Toxic effects of pesticides on the marine microalga Skeletonema costatum and their biological degradation
IMAGE: THE GROWTH CURVES BASED ON THE CELL DENSITY AND CHL-A CONTENT WERE SIMILAR. FIGURE CREDIT: BO CHEN. view more
CREDIT: FIGURE CREDIT: BO CHEN.
The study was led by Dr. Zilian ZHANG (College of Ocean and Earth Sciences, Xiamen University) and Dr. Meng CHEN (College of the environment & ecology, Xiamen University). Since in modern agricultural systems, large amounts of pesticides are applied to specific purposes such as weeding and insecticide, and most pesticides are eventually entering the ocean, however, the toxic effects of pesticides on marine microes are unlear. Therefore, in this study, the toxic effects of three representative pesticides (chlorpyrifos, acetochlor, and dicofol) on the growth of marine microbe microalga Skeletonema costatum were studied by analyzing microalgal cell density and chlorophyll-a content. The research team found that the toxic effects of three widely used pesticides on the marine microalga S. costatum are different. Among these pesticides, acetochlor showed the strongest toxic effect, while chlorpyrifos had the weakest effect. Combined toxicity analysis indicates that the presence of acetochlor increases the toxicity of dicofol and chlorpyrifos, while the toxicity of acetochlor and chlorpyrifos could be reduced by the presence of dicofol. The pesticides were partially degraded by marine microalgae during the cultivation. Among the three pesticides, acetochlor had relatively longer half-lives under both individual and combined conditions.
This study provides new insights into the toxicity of three pesticides to marine microalgae as well as the evidence concerning the contribution of microalgae in the removal of these pesticides from the environment. The molecular processes and mechanisms of degradation of pesticides by marine microalgae will to be further investigated.
See the article:
Zhang Z, Chen Q, Chen B, Dong T, Chen M. 2023. Toxic effects of pesticides on the marine microalga Skeletonema costatum and their biological degradation. Science China Earth Sciences, 66(3): 663–674, https://doi.org/10.1007/s11430-022-1064-7
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Science China Earth Sciences
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Acetochlor was identified as highly toxic to S. costatum, while chlorpyrifos and dicofol were moderately toxic pesticides. Figure credit: Taojie Dong
CREDIT
Figure credit: Taojie Dong
The effects of three pesticides on S. costatum cell morphology were observed after exposure to different concentrations of acetochlor. a-e: The microalgae were exposed to 0, 0.01, 0.025, 0.1 and 0.25 mg/L acetochlor for 96 h respectively. The microalgal cells showed abnormal cell division and morphology (d) or cell shape disappeared completely and became a ‘cluster’ (e), when S. costatum was exposed to 0.1 or 0.25 mg L-1 acetochlor, respectively. The result indicated that the cell membranes of the microalgae were damaged by acetochlor. Photo credit: Qiulan Chen.
CREDIT
Photo credit: Qiulan Chen.
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