Phenotypic plasticity of coralline algae in a High CO2 world@en

It is important to understand how marine calcifying organisms may acclimatize to ocean acidification to assess their survival over the coming century. We cultured the cold water coralline algae, Lithothamnion glaciale, under elevated pCO2 (408, 566, 770, and 1024 µatm) for 10 months. The results show that the cell (inter and intra) wall thickness is maintained, but there is a reduction in growth rate (linear extension) at all elevated pCO2. Furthermore a decrease in Mg content at the two highest CO2 treatments was observed. Comparison between our data and that at 3 months from the same long-term experiment shows that the acclimation differs over time since at 3 months, the samples cultured under high pCO2 showed a reduction in the cell (inter and intra) wall thickness but a maintained growth rate. This suggests a reallocation of the energy budget between 3 and 10 months and highlights the high degree plasticity that is present. This might provide a selective advantage in future high CO2 world.解析海洋钙化生物如何适应海洋酸化，对于评估其在未来百年内的生存状况至关重要。本研究将冷水珊瑚藻冰石叶藻（Lithothamnion glaciale）置于升高的二氧化碳分压（pCO2，浓度分别为408、566、770与1024 µatm）环境中培养10个月。研究结果显示，所有升高pCO2处理组的细胞（胞间与胞内）壁厚均保持稳定，但生长速率（线性延伸）均出现下降。此外，在二氧化碳分压最高的两个处理组中，镁（Mg）含量被观测到有所降低。将本研究数据与同一长期实验3个月时的采样数据进行对比后可见，其驯化过程随时间推移发生变化：实验开展3个月时，高pCO2培养的样本其细胞（胞间与胞内）壁厚出现下降，但生长速率保持稳定。这表明在实验进行的3至10个月期间，生物的能量预算发生了重新分配，同时凸显了其极强的表型可塑性。这或许能为该物种在未来高二氧化碳分压的海洋环境中提供选择优势。