CO2浓度变化对拟柱胞藻生长与光合作用的影响

为了探讨大气CO₂浓度升高对水华藻类的影响，利用水华蓝藻-拟柱胞藻作为实验材料，研究了CO₂浓度升高对其生长生理和光合作用的影响，结果表明CO₂浓度升高，导致拟柱胞藻的生物量、最大光合放氧速率、光合效率显著增加。当CO₂浓度为700 mg/L以下，暗呼吸速率和光饱和点无明显影响，而CO₂浓度为1000 mg/L时，暗呼吸速率和光饱和点显著提高。随着CO₂浓度增加，藻细胞光合作用对无机碳的亲和力降低，同时胞外碳酸酐酶活性显著下降。这表明大气CO₂浓度的增加，有利于拟柱胞藻的生长和光合，进而增加了水华发生的风险。

EFFECTS OF CHANGED CO2 CONCENTRATION ON GROWTH AND PHOTOSYNTHESIS OF CYLINDROSPERMOPSIS RACIBORSKII

To explore the influence of elevated atmospheric CO2 concentration on algae blooms, we studied effects of elevated CO2 concentration on the growth, physiological and photosynthesis of a bloom-forming cyanobacterium,Cy-lindrospermopsis raciborskii. The results showed that elevated CO2 concentration significantly increased the biomass, the maximum photosynthetic rate and photosynthetic efficiency ofC. raciborskii. The concentration of CO2 at 700 mg/L did not impact dark respiration rate and light saturation point ofC. raciborskii but had significant effect at 1000 mg/L. The increased CO2 reduced the affinity of algal cell photosynthesis to inorganic carbon and, the extracellular car-bonic anhydrase activity. These results suggest that the increase in atmospheric CO2 concentration might be beneficial to growth and photosynthesis ofC. raciborskii, which may increase the risk of blooms.