二氧化碳加富与阳光紫外辐射对球形棕囊藻的耦合效应

The coupled effects of carbon dioxide enrichment and ultroviolet radiation on Phaeocystis globosa Scherffel

在含有和滤除紫外（UV）辐射（UVR,280-400 nm）的阳光条件下,向静止、恒温的培养体系中分别充含390×10^-6和800×10^-6体积CO2的空气,以期探讨CO2浓度升高与阳光UV辐射对球形棕囊藻（Phaeocystis globosa Scherffel）的生理生态学影响。结果显示,该藻对CO2加富和UVR的响应与细胞密度密切相关。在细胞密度较低时,CO2加富导致生长和有效光化学效率分别下降了11.0%和10.7%,UVR对两者的抑制率分别达19.2%和41.7%。在细胞密度较高时,CO2加富和UVR的影响明显减小,UVR的存在甚至导致生长速率的增加。UVR降低了该藻的最大电子传递速率及光能利用效率,在周围空气下分别达14.1%和21.0%,CO2加富使其进一步下降,分别达8.2%和17.6%。细胞Chl a和Chl c及类胡萝卜素含量在高CO2条件下显著增加（达4.6%,5.9%和5.2%）;UVR导致类胡萝素含量升高（达4.3%）。结果表明,在阳光辐射下,CO2加富导致球形棕囊藻抵御强光及UVR胁迫能力下降,其对此的生化响应是增加具有保护作用的类胡萝卜素的含量。

CO2 perturbation experiments were carried out under the solar radiation with or without UV radiation（280~400 nm） in a temperature-controlled water bath to evaluate the coupled effects of CO2 and UVR on Phaeocystis globosa Scherffel that forms harmful algal blooms.The results show that both of high CO2 and UVR stress on the algae.The high concentration CO2 decreases a specific growth rate and the photochemical efficiency of the algae by up to 11.0% and 10.7%,respectively,and the UVR does further them 19.2% and 41.7%.With its cell density increasing,however,their inhibition to the alga was declining,and to minus value.UVR decreases its maximal relative electron transpert rate and photosynthetic efficiency by 14.1% and 21.0%,respectively,in ambient air,and additional 8.2% and 17.6% in the CO2-enriched.CO2 enrichment increases chlorophyll a,chlorophyll c and carotenoids by 4.6%,5.9% and 5.2%,respectively.The UVR increases carotenoids by 4.3%.The studies indicate that the high concentration CO2 aggravates the damage of UVR to the algae,which increaseds in carotenoids as a protective response.