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Comparison of the Effects of Two Herbicides and an Insecticide on Tropical Freshwater Plankton in Microcosms
- Source :
- Archives of Environmental Contamination and Toxicology, Archives of Environmental Contamination and Toxicology, Springer Verlag, 2011, 61 (4), pp.599-613. ⟨10.1007/s00244-011-9653-3⟩
- Publication Year :
- 2011
- Publisher :
- HAL CCSD, 2011.
-
Abstract
- International audience; Natural plankton communities from a tropical freshwater reservoir (Combani Reservoir, Mayotte Island, Mozambique Channel) were exposed, in 20-l nutrient-enriched microcosms, to two nominal concentrations of three pesticides: the herbicides diuron (2.2 and 11 mu g/l) and paraquat (10 and 40.5 mu g/l) and the insecticide fenitrothion (10 and 100 mu g/l), commonly used in the tropics for agriculture and disease vector control. Bacterioplankton, phytoplankton, and zooplankton communities were monitored for 5 days after exposure, and the concentrations of toxicant and major nutrients were measured. Bacterioplankton growth was noticeable in all systems and was slightly affected by pesticide at any concentration. A transitory increase in thymidine-based bacterial production was observed in diuron- and fenitrothion-treated microcosms, followed by a marked decrease in all microcosms after 5 days. The functional diversity of bacterioplankton, evaluated using BIOLOG ECO (R) microplates, was reduced by exposure to the highest pesticide concentrations. Phytoplankton was affected by pesticides in different ways. Chlorophyll biomass and biovolumes were increased by diuron addition and decreased by paraquat, whereas fenitrothion-treated microcosms remained unaffected relative to controls. Phytoplankton taxonomic diversity was decreased by paraquat and high doses of fenitrothion but was unaffected by addition of diuron. The decrease in diversity was due to a reduction in the number of species, whereas the density of small cells increased, especially after addition of paraquat. Heterotrophic flagellates were sensitive to paraquat and to the highest diuron concentration; a reduction in biomass of up to 90% was observed for 40.5 mu g/l paraquat. Zooplankton, dominated by Thermocyclops decipiens and Diaphanosoma excisum, was slightly sensitive to diuron, and very sensitive to paraquat. High concentrations of the insecticide fenitrothion were effective only on young stages. The potential direct and indirect effects of pesticide contamination on such a simplified plankton food web, typical of newly constructed reservoirs, appear to differ significantly depending on the biological compartment considered. The overall sensitivity of tropical plankton is comparable to the sensitivity for temperate systems, and direct and indirect effects appeared rapidly, within 5 days of exposure.
- Subjects :
- Paraquat
0106 biological sciences
Insecticides
Food Chain
Health, Toxicology and Mutagenesis
[SDU.STU]Sciences of the Universe [physics]/Earth Sciences
010501 environmental sciences
Biology
01 natural sciences
Zooplankton
Fenitrothion
chemistry.chemical_compound
Phytoplankton
Animals
Biomass
Mozambique
0105 earth and related environmental sciences
2. Zero hunger
Herbicides
010604 marine biology & hydrobiology
fungi
General Medicine
Bacterioplankton
Plankton
Pesticide
environmental monitoring/analysis
Pollution
[SDE.ES]Environmental Sciences/Environmental and Society
6. Clean water
chemistry
13. Climate action
Diuron
Environmental chemistry
environmental sciences and ecology
Microcosm
natural plankton communities
tropical freshwater reservoir
Water Pollutants, Chemical
Environmental Monitoring
toxicology
Subjects
Details
- Language :
- English
- ISSN :
- 00904341 and 14320703
- Database :
- OpenAIRE
- Journal :
- Archives of Environmental Contamination and Toxicology, Archives of Environmental Contamination and Toxicology, Springer Verlag, 2011, 61 (4), pp.599-613. ⟨10.1007/s00244-011-9653-3⟩
- Accession number :
- edsair.doi.dedup.....90439ba28bd273abe8916ae6bdce7cd0