Micro-crustaceans are important grazers that control the algal blooms in eutrophic lakes. However, we know little about how these key species may be affected by long-term exposure to contaminants and when the transgenerational effects are reversible and irreversible. To address this, we investigated the effects of lead (Pb, 100 μg L⁻¹) exposure on morphology and reproduction of Moina dubia for nine consecutive generations (F1–F9) in three treatments: control, Pb, and pPb (M. dubia from Pb-exposed parents returned to the control condition). In F1–F2, Pb did not affect morphology, and reproduction of M. dubia. In all later generations, Pb-exposed M. dubia had a smaller body and shorter antennae than those in control. In F3–F6, pPb-exposed animals showed no differences in body size and antennae compared to the control, suggesting recoverable effects. In F7–F9, the body size and antennae of pPb-exposed animals did not differ compared to Pb-exposed ones, and both were smaller than the control animals, suggesting irreversible effects. Pb exposure reduced the brood size, number of broods and total neonates per female in F3–F9, yet the reproduction could recover in pPb treatment until F7. No recovery of the brood size and number of broods per female was observed in pPb-exposed animals in the F8–F9. Our study suggests that long-term exposure to metals, here Pb, may cause irreversible impairments in morphology and reproduction of tropical urban micro-crustaceans that may lower the top-down control on algal blooms and functioning of eutrophic urban lakes.

微甲壳类动物是重要的放牧者，它们控制着富营养化湖泊中的藻华。但是，我们对这些关键物种如何受到长期暴露于污染物的影响以及何时的转基因效应是可逆的和不可逆的知之甚少。为了解决这个问题，我们研究了铅（Pb，100μgL ^-1）在三个处理中连续九个世代（F1-F9）暴露于Moina dubia的形态和繁殖：对照，Pb和pPb（来自暴露于Pb的父母的Dubia。Mbia回到对照状态）。在F1-F2中，Pb不会影响形态，也不会影响M. dubia。在所有后代中，与对照相比，暴露于铅的M. dubia的身体较小，触角较短。在F3-F6中，与对照相比，暴露于pPb的动物的体型和触角没有差异，表明具有可恢复的作用。在F7–F9中，暴露于pPb的动物的体形和触角与暴露于Pb的动物没有差异，并且均小于对照动物，表明存在不可逆的作用。在F3–F9中，铅的暴露减少了每只雌性的育雏数量，育雏数量和新生儿总数，然而，直到F7为止，在pPb处理中繁殖都可以恢复。在F8–F9中，暴露于pPb的动物中没有观察到雌性的育雏尺寸和育雏数量的恢复。我们的研究表明，长期暴露于金属（这里为Pb）可能会导致热带城市微型甲壳类动物形态和繁殖的不可逆转的损害，从而可能降低对藻华和水体富营养化城市湖泊的自上而下的控制。