Xu Ruichen, Chapman Duane C, Elliott Caroline M, Call Bruce C, Jacobson Robert B, Wang Binbin
Department of Civil and Environmental Engineering, University of Missouri, Columbia, MO, 65211, USA.
U.S. Geological Survey Columbia Environmental Research Center, Columbia, MO, 65211, USA.
Sci Rep. 2024 Apr 25;14(1):9556. doi: 10.1038/s41598-024-60189-1.
Bighead carp (Hypophthalmichthys nobilis), silver carp (H. molitrix), black carp (Mylopharyngodon piceus), and grass carp (Ctenopharyngodon idella), are invasive species in North America. However, they hold significant economic importance as food sources in China. The drifting stage of carp eggs has received great attention because egg survival rate is strongly affected by river hydrodynamics. In this study, we explored egg-drift dynamics using computational fluid dynamics (CFD) models to infer potential egg settling zones based on mechanistic criteria from simulated turbulence in the Lower Missouri River. Using an 8-km reach, we simulated flow characteristics with four different discharges, representing 45-3% daily flow exceedance. The CFD results elucidate the highly heterogeneous spatial distribution of flow velocity, flow depth, turbulence kinetic energy (TKE), and the dissipation rate of TKE. The river hydrodynamics were used to determine potential egg settling zones using criteria based on shear velocity, vertical turbulence intensity, and Rouse number. Importantly, we examined the difference between hydrodynamic-inferred settling zones and settling zones predicted using an egg-drift transport model. The results indicate that hydrodynamic inference is useful in determining the 'potential' of egg settling, however, egg drifting paths should be taken into account to improve prediction. Our simulation results also indicate that the river turbulence does not surpass the laboratory-identified threshold to pose a threat to carp eggs.
鳙鱼（Hypophthalmichthys nobilis）、鲢鱼（H. molitrix）、青鱼（Mylopharyngodon piceus）和草鱼（Ctenopharyngodon idella）是北美洲的入侵物种。然而，在中国，它们作为食物来源具有重要的经济价值。鲤鱼卵的漂流阶段备受关注，因为卵的存活率受河流水动力的强烈影响。在本研究中，我们使用计算流体动力学（CFD）模型探索了鱼卵漂流动力学，以便根据密苏里河下游模拟湍流的机理标准推断潜在的鱼卵沉降区。我们利用8公里长的河段，模拟了四种不同流量下的水流特性，这些流量代表了超过日流量45%-3%的情况。CFD结果阐明了流速、水深、湍动能（TKE）和TKE耗散率高度不均匀的空间分布。利用基于剪切速度、垂直湍流强度和劳斯数的标准，通过河流水动力来确定潜在的鱼卵沉降区。重要的是，我们研究了水动力推断的沉降区与使用鱼卵漂流运输模型预测的沉降区之间的差异。结果表明，水动力推断在确定鱼卵沉降的“潜力”方面是有用的，然而，为了改进预测，应考虑鱼卵的漂流路径。我们的模拟结果还表明，河流湍流并未超过实验室确定的对鲤鱼卵构成威胁的阈值。
