School of Environment, Nanjing Normal University, Jiangsu Center for Collaborative Innovation in Geographical Information Resource Development and Application, Jiangsu Key Laboratory of Environmental Change and Ecological Construction, Nanjing 210,023, China.
School of Environment, Nanjing Normal University, Jiangsu Center for Collaborative Innovation in Geographical Information Resource Development and Application, Jiangsu Key Laboratory of Environmental Change and Ecological Construction, Nanjing 210,023, China..
Sci Total Environ. 2021 May 10;768:144336. doi: 10.1016/j.scitotenv.2020.144336. Epub 2020 Dec 25.
Sulfur reduction in freshwater ecosystems has previously been considered as negligible because of often very low sulfate concentrations and generally low sulfate reducing capacity in freshwater sediments. In this study, seasonal variations on three types of sediments from central lake, dredged and algae accumulated areas in a eutrophic lake in China, Lake Taihu, were investigated. The high temperature in summer and the accumulation of algae are conducive to the reduction processes in freshwater lake sediments. Iron reduction was observed as the major anaerobic process in all types of sediments, while sulfate reduction was weak in central and dredged lake areas. However, strong sulfate reduction with increase of sulfate reducing bacteria and sulfides generation (119.5 ± 0.2 μmol L) was found in surface sediments in algae accumulated areas. Based on the results of Fe reduction rate and the quantity of Fe reducing bacteria, extensive sulfate reduction in algae accumulated sediments inhibited the microbial Fe reduction, and the ΣS-mediated chemical Fe reduction (SCIR) dominated instead. Iron was principally stored in the sediments as Fe sulfide compounds, which weakened the rebinding of phosphorus and stimulated phosphorus mobilization. Therefore, attention should be paid to the alteration of Fe cycling and phosphorus mobility caused by the SCIR in algae accumulated sediments and the consequent effects on the eutrophication of freshwater lakes.
在富营养化的太湖中，本研究调查了来自湖泊中心、疏浚区和藻类聚集区的三种沉积物的季节性变化。夏季高温和藻类的积累有利于淡水湖泊沉积物中的还原过程。在所有类型的沉积物中，铁还原被观察为主要的厌氧过程，而硫酸盐还原在湖泊中心和疏浚区较弱。然而，在藻类聚集区的表层沉积物中发现了强烈的硫酸盐还原，伴随着硫酸盐还原菌的增加和硫化物的产生（119.5±0.2 μmol L）。基于铁还原率和铁还原菌数量的结果，藻类聚集沉积物中的广泛硫酸盐还原抑制了微生物铁还原，而ΣS 介导的化学铁还原（SCIR）占主导地位。铁主要以硫化铁化合物的形式储存在沉积物中，这削弱了磷的再结合并刺激了磷的迁移。因此，应注意藻类聚集沉积物中 SCIR 引起的铁循环和磷迁移的变化，以及对淡水湖泊富营养化的影响。
