Effects of pesticides on community composition and activity of sediment microbes--responses at various levels of microbial community organization.
A freshwater sediment was exposed to the pesticides captan, glyphosate, isoproturon, and pirimicarb at environmentally relevant and high concentrations. Effects on sediment microorganisms were studied by measuring bacterial activity, fungal and total microbial biomass as community-level endpoints. At the sub-community level, microbial community structure was analysed (PLFA composition and bacterial 16S rRNA genotyping, T-RFLP). Community-level endpoints were not affected by pesticide exposure. At lower levels of microbial community organization, however, molecular methods revealed treatment-induced changes in community composition. Captan and glyphosate exposure caused significant shifts in bacterial community composition (as T-RFLP) at environmentally relevant concentrations. Furthermore, differences in microbial community composition among pesticide treatments were found, indicating that test compounds and exposure concentrations induced multidirectional shifts. Our study showed that community-level end points failed to detect these changes, underpinning the need for application of molecular techniques in aquatic ecotoxicology.
Widenfalk
Anneli
A
Department of Environmental Assessment, Swedish University of Agricultural Sciences, P.O. Box 7050, SE-750 07 Uppsala, Sweden. anneli.widenfalk@kemi.se
Bertilsson
Stefan
S
Sundh
Ingvar
I
Goedkoop
Willem
W
D001419:Bacteria / Q000187:drug effects* / Q000254:growth & development; D044822:Biodiversity; D002215:Captan / Q000633:toxicity; D002219:Carbamates / Q000633:toxicity; D017753:Ecosystem; D004875:Ergosterol / Q000032:analysis; D005227:Fatty Acids / Q000032:analysis; D005618:Fresh Water; D005658:Fungi / Q000187:drug effects / Q000254:growth & development; D019015:Geologic Sediments / Q000737:chemistry* / Q000382:microbiology; D005998:Glycine / Q000031:analogs & derivatives / Q000633:toxicity; D010575:Pesticides / Q000633:toxicity*; D010671:Phenylurea Compounds / Q000633:toxicity; D010743:Phospholipids / Q000032:analysis; D011743:Pyrimidines / Q000633:toxicity; D012336:RNA, Ribosomal, 16S / Q000032:analysis; D012988:Soil Microbiology; D012989:Soil Pollutants / Q000633:toxicity*; D014874:Water Pollutants, Chemical / Q000633:toxicity; D000097797:Glyphosate