Glyphosate influence on phytoplankton community structure in Lake Erie

Saxton, Matthew; Morrow, Elizabeth A.; Bourbonniere, Richard A.; Wilhelm, Steven W.

doi:10.1016/j.jglr.2011.07.004

Cited by 76 publications

(52 citation statements)

References 42 publications

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“…Similar results have been reported with Roundup® (Pérez et al 2007;Vera et al 2010), Glifosato Atanor® (Vera et al 2012), and technicalgrade glyphosate (Saxton et al 2011;Pizarro et al 2015b). Mussels in combination with the active ingredient and Roundup Max® induced a downward trend in TP concentration throughout the experiment.…”

Section: Discussionsupporting

confidence: 84%

“…Some researchers reported that commercial formulations had positive effects on phytoplankton abundances (Vera et al 2012) while others found negative effects (Pérez et al 2007). Experiments using technical-grade glyphosate showed positive and negative effects (Saxton et al 2011) or no effect (Pizarro et al 2015b) on phytoplankton. In contrast, treatments with mussels alone or in combination with both herbicides impacted negatively on the abundance of all algal groups, probably explained by L. fortunei grazing.…”

Section: Discussionmentioning

confidence: 97%

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Differential impact of Limnoperna fortunei-herbicide interaction between Roundup Max® and glyphosate on freshwater microscopic communities

Gattás

Vinocur

Graziano

et al. 2016

Environ Sci Pollut Res

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Multiple anthropogenic stressors act simultaneously on the environment, with consequences different from those caused by single-stressor exposure. We investigated how the combination of the invasive mussel Limnoperna fortunei and a widely applied herbicide, Roundup Max®, affected freshwater microscopic communities and water quality. Further, we compared these results with those induced by the combination of the mussel and technical-grade glyphosate. We carried out a 34-day experiment in outdoor mesocosms, applying the following six treatments: 6 mg L(-1) of technical-grade glyphosate (G), the equivalent concentration of glyphosate in Roundup Max® (R), 100 mussels (M), the combination of mussels and herbicide either in the technical-grade or formulated form (MG and MR, respectively), and control (C). Herbicides significantly increased total phosphorus in water; R and MR showed greater initial total nitrogen and ammonium. R increased picoplankton abundance and caused an eightfold increase in phytoplankton, with high turbidity values; G had a lower effect on these variables. Herbicide-mussel combination induced an accelerated dissipation of glyphosate in water (MG 6.36 ± 0.83 mg G g DW(-1) day(-1) and MR 5.16 ± 1.26 mg G g DW(-1) day(-1)). A synergistic effect on ammonium was observed in MR but not in MG. MR and MG had an antagonistic effect on phytoplankton, which showed a drastic reduction due to grazing, as revealed by M. We provide evidence of differential effects of Roundup Max® and technical-grade glyphosate over water quality and microscopic communities, and in combination with mussels. However, in the combination of mussels and herbicides, mussels seem to play a leading role. In the presence of L. fortunei, the effects of higher nutrient availability provided by herbicides addition were counteracted by the filtration activity of mussels, which released nutrients, grazed on picoplankton and phytoplankton, and boosted the development of other primary producers, periphyton and metaphyton.

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Section: Discussionsupporting

confidence: 84%

Section: Discussionmentioning

confidence: 97%

Differential impact of Limnoperna fortunei-herbicide interaction between Roundup Max® and glyphosate on freshwater microscopic communities

Gattás

Vinocur

Graziano

et al. 2016

Environ Sci Pollut Res

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“…Not only do bloom-forming organisms such as Microcystis aeruginosa live in competition with other phytoplankton species, they also live in concert with heterotrophic bacteria, which can attach to the mucilaginous matrix produced by M. aeruginosa colonies (15, 16). There is a dearth of information concerning the functional role that co-occurring bacteria may play in bloom dynamics, although recent studies suggest that heterotrophs may play an important role in the metabolism of some nutrients (17, 18).As metagenomic surveys have provided new insight into the dynamics of microbial communities, a growing number have suggested that microbial community function is independent of the identity of the member organisms, including one study of a Lake Erie cHAB community (18)(19)(20). These studies, however, allow only for inference about community functional potential, as they are based on the analysis of DNA.…”

mentioning

confidence: 99%

“…As metagenomic surveys have provided new insight into the dynamics of microbial communities, a growing number have suggested that microbial community function is independent of the identity of the member organisms, including one study of a Lake Erie cHAB community (18)(19)(20). These studies, however, allow only for inference about community functional potential, as they are based on the analysis of DNA.…”

mentioning

confidence: 99%

Metatranscriptomic Evidence for Co-Occurring Top-Down and Bottom-Up Controls on Toxic Cyanobacterial Communities

Steffen

Belisle

Watson

et al. 2015

Appl Environ Microbiol

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Little is known about the molecular and physiological function of co-occurring microbes within freshwater cyanobacterial harmful algal blooms (cHABs). To address this, community metatranscriptomes collected from the western basin of Lake Erie during August 2012 were examined. Using sequence data, we tested the hypothesis that the activity of the microbial community members is independent of community structure. Predicted metabolic and physiological functional profiles from spatially distinct metatranscriptomes were determined to be >90% similar between sites. Targeted analysis of Microcystis aeruginosa, the historical causative agent of cyanobacterial harmful algal blooms over the past ϳ20 years, as well as analysis of Planktothrix agardhii and Anabaena cylindrica, revealed ongoing transcription of genes involved in microcystin toxin synthesis as well as the acquisition of both nitrogen and phosphorus, nutrients often implicated as independent bottom-up drivers of eutrophication in aquatic systems. Transcription of genes involved in carbon dioxide (CO 2 ) concentration and metabolism also provided support for the alternate hypothesis that high-pH conditions and dense algal biomass result in CO 2 -limiting conditions that further favor cyanobacterial dominance. Additionally, the presence of Microcystis-specific cyanophage sequences provided preliminary evidence of possible top-down virus-mediated control of cHAB populations. Overall, these data provide insight into the complex series of constraints associated with Microcystis blooms that dominate the western basin of Lake Erie during summer months, demonstrating that multiple environmental factors work to shape the microbial community. F reshwater ecosystems are considered among the most endangered in the biosphere (1). One threat to fresh waters around the world is the now nearly annual occurrence of blooms of toxic cyanobacteria. Molecular signatures of cyanobacterial harmful algal blooms (cHABs) have been identified on all seven continents, and these blooms have been occurring with increased frequency and duration in recent years (2-4). The accumulation of bloom biomass has been associated with fish, avian, and mammal intoxication (5, 6); the formation of hypoxic zones (7); the production of taste and odor compounds (8, 9); and even human liver failure in extreme cases (10).The Laurentian Great Lakes are an important freshwater resource, holding ϳ18% of the world's potable water and ϳ84% of the surface waters in North America (11). cHABs have had a persistent presence in Lake Erie and other Laurentian Great Lakes for several decades (3, 12, 13). Nuisance biomass and toxin production associated with cHABs in the Great Lakes have had a detrimental effect not only on ecosystem health but also on the economic health of the surrounding communities; indeed, in August 2014, a bloom event led to the shutdown of the water supply for some ϳ500,000 residents in the region of the city of Toledo, OH (14). To date, research efforts have broadly identified nutrient inputs an...

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“…Planktothrix sp showed capacity to resist to high RoundUp® Flash concentration (up to 200 µM) in the field (Saxton et al, 2011), the concomitant exposure of gastropods to both stressors is environmentally realistic. The duration of exposure mimics the duration of cyanobacterial blooms, changing with weather conditions.…”

Section: Introductionmentioning

confidence: 99%

Accumulation and detoxication responses of the gastropod Lymnaea stagnalis to single and combined exposures to natural (cyanobacteria) and anthropogenic (the herbicide RoundUp® Flash) stressors

et al. 2016

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Glyphosate influence on phytoplankton community structure in Lake Erie

Cited by 76 publications

References 42 publications

Differential impact of Limnoperna fortunei-herbicide interaction between Roundup Max® and glyphosate on freshwater microscopic communities

Differential impact of Limnoperna fortunei-herbicide interaction between Roundup Max® and glyphosate on freshwater microscopic communities

Metatranscriptomic Evidence for Co-Occurring Top-Down and Bottom-Up Controls on Toxic Cyanobacterial Communities

Accumulation and detoxication responses of the gastropod Lymnaea stagnalis to single and combined exposures to natural (cyanobacteria) and anthropogenic (the herbicide RoundUp® Flash) stressors

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