The spatial distribution of the photosynthetic picoeukaryotes community structure in Lake Hongze Raw sequence reads

The spatial dynamics of picophytoplankton were investigated by flow cytometry and high-throughput sequencing in Lake Hongze, a large river-connecting lake. Picophytoplankton were mainly composed of phycocyanin-rich picocyanobacteria (PCY) and photosynthetic picoeukaryotes (PPEs). PCY was the dominant picophytoplankton group since the contribution of PPEs to total picophytoplankton was only 11.78%. However, PPEs were highly diverse and were composed of Chlorophyta, Bacillariophyta and Chrysophyceae. Environmental factors indicated spatial differences, particularly in total phosphorus (TP) , suspended solids (SS) and CODMn, which showed relatively high concentrations around the river channel. The abundances of PPEs and PCY showed similar spatial patterns, which were relatively low in the river course since they were negatively related to SS and CODMn. The top 10 OTUs contributed 79.18% of the total PPEs abundance.

本研究针对大型通江湖泊洪泽湖，采用流式细胞术（flow cytometry）与高通量测序（high-throughput sequencing）技术，解析了超微型浮游植物（picophytoplankton）的空间动态变化规律。超微型浮游植物主要由富含藻蓝蛋白的超微型蓝细菌（PCY）与光合超微型真核浮游生物（PPEs）组成。其中PCY为优势类群，PPEs对超微型浮游植物总丰度的贡献仅为11.78%。尽管PPEs的丰度占比不高，但其物种多样性较高，类群涵盖绿藻门（Chlorophyta）、硅藻门（Bacillariophyta）与金藻纲（Chrysophyceae）。
环境因子存在显著空间异质性，其中总磷（TP）、悬浮颗粒物（SS）与高锰酸盐指数（CODMn）在河道周边区域的浓度相对较高。PPEs与PCY的丰度呈现相似的空间分布模式，河道区域内二者丰度相对偏低，这是由于其丰度与SS、CODMn呈负相关关系。丰度排名前10的操作分类单元（OTUs）占PPEs总丰度的79.18%。