| 摘要: |
| 反硝化作用是将氮素从湖泊中彻底去除的重要途径之一，对于减轻湖泊富营养化具有重要意义。为了探究太湖沉水植物附着生物的生物量、潜在反硝化速率变化规律及其与环境因素的关系，在沉水植物生长盛期（7月），以太湖沉水植物主要分布区域东部湖湾作为采样区域，野外采样结合室内分析研究了太湖常见的3种沉水植物上附着生物的生物量，并利用乙炔抑制法测定沉水植物上附着生物的潜在反硝化速率，分析了太湖沉水植物附着生物的生物量及其潜在反硝化速率的主要影响因素。结果表明，太湖常见的几种沉水植物单位体表面积附着生物的生物量（AFDM）在0.037 ~ 0.789 mg/ m^2之间，均值为（0.389±0.261）mg/ m^2，沉水植物上附着生物的生物量存在空间差异，最大值出现在贡湖湾G1采样点（0.794±0.007 mg/ m^2），最小值出现在胥口湾X1采样点（0.041±0.005 mg/ m^2）。太湖沉水植物单位体表面积附着生物的潜在反硝化速率在3.09 ~58.80 μmol N_2 O m^(-2) h^(-1)之间，均值为（24.75±5.96）μmol N_2 O m^(-2) h^(-1)。太湖沉水植物附着生物的潜在反硝化速率存在空间差异，其中最大值出现在贡湖湾G1采样点（58.80±20.20 μmol N_2 O m^(-2) h^(-1)），最小值出现在胥口湾X1采样点（3.09±1.79 μmol N_2 O m^(-2) h^(-1)）。相同条件下，沉水植物附着生物的生物量及潜在反硝化速率因植物种类的不同而存在差异，狐尾藻（Myriophyllum spicatum）上的附着生物的生物量及潜在反硝化速率显著高于苦草（Vallisneria natans）上的附着生物的生物量及潜在反硝化速率。相关分析结果表明，沉水植物上附着生物的生物量与水体氮磷含量相关。沉水植物附着生物的潜在反硝化速率与附着藻类的生物量、水体溶解有机碳（DOC）及pH存在显著相关关系（p < 0.01），这三种因子可以解释81.2%的沉水植物附着生物的潜在反硝化速率的变化，本研究结果为进一步研究浅水湖泊脱氮过程及富营养化治理提供一定的理论依据。 |
| 关键词: 附着生物 潜在反硝化速率 太湖 沉水植物 |
| DOI： |
| 分类号: |
| 基金项目:国家自然科学(42077303)；江苏省科技计划项目(BK20220021) |
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| Study on the biomass and the potential denitrification rate of the epiphyton on three kinds of submerged plants in Lake Taihu |
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Ren Tianyi,Xu Xianghua,Song Yuzhi,Guo Jing
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1.Nanjing University of Information Science and Technology, Key Laboratory of Ecosystem Carbon Source and Sequestration, China Meteorological Administration;2.Nanjing University of Information Science and Technology, Key Laboratory of Ecosystem Carbon Source and Sequestration, China Meteorological Administration，Research Center for Carbon Sequestration and Global Change, Nanjing University of Information Science and Technology
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| Abstract: |
| Denitrification, as an important way to completely remove nitrogen from lakes, is important for reducing eutrophication in lakes. In order to explore the variation of biomass and potential denitrification rate of epiphyton in Lake Taihu, during the vigorous growing stage（July），three types of submerged macrophytes were sampled from the eastern lake bay of Lake Taihu for the distributions of submerged, the biomass of epiphyton was analyzed and the potential denitrification rate of periphytic biofilm was determined by acetylene inhibition. The main influencing factors of the biomass and potential denitrification rate of epiphyton in Lake Taihu were also explored. The results showed that there were spatial differences in the biomass of epiphyton in Lake Taihu. The biomass per unit submerged plant body surface area of epiphyton in Lake Taihu ranged from 0.037 ~ 0.789 mg/ m^2 and the mean value was (0.389±0.261) mg/ m^2. The maximum biomass of epiphyton occurred at sample point G1 (0.794±0.007 mg/ m^2) in Gonghu Bay, and the minimum value occurred at sample point X1 (0.041±0.005 mg/ m^2) in Xukou Bay. The potential denitrification rate per unit submerged plant body surface area of epiphyton in Lake Taihu ranged from 3.09 ~58.80 μmol N_2 O m^(-2) h^(-1)and the mean value was (24.75±5.96) μmol N_2 O m^(-2) h^(-1). There were obvious spatial differences in the potential denitrification rates of epiphyton in Lake Taihu, the maximum value occured at sample point G1 (58.80±20.20 μmol N_2 O m^(-2) h^(-1)) and the minimum value occurred at sample point X1 (3.09±1.79 μmol N_2 O m^(-2) h^(-1)). There were differences in the potential denitrification rates of epiphyton for the host plants, the potential denitrification rate of epiphyton on the Myriophyllum spicatum was significantly higher than that on the Vallisneria natans,.The results of the correlation analysis showed that there was a significant correlation between the biomass of epiphytons and the nitrogen of the water (p < 0.01), and there was significant correlation between the potential denitrification rate of epiphyton and the biomass of epiphytic algae, DOC and pH of the water (p < 0.01), which could explained 81.2% of the variation of the periphytic biofilm potential denitrification rate. The results of this study provide some theoretical basis for further research on the process of denitrification and eutrophication management in shallow lakes. |
| Key words: epiphyton the potential denitrification rate Lake Taihu submerged plants |
