Recently, CO₂ recycling for the production of valuable microalgae has acquired substantial interest. Most studies investigating CO₂ conversion efficiency in algal cultures were based on single species, although a stabilising effect of algal diversity on biomass production was recently highlighted. However, addition of CO₂ into polyalgal cultures requires a careful control of pH; performance of CO₂ conversion, growth and carbon biomass production are affected by pH differently, depending on the species of microalgae. This study investigates the efficiency of CO₂ conversion by natural marine algal assemblage cultivated in open, land-based raceways (4.5 m³, 10 m²), working as high rate algal ponds (HRAP). Ponds were enriched with nitrogen and phosphate, pure CO₂ was added and algal cultures were grown under three different fixed pH levels: pH 6, 7 and 8. The highest conversion of photosynthetically fixed CO₂ into carbon biomass (40 %) was reached at pH 7, an intermediate level, due to the partial CO₂ asphyxiation of algal predators (copepods, ciliates), while being under the suboptimal conditions for the development of marine amoebae. Under this pH, the theoretical maximal biological conversion of available CO₂ into carbon biomass was estimated to be 60 % in naturally inoculated open ponds.

近来，用于生产有价值的微藻的CO ₂再循环已经引起了广泛的兴趣。大多数研究藻类培养物中CO ₂转化效率的研究都是基于单一物种，尽管最近强调了藻类多样性对生物量生产的稳定作用。但是，向多藻培养物中添加CO ₂需要仔细控制pH。pH值取决于微藻的种类，CO ₂转化，生长和碳生物量生产的性能受到不同的影响。本研究探讨CO的效率₂转换由天然海藻装配在开放的，基于陆地的滚道（4.5米栽培³为10μm ²），用作高速率藻类池塘（HRAP）。池塘中富含氮和磷酸盐，添加了纯净的CO ₂，藻类培养物在三种不同的固定pH值下生长：pH 6、7和8。光合作用固定的CO ₂转化为碳生物量的最高转化率（40％） pH 7为中等水平，这是由于藻类捕食者（足足类，纤毛虫）被部分CO ₂窒息而处于海洋变形虫发育的次佳条件下。在此pH值下，自然接种的开放池塘中可用CO ₂转化为碳生物量的理论最大生物转化率估计为60％。