陈默,张雅庆,焦一滢,陈俊辰,包雲舟,赵丽娅,宋慧婷,李兆华.菹草残体厌氧分解过程中上覆水的硫酸盐还原特征[J].环境科学学报,2020,40(1):197-204
菹草残体厌氧分解过程中上覆水的硫酸盐还原特征
- Sulfate reduction in the water column during anaerobic decomposition of Potamogeton crispus L. residue
- 基金项目：国家自然科学基金项目（No.41807452）；湖北省自然科学基金项目（No.2018CFB311）；湖泊与环境国家重点实验室开放基金资助项目（No.2018SKL011）
- 陈默
- 1. 湖北大学资源环境学院, 武汉 430062;2. 湖泊与环境国家重点实验室, 南京 210008
- 焦一滢
- 河湖生态修复及藻类利用湖北省重点实验室, 湖北工业大学土木建筑与环境学院, 武汉 430068
- 摘要：在富营养化淡水湖泊中，微生物对水生植物的厌氧分解会导致局部水域泛黑发臭，产生草源性"湖泛"现象，但是当前对上覆水中硫酸盐还原细菌（SRB）在水生植物残体分解中的作用还不甚了解.本研究通过室内模拟实验，分别向湖水（本底硫酸根浓度为40 mg·L-1）中添加不同浓度的硫酸根，研究了硫酸根浓度升高对上覆水中SRB参与水生植物菹草（P.crispus）残体分解的影响.结果表明，硫酸根浓度升高显著促进了上覆水中硫酸盐还原作用，实验第50 d时，添加了40 mg·L-1硫酸根实验组（40S）中可溶性硫化物（∑H2S）为（100.11±5.08）mg·L-1，远高于未添加硫酸根对照组（CK）的（46.83±3.79）mg·L-1.硫还原细菌如脱硫化弧菌属（Desulfovibrio）、脱硫肠状菌属（Desulfotomaculum）和脱硫微菌属（Desulfomicrobium）在40S中的相对丰度显著高于CK（p<0.05），而脱硫化孢弯菌属（Desulfosporosinus）则在CK中的相对丰度更高，这说明硫酸根浓度升高促进了菹草残体厌氧分解过程中某些特定种属SRB的生长繁殖.此外，硫酸根浓度升高也影响了菹草厌氧分解过程中有色溶解有机物（CDOM）组分含量的变化，类腐殖质组分在第63 d的荧光强度显著高于第10 d（p<0.05），这说明硫酸根浓度升高促进了菹草厌氧分解过程中类腐殖质的产生.本研究对于进一步认识淡水水体中硫酸盐还原的环境效应及生物学机制具有重要意义，也为富营养化水体生态系统修复提供理论依据.
- Abstract：Anaerobic decomposition of macrophytes induces black and odorous bloom forming the phenomenon "colored zone" in eutrophic freshwater lakes. However, the role of sulfate reduction for the decomposition of macrophytes in overlying water has received little attention. In this study, the effects of sulfate concentrations on anaerobic decomposition of Potamogeton crispus L. (P. crispus) under sulfate reduction conditions were investigated by using the mesocosm experiments. The results indicate that an increase in sulfate concentrations stimulated sulfate reduction in the overlying water. On day 50, the concentration ((100.11±5.08) mg·L-1) of dissolved sulfide (∑H2S) in treatment amended with sulfate concentration of 40 mg·L-1 (40S) was obviously higher than control (sulfate un-amendment) ((46.83±3.79) mg·L-1). The relative abundance of typical SRB genera, like Desulfovibrio, Desulfotomaculum and Desulfomicrobium in 40S was significantly higher than in control on day 50 (p<0.05), however, the average relative abundance of Desulfosporosinus was higher in control (3.53%) than in 40S (1.29%), indicating higher level of sulfate possibly favors some groups of SRB specifically and allows them to outcompete the others for substrate in the study. Additionally, the dynamics of chromophoric dissolved organic matter (CDOM) were influenced by increases in sulfate input. Results indicated that fluorescence intensities of humic-like component in 40S were significantly higher on day 63 than day 10 (p<0.05), indicating that increases in sulfate input stimulated the production of humic-like substance during anaerobic decomposition of P. crispus in the overlying water. The study has important implication for further understanding of environmental effects of sulfate reduction and the microbial mechanism of sulfate reduction in freshwater lakes, and provides theoretical foundation for the remediation of ecosystems in eutrophic freshwater lakes.
