滨海湿地不同水位梯度下的土壤CO_2通量比较  

Comparison of soil CO_2 flux among different water levels in coastal wetlands

作　　者：欧强[1] 王江涛[1] 周剑虹[1] 李艳[1] 姜楠[1] 王开运[1,2] 

机构地区：[1]华东师范大学生态环境学院,上海200062 [2]上海市城市化生态过程与生态恢复重点实验室,上海200062

出　　处：《应用与环境生物学报》2014年第6期992-998,共7页Chinese Journal of Applied and Environmental Biology

基　　金：国家科技支撑计划后世博科技专项(10dz1200602);上海市科委崇明科技专项(11dz1210903)资助~~

摘　　要：为了解水位对滨海湿地土壤CO2通量的影响,利用Licor-8100土壤CO2通量测定仪器对崇明东滩滨海湿地植物生长季(4-10月)不同水位梯度(低水位、中水位和高水位)下的土壤CO2通量进行观测,主要包括CO2通量日动态、季节动态、温度敏感性指数(Q10)、总CO2通量释放量以及土壤温度和CO2通量之间的关系.结果表明,低、中、高水位生长季土壤CO2通量总量分别为32 490.36、38 173.46和26 200.94 kg hm-2;3个水位梯度土壤CO2通量的日动态和季节动态均主要受温度影响.中、低水位土壤CO2通量的日变化峰值出现在12:00左右,比高水位提前2 h左右,不同水位梯度最小值均出现在凌晨4:00左右.不同水位梯度下的土壤CO2通量具有明显的季节性变化,呈单峰型,最大通量均出现在7月底;低、中、高水位生长季土壤CO2通量均值分别为644.65、757.41和519.86 mg m-2 h-1,不同水位梯度间差异显著.这表明,水位降低会促进土壤CO2释放,但水位下降超过一定限度,则会抑制其释放.各水位梯度下的土壤CO2通量与土壤5 cm温度均呈显著指数关系,土壤温度对土壤CO2通量的解释率由低水位到高水位依次降低.Q10值高水位最大(3.9)、中水位最低(2.8).整个生长季不同水位梯度下土壤含水量对土壤CO2通量影响不显著,但高温季节有较大影响.土壤温度、土壤含水量的二元方程仅对高水位土壤CO2通量季节变异的解释率有所增强,对中、低水位的解释率均降低.综上所述,合理调控滨海湿地水位有助于降低其土壤CO2通量,进而增强其碳汇功能.For a comprehensive understanding of the influence of water level on soil CO2 flux of coastal wetlands, we measured the soil CO2 flux of three different water levels in the Dongtan coastal wetland of the Chongming Island with Li-8100 automated soil CO2 flux system. The diurnal dynamics, seasonal dynamics, temperature sensitivity index （Qlo）, total CO2 emissions, and relationship between soil temperature and soil CO2 flux were investigated in three different water levels including low water level （L）, medium water level （M） and high water level （H）. The results showed the growing-season total CO2 emissions in the wetland as 32 490.36 kg hm＂2 from the low water level, 38 173.46 kg hm＂2 from the medium and 26 200.94 kg hm2 from high water level. Diurnal and seasonal variations of soil CO2 flux among different water levels were mainly affected by soil temperatures. Soil CO2 flux reached the maximum around the noon in low and medium water levels, but about two hours earlier in the high water level. Minimum flux occurred at 4：00 am in all three water levels. There was an obvious single-peak seasonal variation in the CO2 emissions during the whole observation period, with the peak on July 30th. The growing-season mean value was 644.65 mg m＂2 h＂1 for the low water level, 757.41 mg m2 h~ for the medium and 519.86 mg m2 h1 for the high water level, with significant differences among the water levels. Significant relationships were found between the soil temperature at 5 cm depth and soil CO2 flux from different water levels, which could be best described by the exponential equations. Rate of interpretation of soil temperature to soil CO2 flux reduced from low to high water level. The Q10 value was the highest （3.9） in high water level and the lowest （2.8） in the medium level. Throughout the whole growing season, soil moisture did not affect soil CO： flux significantly except for the high temperature season. Two-dimensional equations based on soil temperature and soil water content were b

关 键 词：水位梯度 滨海湿地 CO2通量 土壤温度 土壤含水量 

分 类 号：S152.6[农业科学—土壤学]