy of Sciences (IOCAS), Qingdao, Shandong, 266000, PR China; Laboratory for Marine Ecology and Environmental Science, Qingdao Marine Science and Technology Center, Qingdao, Shandong, 266237, PR China; College of Marine Science, University of Chinese Academy of Sciences, Beijing 101408, PR China; Center for Ocean Mega-Science, Chinese Academy of Sciences, Qingdao, Shandong, 266000, PR China.
CAS Key Laboratory of Marine Ecology and Environmental Sciences, Institute of Oceanology, Chinese Academy of Sciences (IOCAS), Qingdao, Shandong, 266000, PR China; Laboratory for Marine Ecology and Environmental Science, Qingdao Marine Science and Technology Center, Qingdao, Shandong, 266237, PR China; Center for Ocean Mega-Science, Chinese Academy of Sciences, Qingdao, Shandong, 266000, PR China.
Mar Environ Res. 2024 Nov;202:106764. doi: 10.1016/j.marenvres.2024.106764. Epub 2024 Sep 24.
Ostreococcus (Mamiellophyceae, Chlorophyta) is a cosmopolitan genus of marine pico-phytoplankton and the smallest free-living photosynthetic eukaryotes with cell size of 1-2 μm. To understand the diversity and spatio-temporal distribution of Ostreococcus in the Rongcheng coastal regions in northern China, metabarcoding analysis based on the 18S rDNA V4 molecular marker was applied to study the molecular diversity and seasonal dynamics of Ostreococcus in three typical mariculture bays (Rongcheng Bay, Lidao Bay and Sanggou Bay). A total of 103 amplicon sequence variants (ASVs) annotated as Ostreococcus were detected in these three typical mariculture bays throughout the year. The top five ASVs in terms of abundance were ASV4, ASV9, ASV14, ASV28 and ASV109, totally occupying 99.1% of Ostreococcus reads. Phylogenetic analysis showed that these five dominant ASVs represented two Ostreococcus ecotypes (OI and OII) and were grouped into four Ostreococcus clades including Ostreococcus lucimarinus (ASV9) and Ostreococcus tauri (ASV28 and ASV109) in OI, and Ostreococcus sp. RC1 (ASV4) and Ostreococcus sp. RC2 (ASV14) in OII, which provided direct evidence to support the co-existence of two ecotypes in the Rongcheng coastal regions. Five dominant ASVs in OI and OII exhibited two distinct seasonal distribution patterns. Three dominant ASVs (ASV9, ASV28 and ASV109) in OI could be detected in all four seasons of the year, exhibiting native distribution properties, while two ASVs (ASV4 and ASV14) in OII decreased sharply in winter and could not be detected in spring, exhibiting characteristics of alien inputs. The composition, succession and association of Ostreococcus community were mainly driven by water temperature in these mariculture bays. This study helps us systematically understand the molecular diversity and distribution patterns of Ostreococcus in typical mariculture bays in northern China, laying the foundation for understanding and revealing the ecological functions of pico-phytoplankton.
微藻盘藻（Mamiellophyceae，绿藻门）是一种世界性的海洋微微型浮游植物属，是细胞尺寸为 1-2μm 的最小自由生活的光合真核生物。为了了解中国北方荣成沿海地区盘藻属的多样性和时空分布，应用基于 18S rDNA V4 分子标记的 metabarcoding 分析，研究了三个典型养殖海湾（荣成湾、俚岛湾和桑沟湾）中盘藻属的分子多样性和季节性动态。在这三个典型养殖海湾中，全年共检测到 103 个可注释为盘藻属的扩增子序列变异体（ASV）。丰度最高的前五个 ASV 分别为 ASV4、ASV9、ASV14、ASV28 和 ASV109，总共占盘藻属读数的 99.1%。系统发育分析表明，这五个优势 ASV 代表两种盘藻属生态型（OI 和 OII），并分为四个盘藻属分支，包括 Ostreococcus lucimarinus（ASV9）和 Ostreococcus tauri（ASV28 和 ASV109）在 OI 中，以及 Ostreococcus sp. RC1（ASV4）和 Ostreococcus sp. RC2（ASV14）在 OII 中，这为两种生态型在荣成沿海地区共存提供了直接证据。OI 和 OII 中的五个优势 ASV 表现出两种截然不同的季节性分布模式。OI 中的三个优势 ASV（ASV9、ASV28 和 ASV109）可在一年的四季中检测到，表现出本地分布特性，而 OII 中的两个 ASV（ASV4 和 ASV14）在冬季急剧减少，春季无法检测到，表现出外来输入的特征。这些养殖海湾中盘藻属群落的组成、演替和关联主要受水温驱动。本研究有助于我们系统地了解中国北方典型养殖海湾中盘藻属的分子多样性和分布模式，为了解和揭示微微型浮游植物的生态功能奠定了基础。
