【作者】 刘清学；

【导师】 王犇；

【作者基本信息】 青岛科技大学 ， 安全技术及工程， 2011， 硕士

【摘要】 氮是水生生物最基础的营养物质,沉积物中的氮在整个水生生态系统氮循环中占据重要地位。湖泊生态系统中的溶解有机质(DOM)对湖泊系统各种物理、化学和生物过程都发挥着重要作用。本文对我国湖泊沉积物中氮的化学结合形态进行了分析,研究了各形态氮的含量和分布特征;对湖泊沉积物DOM进行了紫外-可见光谱、同步荧光光谱和三维荧光光谱的测定和分析,得到主要结果如下:(1)湖泊表层沉积物中有机氮主导了总氮的分布,有机氮是总氮的主要存在形式,各湖区湖泊沉积物中有机氮占总氮的比例均超过了80%;固定态铵是总氮的重要组成部分,蒙新高原湖区湖泊沉积物中固定态铵占总氮的比例最低,为8.99%,东部平原湖区最高,为13.83%;可交换态氮占总氮的比例最低。(2)湖泊沉积物中可交换态氮一般以可交换态氨氮为主,可交换态硝氮次之,且氨氮含量远大于硝氮,青藏高原湖区与此不同,其有半数的湖泊沉积物样中硝氮含量大于氨氮。(3)各湖区湖泊沉积物中氨氮和硝氮均与总氮、有机氮和TOC呈显著正相关关系。固定态铵与其他氮形态和TOC的关系不明显,东部平原湖区、蒙新高原湖区和青藏高原湖区湖泊沉积物中固定态铵与其他形态氮和TOC之间无显著相关关系;东北平原与山地湖区湖泊沉积物中固定态铵与硝氮、总氮、有机氮和TOC呈显著正相关关系;云贵高原湖区湖泊沉积物中固定态铵与TOC呈显著负相关关系。(4)不同湖泊沉积物DOM的紫外-可见光谱图形不同,且与地域分异无关;各湖泊沉积物DOM的同步荧光光谱均在280nm附近有较强的吸收峰,长波处吸收峰较弱,说明湖泊沉积物DOM的组分中含有大量的类蛋白等小分子物质。(5)湖泊沉积物DOM的三维荧光光谱中类蛋白峰、紫外区类腐殖质峰、可见光区类腐殖质峰均有出现;湖泊沉积物DOM三维荧光光谱中类蛋白峰的强度要普遍高于类腐殖质峰;但东北平原与山地湖区湖泊沉积物DOM的类腐殖质峰强度普遍高于类蛋白峰。更多还原

【Abstract】 Nitrogen is the most basic nutriment of aquatic organism, and nitrogen in lake sediment plays an important role in nitrogen cycling of aquatic ecosystem. Dissolved organic matter (DOM) in Lake Ecosystem involves in all kinds of physical, chemical and biological processes in lake system. The content and distribution of various nitrogen in lake sediments in China was studied, and UV-VIS absorbance, synchronous fluorescence spectroscopy and three-dimensional excitation emission matrix fluorescence spectroscopy (3DEEM) were selected to characterize DOM in lake sediments in this paper. The main results as follows:(1) Organic nitrogen (No) was the main form of nitrogen in superficial sediment, accounting for over 80% of total nitrogen (TN) in all regions. Fixed ammonium (NFIX) was an important part of total nitrogen, the proportion of NFIX in TN in lake sediments in Mengxin Plateau was lowest, which was 8.99%, and East Plain was highest, which was 13.83%. Exchangeable nitrogen (NEX) was least in nitrogen.(2) In most lake sediments, exchangeable ammonia nitrogen was more than exchangeable nitrate nitrogen. But in Tibetan Plateau, exchangeable nitrate nitrogen was more than exchangeable ammonia nitrogen in half lake sediments.(3) Ammonia nitrogen and nitrate nitrogen had positive correlations with total nitrogen, organic nitrogen and TOC. There was no correlation between NFIX and other various nitrogen fractions and TOC in East Plain, Mengxin Plateau and Tibetan Plateau; There was a strong positive correlation between NFIX and nitrate nitrogen, organic nitrogen, total nitrogen and TOC in lake sediments in Northeast plain and mountainous region; And in Yungui Plateau, NFIX had a negative correlation with TOC. (4) UV-VIS spectrums of DOM in lake sediments were different, including in same regions. All synchronous spectrums exhibited a peak at about 280nm, showing that there were a large number of small molecular weight matters, such as protein-like matters.(5) There were protein-like fluorophores, UV humic-like fluorophores and VIS humic-like fluorophores in 3DEEMs of DOM in lake sediments. Generally, the fluorescence intensity of protein-like was higher than humic-like in 3DEEMs of DOM in lake sediments. But, the fluorescence intensity of humic-like was higher than protein-like commonly in northeast plain and mountainous region.更多还原