江苏滨海县海域漂浮浒苔光合生理特性及其固碳潜力评估

The photosynthetic physiological characteristics and evaluation of carbon fixation capacity of Ulva prolifera in Binhai sea area,Jiangsu province

测定了江苏滨海县海域漂浮浒苔（Ulva prolifera）的光合生理特性（叶绿素荧光参数、叶绿素含量、Rubisco活性、光合速率）和组织含碳量,并分析了浒苔暴发海区水体溶解性无机碳（dissolved inorganic carbon,DIC）浓度及pH值变化特征.结果表明：1）浒苔漂到滨海海域时藻体状态良好,藻体F/Fm达到0.67,Yield为0.57,总光合速率为66.99 μmol（C）·g-1 （FW）·h-1,叶绿素a和b的含量分别为0.91 mg·g-1和0.65mg·g-1,Rubisco活性达到11.39 μmol（CO2）·g-1（FW）·min-1;2）覆盖区域不同位点海水无机碳体系各参数均出现不同程度的变化,从浒苔覆盖区边缘到中心,海水中DIC和HCO3浓度逐步降低（P＜0.05）,而海水pH值却逐渐升高（Pp＜0.05）.3）2008 ～ 2013连续6年暴发的绿潮藻生物量累计约达9 832.8×104 t湿重,可固定CO2量达1 843.67×104 t,说明浒苔对DIC的吸收能力较强,能促进海水无机碳体系循环,提高海水pH值,能一定程度上增加海洋碳汇强度.

The photosynthetic physiological characteristics of Ulva prolifera in Binhai Sea were investigated in June, 2013. The key indicators included Chlorophyll fluorescence parameters, Chlorophyll contents, Rubisco activity, photosynthetic rate and carbon contents in the base tissue. And we surveyed seawater dissolved inorganic carbon （DIC） contents, HCO3-, CO1-, CO2 （T）, and pH changes in green tide coverage area. Results showed that ： （ 1 ） The state of thalli was healthy with U. prolifera floating in Binhai sea area. The thalli exhibited Fv/F,, of 0.67 and Yield of 0.57. The chlorophyll a （ Ca） and chlorophyll b （ Cb ） contents were 0.91 and O. 65 mg·g - 1, respectively. And U. prolifera Rubisco activity was 11.39 μmol （ CO2 ）·g- 1 （FW）min-1 ; （2） Seawater inorganic carbon system parameters in different sites of thalli coverage showed different degrees of changes. From the edge of coverage area to the centre, DIC and HCO3 - concentrations decreased, and there was a significant difference （ P 〈 0.05 ）. At the same time, these values were much lower than that of uncovered region. The concentrations of CO： （T） among different coverage areas had no significant difference. CO23- concentrations among different coverage areas showed significant differences （P 〈 0.05）. Values of pH gradually increased from the uncovered region to the covered centre （P 〈 0.05 ）. And the highest value was 8.52 in the covered centre; （3） The carbon fixation was estimated to be 18. 436 7 million tons for green tide algae ,with a biomass sum of 98. 328 million tons in wet weight from 2008 to 2013. This study showed that U. prolifera had strong absorptive capacity for DIC, could promote seawater inorganic carbon system circulation, improving sea water pH. Besides, the huge green tide algae biomass can increase ocean carbon sinking to a certain extent.