Fish inhabiting rice field: Bioaccumulation, oxidative stress and neurotoxic effects after pesticides application

The present study aimed to evaluate the biological effects triggered by the application of a current-use mixture of pesticides (the herbicide glyphosate, the insecticide bifenthrin, BF, and the fungicides azoxystrobin, AZ, and cyproconazole, CYP) on two native fish (Markiana nigripinnis and Astyanax lacustris) inhabiting a rice field. We analyzed pesticide residues in water, sediment and fish samples 21 days before and after a fumigation event. Additionally, organismic indices, oxidative stress and neurotoxicity biomarkers in fish at both sampling periods were compared. After fumigation, glyphosate, BF, AZ and CYP were detected in water and sediment samples, being also bioaccumulated in both fish species. A decreasing condition factor in A. lacustris and a higher liver somatic index in M. nigripinnis were observed as well. Overall, results showed that, after the application of the pesticide mixture, antioxidant mechanisms failed to prevent oxidative damage in the liver and gills of M. nigripinnis. Meanwhile, A. lacustris showed a different response: an inhibition of the antioxidant defenses without tissue lipid oxidative damage. Furthermore, acetylcholinesterase activity after spraying was significantly reduced in brain and muscle tissues of A. lacustris and in the brain of M. nigripinnis. Our results show that current-use pesticides, like glyphosate, BF, AZ and CYP, pose health risks on native fish populations inhabiting rice fields.Fil: Rossi, Andrea Silvana. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Instituto Nacional de Limnología. Universidad Nacional del Litoral. Instituto Nacional de Limnología; ArgentinaFil: Fantón, Noelia Isabel. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Instituto Nacional de Limnología. Universidad Nacional del Litoral. Instituto Nacional de Limnología; ArgentinaFil: Michlig, Melina Paola. Universidad Nacional del Litoral. Facultad de Ingeniería Química. Programa de Investigación y Análisis de Residuos y Contaminantes Químicos; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Repetti, María Rosa. Universidad Nacional del Litoral. Facultad de Ingeniería Química. Programa de Investigación y Análisis de Residuos y Contaminantes Químicos; ArgentinaFil: Cazenave, Jimena. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Instituto Nacional de Limnología. Universidad Nacional del Litoral. Instituto Nacional de Limnología; Argentin

Effects of a glyphosate-based herbicide on the development and biochemical biomarkers of the freshwater copepod Notodiaptomus carteri (Lowndes, 1934)

In this work we analyzed the effects of Sulfosato Touchdown®, a glyphosate-based herbicide, on the ontogenic development and biochemical markers of the freshwater copepod Notodiaptomus carteri. A 30-days life-cycle experiment was carried out with three different glyphosate concentrations (0, 0.38, and 0.81 mg L−1) to analyze the developmental time from nauplii to adult copepods and their individual growth. An additional 10-days experiment with the same glyphosate concentrations was designed to evaluate the energy reserves (glycogen, proteins and lipids) and the activity of three antioxidant enzymes, superoxide dismutase (SOD), catalase, and glutathione-S-transferase (GST) in adult copepods, separately for females and males. We found that the lowest glyphosate concentration increased the nauplii and total development time. The highest glyphosate concentration prevented copepods from reaching the adult stage, inhibited the growth of the first copepodite stage and increased the GST and SOD activity in adult females. According to our results, the presence of this herbicide in freshwater systems could impose a risk in the ecological role of copepods in nature. This study will contribute to propose the Notodiaptomus genus as model specie for monitoring purposes in the Neotropical aquatic systems.Fil: Fantón, Noelia Isabel. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Instituto Nacional de Limnología. Universidad Nacional del Litoral. Instituto Nacional de Limnología; ArgentinaFil: Bacchetta, Carla. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Instituto Nacional de Limnología. Universidad Nacional del Litoral. Instituto Nacional de Limnología; ArgentinaFil: Rossi, Andrea Silvana. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Instituto Nacional de Limnología. Universidad Nacional del Litoral. Instituto Nacional de Limnología; Argentina. Universidad Nacional del Litoral. Facultad de Humanidades y Ciencias; ArgentinaFil: Gutierrez, Marìa Florencia. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Instituto Nacional de Limnología. Universidad Nacional del Litoral. Instituto Nacional de Limnología; Argentina. Universidad Nacional del Litoral. Facultad de Bioquímica y Ciencias Biológicas. Escuela Superior de Sanidad; Argentin

Shifts in Zooplankton Behavior Caused by a Mixture of Pesticides

Behavioral changes have been considered as appropriate to evaluate sublethal effects of pollutants. The aim of this study was to evaluate the effects of a mixture of pesticides, with glyphosate and 2,4-D (Gly + 2,4-D) as active ingredients, on the zooplankton evasion behavior from the fish Cnesterodon decemmaculatus. An increase in the evasion behavior was observed for copepods at two different concentrations of the Gly + 2,4-D mixture, for cladocerans at the lowest pesticide concentration, and for rotifers at the highest pesticide concentration. The response time to the fish signals also differed, being copepods faster than cladocerans and rotifers. All the exposed organisms showed higher variability in their distribution over time than those of controls (without pesticides). Our results suggest that the Gly + 2,4-D mixture formulations may have a mimetic effect with the fish alarm signals. The potential consequences of maladaptive responses triggered by pesticides, as well as the increased swimming activity, are discussed.Fil: Andrade, Victoria Soledad. Universidad Nacional del Litoral. Facultad de Humanidades y Ciencias; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe; ArgentinaFil: Gutierrez, Marìa Florencia. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Instituto Nacional de Limnología. Universidad Nacional del Litoral. Instituto Nacional de Limnología; ArgentinaFil: Fantón, Noelia Isabel. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe; Argentina. Universidad Nacional del Litoral. Facultad de Humanidades y Ciencias; ArgentinaFil: Gagneten, Ana María. Universidad Nacional del Litoral. Facultad de Humanidades y Ciencias; Argentin

Facing predation risk in aquatic systems: Differential response of zooplankton and habituation to the false alarm

In aquatic systems, physical and chemical alarm signals favor early detection of predators and promote the development of antipredation behaviors in prey. However, further studies are needed to understand how different antipredation behavior could be among different species coexisting in a natural assembly. In this study, we conducted an indoor experiment with a zooplankton assemblage from a natural subtropical system to experimentally analyze their evasion behavior when exposed to an enclosed visual predator. We aimed to assess whether such behavior was different depending on the species within the assemblage and if they habituate to the alarm signals released by the predator after a certain period of time without receiving any real attack. Ostracods, cladocerans and copepod nauplii evaded the predator, but differed in the magnitude of the response as well as in the response time. However, the evasion behavior was not maintained through time and most organisms returned to an even distribution as time passed, suggesting that zooplankters may habituate to alarm signals. Adult copepods and copepodites (here analyzed together) did not evade fish and showed an almost homogeneous distribution over time. Rotifers moved over time, independently of fish presence. Differential responses to the same alarm signals may contribute to determining the spatial distribution of zooplankton in natural aquatic ecosystems.Fil: Gutierrez, Marìa Florencia. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Instituto Nacional de Limnología. Universidad Nacional del Litoral. Instituto Nacional de Limnología; ArgentinaFil: Andrade, Victoria Soledad. Universidad Nacional del Litoral. Facultad de Humanidades y Ciencias; ArgentinaFil: Fantón, Noelia Isabel. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Instituto Nacional de Limnología. Universidad Nacional del Litoral. Instituto Nacional de Limnología; ArgentinaFil: Gagneten, Ana María. Universidad Nacional del Litoral. Facultad de Humanidades y Ciencias; Argentin