Diuron effects on photosynthesis and vertical migration of microphytobenthos: Potential rapid bioassessment of herbicide toxicity in coastal sediments

Du, Guo-ying; Zhong, Xue-feng; Dupuy, Christine; Che, Shuai; Lavaud, Johann

Diuron effects on photosynthesis and vertical migration of microphytobenthos: Potential rapid bioassessment of herbicide toxicity in coastal sediments

2021

Du, Guo-ying | Zhong, Xue-feng | Dupuy, Christine | Che, Shuai | Lavaud, Johann

The effects of herbicide diuron on photosynthesis and vertical migration of intertidal microphytobenthos (MPB) assemblages were investigated using chlorophyll fluorometry. The results shown diuron ≤ 60 μg L⁻¹ had no obvious effect on MPB vertical migration during 24 h indicated by consistent rhythm. Low concentration of 10 μg L⁻¹ diuron had no significant influence on MPB photosynthesis throughout, however, high concentrations of 40, 50, and 60 μg L⁻¹ had significant impacts exhibited by decreased parameters of maximum relative electron transport rate (rETRₘₐₓ), maximal PS II quantum yield (Fᵥ/Fₘ) and non-photochemical quenching (NPQ). For middle concentrations of 20 and 30 μg L⁻¹, above decreased 3 parameters recovered sooner or later after 2 h or 16.5 h. Comparatively, rETRₘₐₓ, Fᵥ/Fₘ and NPQ are concentration dependent and more sensitive than other parameters in assessing diuron toxicity. This study revealed the potential of using MPB assemblages and chlorophyll fluorometry for rapid assessing diuron toxicity in coastal sediments.

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