Department of Civil and Environmental Engineering, Faculty of Engineering , University of Miyazaki , 1-1 Gakuen Kibanadai-Nishi , Miyazaki 889-2192 , Japan.
Environ Sci Technol. 2018 Sep 18;52(18):10562-10570. doi: 10.1021/acs.est.8b02293. Epub 2018 Aug 24.
The environmental DNA (eDNA) method is a novel technique for precise and efficient biological surveillance. Although eDNA has been widely used to monitor various freshwater organisms, eDNA dynamics in streams remain poorly understood. In this study, we investigated the eDNA dynamics of common carp ( Cyprinus carpio) in a forested headwater stream affected by the effluent from a carp farm. We evaluated the longitudinal variation in carp eDNA along a river downstream from the farm and performed a temporal eDNA decay experiment using digital polymerase chain reaction. On the basis of the resulting decay constants, we built a model to simulate the advection and degradation of eDNA along the studied river. The observed eDNA flux (concentration multiplied by flow rate) decreased exponentially with distance downstream from the farm, and eDNA was detected 3 km downstream of the farm. Although the water temperatures were similar, the eDNA decay constant was lower in autumn than in summer. The simulated eDNA concentration was markedly larger (>10 times) than the observed concentration, suggesting that eDNA removal is accelerated in the stream environment compared to in conventional experimental settings.
环境 DNA（eDNA）方法是一种精确而高效的生物监测新技术。尽管 eDNA 已被广泛用于监测各种淡水生物，但溪流中的 eDNA 动态仍知之甚少。在这项研究中，我们调查了受鲤鱼养殖场废水影响的森林溪流中普通鲤鱼（Cyprinus carpio）的 eDNA 动态。我们评估了鲤鱼 eDNA 沿养殖场下游河流的纵向变化，并使用数字聚合酶链反应进行了时间 eDNA 衰减实验。根据得出的衰减常数，我们建立了一个模型来模拟研究河流中 eDNA 的对流和降解。观察到的 eDNA 通量（浓度乘以流速）随养殖场下游距离的增加呈指数下降，并且在养殖场下游 3 公里处检测到了 eDNA。尽管水温相似，但秋季的 eDNA 衰减常数低于夏季。模拟的 eDNA 浓度明显大于（> 10 倍）观察到的浓度，这表明与传统实验设置相比，eDNA 在溪流环境中被更快地去除。
