Motility plays a critical role in algal survival and reproduction, with implications for aquatic ecosystem stability. However, the effect of elevated CO₂ on marine, brackish and freshwater algal motility is unclear. Here we show, using laboratory microscale and field mesoscale experiments, that three typical phytoplankton species had decreased motility with increased CO₂. Polar marine Microglena sp., euryhaline Dunaliella salina and freshwater Chlamydomonas reinhardtii were grown under different CO₂ concentrations for 5 years. Long-term acclimated Microglena sp. showed substantially decreased photo-responses in all treatments, with a photophobic reaction affecting intracellular calcium concentration. Genes regulating flagellar movement were significantly downregulated (P < 0.05), alongside a significant increase in gene expression for flagellar shedding (P < 0.05). D. salina and C. reinhardtii showed similar results, suggesting that motility changes are common across flagellated species. As the flagella structure and bending mechanism are conserved from unicellular organisms to vertebrates, these results suggest that increasing surface water CO₂ concentrations may affect flagellated cells from algae to fish.

运动在藻类的生存和繁殖中起着至关重要的作用，对水生生态系统的稳定性具有影响。然而，尚不清楚CO ₂升高对海洋，微咸水和淡水藻运动性的影响。在这里，我们使用实验室的微尺度和中尺度尺度的实验表明，三种典型的浮游植物物种随着CO _2的增加而运动性降低。在不同的CO ₂浓度下，将极地海洋微藻（Microglena sp。），欧洲淡色杜氏盐藻（Dyaliella salina）和淡水莱茵衣藻（Chlamydomonas reinhardtii）种植了5年。长期适应的Microglenasp。在所有处理中均显示出显着降低的光反应，并且有憎光反应影响细胞内钙浓度。调节鞭毛运动的基因被显着下调（P <0.05），同时鞭毛脱落的基因表达也显着增加（P <0.05）。D. salina和C. reinhardtii表现出相似的结果，这表明活力变化在鞭毛物种中很常见。由于鞭毛的结构和弯曲机制从单细胞生物到脊椎动物都是保守的，这些结果表明增加的地表水CO ₂浓度可能影响从藻类到鱼类的鞭毛细胞。