Effects of low concentrations of the phenylurea herbicide diuron on biofilm algae and bacteria.
A system of recirculating channels was used in this study to examine the long-term effects (29d) of environmentally realistic concentrations of the herbicide diuron (from 0.07 to 7 microg L(-1)) on biofilm communities. The autotrophic activity of biofilms was affected by this herbicide, as reflected by a marked decrease in the photosynthetic efficiency. Diuron exposure also increased chlorophyll-a content and reduced the biovolume of diatom taxa at low concentrations. The effects on bacteria were also remarkable. Bacterial abundance was reduced after a week of exposure to the herbicide at a range of concentrations. Effects were on the number of live bacteria and on the increase in the leucine-aminopeptidase activity. It is suggested that inputs of herbicides to the river ecosystem at low concentrations may cause a chain of effects in the biofilm, which include inhibitory effects on algae but also indirect effects on the relationships between biofilm components.
Ricart
Marta
M
Institute of Aquatic Ecology, University of Girona, Faculty of Sciences, Campus Montilivi, Girona, Spain. martarivi@gmail.com
Barceló
Damià
D
Geiszinger
Anita
A
Guasch
Helena
H
de Alda
Miren López
ML
Romaní
Anna M
AM
Vidal
Gemma
G
Villagrasa
Marta
M
Sabater
Sergi
S
D001419:Bacteria / Q000187:drug effects*; D018441:Biofilms / Q000187:drug effects*; D002734:Chlorophyll / Q000378:metabolism; D000077194:Chlorophyll A; D004237:Diuron / Q000633:toxicity*; D056890:Eukaryota / Q000187:drug effects* / Q000502:physiology; D006540:Herbicides / Q000633:toxicity*; D007931:Leucyl Aminopeptidase / Q000378:metabolism; D013997:Time Factors; D014874:Water Pollutants, Chemical / Q000633:toxicity
D006540:Herbicides; D014874:Water Pollutants, Chemical; D002734:Chlorophyll; D004237:Diuron; D007931:Leucyl Aminopeptidase; D000077194:Chlorophyll A