Publicação
Effect of Pesticides on the Interactions Between Springtails and Soil Microbial Communities and their Role in Soil Functioning
| Resumo: | This work explores the relationship between chemical pollutants, soil fauna, and microbial processes within the framework of Ecological Risk Assessment (ERA). Collembola have been widely studied in ecotoxicology. Folsomia candida is used as the standard species in toxicity tests to be indicative of pollutant effects on soil microarthropods; however, such single species tests ignore interactions with other species and functional endpoints. The connection between Collembola and microbial biomass remains unclear, highlighting a research gap in under- standing their interdependence. Using a microcosm test, we investigated the impact of six dif- ferent concentrations of the insecticide Teflubenzuron (0.025, 0.08, 0.25, 0.8, 2.53, and 8 mg/kg soildw), dosed to the top 2 cm soil layer, on a community of four species of Collembola (Folsomia candida, Sinella curviseta, Ceratophysella denticulata, and Protaphorura fimata) and its subsequent effects on microbial community structure. We looked at soil respiration rate and the activity of four enzymes: Phosphomonoesterase, β-glucanase, β-glucosidase and Leucine aminopepti- dase. At 4 different time points (12, 33, 54 and 78 days of), 5 replicates of each soil contaminated with the different concentrations of Teflubenzuron and the controls were destructively sam- pled and the Collembola community composition and abundance were analysed in different soil layers (A = 0 - 2 cm, B = 2 - 4 cm, C = 4 - 10 cm). At the end of the experiment, almost all adult springtails disappeared, also from the controls. When compared to the control groups, the highest concentrations of Teflubenzuron caused a lower production of juveniles, particu- larly in the later stages of the study, consistent with prior research indicating the heightened toxicity of Teflubenzuron to juvenile springtails. Soil respiration rate decreased at 8 mg/kg soildw of Teflubenzuron. Whilst springtail abundance decreased in all soil layers, enzymatic activity showed a general increasing trend until 54 days after the start of the experiment and Teflubenzuron concentration until 0.08 mg/kg soildw. We discuss the complex patterns of the interaction between springtails and microbial parameters exhibited over time and across dif- ferent concentrations of Teflubenzuron, and its consequences for risk assessment. |
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| Autores principais: | Menezes, Laura Adriana van Raaij Ferraz de |
| Assunto: | Collembola Microbial community Teflubenzuron Microcosm |
| Ano: | 2023 |
| País: | Portugal |
| Tipo de documento: | dissertação de mestrado |
| Tipo de acesso: | acesso aberto |
| Instituição associada: | Universidade Nova de Lisboa |
| Idioma: | inglês |
| Origem: | Repositório Institucional da UNL |
| Resumo: | This work explores the relationship between chemical pollutants, soil fauna, and microbial processes within the framework of Ecological Risk Assessment (ERA). Collembola have been widely studied in ecotoxicology. Folsomia candida is used as the standard species in toxicity tests to be indicative of pollutant effects on soil microarthropods; however, such single species tests ignore interactions with other species and functional endpoints. The connection between Collembola and microbial biomass remains unclear, highlighting a research gap in under- standing their interdependence. Using a microcosm test, we investigated the impact of six dif- ferent concentrations of the insecticide Teflubenzuron (0.025, 0.08, 0.25, 0.8, 2.53, and 8 mg/kg soildw), dosed to the top 2 cm soil layer, on a community of four species of Collembola (Folsomia candida, Sinella curviseta, Ceratophysella denticulata, and Protaphorura fimata) and its subsequent effects on microbial community structure. We looked at soil respiration rate and the activity of four enzymes: Phosphomonoesterase, β-glucanase, β-glucosidase and Leucine aminopepti- dase. At 4 different time points (12, 33, 54 and 78 days of), 5 replicates of each soil contaminated with the different concentrations of Teflubenzuron and the controls were destructively sam- pled and the Collembola community composition and abundance were analysed in different soil layers (A = 0 - 2 cm, B = 2 - 4 cm, C = 4 - 10 cm). At the end of the experiment, almost all adult springtails disappeared, also from the controls. When compared to the control groups, the highest concentrations of Teflubenzuron caused a lower production of juveniles, particu- larly in the later stages of the study, consistent with prior research indicating the heightened toxicity of Teflubenzuron to juvenile springtails. Soil respiration rate decreased at 8 mg/kg soildw of Teflubenzuron. Whilst springtail abundance decreased in all soil layers, enzymatic activity showed a general increasing trend until 54 days after the start of the experiment and Teflubenzuron concentration until 0.08 mg/kg soildw. We discuss the complex patterns of the interaction between springtails and microbial parameters exhibited over time and across dif- ferent concentrations of Teflubenzuron, and its consequences for risk assessment. |
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