Effects of diquat on freshwater microbial communities

Meléndez, Acuña; Kepner, R. L.; Balczon, J. M.; Pratt, Jon R.

doi:10.1007/bf00230718

Cited by 25 publications

(26 citation statements)

References 20 publications

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“…Within the microcosm, unicellular green algae appear to be relatively resistant to the effects of diquat with Oocystis spp. being more resistant than the other species (Melendez et al, 1993). Unicellular green algae typically appear to be more tolerant of diquat (EC50 = 0.65 to 43 ppm c.e.)…”

Section: Potential Impact On Plant and Algae Densitiesmentioning

confidence: 99%

“…These concentrations initially cause a decrease in filamentous green algal density but by the 21 st day after treatment in a laboratory microcosm, the filamentous green algal density increased to 13-to 19-fold above control levels. Since the unicellular green algae appear to be resistant to diquat at levels up to 10 ppm, it is likely that these species will also exhibit increases in density when exposed to diquat (Cullimore, 1975 in Melendez et al, 1993). Other algal groups including green colonial algae, diatoms, and blue-green algae were reduced in numbers at all time periods tested .…”

Section: Potential Impacts Of Single Versus Multiple Applicationsmentioning

confidence: 99%

“…Somewhat different values were reported by Singh and Williams (2000), who reported that a 400 foot setback distance was necessary in large reservoirs with a treatment area of 0.32 acres but a 1,400 foot setback distance was necessary for large reservoirs with a treatment area of 50. (Sewell, 1969), , Warner, 1986 andSerdar (1997) (Melendez et al, 1993 andPratt et al, 1990) as well as Chara (Johnson, 1962), Mougeotia (Cook, 1977) and other algae (Inabinet, 1976) (Pratt, 1990). (Walsh, 1972).…”

Section: Seismentioning

confidence: 99%

“…75 , Tatum and Blackburn, 1962and Fish, 1966in Shearer and Halter, 1980. There is some evidence that there can be algal blooms with Chara (Johnson, 1962) and Mougeotia (Cook, 1977) and other algae (Inabinet, 1976) (Melendez et al, 1993) in absence of sediment; but if sediment is present, this effect is only transitory and typically lasts less than a week (Pratt et al, 1990).…”

Section: Seismentioning

confidence: 99%

“…It is generally agreed that diquat exposure can lead to algal blooms. However, since the concentrations that are directly stimulatory to algal growth are typically higher than the maximum use rate, it is likely that stimulation of algal growth in the field is due to the release of plant nutrients rather than a direct stimulatory effect from the chemical (Melendez et al, 1993;Peverly and Johnson, 1979;Inabinet, 1976;Daniel, 1967). In the field inhibiting effects on phytoplankton growth are probably limited to the first few days after diquat treatment (Inabinet, 1972;Tatum andBlackwell, 1962, andCooke, 1977).…”

Section: Potential Impacts Of Single Versus Multiple Applicationsmentioning

confidence: 99%

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Effects of Aquatic Herbicides and Housing Density on Abundance of Pond-Breeding Frogs

Picone

2015

Northeastern Naturalist

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Section: Potential Impact On Plant and Algae Densitiesmentioning

confidence: 99%

Section: Potential Impacts Of Single Versus Multiple Applicationsmentioning

confidence: 99%

Section: Seismentioning

confidence: 99%

Section: Seismentioning

confidence: 99%

Section: Potential Impacts Of Single Versus Multiple Applicationsmentioning

confidence: 99%

See 3 more Smart Citations

Effects of Aquatic Herbicides and Housing Density on Abundance of Pond-Breeding Frogs

Picone

2015

Northeastern Naturalist

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Interaction of toxicants and communities: The role of nutrients

Lozano

Pratt

1994

Enviro Toxic and Chemistry

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The interaction between community nutrient status and toxicity was studied in laboratory microcosms containing natural periphyton communities The three experimental nutrient treatments (low, medium, high) increased by orders of mag nitude from 0 05 mg N per liter + 0 01 mg P per liter Communities were developed with nutrient treatments for 25 d and were then exposed to 3 5 mg/L diquat, a photosynthetic inhibitor, and studied for an additional 23 d The effects of toxicant addi tion were assessed by measuring changes in biomass (protein, chlorophyll), enzyme activity (alkaline phosphatase electron trans port), nutrient release, diurnal changes in microcosm oxygen (gross productivity), and toxicant fate The rate of diquat loss was lowest in the low nutrient treatment Gross photosynthesis was nearly eliminated by diquat in the low nutrient treatment and showed limited recovery Productivities in the medium and high nutrient treatments were equivalent and showed evidence of both effect (approximately 50% reduction) and recovery Protein biomass was reduced in low nutrient microcosms treated with diquat, but no effect on chlorophyll biomass was observed Diquat inhibited respiratory electron transport activity, and mi crocosms with low nutrient availability had limited ability to recover from the diquat stress These studies suggest that commu nity nutrient status affects both the magnitude of effect and the rate of recovery of processes following stress

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Toxicity of pesticides to aquatic microorganisms: A review

DeLorenzo

Scott

Ross

2001

Enviro Toxic and Chemistry

452

173

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Microorganisms contribute significantly to primary production, nutrient cycling, and decomposition in estuarine eco-systems; therefore, detrimental effects of pesticides on microbial species may have subsequent impacts on higher trophic levels. Pesticides may affect estuarine microorganisms via spills, runoff, and drift. Both the structure and the function of microbial communities may be impaired by pesticide toxicity. Pesticides may also be metabolized or bioaccumulated by microorganisms. Mechanisms of toxicity vary, depending on the type of pesticide and the microbial species exposed. Herbicides are generally most toxic to phototrophic microorganisms, exhibiting toxicity by disrupting photosynthesis. Atrazine is the most widely used and most extensively studied herbicide. Toxic effects of organophosphate and organochlorine insecticides on microbial species have also been demonstrated, although their mechanisms of toxicity in such nontarget species remain unclear. There is a great deal of variability in the toxicity of even a single pesticide among microbial species. When attempting to predict the toxicity of pesticides in estuarine ecosystems, effects of pesticide mixtures and interactions with nutrients should be considered. The toxicity of pesticides to aquatic microorganisms, especially bacteria and protozoa, is an area of research requiring further study.

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Effects of diquat on freshwater microbial communities

Cited by 25 publications

References 20 publications

Effects of Aquatic Herbicides and Housing Density on Abundance of Pond-Breeding Frogs

Effects of Aquatic Herbicides and Housing Density on Abundance of Pond-Breeding Frogs

Interaction of toxicants and communities: The role of nutrients

Toxicity of pesticides to aquatic microorganisms: A review

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