菲律宾蛤仔对养殖池塘沉积物/水界面反硝化和厌氧氨氧化反应速率的影响

Effects of Ruditapes philippinarum on Denitrification and Anaerobic Ammonia Oxidation Rates of the Sediment/Water Interface in Seawater Aquaculture Pond

关键词:  菲律宾蛤仔  反硝化  厌氧氨氧化  沉积物

Key words:  Ruditapes philippinarum  Denitrification  Anaerobic ammonia oxidation  Sediment

摘要:

养殖尾水氮含量过高等富营养化问题是影响当前我国池塘养殖产业健康可持续发展的重要因素，反硝化和厌氧氨氧化是自然水生态系统中重要的氮循环过程，是沉积物氮素营养迁出的主要途径，埋栖型贝类通过滤水和蠕动等生命活动不仅能净化水质，还可以使沉积物颗粒混合并改变沉积物/水界面的物质交换。本研究于2020年9、10、11、12月采集菲律宾蛤仔(Ruditapes philippinarum)养殖池塘贝类区域(有贝区)和对照区域(无贝区)的沉积物表层样品，进行泥浆培养实验，利用氮稳定同位素示踪技术检测其反硝化和厌氧氨氧化反应速率，并分析了其与间隙水理化参数的相关性。结果显示，菲律宾蛤仔养殖池塘有贝区10月和11月样品检测到厌氧氨氧化反应，并有反硝化—厌氧氨氧化耦合反应；有贝区9—12月沉积物反硝化反应速率均高于无贝区，有贝区9月的反硝化反应速率最高(0.005 8 μmol/kg·h)；水体温度与沉积物反硝化反应速率呈极显著正相关(P<0.01)，氨氮(NH4+-N)浓度与厌氧氨氧化反应速率呈极显著正相关(P<0.01)。研究表明，海水池塘养殖生态系统中也存在厌氧氨氧化过程，养殖菲律宾蛤仔等埋栖型贝类有利于池塘沉积物/水界面的反硝化和厌氧氨氧化反应，有效地促进池塘沉积物脱氮过程，研究结果不仅丰富了海水养殖生态系统氮循环理论，也为开展尾水生物净化工作提供了新思路。

Abstract:

The eutrophication problem caused by various reasons such as excessive nitrogen level in aquaculture wastewater are the most critical obstacle to the sustainability of aquaculture industry in China at present. Denitrification and anaerobic ammonium oxidation (Anammox) are important nitrogen cycling processes in natural water ecosystems, which are the main nitrogen removal pathways in the sediments. Clams could not only purify aquaculture water column by their water-filtering activities and wriggle behaviors, but also change the material transportation which occurs in the sediment/water interface. In the present study, the slurry incubation experiments using the sediment samples collected at the area with or without Manila clam (Ruditapes philippinarum) in a biological wastewater treatment pond in Sept., Oct., Nov. and Dec., 2020 have been performed to investigate the potential denitrification and anammox activity rate, and the relationship between the denitrification or anammox activity rate and the porewater physicochemical parameters have also been analyzed. The results showed that the anammox was found in the sediment of clam culture area in Oct. and Nov., and the denitrification-anammox coupling were also found. The denitrification activity rate of sediments with clam culture in the four months were higher than that of sediments without clam, and the highest rate (0.005 8 μmol/kg·h) was found in the sample of Sept. There was a significant positive correlation (P<0.01) between the denitrification activity rate and porewater temperature in clam culture area, and between the porewater NH4+ level and anammox activity rate. The anammox has been found in the seawater aquaculture pond. The clam promoted denitrification and anammox processes in sediment/water interface which showed a vital role in nitrogen removal in sediment in the present study. The results will not only enrich the nitrogen cycling theory of aquaculture ecosystem, but also provided insights to establishing new biological wastewater treatment measures.