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题名	红树林沉积物的硝化和反硝化过程研究; Studies on Nitrification and Denitrification Processes in Mangrove Sediments
作者	王飞飞
答辩日期	2012 ; 2012
导师	曹文志
关键词	Mangrove ecosystems 红树林系统 Under the tidal condition 潮汐条件下 Nitrification 硝化作用 Denitrification 反硝化作用 Mineralization 有机氮矿化作用
英文摘要	氮（N）是生态系统中营养盐的重要组分，也是防治全球水体污染和控制温室气体排放的关键因子。氮循环对全球气候、海洋初级生产力和海洋生态系统等都有重要的调节和控制作用。红树林湿地是地球上生产力水平最高的自然生态系统之一，其生产力水平和种群结构直接受到营养盐的影响。由于红树林湿地特殊的地理环境和系统特点，使其具有独特的生物地球化学特征，从而使其成为全球氮循环的一个重要场所和研究热点。同时，硝化、反硝化和氮矿化过程是氮循环的核心控制机制，因此研究红树林区域的硝化、反硝化和氮矿化作用对于弄清红树林系统对N的自净和全球气候变化都有重要的意义。 本研究选取九龙江口浮宫红树林和沙埕湾巽城红树林为研究区域，采用乙炔抑制法测定了淹水时沉积物的硝化和反硝化作用及非淹水时沉积物的反硝化作用，通过原位培养实验测定了红树林沉积物氮的净矿化作用，并综合考虑淹水和非淹水条件，估计红树林系统的日平均反硝化强度。研究的主要结论如下： （1）在非淹水条件下，浮宫红树林系统反硝化作用速率范围为1.82~15.70 μmol N m-2 h-1，平均值为6.02 μmol N m-2 h-1，巽城红树林反硝化速率为3.32 μmol N m-2 h-1，表现出较大的差异。红树林沉积物反硝化速率高于其他非农业用地的地区，表明浮宫红树林具有较高的反硝化作用，是系统中削纳氮的重要机制之一。 （2）浮宫红树林系统氮的净矿化速率在-0.92~0.76 mg N kg-1 d-1之间，净氨化速率-0.93~0.73 mg N kg-1 d-1，净硝化速率0.0052~0.0431 mg N kg-1 d-1，净氨化、硝化和矿化强度存在着较大的差异。林龄大的红树林沉积物净矿化作用更加强烈。净氨化和矿化速率与培养前后NH4+-N含量和NO3--N含量均有显著相关性，而净硝化速率仅与培养后NO3--N显著相关。 （3）研究区在涨潮淹水时沉积物硝化速率在116~587 μmol N m-2 h-1之间，平均为328 μmol N m-2 h-1，站点间的硝化速率在不同月份也存在着较大差异。红树林系统沉积物的硝化速率高于其他河口和湿地系统，但低于农业源头溪流，这是由于农业源头溪流周边土壤施肥的原因。硝化速率具有明显的季节性变化。 （4）涨潮淹水条件下，浮宫红树林沉积物的反硝化速率为0.49~5.83 μmol N m-2 h-1，平均值为2.45 μmol N m-2 h-1。平均反硝化速率在林龄大的秋茄林相对较高，这与硝化速率呈现相同的趋势。本研究中的反硝化速率与其他系统相比较低，这可能是红树林沉积物中的硫化物含量高，会限制乙炔的抑制作用。此外，乙炔抑制法同时抑制硝化作用而造成红树林沉积物反硝化速率的低估。 （5）红树林沉积物的反硝化作用主要发生在退潮非淹水条件下，其反硝化速率是淹水时的2.5倍。浮宫红树林系统在潮汐周期内的日平均反硝化速率为139 μmol N m-2 d-1。九龙江口红树林保护区和核心区通过反硝化作用每年分别可去除约3.0 t和1.7 t的氮。; Nitrogen is an important component of nutrient in ecological system, also is the key factor of the global water pollution prevention and greenhouse gas emissions control. Nitrogen cycle has important adjustment and control function on global climate, marine primary productivity and marine ecological system. Mangrove wetland is one of the highest productivity level in natural ecosystems, the distribution of productive and the percentage of tree species in the community are influenced by the nutrient in sediments. The special geographical environment and the system characteristics of mangrove wetland, make its unique biological geochemistry characteristics, and make it become the global nitrogen cycling an important place and hotspot. Meanwhile, nitrification, denitrification and nitrogen mineralization processes are the core control mechanisms of the nitrogen cycling, so it has important significance to study on nitrification, denitrification and mineralization in mangrove area in order to make clear of N self-purification ability in mangrove system and global climate change. Our study selected Fugong mangrove in Jiulong river estuary and Xuncheng mangrove in Shacheng Bay as the study area. We used the acetylene inhibit method to explore the nitrification and denitrification rates under flooding condition, and denitrification rates under non-flooding condition. We developed the field experiments to determine the ammonification, nitrification and net nitrogen mineralization rates in the mangrove sediment. Through comprehensive consideration of the flooding and the non-flooding conditions, we estimated the denitrifying capacity of mangrove system. The main conclusions are as follows: (1) Under non-flooding condition, denitrification rates in Fugong mangrove system were 1.82~15.70 μmol N m-2 h-1, the average was 6.02 μmol N m-2 h-1, and the denitrification rate in Xuncheng mangrove sediment was 3.32 μmol N m-2 h-1. Denitrificaiton rates showed much difference. The denitrification rate in mangrove sediment was higher than the non-agricultural areaes, show that Fugong mangrove has high denitrification, which is the important mechanism of reducting the system nitrogen. (2) The nitrogen net mineralization rate in Fugong mangrove system was -0.92~0.76 mg N kg-1 d-1, the net ammonification rate was -0.93~0.73 mg N kg-1 d-1, the net nitrification rate was 0.0052~0.0431 mg N kg-1 d-1. Sediment net mineralization was higher in older mangrove. The net ammonification and mineralization rates had significantly correlation with NH4+-N and NO3--N content before and after training, and net nitrification rate only had significant correlation with NO3--N after training. (3) Nitrification rate in the study area sediment were 116~587 μmol N m-2 h-1 under high tide flooding condition, and the average rate was 328 μmol N m-2 h-1. Nitrification rates among sites had big differences in different months. The nitrification rate in mangrove system sediment was higher than other estuaries and wetland system, but less than agriculture source streams, which because of agriculture fertilization surrounding agriculture headstream. Nitrification rates had obvious seasonal changes. (4) Under high tide flooding condition, the denitrification rates in Fugong mangrove were 0.14~6.13 μmol N m-2 h-1, the average rate was 2.45 μmol N m-2 h-1. The average denitrification rate in older Kandelia candel forest was higher, which had the same trend to nitrification rate. Compared with other areas, the denitrification rate in the study area was low. Mangrove sediments have high sulfide content, and the sulfide in sediment will limit the acetylene inhibition. In addition, acetylene inhibit method inhibits nitrification simultaneously and then underestimate denitrification rate in mangrove sediment, so it is debatable to measure denitrification rate in mangrove sediment useing acetylene inhibit methods. (5) The denitrification in Fugong mangrove sediments mainly occur in non-flooding conditions, which was 2.5 times of flooding conditions. The average daily denitrification rate of Fugong mangrove system in tidal cycle was 119 μ mol N m-2 d-1. The Jiulong river estuary mangrove reserve area and core area can remove about 2.5 and 1.4 t nitrogen content each year through the denitrification, respectively.; 学位：理学硕士; 院系专业：海洋与环境学院环境科学与工程系_环境管理; 学号：22620091151190
语种	zh_CN
出处	http://210.34.4.13:8080/lunwen/detail.asp?serial=35295
内容类型	学位论文
源URL	[http://dspace.xmu.edu.cn/handle/2288/53660]
专题	环境生态－学位论文
推荐引用方式 GB/T 7714	王飞飞. 红树林沉积物的硝化和反硝化过程研究, Studies on Nitrification and Denitrification Processes in Mangrove Sediments[D]. 2012, 2012.

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