Effects of the Herbicide Metazachlor on Phytoplankton and Periphyton Communities in Outdoor Mesocosms

Noack, U.; Geffke, Thomas; Ramani, Balasubramanian; Papenbrock, Jutta; Braune, Mike; Scheerbaum, Dirk

doi:10.1002/aheh.200200508

Cited by 19 publications

(11 citation statements)

References 9 publications

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“…However, studies have explored the impact of metolachlor, metazachlor or acetochlor, chloroacetanilide herbicides which share a similar mode of action than alachlor (e.g. Noack et al, 2004;Relyea, 2009;Debenest et al, 2009;Roubeix et al, 2011aRoubeix et al, , 2012. For example, previous studies observed that metolachlor and metazachlor generated growth inhibition suggested by lower chlorophyll a levels of phototrophic biofilms exposed at 5 and 30 g L −1 (Noack et al, 2004;Debenest et al, 2009).…”

Section: Alachlor Toxicity Throughout Development Stagesmentioning

confidence: 99%

Changes in tolerance to herbicide toxicity throughout development stages of phototrophic biofilms

Paule¹,

Roubeix²,

Lauga³

et al. 2013

Aquatic Toxicology

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Ecotoxicological experiments have been performed in laboratory-scale microcosms to investigate the sensitivity of phototrophic biofilm communities to the alachlor herbicide, in relation to the stages of phototrophic biofilm maturation (age of the phototrophic biofilms) and physical structure (intact biofilm versus recolonization). The phototrophic biofilms were initially cultivated on artificial supports in a prototype rotating annular bioreactor (RAB) with Taylor-Couette type flow under constant operating conditions. Biofilms were collected after 1.6 and 4.4 weeks of culture providing biofilms with different maturation levels, and then exposed to nominal initial alachlor concentration of 10 μg L(-1) in either intact or recolonized biofilms for 15 days in microcosms (mean time-weighted average concentration - TWAC of 5.52 ± 0.74 μg L(-1)). At the end of the exposure period, alachlor effects were monitored by a combination of biomass descriptors (ash-free dry mass - AFDM, chlorophyll a), structural molecular fingerprinting (T-RFLP), carbon utilization spectra (Biolog) and diatom species composition. We found significant effects that in terms of AFDM, alachlor inhibited growth of the intact phototrophic biofilms. No effect of alachlor was observed on diatom composition or functional and structural properties of the bacterial community regardless of whether they were intact or recolonized. The intact three-dimensional structure of the biofilm did not appear to confer protection from the effects of alachlor. Bacterial community structure and biomass level of 4.4 weeks - intact phototrophic biofilms were significantly influenced by the biofilm maturation processes rather than alachlor exposure. The diatom communities which were largely composed of mobile and colonizer life-form populations were not affected by alachlor. This study showed that the effect of alachlor (at initial concentration of 10 μg L(-1) or mean TWAC of 5.52 ± 0.74 μg L(-1)) is mainly limited to biomass reduction without apparent changes in the ecological succession trajectories of bacterial and diatom communities and suggested that carbon utilization spectra of the biofilm are not damaged resulting. These results confirmed the importance of considering the influence of maturation processes or community age when investigating herbicide effects. This is particularly important with regard to the use of phototrophic biofilms as bio-indicators.

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Section: Alachlor Toxicity Throughout Development Stagesmentioning

confidence: 99%

Changes in tolerance to herbicide toxicity throughout development stages of phototrophic biofilms

Paule¹,

Roubeix²,

Lauga³

et al. 2013

Aquatic Toxicology

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“…The experimental exposure of diatom communities to a chosen toxicant in enclosed controlled systems is then a suitable complementary approach. A large set of examples can be found in the literature with various herbicide molecules tested in either mesocosms or microcosms (Kosinski, 1984;Hamala and Kollig, 1985;Noack et al, 2003;Schmitt-Jansen and Altenburger, 2005;Mohr et al, 2008;Ricart et al, 2009;Vera et al, 2010).…”

Section: Introductionmentioning

confidence: 99%

Impact of the herbicide metolachlor on river periphytic diatoms: Experimental comparison of descriptors at different biological organization levels

Roubeix

Mazzella

Méchin

et al. 2011

Ann. Limnol. - Int. J. Lim.

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-A microcosm experiment was carried out in order to test the effect of the herbicide metolachlor on river periphytic diatoms and to find potential diatom bioindicators of contamination. Effects were investigated at different biological organization levels (biofilm, diatom community, population and individual levels). The colonization of glass substrates by natural biofilm in artificial streams did not vary quantitatively between control and contaminated conditions (5 and 30 mg.L x1 ). However, non-parametric multivariate analysis of variance revealed a significant difference between contaminated and control diatom communities with regard to species composition. The difference was due to the greater development of probably tolerant species in the presence of the herbicide (e.g., Planothidium frequentissimum, Planothidium lanceolatum, Amphora montana, Surirella brebissonii and Nitzschia gracilis). An increase in the occurrence of abnormal forms was observed in relation to metolachlor concentration. In particular, up to 8% of the frustules of the species Surirella angusta exhibited prominent deformities. Monospecific acute toxicity tests were then performed on two species to estimate toxicity parameters based on growth inhibition. These tests also confirmed the teratogenic effect of the herbicide on S. angusta. This study shows that low concentrations of metolachlor in natural streams may significantly alter diatom community structure and that abnormal diatom forms should be taken into account in water contamination assessment.

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“…PS II inhibitors such as diuron and atrazine bind to 32 kilo daltons proteins in cyanobacterium Aphanocapsa 6308 and have kinetics similar to higher plants (Allen et al 1983). The exact site of action of pretilachlor in cyanobacteria is not clear; however, chloracetanilides (the class to which pretilachlor belongs) have been used in toxicity studies involving cyanobacteria (Noack et al 2003). In cyanobacteria Anabaena variabilis and Spirulina platensis, glyphosate acts by inhibiting the enzyme EPSPs, as is the case in higher plants (Powell et al 1992;Forlani and Campani 2002).…”

Section: Discussionmentioning

confidence: 98%

Effect of herbicides with different modes of action on physiological and cellular traits of Anabaena fertilissima

Inderjit

Kaushik

2010

Paddy Water Environ

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Cyanobacteria are important components of the lowland rice ecosystem. Therefore, it is important to examine the effect of herbicides (commonly used against weeds of rice crop) on the performance of cyanobacteria. We studied the toxic effects of three herbicides often used in rice field, viz. propanil, pretilachlor and glyphosate, on the performance traits of Anabaena fertilissima C.B. Rao. Pretilachlor [0-40 active ingredient (ai) mg/L] and glyphosate (0-80 ai mg/L) exhibited toxicity to A. fertilissima at higher doses than propanil (0-1.5 mg/L). Propanil had severe damaging effects on cellular characteristics of A. fertilissima when compared to pretilachlor or glyphosate. Propanil treatment of A. fertilissima resulted in the leakage of protoplast from the heterocyst due to the breakage of the plasma membrane and surrounding wall. Our study shows that photosystem II herbicides such as propanil could have deleterious effects on phototrophic (cyanobacterial) communities, which are an integral part of the rice ecosystem.

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Effects of the Herbicide Metazachlor on Phytoplankton and Periphyton Communities in Outdoor Mesocosms

Cited by 19 publications

References 9 publications

Changes in tolerance to herbicide toxicity throughout development stages of phototrophic biofilms

Changes in tolerance to herbicide toxicity throughout development stages of phototrophic biofilms

Impact of the herbicide metolachlor on river periphytic diatoms: Experimental comparison of descriptors at different biological organization levels

Effect of herbicides with different modes of action on physiological and cellular traits of Anabaena fertilissima

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