崇明东滩滨海围垦湿地生长季CO2通量特征

利用涡度相关法,观测了崇明东滩滨海围垦湿地2013年生长季的CO2通量，并分析了CO2通量动态特征及相关环境因子对其的影响。结果表明：该湿地2013年生长季累积净生态系统CO2交换量(NEE)达-1 033257 g/m2，表现为明显的CO2的“汇”。各月NEE平均日动态虽有差异，但均表现为典型的“U”型曲线；各月均表现为吸收CO2，其中7月份月累积NEE值最小，为-274928 g/m2,而9月份最大，为-67440 g/m2；就生态系统呼吸(Reco)占生态系统总第一性生产力(GPP)的比例(Z值)而言，4月份最小，而9月份最大。光合有效辐射(PAR)和日间净生态系统CO2交换量(NEEd)之间符合直角双曲线关系，表观量子效率(α)和最大光合速率(Pmax)分别在6月份和8月份达到最大值；相对于土壤温度(Ts)，4 m气温(Ta4)能够更好的解释NEEn和NEEd的变化；各月NEEn与Ta4之间符合极显著指数函数关系；在7和8月份,NEEn与Ta4之间呈现出极显著负相关，即Ta4的升高能够抑制NEEn的增大，而其余月份则为极显著正相关。各月NEEd与Ta4之间均符合极显著二次函数关系，而在4、6以及9月份，NEEd与Ts10及Ts30之间并无显著相关性。就Q10值而言，除了7和8月，其余月份均呈现出Q10(Ta4)<Q10(Ts10)<Q10(Ts30)的规律。土壤体积含水量(SWC)和土壤盐度(Ss)是NEE的重要影响因子，二者与NEEn及NEEd之间均表现为极显著的相关性

CHARACTERISTIC OF CO2 FLUX IN THE COASTAL RECLAIMED WETLAND OF CHONGMING DONGTAN DURING THE GROWING SEASON

Druing the growing season of 2013, the eddy covariance method was applied to measure the CO2 flux in the coastal Reclaimed wetland of Chongming Dongtan, and the variation characteristic and the effects of related environmental factors were analyzed. The results showed that: druing the whole growing season of 2013, the accumulated CO2 exchange (NEE) value of the net ecosystem was -1 033257 g/m2, and the wetland was characterized by obvious carbon “sink”. The average diurnal variation of NEE varied among months but all appeared as the typical “U” type curve. All the seven months were manifested to be CO2 uptake, and the minimum accumulated NEE value was in July (-274928 g/m2), while the maximum was in September (-67440 g/m2). As far as the ratio of Ecosystem Respiration to Gross Ecosystem Primary Productivity (Z value), April had the minimum Z, while September had the maximum one. In the whole growing season, 722% of GPP was consumed by Reco. There was a rectangular hyperbolic correlation between the photosynthetic active radiation and daytime net ecosystem CO2 exchange (NEEd). The apparent quantum yield (α) and maximum photosynthetic rate (Pmax) reached its maximum in June and August, respectively. Compared with the soil temperature(Ts), the 4m air temperature (Ta4) could explain the variation of nighttime net ecosystem CO2 exchange (NEEn) and NEEd better. There was a significant exponential function correlation between NEEn and Ta4 in every month of the growing season. In July and August, it showed a significant negative correlation between NEEn and Ta4, which means that the increase of Ta4 lead to the inhibition of NEEn, but in other months, it showed a significant positive correlation. Although the discriminant coefficient (R2) between NEEd and Ta4 was small, all of them obey significant quadratic function correlation. But in April, June and September， there were no significant correlation between NEEd and Ts. As far as Q10 vaule, it showed the order of Q10 (Ta4)