eDNA揭示调水对棘洪滩水库浮游植物的影响

Effect of Water Diversion on Phytoplankton in the Jihongtan Reservoir Revealed by eDNA

引水已被广泛用于解决水资源短缺和安全问题。然而,由于传统浮游植物监测的局限性,热点区域水体的浮游植物多样性及群落结构变化规律并未得到很好的掌握。该研究以胶东调水工程重要的调蓄水库棘洪滩水库为例,利用环境DNA(eDNA)方法分析调水对其浮游植物的影响。对棘洪滩水库全年22个浮游植物样品的16S rDNA V3-V4和18S rDNA V4区域进行扩增子测序。共检测出浮游植物182属种,其中蓝藻40属种,真核浮游植物142属种。与形态学方法相比,eDNA方法在检测纳米/微型浮游植物(尺寸<20μm)方面显示出明显优势。调水显著影响了棘洪滩水库浮游植物物种组成和群落结构的稳定性。调水导致棘洪滩水库蓝藻的相对丰度及多样性升高,真核藻类多样性降低,加之理化因子剧烈变化,为引入的藻类提供了更多的生态位,多种藻类尤其是蓝藻具有较强利用不同资源的能力,共同成为棘洪滩水库的优势种。管理部门要警惕这些粒径较小的优势浮游植物对水库水质可能造成的影响。该研究为调水管理和水质安全预警提供技术支撑。

Water diversion has been widely used to address water shortages and security issues.However,due to the limita⁃tions of traditional phytoplankton monitoring,the phytoplankton diversity and community structure in hotspot areas have not been well understood.In this study,Jihongtan,an important water diversion and storage reservoir of Jiaodong Water Diversion Project,was taken as an example,and the environmental DNA(eDNA)method was used to analyze the impact of water diver⁃sion on its phytoplankton.Amplicon sequencing was performed on the 16S rDNA V3-V4 and 18S rDNA V4 regions of 22 phytoplankton samples from Jihongtan Reservoir throughout the year.A total of 182 genera/species of phytoplankton were detected,including 40 genera/species of cyanobacteria and 142 genera/species of eukaryotic phytoplankton.Compared with morphological methods,the eDNA method showed clear advantages in detecting nano/micro-phytoplankton(<20μm in size).Water transfer significantly affected the stability of phytoplankton species composition and community structure in Jihongtan Reservoir.Water diversion led to an increase in the relative abundance and diversity of the cyanobacteria,and a decrease in the diversity of eukaryotic algae.In addition,the drastic changes in physical and chemical factors provided more ecological niches for the input algae.Various algae,especially the cyanobacteria,with strong ability to utilize different resources have be⁃come the dominant species of the Reservoir.The management department should be alert to the possible impact of these domi⁃nant phytoplankton with smaller particle size on the water quality of the Reservoir.This study provides technical support for water diversion management and water quality safety early warning.