Departamento de Ecología, Genética y Evolución, Facultad de Ciencias Exactas y Naturales (C1428EGA), Universidad de Buenos Aires, Buenos Aires, Argentina; Instituto de Ecología, Genética y Evolución de Buenos Aires (IEGEBA), CONICET - Universidad de Buenos Aires (C1428EGA), Buenos Aires, Argentina.
Departamento de Ecología, Genética y Evolución, Facultad de Ciencias Exactas y Naturales (C1428EGA), Universidad de Buenos Aires, Buenos Aires, Argentina.
Chemosphere. 2018 Oct;209:748-757. doi: 10.1016/j.chemosphere.2018.06.129. Epub 2018 Jun 20.
The joint impact of the glyphosate-based commercial formulation Roundup Max and the invasive mussel Limnoperna fortunei on phytoplankton and water quality was assessed in Salto Grande reservoir, a scenario were both stressors coexist. We performed an in situ mesocosm approach, through a 7-day experiment using 400-L enclosures. The following treatments were applied by triplicate: addition of 250 mussels (M); addition of 5 mg L of active ingredient (a.i.) in Roundup Max (R); addition of 250 mussels and 5 mg L of a.i. in Roundup Max (MR), and controls, without any addition (C). R showed higher total phosphorus (TP) and ammonium nitrogen (NNH) concentrations due to the herbicide input, and a significant increase in algal abundance, biovolume and chlorophyll a levels (Chl-a). In M mussels grazed on phytoplankton, which resulted in subsequent phosphates (SRP) release. A decrease in species diversity was observed in R and M with respect to C. In MR, there were higher TP and NNH concentrations, a decrease in biovolume, an antagonistic effect on Chl-a and a synergistic effect on phytoplankton abundance. Species diversity and evenness showed a significant decrease due to the explosive growth of a small and opportunistic Chlorophyta, Spermatozopsis exsultans. The dominance of this species may be due to negative selectivity for S. exsultans and/or release of potential competitors by L. fortunei, and to the input of nutrients by Roundup Max and/or removal of competitors by its toxicity.
评估了草甘膦商业制剂 Roundup Max 和入侵贻贝 Limnoperna fortunei 对 Salto Grande 水库浮游植物和水质的联合影响，在这种情况下两种胁迫因素共存。我们采用原位中尺度方法，通过 7 天的 400-L 围隔实验进行。通过重复 3 次处理应用以下处理：添加 250 只贻贝（M）；添加 5mg/L 的草甘膦有效成分（a.i.）在 Roundup Max 中（R）；添加 250 只贻贝和 5mg/L 的草甘膦有效成分在 Roundup Max 中（MR），以及对照组，没有任何添加（C）。由于除草剂的输入，R 表现出更高的总磷（TP）和铵氮（NNH）浓度，藻类丰度、生物量和叶绿素 a 水平（Chl-a）显著增加。在 M 贻贝中，藻类被贻贝摄食，导致随后磷酸盐（SRP）释放。与 C 相比，R 和 M 的物种多样性减少。在 MR 中，TP 和 NNH 浓度较高，生物量减少，对 Chl-a 有拮抗作用，对浮游植物丰度有协同作用。由于小型和机会主义绿藻 Spermatozopsis exsultans 的爆发式生长，物种多样性和均匀度显著下降。这种物种的优势可能是由于对 S. exsultans 的负选择性和/或 L. fortunei 释放潜在竞争者，以及 Roundup Max 的养分输入和/或其毒性去除竞争者。
