Snyder Elise D, Tank Jennifer L, Brandão-Dias Pedro F P, Bibby Kyle, Shogren Arial J, Bivins Aaron W, Peters Brett, Curtis Erik M, Bolster Diogo, Egan Scott P, Lamberti Gary A
Department of Biological Sciences, University of Notre Dame, 100 Galvin Life Sciences, Notre Dame, IN 46556, USA.
Department of BioSciences, Rice University, 6100 Main St, Houston, TX 77005-1827, USA.
Sci Total Environ. 2023 Dec 10;903:166469. doi: 10.1016/j.scitotenv.2023.166469. Epub 2023 Aug 24.
The use of environmental DNA (eDNA) as a sampling tool offers insights into the detection of invasive and/or rare aquatic species and enables biodiversity assessment without traditional sampling approaches, which are often labor-intensive. However, our understanding of the environmental factors that impact eDNA removal (i.e., how rapidly eDNA is removed from the water column by the combination of decay and physical removal) in flowing waters is limited. This limitation constrains predictions about the location and density of target organisms after positive detection. To address this question, we spiked Common Carp (Cyprinus carpio) eDNA into recirculating mesocosms (n = 24) under varying light (shaded versus open) and benthic substrate conditions (no substrate, bare substrate, and biofilm-colonized substrate). We then collected water samples from each mesocosm at four time points (40 min, 6 h, 18 h, and 48 h), and sequentially filtered the samples through 10, 1.0, and 0.2 μm filters to quantify removal rates for different eDNA particle sizes under varying light and substrate conditions. Combining all size classes, total eDNA removal rates were higher for mesocosms with biofilm-colonized substrate compared to those with no substrate or bare (i.e., no biofilm) substrate, which is consistent with previous findings linking biofilm colonization with increased eDNA removal and degradation. Additionally, when biofilm was present, light availability increased eDNA removal; eDNA levels fell below detection after 6-18 h for open mesocosms versus 18-48 h for shaded mesocosms. Among size classes, larger particles (>10 μm) were removed faster than small particles (1.0-0.2 μm). These results suggest that changes in the distribution of eDNA size classes over time (e.g., with downstream transport) and with differing environmental conditions could be used to predict the location of target organisms in flowing waters, which will advance the use of eDNA as a tool for species monitoring and management.
将环境DNA（eDNA）用作采样工具，有助于洞察入侵性和/或珍稀水生物种的检测情况，还能在无需传统采样方法（通常需要耗费大量人力）的情况下实现生物多样性评估。然而，我们对影响流水环境中eDNA去除的环境因素（即通过衰变和物理去除相结合的方式，eDNA从水柱中被去除的速度有多快）的了解有限。这一限制制约了在检测到目标生物后对其位置和密度的预测。为解决这个问题，我们在不同光照条件（遮蔽与开阔）和底栖底物条件（无底物、光秃底物和有生物膜附着的底物）下，将鲤鱼（Cyprinus carpio）的eDNA添加到循环中宇宙（n = 24）中。然后，我们在四个时间点（40分钟、6小时、18小时和48小时）从每个中宇宙采集水样，并依次通过10微米、1.0微米和0.2微米的滤膜对样品进行过滤，以量化在不同光照和底物条件下不同eDNA粒径的去除率。综合所有粒径类别来看，与没有底物或光秃（即无生物膜）底物的中宇宙相比，有生物膜附着底物的中宇宙中eDNA的总去除率更高，这与之前将生物膜附着与eDNA去除和降解增加联系起来的研究结果一致。此外，当存在生物膜时，光照可提高eDNA的去除率；开阔中宇宙中的eDNA水平在6 - 18小时后降至检测限以下，而遮蔽中宇宙则在18 - 48小时后。在不同粒径类别中，较大颗粒（>10微米）的去除速度比小颗粒（1.0 - 0.2微米）更快。这些结果表明，eDNA粒径类别随时间（例如随着下游传输）和不同环境条件的变化，可用于预测流水环境中目标生物的位置，这将推动eDNA作为物种监测和管理工具的应用。
