Institute of Soil and Water Resources and Environmental Science, Zhejiang Provincial Key Laboratory of Agricultural Resources and Environment, Zhejiang University, 866 Yuhangtang Road, Hangzhou 310058, China; Department of Biological Sciences, North Carolina State University, Raleigh, NC 27695, United States.
School of Chemistry, Environmental & Life Sciences, University of The Bahamas, Nassau, New Providence, The Bahamas.
J Hazard Mater. 2021 May 5;409:124946. doi: 10.1016/j.jhazmat.2020.124946. Epub 2020 Dec 24.
Periphyton is ubiquitous in rice paddy fields, however its role in paddy soil arsenic (As) biogeochemistry remains unexplored. In this study, microcosm incubations and extensive field sampling were used to better understand the roles of periphyton on As mobility and transformation at the soil-water interface. Microcosm incubations revealed that periphyton on the paddy soil surface enhanced As release to water and increased methylated As contents at the soil-water interface. Experimental additions of dissolved phosphate did not significantly affect these processes. The presence of periphyton increased the dissolved organic carbon (DOC) content of the surface soil which may have played a role in the increased As mobility. However, the increase in methylated As species at the soil-water interface is indicative of detoxification processes of As by periphyton. The results from the field study revealed a high abundance and diversity of As biotransformation and detoxification genes in periphyton. Genera of Kineosporia, Limisphaera, Ornatilinea, Ktedonosporobacter and Anaerolinea played key roles in shaping arsM harboring microbe communities in field periphyton. These results highlight the importance of periphyton in the behavior of As in paddy soils and can potentially facilitate improved management of As contamination in paddy soils.
底栖藻广泛存在于稻田中，但它在稻田土壤砷（As）生物地球化学中的作用尚未被探索。在这项研究中，微宇宙培养和广泛的田间采样被用于更好地理解底栖藻在土壤-水界面上对 As 迁移和转化的作用。微宇宙培养表明，稻田表面的底栖藻促进了 As 向水中的释放，并增加了土壤-水界面处的甲基化 As 含量。溶解磷酸盐的实验添加并没有显著影响这些过程。底栖藻的存在增加了表层土壤中溶解有机碳（DOC）的含量，这可能在增加 As 的迁移性方面发挥了作用。然而，土壤-水界面处甲基化 As 物种的增加表明底栖藻对 As 的解毒过程。田间研究的结果表明，底栖藻中存在丰富多样的 As 生物转化和解毒基因。动性球菌属、单枝藻属、Ornatilinea 属、Ktedonosporobacter 属和产甲烷菌属在形成 ArsM 基因的微生物群落方面发挥了关键作用。这些结果强调了底栖藻在稻田土壤 As 行为中的重要性，并可能有助于改善稻田土壤中 As 污染的管理。
