湖泊沉积物溶解性有机氮特征研究

分类号 X52 U D C 502
学校代码 10129 学 号 2009204023
湖泊沉积物溶解性有机氮特征研究 Characteristics of dissolved organic nitrogen in lake sediments
申 请 人：高悦文 学科门类：农 学 学科专业：土壤学 研究方向：土壤资源利用与改良 指导教师: 张伟华 副教授
关键词：溶解性有机氮；组成；来源；季节性变化；生物有效性；结构特征；湖泊 沉积物
Characteristics of dissolved organic nitrogen in lake sediments
Abstract Eutrophication and algal bloom are global environmental problems. Distribution and structure characteristics of dissolved organic nitrogen (DON), major nutrition source of aquatic and main element of eutrophication, is important to make out eutrophication and algal bloom. It is necessary to analysis DON of lake sediment. In this study, composition, sources, seasonal variation, biological validity and structure characteristics of lake sediment DON in Yangtze valley were researched with 3D fluorescence spectra and High performance liquid chromatography techniques. 1、DON extracted with 6 different soil extractant. Based on aggregate analysis of DON concentration and fluorescence structure stability, CaCl2 was the best soil extractant of the 6 extractant. 2、Through the research on structure and content of DON of 4 lakes, we know that content of DON of lake sediment highest in Erhai Lake followed by Dongting Lake, Chaohu Lake and Poyang Lake. Source of DON of lake sediment in Erhai Lake, Chaohu Lake and Poyang Lake is biogenetic derivation; Exogenous input is also important source for Dongting Lake. 3、 DON concentration of Dongting Lake(3 sites) and Poyang Lake(3 sites) were incubation under different temperature without light and vibration. Results shows that DON concentration changes over time show clear “w” type, bioavailability of DON among 12% to 85%. Incubation constituents were change in consistent, Kind of humic acid material increased and Kind of protein material decreased. This due to the tyrosine or tryptophan degradation or transformation. 4、The seasonal variation of dissolved organic nitrogen (DON) and dissolved free amino acids (DFAA) were studied by the 10 sediment samples selected from the Erhai Lake. The results shown that, (1) the w(DON) of the sediments changed from 10.41 to 59.58 mg/kg, average of 27.43mg/kg, account for the 40% of total dissolved nitrogen (TDN) and the 6% of total nitrogen. The rank order of the seasonal variation of the w(DON) was the spring> the winter> the summer> the autumn, and that of the regional variation was the south > the north > the middle of Erhai Lake. (2) The w(DFAA) of the sediments changed from 4.11 to 9.89mg/kg, average of 5.96mg/kg, account for 22% of DON and 9% of TDN. The highest value of DFAA was in the autumn and the lowest was in the summer, and that of the regional variation was the same as DON. The more serious
3．选取洞庭湖（3 个）和鄱阳湖（3 个）表层沉积物样品，不同温度避光静养 DON 溶液，研究湖泊 DON 生物有效性。结果表明：（1）培养过程中 DON 含量随 时间变化明显，基本呈现“W”型变化趋势。各湖泊沉积物 DON 生物利用率大约 为 12%~85%。（2）各湖泊沉积物 DON 组分变化较为一致，类腐殖酸物质不断增加， 类蛋白物质不断减少，这与络氨酸或色氨酸的降解或转化有很重要的关系。
王圣瑞 研究员
论文提交日期：二〇一二年五月
Байду номын сангаас
摘要
湖泊富营养化及伴随蓝藻水华爆发已成为全球性的环境问题。溶解性有机氮不 仅是蓝藻等水生植物生长的重要氮营养源，而且是湖泊富营养化的重要内在因素， 其分布与结构特征对深入理解湖泊的富营养化及蓝藻水华爆发机理具有重要的作 用。因此，对于湖泊沉积物溶解性有机氮的研究显得尤为重要。本研究利用三维荧 光光谱、高效液相色谱等技术，对长江流域及云贵高原湖泊沉积物溶解性有机氮的 提取方法、组成、来源、季节性变化、生物有效性及结构特征等方面进行研究，以 期为揭示湖泊富营养化及蓝藻水华爆发机理提供参考价值。主要研究结果如下：
1．利用 6 种 DON 提取方法分析洱海、太湖和滇池 3 个湖泊 8 个表层沉积物样 品。通过 DON 含量与荧光结构稳定性综合分析，认为 CaCl2 溶液作为浸提剂提取 DON 效果较好。
2．选取洱海（10 个），洞庭湖（16 个），巢湖（13 个），鄱阳湖（14 个）沉积 物样品，研究了不同湖泊 DON 含量及结构变化。结果表明：不同湖泊表层沉积物 DON 含量呈现洱海>洞庭湖>巢湖>鄱阳湖的特点。影响沉积物 DON 含量动态变化 的关键因素是 DON 的来源。各湖泊 DON 来源不同，洱海、鄱阳湖、巢湖主要是生 物来源即内源输入；洞庭湖是陆源与生物来源共同作用的结果，并以内源输入为主。
polluted region the higher w(DFAA).(3) The seasonal variation of w(DON) and w(DFAA) was obviously, and which play an important role in nitrogen cycling of lakes ecosystem, especially for the place where aquatic plants flourish. So expect that the total nitrogen should be considered during the eutrophicatic control of Erhai Lake, and the effects of DON in the lake nitrogen cycling and in the eutrophication should also be paid more attention. 5、Concentration of Levorotatory right amino acids for Erhai Lake(7sites), Dongting Lake (3sites), Poyang Lake(3sites) and Taihu Lake(2sites) were analyzed with HPLC. Results shows that main constituents of free amino acid for Dongting Lake, Poyang Lake and Taihu Lake including serine, isoleucine, histidine and lysine. Main constituents of Erhai Lake contain another two free amino acid, aspartic and alanine. Concentration of serine between 1.2 to 12.89mg/kg, isoleucine among 1.12 to 24.6mg/kg, histidine among 0.42 to 7.22mg/kg, lysine among 0.71 to 7.73mg/kg, aspartic among 0.32 and 0.82mg/kg, alanine among 1.2 and 2.55 mg/kg. Erhai sediment DON free amino acids sequence is: isoleucine> serine> lysine> alanine> histidine> aspartic acid, aspartic acid content is relatively small.
4．选取洱海 10 个表层沉积物样品，研究了不同季节 DON 和易分解组分游离 氨基酸（DFAA）的含量变化。结果表明：（1）洱海沉积物 w(DON)在 10.41~59.58mg/kg 之间，平均值为 27.43 mg/kg，约占可溶性总氮(TDN)的 40%，沉积物总氮的 6%， 其季节性变化呈现“春季>冬季>夏季>秋季”的趋势，不同季节洱海不同湖区均呈 现“南部>北部>中部”的特点。（2）洱海沉积物 w(DFAA)含量在 4.11~9.89mg/kg 之间变化，平均值为 5.96mg/kg，约占 DON 的 22%，TDN 的 9%。季节性变化呈现 “秋季相对较高，冬春次之，夏季相对较少”的趋势。区域性变化呈现“南北高， 中间低”的特点，污染较严重的区域，沉积物 w(DFAA)较高。（3）作为沉积物活性 氮重要组成的 w(DON)和 w(DFAA)的季节性变化明显，对湖泊氮代谢有重要影响， 在水生植物旺盛区域尤为明显。在洱海富营养化治理中，除了关注沉积物总氮，更 应关注其 DON 在湖泊氮循环及其富营养化中的作用。
5．选取洱海（7 个），洞庭湖（3 个），鄱阳湖（3 个），太湖（2 个）表层沉积 物样品，利用 HPLC 法测定 DON 中左旋游氨基酸含量。结果表明：（1）长江中下 游 3 个湖泊沉积物 DON 中主要的游离氨基酸有 4 种，分别为：丝氨酸、异亮氨酸、 组氨酸、赖氨酸。洱海较其多 2 种：天冬氨酸、丙氨酸。（2）4 个湖泊沉积物 DON 中丝氨酸在 1.2~12.89mg/kg 之间，异亮氨酸在 1.12~24.6mg/kg 之间，组氨酸在 0.42~7.22mg/kg 之间，赖氨酸在 0.71~7.73mg/kg 之间，天冬氨酸在 0.32~0.82mg/kg 之间、丙氨酸在 1.2~2.55mg/kg 之间。洱海沉积物 DON 中游离氨基酸含量为：异亮 氨酸>丝氨酸>赖氨酸>丙氨酸>组氨酸>天冬氨酸，酸性天冬氨酸含量相对较少。