Effects of herbicides diuron and atrazine on corals of the Great Barrier Reef, Australia

Jones, R. J., Mueller, J. F., Haynes, D. and Schreiber, U. (2003) Effects of herbicides diuron and atrazine on corals of the Great Barrier Reef, Australia. Marine Ecology-progress Series, 251 153-167. doi:10.3354/meps251153

Author Jones, R. J.
Mueller, J. F.
Haynes, D.
Schreiber, U.
Title Effects of herbicides diuron and atrazine on corals of the Great Barrier Reef, Australia
Journal name Marine Ecology-progress Series   Check publisher's open access policy
ISSN 0171-8630
Publication date 2003-04-11
Sub-type Article (original research)
DOI 10.3354/meps251153
Open Access Status DOI
Volume 251
Start page 153
End page 167
Total pages 15
Place of publication Oldendorf, Germany
Publisher Inter-Research
Collection year 2003
Language eng
Abstract In response to recent reports of contamination of the nearshore marine environment along the Queensland coast by herbicides (including areas inside the Great Barrier Reef Marine Park), an ecotoxicological assessment was conducted of the impact of the herbicides diuron and atrazine on scleractinian corals. Pulse-amplitude modulated (PAM) chlorophyll fluorescence techniques were used to assess the herbicide effects on the symbiotic dinoflagellates within the tissues (in hospite) of 4 species of coral (Acropora formosa, Montipora digitata, Porites cylindrica, Seriatopora hystrix) in static toxicity tests, and in freshly isolated symbiotic dinoflagellates from Stylophora pistillata. Using change in the effective quantum yield (DeltaF/F-m') as an effect criterion, diuron (no observable effect concentration, NOEC = 0.3 mug 1(-1); lowest observable effect concentration, LOEC = 1 mug 1(-1); median effective concentration, EC50 4 to 6 mug 1(-1)) was found to be more toxic than atrazine (NOEC = 1 mug 1(-1), LOEC = 3 mug 1(-1), EC50 40 to 90 mug 1(-1)) in short-term (10 h) toxicity tests. In the tests with isolated algae, significant reductions in DeltaF/F-m' were recorded as low as 0.25 mug 1(-1) diuron (LOEC, EC50 = 5 mug 1(-1)). Time-course experiments indicated that the effects of diuron were rapid and reversible. At 10 mug 1(-1) diuron, DeltaF/F-m' was reduced by 25% in 20 to 30 min, and by 50% in 60 to 90 min. Recovery of DeltaF/F-m' in corals exposed to 10 mug 1(-1) diuron and then transferred to running seawater was slower, returning to within 10% of control values inside 1 to 7 h. The effect of a reduction in salinity (35 to 27%) on diuron toxicity (at 1 and 3 mug 1(-1) diuron) was tested to examine the potential consequences of contaminated coastal flood plumes inundating inshore reefs. DeltaF/F-m' was reduced in the diuron-exposed corals, but there was no significant interaction between diuron and reduced salinity seawater within the 10 h duration of the test. Exposure to higher (100 and 1000 mug 1(-1)) diuron concentrations for 96 h caused a reduction in DeltaF/F-m' the ratio variable to maximal fluorescence (F,1F.), significant loss of symbiotic dinoflagellates and pronounced tissue retraction, causing the corals to pale or bleach. The significance of the results in relation to diuron contamination of the coastal marine environment from terrestrial sources (mainly agricultural) and marine sources (antifouling paints) are discussed.
Keyword Ecology
Marine & Freshwater Biology
Coral Bleaching
Symbiotic Dinoflagellate
Chlorophyll Fluorescence
Antifouling Biocides
Oxidative Stress
Q-Index Code C1

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Created: Wed, 15 Aug 2007, 01:42:57 EST