环境DNA在监测表层沉积物中的运用及其与环境变量的关系

Application of environmental DNA in monitorining surface sediment and its relationship to environment variables

环境DNA技术是近几年出现的新兴环境生态监测技术,为研究环境变量对表层沉积物中环境DNA变化的影响,通过小试实验模拟海水环境并以日本大螯蜚作为目标生物,引入4组不同的生物丰度,运用环境DNA技术研究了表层沉积物中环境DNA含量变化与周边环境变量的关系。在小试装置中养殖日本大螯蜚4 d后全部取出,之后启动实验。在实验启动后的第0、6、12、18、24、72、144、264、384小时进行取样,提取出的环境DNA片段含量通过实时荧光进行定量PCR检测。结果表明,表层沉积物中的环境DNA在源生物移除后72 h内降低至较低含量水平,与水体中的环境DNA有较为相似的变化特征。通过广义线性回归分析,发现环境DNA降解速率与水质盐度呈显著负相关(P=0.0005),与pH呈显著正相关(P=0.04),说明表层沉积物中的环境DNA对于周边环境变化具有一定指示意义。上述结果为进一步推动环境DNA技术的应用及其对环境变量影响作用的深入研究提供参考。

Environmental DNA(eDNA)is an emerging tool for environmental and ecological monitoring in recent years.To clarify the effects of environment variables on the variation of eDNA in surface sediment,through the lab-scale experiments which could simulate marine environment and choose benthic organism Grandidierella japonica as target species with 4 groups of different bioabundance,the relationship between the variation of eDNA in surface sediment and ambient environment variables was investigated by using environmental DNA technology.After Grandidierella japonica were cultured for 4 days,and they were taken out from the experimental devices,then the following experiments start-up.The surface sediment samples and water samples were collected at 0,6,12,18,24,72,144,264,384 h from the start-up of the eperiments,the eDNA was extracted from these surface sediment samples and target eDNA copy numbers were determined by quantitative PCR with species-specific primers.The results showed that after removal of Grandidierella japonica,environmental DNA in surface sediment decreased to low level within 72 hours,which was similar to the decreasing characteristics of environmental DNA in water.The general linear modelling regression showed that the eDNA decay rate was significantly and negatively(P=0.0005)related to the water salinity and significantly and positively(P=0.04)related to the pH value,indicating that environment DNA in surface sediment could reflect the changes of surrounding environment at a certain degree.This study provide a reference for promoting the application of eDNA and profoundly studying its effects on environment variables.