Great Lakes Institute for Environmental Research, University of Windsor, Windsor, ON N9B 3P4, Canada.
School of Ecology and Environmental Science, Yunnan University, Kunming 650091, China; Great Lakes Institute for Environmental Research, University of Windsor, Windsor, ON N9B 3P4, Canada.
Sci Total Environ. 2021 Apr 15;765:144435. doi: 10.1016/j.scitotenv.2020.144435. Epub 2020 Dec 24.
The quagga mussel (Dreissena rostriformis bugensis) is a filter-feeding invasive species that has re-engineered many freshwater ecosystems worldwide. High clearance rates (CRs) and dense populations underpin their ecological impacts. CRs, however, are highly variable, as are environmental factors that regulate them. Despite their widespread distribution in Europe and North America, knowledge of how multiple environmental factors regulate CRs of quagga mussels remains limited. We investigated quagga mussel CRs under varying conditions including water temperature, food availability, habitat depth, flow velocity, and duration of incubation in chambers with both static and flowing water. We found that CR was positively related to water temperature and initial food concentration in static chambers. When coupled with limited food concentration, cold water (7.5 °C), due to a deep-water upwelling event, produced very low CR (~ 10× lower) compared to warmer water (12-24 °C) (0.47 vs. 3.12-5.84 L g DW h). Mussels from deeper water (20 m) had CRs that were ~ 3.5× higher than from shallower depths (2-10 m) and CRs were inversely affected by total mussel dry weight. Flow rates from 1 to 22 cm s generated a unimodal pattern of CR with an optimal flow velocity of 6-12 cm s (~ 2× higher than suboptimal CRs). Enhanced flow velocity (22 cm s), reflective of storm conditions in shallow waters, significantly increased the closing/reopening activity of mussel valves relative to lower velocities (1-12 cm s). Incubation time had a strong negative effect (~ 2-4× reduction) on CRs likely reflecting refiltration in static chambers versus food saturation of mussels in flowing chambers, respectively. Our findings highlight how multiple factors can influence quagga mussel CRs by factors of 2-10. Given widespread habitat heterogeneity in large aquatic ecosystems, whole-lake estimates of mussel impacts should include multiple regulatory factors that affect mussel filtration.
斑马贻贝（Dreissena rostriformis bugensis）是一种滤食性入侵物种，它重新塑造了全球许多淡水生态系统。高清除率（CR）和密集的种群是其生态影响的基础。然而，CR 变化很大，调节 CR 的环境因素也是如此。尽管斑马贻贝在欧洲和北美广泛分布，但对多种环境因素如何调节斑马贻贝 CR 的了解仍然有限。我们在静态和流动水室中，研究了在不同条件下，包括水温、食物供应、栖息地深度、流速以及孵育时间，对斑马贻贝 CR 的影响。我们发现，在静态室中，CR 与水温呈正相关，与初始食物浓度也呈正相关。当与有限的食物浓度结合时，由于深水上升事件，冷水（7.5°C）会产生非常低的 CR（低 10 倍），与较温暖的水（12-24°C）相比（0.47 对 3.12-5.84 L g DW h）。来自较深水域（20 米）的贻贝的 CR 比来自较浅水域（2-10 米）的贻贝高约 3.5 倍，并且 CR 受到贻贝总干重的影响呈反比。流速从 1 到 22 cm s 产生 CR 的单峰模式，最佳流速为 6-12 cm s（比次优 CR 高约 2 倍）。增强的流速（22 cm s），反映了浅水的风暴条件，相对于较低的流速（1-12 cm s），显著增加了贻贝阀的关闭/打开活动。孵育时间对 CR 有很强的负面影响（减少约 2-4 倍），这可能反映了在静态室中再过滤与在流动室中贻贝食物饱和的分别。我们的研究结果表明，多种因素可以通过 2-10 倍的因子影响斑马贻贝的 CR。考虑到大型水生生态系统中广泛存在的栖息地异质性，对贻贝影响的全湖估计应该包括影响贻贝过滤的多个调节因素。
