Laboratório de Limnologia, Departamento de Ecologia, Universidade Federal do Rio de Janeiro (UFRJ), Ilha do Fundão, CEP 21941-590, PO Box 68020, Rio de Janeiro, Rio de Janeiro, Brazil.
Environ Sci Pollut Res Int. 2011 Jul;18(6):1004-14. doi: 10.1007/s11356-011-0455-y. Epub 2011 Feb 8.
Evidence has accumulated that humic substances (HS) are not inert biogeochemicals. Rather, they cause stress symptoms and may modulate the life history of aquatic organisms. Nevertheless, it is still not clear how HS interact with additional stressors and if their effects are transgenerational. We tested the interactive effects of HS and salt to cladocerans, discussing their consequences for the persistence in fluctuating environments, such as coastal lagoons.
We used life-table experiments to test the effects of natural HS from a polyhumic coastal lagoon (0, 5, 10, 20, 50, and 100 mg dissolved organic carbon (DOC) L(-1)) on the life-history of the cladoceran Moina macrocopa. We further tested the effects of HS (10 mg DOC L(-1)), within and across generations, on the resistance of M. macrocopa to salt stress (5.5 g L(-1)).
HS at 5-20 mg DOC L(-1) extended the mean lifespan of M. macrocopa by ~30%. HS also increased body length at maturity by ~4% at 5-50 mg DOC L(-1) and stimulated male offspring production at all tested concentrations. Exposure to HS (even maternal only) alleviated the salt-induced reduction of somatic growth. Co-exposure to HS increased body volume by 12-22% relative to salt-only treatments, while pre-exposure to HS increased body volume by 40-56% in treatments with salt presence, when compared to non-pre-exposed animals.
HS at environmentally realistic concentrations, by acting as mild chemical stressors, modify crucial life-history traits of M. macrocopa, favoring its persistence in fluctuating environments. Some of the effects of HS are even transgenerational.
有证据表明腐殖质（HS）并非惰性的生物地球化学物质。相反，它们会导致应激症状，并可能调节水生生物的生活史。然而，目前仍不清楚 HS 如何与其他胁迫因素相互作用，以及它们的影响是否具有跨代效应。我们测试了 HS 和盐对枝角类动物的相互作用效应，讨论了它们对沿海泻湖等波动环境中持久性的影响。
我们使用生命表实验来测试来自多腐殖质沿海泻湖的天然 HS（0、5、10、20、50 和 100 mg 溶解有机碳（DOC）L(-1)）对枝角类动物大型溞（Moina macrocopa）生活史的影响。我们进一步测试了 HS（10 mg DOC L(-1)）在代内和跨代内对 M. macrocopa 对盐胁迫（5.5 g L(-1)）抗性的影响。
HS 在 5-20 mg DOC L(-1) 范围内将 M. macrocopa 的平均寿命延长了约 30%。HS 还在 5-50 mg DOC L(-1) 范围内将成熟时的体长增加了约 4%，并在所有测试浓度下刺激了雄性后代的产生。暴露于 HS（即使仅母体暴露）减轻了盐诱导的体生长减少。与仅盐处理相比，HS 共暴露将体体积增加了 12-22%，而与未预暴露动物相比，HS 预暴露将盐存在处理中的体体积增加了 40-56%。
在环境现实浓度下，HS 作为轻度化学胁迫因素，改变了大型溞的关键生活史特征，有利于其在波动环境中的持久性。HS 的一些影响甚至具有跨代效应。
