大气CO2水平升高对微藻影响的研究进展

大气CO₂浓度升高将干扰水体的碳酸盐缓冲系统,导致水体pH值下降,对水生微藻产生一定的影响。文章从生长状况、光合作用、藻细胞化学元素组成和群落结构4方面分别综述大气CO₂浓度升高对海洋微藻和淡水微藻的影响。在生长方面,大气CO₂浓度升高不仅会影响某些海洋微藻和淡水微藻的生长速率,还会使某些藻细胞的形态发生变化。在光合作用方面,大气CO₂浓度升高可能会减弱微藻对CCM机制的依赖性;对不具有CCM机制的微藻来说,CO₂浓度增加可能会减弱其碳限制程度,有利于微藻光合作用。在藻细胞化学元素组成方面,大气CO₂浓度的升高对微藻细胞化学元素组成的影响与藻类的生长是否受营养盐限制有关,只有当藻类生长受到水体营养盐浓度限制时,CO₂浓度升高才会显著改变其元素组成。在群落结构方面,当微藻个体发生变化时,微藻种群间的竞争优势也会发生改变,体积较小的微藻可能将从全球CO₂水平升高的趋势中受益更多。在间接因素温度导致的水生环境变化的条件下,可能更有利于蓝藻生长,使其拥有更大的竞争优势。微藻群落结构的改变,对整个海洋生态系统和淡水生态系统都可能会造成严重的影响。最后展望了在全球大气CO₂水平升高的背景下微藻响应机制方面研究方向。

Research Progress on Effect of Enhanced Atmospheric CO2 Concentration on Microalgae

Abstract: Since the industrial revolution, global CO2 emissions had been increasing year by year, resulting in increasing atmospheric CO2 levels. It was estimated that by the year 2100, the concentration of CO2 in the atmosphere would reach 1000 ppmv. The increased atmospheric CO2 concentration would break the balance of carbonate buffer system in the water, which leads to a decrease of pH value of water body, and pH decrease would have some influences on some microalgae living in water. In this paper, the effects of increased atmospheric CO2 concentration on the growth status, photosynthesis, C, N, P and chemical element composition of microalgae cells, and community structure of marine microalgae and freshwater microalgae were discussed. In terms of growth, the increased atmospheric CO2 concentration would not only affect the growth rate of some marine microalgae and freshwater microalgae, exiting interspecific differences, but also cause changes in the morphology of some algal cells. In terms of photosynthesis, the increased atmospheric CO2 concentration might weaken the dependence of microalgae on CCM mechanism. For microalgae that do not have CCM mechanism, increased CO2 concentration might weaken the degree of carbon limitation, which is beneficial to microalgae photosynthesis. In general, the increased atmospheric CO2 concentration promoted the photosynthesis of microalgae. In terms of chemical elements composition of microalgae cells, the influence of atmospheric CO2 concentration on chemical elements composition of microalgae cells was related to whether algal growth was restricted by nutrient concentration. Only when algal growth is restricted by water nutrient concentration, the increased CO2 concentration would significantly change its element composition. In terms of community structure of microalgae, when microalgae individuals is changed, the competitive advantage among microalgae species is also changed, and smaller microalgae might benefit more from the global trend of rising CO2 levels. Under the conditions of changes in aquatic environment caused by indirect factors of temperature, cyanobacterium might be more favorable for growth and has a greater competitive advantage. The change of microalgae community structure might have serious impact on the whole marine ecosystem and freshwater ecosystem. In the end, an outlook is made on the feasible research directions of the response of microalgae to the global increasing atmospheric CO2.