The impact of the herbicide diuron on photosynthesis in three species of tropical seagrass (Page 1)  
location map


The impact of the herbicide diuron on photosynthesis in three species of tropical seagrass

The impact and recovery from exposure to the herbicide diuron [DCMU; 3-(3′,4′-dichlorophenyl)-1,1-dimethylurea] was assessed for three tropical seagrasses, maintained in outdoor aquaria over a 10-day period. Photosynthetic stress was detected using chlorophyll a fluorescence, measured with a Diving-PAM (pulse amplitude modulated fluorometer). Exposure to 10 and 100 μg l−1 diuron resulted in a decline in effective quantum yield (ΔF/Fm′) within 2 h of herbicide exposure in Cymodocea serrulata, Halophila ovalis and Zostera capricorni. Effective quantum yield also declined over the first 24 h of exposure in H. ovalis at even lower diuron concentrations (0.1 and 1.0 μg l−1). Effective quantum yield in H. ovalis and Z. capricorni was significantly depressed at all diuron concentrations (0.1–100 μg l−1) after 5 days exposure, whereas effective quantum yield in C. serrulata was only significantly lower in plants exposed to highest diuron concentrations (10 and 100 μg l−1). Effective quantum yield depression was present 5 days after plants exposed to 10 and 100 μg l−1 diuron were returned to fresh seawater. These results indicate that exposure to herbicide concentrations present in nearshore Queensland sediments present a potential risk to seagrass functioning.

Keywords: diuron, fluorometry, pollution effects, seagrass, toxicity, water quality

Author(s)Haynes D, Ralph P, Prange J, and Dennison WC
IAN Author(s)Bill Dennison
PublisherPergamon-elsevier Science Ltd
Journal / BookMarine Pollution Bulletin 41 (7-12): 288-293
Year2000
TypePaper | Journal Article
Location(s)South East Queensland
Number of Pages6
ISSN0025-326x