Assessing effects of the fungicide tebuconazole to heterotrophic microbes in aquatic microcosms

Dimitrov, Maurício R.; Kosol, Sujitra; Smidt, Hauke; Buijse, Laura; Brink, Paul J. Van den; Wijngaarden, R.P.A. van; Brock, T.C.M.; Maltby, Lorraine

doi:10.1016/j.scitotenv.2014.05.073

Cited by 61 publications

(52 citation statements)

References 72 publications

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“…Indeed, the response of natural microbial communities to toxicant exposure likely depends on a combination of parameters such as initial composition, physiological status, or the environmental characteristics of the sampling site and the experimental systems. This could explain why Dimitrov et al (2014) observed no response of fungal communities decomposing Alnus leaves at very high TBZ concentrations (238 µg L−1) over a 52-day exposure in a semi-field study (experimental ditches). Overall, the great heterogeneity among studies on microbial responses to TBZ confirms the need to increase the ecological relevance of ecotoxicological risk assessment by considering the biodiversity, functions and response dynamics involved (Clements andRohr, 2009 andGeiszinger et al, 2009).…”

Section: Effects Of Individual Stressors On Microbial Leaf Litter Decmentioning

confidence: 98%

Combined effects of drought and the fungicide tebuconazole on aquatic leaf litter decomposition

et al. 2016

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Highlights• The combined effects of drought and the fungicide tebuconazole on aquatic leaf litter decomposition (LLD) were assessed.• TBZ applied alone had no significant effect on LLD.• Drought strongly impacted the microbial LLD process and led to cascading effects on Gammarus feeding.• Structural and functional effects increased when drought and TBZ were applied simultaneously. AbstractLoss of biodiversity and altered ecosystem functioning are driven by the cumulative effects of multiple natural and anthropogenic stressors affecting both quantity and quality of water resources. Here we performed a 40-day laboratory microcosm experiment to assess the individual and combined effects of drought and the model fungicide tebuconazole (TBZ) on leaf litter decomposition (LLD), a fundamental biogeochemical process in freshwater ecosystems. Starting out from a worst-case scenario perspective, leaf-associated microbial communities were exposed to severe drought conditions (four 5-day drought periods alternated with 4-day immersion periods) and/or a chronic exposure to TBZ (nominal concentration of 20 µg L−1). We assessed the direct effects of drought and fungicide on the structure (biomass, diversity) and activity (extracellular enzymatic potential) of fungal and bacterial assemblages colonizing leaves. We also investigated indirect effects on the feeding rates of the amphipod Gammarus fossarum on leaves previously exposed to drought and/or TBZ contamination. Results indicate a stronger effect of drought stress than fungicide contamination under the experimental conditions applied. Indeed, the drought stress strongly impacted microbial community structure and activities, inhibiting the LLD process and leading to cascading effects on macroinvertebrate feeding. However, despite the lack of significant effect of TBZ applied alone, the effects of drought on microbial functions (i.e., decrease in LLD and in enzymatic activities) and on Gammarus feeding rates were more pronounced when drought and TBZ stresses were applied together. In a perspective of ecological risk assessment and ecosystem management for sustainability, these findings stress the need for deeper insight into how multiple stressors can affect the functioning of aquatic ecosystems and associated services.

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Section: Effects Of Individual Stressors On Microbial Leaf Litter Decmentioning

confidence: 98%

Combined effects of drought and the fungicide tebuconazole on aquatic leaf litter decomposition

et al. 2016

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“…Cordova-Kreylos et al, 2006;Widenfalk et al, 2008b;Lin et al, 2012;Dimitrov et al, 2014). Despite the detailed information that these methods provide, the recent studies of Lin et al (2012) and Dimitrov et al (2014) failed to demonstrate significant effects of two fungicides on the structure of total bacterial and fungal communities in sediments.…”

Section: Current Knowledge On Effects Of Pesticides On Sediment Micromentioning

confidence: 99%

“…Diepens et al (2014a) argue that a combination of endpoints relating to functioning (enzyme activity, functional genomics) and microbial composition (targeting ribosomal RNA) may offer a more complete overview of the effects of sediment-bound toxicants on microbial communities. Examples of such an approach are provided by Widenfalk et al (2008a) and Dimitrov et al (2014), who studied the responses of benthic microbial communities to pesticide exposure. Measuring effects on community-level functions in laboratory microcosms can be comparatively straight-forward, following similar approaches as for the tests of effects of PPPs on microbial assemblages of sewage treatment processes and on microbial nitrogen transformation in soil, already included in the EU data requirements.…”

Section: Investigating Community-level Properties Of Sediment Microormentioning

confidence: 99%

“…Nucleic acid-based molecular methods have higher potential to give detailed information on the structure and diversity of microbial communities and specific phylogenetic or functional groups. Thus, investigations of pesticide effects on aquatic microbial assemblages have employed denaturing or temperature gradient gel electrophoresis, terminal restriction fragment length polymorphism, fluorescence in situ hybridisation and, more recently, 454 pyrosequencing (Chinalia and Killham, 2006;Pesce et al, 2006;Stachowski-Haberkorn et al, 2008;Pesce et al, 2009;Tadonléké et al, 2009;Vercraene-Eairmal et al, 2010;Lin et al, 2012;Aguayo et al, 2014;Dimitrov et al, 2014).…”

Section: Investigating Community-level Properties Of Sediment Microormentioning

confidence: 99%

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Scientific Opinion on the effect assessment for pesticides on sediment organisms in edge‐of‐field surface water

2015

EFS2

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The EFSA Panel on Plant Protection Products and their Residues (PPR Panel) was tasked to revise the Guidance Document (GD) on Aquatic Ecotoxicology under Council Directive 91/414/EEC (SANCO/3268/2001 rev. 4 (final), 17 October 2002. This scientific opinion of the PPR Panel is the second of three requested deliverables within this mandate. The scientific background for the risk assessment on sediment organisms in edge-of-field surface waters is provided, with reference to benthic ecology and ecotoxicology, available test protocols and current knowledge on exposure and effects of sediment-bound plant protection products (PPPs). The scientific opinion provides approaches on how to derive regulatory acceptable concentrations (RACs) for sediment organisms and exposure to active substances of PPPs and transformation products of these substances, and how to link them in a tiered approach to predicted environmental concentrations (PECs) for the sediment compartment. A list of uncertainties in relation to such approaches is given. SUMMARYSediment Environmental Risk Assessment (ERA) is a combination of exposure and effect assessment. Proposals for these assessments are provided. The opinion describes specific protection goals (SPGs) for sediment-inhabiting organisms based on two options (1) the ecological threshold option (ETO), accepting negligible population effects only, and (2) if applicable, the ecological recovery option (ERO), accepting some population-level effects if ecological recovery takes place within an acceptable time period.Triggers for sediment ecotoxicity testing are proposed together with a decision scheme for when additional testing may be required. The ecotoxicologically relevant concentrations (ERCs) for sediment organisms are proposed, as this will be influenced by the choice of sediment layer, exposure metric and test duration.The current Forum for the co-ordination of pesticide fate models and their use (FOCUS) methodology for surface water does not consider the effect of multi-year applications, which could possibly lead to accumulation of pesticides in sediment. To account for this deficit, a proposed methodology for introducing an accumulation factor that can be used until an updated FOCUS methodology becomes available is presented in this opinion. The accumulation factor can be considered a conservative approach, since it does not include any possible transport processes, such as leaching or volatilisation, which may reduce the accumulation in sediment in the real field situation.A tiered effect assessment approach is proposed for different sediment organisms and how to link regulatory acceptable concentrations (RACs) to predicted environmental concentration (PECs). The assessment of bioaccumulation, biomagnification and secondary poisoning is discussed, as well as the prospect of improving ERA for sediment microorganisms.Transformation products from active substances also may need to be assessed, as well as mixture toxicity of formulations of plant protection products (PPPs). The op...

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“…Strobilurins kill fungi by inhibiting respiration and energy synthesis (16). Tebuconazole inhibits ergosterol biosynthesis, which is required for fungal membrane structure and fluidity (17). Pyrimethanil, hymexazol, and chlorothalonil are also potential antifungal agents with different mechanisms against diverse fungi (1820).…”

mentioning

confidence: 99%

Antimicrobial Cocktails to Control Bacterial and Fungal Contamination in Chlamydomonas Reinhardtii Cultures

et al. 2016

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Chlamydomonas reinhardtii is a unicellular green alga widely used for research in photosynthesis, cell cycle regulation, ciliary biogenesis, and other physiological processes. Sterile cultures are needed for these studies, but contamination from bacteria and fungi occurs frequently. Although the One-shot Solution cocktail consisting of carbendazim, ampicillin, and cefotaxime has been developed for removing these contaminants from algal cultures, it is not always effective. Here we report two new antimicrobial cocktails for treating mixed bacterial and fungal contamination of Chlamydomonas cultures. A combination of the bactericide nalidixic acid with one of two fungicides, azoxystrobin or tebuconazole, was more effective than the One-shot Solution cocktail. In some of our tests, we find that alternating use of our new cocktails with One-shot Solution is needed to remove obstinate contaminants.

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Assessing effects of the fungicide tebuconazole to heterotrophic microbes in aquatic microcosms

Cited by 61 publications

References 72 publications

Combined effects of drought and the fungicide tebuconazole on aquatic leaf litter decomposition

Combined effects of drought and the fungicide tebuconazole on aquatic leaf litter decomposition

Scientific Opinion on the effect assessment for pesticides on sediment organisms in edge‐of‐field surface water

Antimicrobial Cocktails to Control Bacterial and Fungal Contamination in Chlamydomonas Reinhardtii Cultures

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