Document Detail


Response to variable light intensity in photoacclimated algae and cyanobacteria exposed to atrazine.
MedLine Citation:
PMID:  23149118     Owner:  NLM     Status:  Publisher    
Abstract/OtherAbstract:
Atrazine is frequently detected in freshwater ecosystems exposed to agricultural waste waters and runoffs worldwide and it can affect non-target organisms (mainly photoautotrophic) and modify community structure. Meanwhile, light environment is known to vary between aquatic ecosystems, but also before and during the exposure to atrazine and these variations may modify the sensitivity to atrazine of photoautotroph organisms. In this study, 10 species of phytoplankton (chlorophytes, baccilariophytes and cyanophytes) acclimated to low or high light intensities were exposed to atrazine and light of different intensities to compare their combined effect. Our data showed that chlorophytes and baccilariophytes were more resistant to atrazine compared to cyanophytes for all light conditions. Atrazine was found to inhibit [Formula: see text] , Ψ(0), P(M) and non-photochemical quenching for all species indicating an effect on electron transport, primary production and photoregulation processes. These data also indicate a higher sensitivity of Ψ(0) (average Ψ(0)-EC(50) of 91±11nM or 19.6±0.9μgL(-1)) compared to [Formula: see text] (average [Formula: see text] of 217±19nM or 46.8±4.1μgL(-1)) and suggest that photoregulation processes activated in presence of light decrease the effect of atrazine. We also showed that increasing light intensity decreased [Formula: see text] in both low (except baccilariophytes) and high light acclimated conditions. Despite this similarity, most species acclimated to high light were found to have higher or similar [Formula: see text] compared to low light acclimated cells and thus, were less sensitive to atrazine in low light and high light environments. We concluded that an increase in the plastoquinone pool induced by acclimation to high light decreased the sensitivity to atrazine in phytoplankton and we hypothesized that the effect observed was the result of a dilution of atrazine toxicity through increased binding site availability (quinones) combined with increased photoregulation processes capacity.
Authors:
Charles P Deblois; Karine Dufresne; Philippe Juneau
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Publication Detail:
Type:  JOURNAL ARTICLE     Date:  2012-10-23
Journal Detail:
Title:  Aquatic toxicology (Amsterdam, Netherlands)     Volume:  126C     ISSN:  1879-1514     ISO Abbreviation:  Aquat. Toxicol.     Publication Date:  2012 Oct 
Date Detail:
Created Date:  2012-11-14     Completed Date:  -     Revised Date:  -    
Medline Journal Info:
Nlm Unique ID:  8500246     Medline TA:  Aquat Toxicol     Country:  -    
Other Details:
Languages:  ENG     Pagination:  77-84     Citation Subset:  -    
Copyright Information:
Crown Copyright © 2012. Published by Elsevier B.V. All rights reserved.
Affiliation:
Department of Biological Sciences-TOXEN, Ecotoxicology of Aquatic Microorganisms Laboratory, Université du Québec à Montréal, Succ. Centre-Ville, Montréal, Québec, Canada.
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