中文摘要：

利用浮游植物荧光仪Phyto-PAM测量了西太平洋浮游植物最大光化学量子产量、快速光曲线系数,结合相应的生态因子,对西太平洋浮游植物进行了原位光合作用特征研究。结果表明：西太平洋走航断面表层浮游植物最大光化学量子产量F_v/F_m值基本在0.2以下,而DY（大洋）断面F_v/F_m平均值仅为0.16,光能利用效率α的变化范围为0.007—0.117,平均值为0.039;相对最大电子传递速率r ETR_（max）变化范围为6.8—113.4（μmol/（s·m2））,平均值为32.72（μmol/（s·m2））;饱和光强Ek的变化范围为60.3—1662.7（μmol/（s·m2））,平均值为846.83（μmol/（s·m2））。DY断面F_v/F_m最大值水层与DCM层（叶绿素最大层）相吻合,既保护了浮游植物光反应中心不受强烈光辐射影响,又支持了DCM层浮游植物相对较强的光合作用和对整个水体初级生产力的贡献率。DY断面浮游植物具有极低的光能利用效率却需要较高的光强来达到光饱和,导致这种生活环境下浮游植物处于一种低活衰老的状态,这是造成某些大洋海区低生产力现象出现的原因之一。

英文摘要：

Photosynthetic characteristics of phytoplankton across three transects in the western Pacific in winter 2014 were studied using Phyto-PAM（Pulse Amplitude Modulation）. Environmental parameters were used to understand relationship between photochemical competence of phytoplankton and ecological factors. Results show that the photosynthetic efficiency of photosystem II（F_v/F_m） on all three transects was below 0.2. For Transect DY however, the mean F_v/F_m was 0.16, the light utilization efficiency（α） ranged from 0.007—0.117 in average of 0.039; maximum relative electron transport rate（r ETRmax） ranged from 6.8—113.4（μmol/（s·m~2）） in average of 32.72; light saturation intensity（Ek） ranged from 60.3—1662.7（μmol/（s·m2）） in average of 846.83（μmol/（s·m2））. The layer with maximum F_v/F_m agreed with the deep chlorophyll maximum（DCM）, which could protect the photochemical reaction center of phytoplankton from harm of intense light radiation, and guarantee the contribution rate of DCM layer to the primary productivity in all water body. The α value of phytoplankton was extremely low as phytoplankton required a higher light intensity to achieve light saturation, reflecting that the photosynthetic activity of phytoplankton was relatively low in the western Pacific, which is one of the reasons for local low productivity.