【作者】 杨文英；

【导师】 刘芸； 吴明；

【作者基本信息】 西南大学 ， 森林培育， 2011， 硕士

【摘要】 湿地作为陆地生态系统碳循环的重要组成部分,包括由淹水而引起的厌氧环境及由水淹而引起的耐水淹型植物。湿地只占陆地表面积很少的部分,但却是巨大的陆地碳库,约为整个土壤碳库的3%～68%。湿地生态系统90%以上的碳储量储存在土壤中,是多种温室气体的源和汇。多数湿地都是温室气体的“汇”,受到人类活动的干扰后,随着水分减少和土壤氧化性能增强,植物残体及泥炭的分解速率将会大大提高,结果导致湿地土壤有机碳的损失,而成为温室气体的“源”。全球气候变暖也加剧了湿地碳排放。目前由于气候变暖,湿地水温及土壤温度升高湿地能量平衡受到影响,导致湿地地表水水位及积水面积变化,进而影响了温室气体排放强度及湿地碳循环模式。杭州湾湿地是我国滨海湿地主要分布区之一,也是受人类活动影响最剧烈的区域之一。改革开放以来已围垦1.33万hm2,分10次向北推移海岸线达16km左右,围垦面积约占城市面积的60%还多。本研究选取杭州湾南岸未围垦的四种湿地环境芦苇、互花米草、海三棱藨草以及光滩作为研究对象,采用LI-6400连接土壤呼吸室进行连续12个月的土壤CO2测定,同时分析土壤活性有机碳含量、土壤酶活性以及其他相关理化指标,以揭示杭州湾典型湿地土壤呼吸特征、土壤CO2年排放量以及湿地土壤碳密度分布状况。主要研究结论如下(1)2010年1～12月利用Li-6400光合仪连接09土壤呼吸室对杭州湾四种湿地环境(芦苇、互花米草、海三棱藨草)以及对照(光滩)进行了连续12个月的土壤呼吸测定。结果表明：湿地夏季土壤呼吸速率日动态表现为昼高夜低,均呈明显的单峰曲线变化。与土壤温度的日动态变化趋势相近,在13：00～14：00之间达到峰值,在凌晨2：00-4：00之间到达低谷。四种湿地环境土壤日平均呼吸速率大小顺序为芦苇(8.34±4.53)umol/(m2.s)>互花米草(7.49±4.21)umol/(m2.s)>海三棱藨草(4.42±2.40)umol/(m2.s)>光滩(2.33±1.53)umol/(m2.s)。四种湿地环境土壤呼吸季节动态变化趋势表现为单峰曲线,从整年来看,土壤呼吸速率在4月到10月份相对较高,7月份达到最高值。从四季来看,四种湿地环境土壤呼吸速率大小顺序为：夏季>秋季>春季>冬季。四种湿地环境土壤呼吸速率与气温、土壤10cm处温度均有显著的指数函数相关性。其中,芦苇湿地,互花米草湿地,光滩湿地土壤10cm处温度与呼吸速率的相关性大于气温与土壤呼吸速率的相关性。海三棱藨草湿地土壤温度与土壤呼吸速率的相关性(R2=0.366)小于气温与土壤呼吸速率的相关性(R2=0.5773)。芦苇、互花米草、海三棱蔗草、光滩四种湿地土壤CO2年通量分别为6483.40 g/m2.a,5228.96 g/m2.a,2295.48 g/m2.a,975.48g/m2.a。(2)2010年从1月到12月采集四种湿地环境芦苇、互花米草、海三棱藨草以及光滩湿地的土壤,测定四种湿地环境的土壤活性有机碳含量季节变化、四种土壤酶活性的年变化以及土壤基本理化性质,结果表明：四种湿地环境土壤微生物量碳年平均含量为：互花米草(143.79 mg/kg)>海三棱藨草(138.39 mg/kg)>芦苇(135.52 mg/kg)>光滩(133.03 mg/kg);土壤溶解性碳年平均含量为：芦苇(319.33 mg/kg)>互花米草(316.47 mg/kg)>海三棱藨草(286.98 mg/kg)>光滩(278.20 mg/kg)；总有机碳年平均含量为：芦苇(7.87 g/kg)>光滩(7.65g/kg)>互花米草(7.39 g/kg)>海三棱藨草(6.81 g/kg)。四种湿地环境土壤总有机碳年变化小,含量相对稳定,而微生物量碳(变异系数>70%)和溶解性碳(变异系数50%)年变异较大。四种湿地环境土壤磷酸酶活性、脲酶活性、β-葡萄糖苷酶活性以及蔗糖酶活性年变异系数(C.V)都在50%以上,甚至超过100%。土壤微生物量碳与土壤磷酸酶、脲酶、β-葡萄糖苷酶以及蔗糖酶活性呈显著性负相关,不同季节相关性有差异。土壤溶解性碳与土壤磷酸酶、脲酶、β-葡萄糖苷酶活性在夏季呈显著的正相关关系。四种湿地0-5cm表层土壤碳密度大小为：芦苇湿地(37.8 t/ha)>互花米草湿地(36.2 t/ha)>海三棱藨草湿地(32.9 t/ha)>光滩(24.9 t/ha)；10-20cm深度土壤碳密度为芦苇湿地(92.3 t/ha)>海三棱藨草(86.8 t/ha)>互花米草(82.3 t/ha)>光滩(78.2 t/ha)。(3)采用开顶式增温法对杭州湾湿地芦苇群落进行短期的模拟增温处理,研究土壤CO2以及土壤酶活性对模拟增温的响应,结果表明：经过短期的模拟增温处理,土壤呼吸速率比常温下提高了17.36%。土壤10cm深度温度与土壤呼吸速率的相关性比气温与土壤呼吸速率的相关性更好；增温处理下的土壤温度敏感性指数高于常温状态；土壤磷酸酶、脲酶、β-葡萄糖苷酶以及蔗糖酶活性在短期的模拟增温后都有不同程度的提高。综上所述,本研究对杭州湾湿地土壤CO2排放情况以及土壤活性有机碳储存规律进行了研究,得出了滨海湿地十壤CO2的年排放规律以及活性有机碳储存的年变化规律,同时明确了该区域湿地固碳潜力。研究结果将有助于区内湿地保护与利用的科学布局,同时也为实施湿地碳增汇减排工程提供了理论指导和基础数据支撑,对湿地管理具有重要的实践意义。更多还原

【Abstract】 As the important part of the ecosystems carbon cycle, wetland ecosystem include water resistant flooded plant and its emvironment. The area of wetland is a few part of of the land surface,and its soil carbon library is huge,about the whole soil carbon library 3%～68%. There are more than 90 percent of the wetland ecosystem carbon storage store in soil, and the wetland ecosystem is the source and remit of a variety of greenhouse gas. Owing to the interferencing,the moisture reduce, the soil oxidation plant residues strenthen, the decompositon rate of plant residues and peat improve,and soil organic carbon wastage,then more greenhouse gas come from the wetland. Global warming has increased wetland carbon emissions.At present due to climate warming, wetland soil temperature and temperature of wetland energy balance affected, surface water and water area of wetland changes, which has affected the greenhouse gas emissions intensity and wetland carbon cycle mode. Hangzhou bay wetland is one of the main coastal wetland, and is also one of the areas affected by human. Since the reform and opening, there are hm21.33 million wetland reclamation. The costline has remove to north about 10 times 16km.The area of reclamation accounts for about 60% of the city area. The research object are Phragmites communis(LW), Spartina alterniflora(MC), Scirpusm ariqueter(BC) and the beach(GT) in south of Hangzhou bay.We measured the soil respiration by LI-6400 connected with the soil respiration chamber, and determin ate the soil organic carbon and the activity of the soil enzyme, to reveal the characteristics of typical wetland soil respiration, soil emissions of CO2 in Volume and typical wetland soil carbon density distribution. The main conclusions are as follows:(1)The soil CO2 was determinated by Li-6400 photosynthesis system connecting 09 of soil respiration chamber from January 2010 to December on LW,MC,BC,GT wetland.The results showed that:the daly dynamic performance in day more than ningt in summer, showed a clear single peak curve. The daily soil temperature trends are similar, the peak between 13:00 and 14:00,2:00 to 4:00 in the trough between the arrival. The order of four kinds of wetlands soil respiration rate:LW (8.34±4.53) umol/(m2.s)> MC (7.49±4.21) umol/(m2.s)> BC (4.42±2.40) umol/(m2.s)> GT (2.33±1.53) umol/(m2.s).Seasonal dynamics trend of four kinds of soil respiration showed a single peak curve, from the point of view throughout the year, soil respiration rate in the April to October is relatively high, the highest value in July. And the order of the season variation is:summer> autumn> spring> winter.There is a significant corrlation on soil respiration with air temperature,soil temperature at 10 cm depth. The corrlation of soil respiraton with soil temperature is bigger than with the air temperature at LW,MC,GT wetland, and smaller at BC wetland (R-=0.5773).The soil CO2 at LW,MC,BC,GT in a year was 6483.40 g/m2.a,5228.96 g/m2.a,2295.48 g/m2.a,975.48 g/m2. a.(2) The soil was acquisited at LW,MC,BC,GT wetland from January 2010 to December, and determinate the soil organic carbon, the soil enzyme activity and the soil physical and chemical properties, the results show that:The soil microbial biomass carbon content of the annual average: MC(143.79 mg/kg)>BC(138.39 mg/kg)>LW(135.52 mg/kg)>GT(133.03 mg/kg); the average carbon content of soil dissolved as:LW (319.33 mg/kg)> MC(316.47 mg/kg)> BC (286.98 mg/kg)> GT(278.20 mg/kg); the average total organic carbon content:LW(7.87 g/kg)>GT (7.65 g/kg)> MC(7.39 g/kg)> BC(6.81 g/kg).The changes in soil organic carbon in the four wetland types is small, and relatively stable, while microbial biomass C and dissolved carbon of variable.The C.V of soil phosphatase activity, urease,β-glucosidase activity and invertase activity above 50%, even more than 100%.There is a significant negatively correlation on microbial biomass carbon with soil phosphatase, urease,β-glucosidase and the activity of invertase activity, and there is a significant positive correlation on soil soluble carbon with soil phosphatase, urease,β-glucosidase activity in summer.The soil carbon density between0-5cm depth:LW(37.8 t/ha)>MC(36.2 t/ha)>BC (32.9 t/ha)>GT(24.9 t/ha); 10-20cm depth of soil carbon density:LW(92.3 t/ha)>BC(86.8 t/ha)>MC(82.3 t/ha)>GT(78.2 t/ha).(3) To research the response of the soil CO2 and soil enzyme activity to the temperature,we warm artificial to the LW by open top container at Hangzhou bay wetland.the results show that:after the short-term simulated warming treatment, soil respiration rate than Increased 17.36%. There is a good correlation of soil respiration with soil temperature at 10 cm depth. The Q10 of warming is bigger than normal state.The phosphatase, urease,β-glucosidase and Invertase activity after simulated warming in the short term has a different degree.In summary, Soil CO2 emissions and soil active organic carbon storage were studied at Hangzhou bay wetland.We harvest the coastal wetlands of CO2 Emission of soil active organic carbon stocks and annual variation, and carbon sequestration potential of wetlands. These results help us to contribute to the adjustment of the region,and provide the basic data for carbon sinks and emission reduction measures.It is important for practice.更多还原