State Key Laboratory of Marine Environmental Science and College of Ocean and Earth Sciences, Xiamen University, 361102, Xiamen, Fujian, China.
State Key Laboratory of Marine Environmental Science and College of the Environment and Ecology, Xiamen University, 361102, Xiamen, Fujian, China.
Nat Commun. 2019 Apr 3;10(1):1521. doi: 10.1038/s41467-019-09554-7.
The response of the prominent marine dinitrogen (N)-fixing cyanobacteria Trichodesmium to ocean acidification (OA) is critical to understanding future oceanic biogeochemical cycles. Recent studies have reported conflicting findings on the effect of OA on growth and N fixation of Trichodesmium. Here, we quantitatively analyzed experimental data on how Trichodesmium reallocated intracellular iron and energy among key cellular processes in response to OA, and integrated the findings to construct an optimality-based cellular model. The model results indicate that Trichodesmium growth rate decreases under OA primarily due to reduced nitrogenase efficiency. The downregulation of the carbon dioxide (CO)-concentrating mechanism under OA has little impact on Trichodesmium, and the energy demand of anti-stress responses to OA has a moderate negative effect. We predict that if anthropogenic CO emissions continue to rise, OA could reduce global N fixation potential of Trichodesmium by 27% in this century, with the largest decrease in iron-limiting regions.
海洋固氮蓝藻束毛藻对海洋酸化（OA）的响应对理解未来海洋生物地球化学循环至关重要。最近的研究报告了 OA 对束毛藻生长和固氮作用影响的相互矛盾的结果。在这里，我们定量分析了实验数据，了解束毛藻如何在 OA 下重新分配细胞内铁和能量在关键细胞过程中的分配，并将这些发现整合到一个基于最优性的细胞模型中。模型结果表明，OA 下束毛藻的生长速率下降主要是由于固氮酶效率降低。OA 下 CO2 浓缩机制的下调对束毛藻影响不大，而 OA 下抗应激反应的能量需求则有适度的负面影响。我们预测，如果人为 CO 排放继续上升，本世纪 OA 可能会使束毛藻的全球固氮潜力降低 27%，在铁限制区域的降幅最大。
