Diao Fei, Anwaier Ailifeire, Qiu Wenjuan, Qian Tian, Guan Baohua, Su Yaling, Li Kuanyi
Key Laboratory of Lake and Watershed Science for Water Security, Nanjing Institute of Geography and Limnology, Chinese Academy of Science, 299 Chuangzhan Road, Qilin Subdistrict, Jiangning District, Nanjing, 211135, China.
University of Chinese Academy of Science, Beijing, 100049, China.
BMC Plant Biol. 2025 May 10;25(1):617. doi: 10.1186/s12870-025-06651-2.
With the increase in the inorganic carbon input from watersheds, elevated dissolved inorganic carbon (DIC) concentrations will significantly impact the carbon cycle in freshwater ecosystems. Moreover, the limited diffusion rate of CO in water, coupled with the lack of functional stomata, greatly restricts the ability of submerged macrophytes to absorb CO from their aquatic environment. The importance of bicarbonate (HCO) for submerged macrophytes becomes more pronounced. Current research focuses on the effects of DIC (notably HCO) on the phenotypic plasticity of submerged macrophytes, while its impact on their carbon stock capabilities has rarely been reported.
In this study, Myriophyllum spicatum served as the model macrophyte within a mesocosm experimental system to assess the impact of HCO enrichment (0.5 to 2.5 mmol L) on carbon stocks and emissions across a one-year period. Our findings indicated that the addition of HCO had a non-significant inhibitory effect on the diffusive fluxes of methane (CH) emissions. Concurrently, it significantly reduced CO fluxes within the systems. The annual average CO fluxes across the four HCO addition levels were -3.48 ± 7.60, -6.78 ± 5.87, -7.15 ± 8.68, and -14.04 ± 14.39 mol m yr, respectively, showing significant differences between low /medium- and high- HCO addition levels.
The addition of HCO enhanced carbon stocks in water, macrophytes and the entire system, with minimal effects on carbon sedimentation stocks. Our study provides valuable insights into understanding the carbon sink capacity of aquatic ecosystems and elucidates the underlying mechanisms driving these processes on a system scale.
随着流域无机碳输入的增加，溶解无机碳（DIC）浓度升高将对淡水生态系统的碳循环产生重大影响。此外，水中CO的扩散速率有限，加上缺乏功能性气孔，极大地限制了沉水植物从水生环境中吸收CO的能力。碳酸氢根（HCO）对沉水植物的重要性更加凸显。目前的研究集中在DIC（尤其是HCO）对沉水植物表型可塑性的影响，而其对沉水植物碳储存能力的影响鲜有报道。
在本研究中，穗状狐尾藻作为中宇宙实验系统中的模式大型植物，以评估HCO富集（0.5至2.5 mmol L）在一年时间内对碳储存和排放的影响。我们的研究结果表明，添加HCO对甲烷（CH）排放的扩散通量具有不显著的抑制作用。同时，它显著降低了系统内的CO通量。四个HCO添加水平下的年平均CO通量分别为-3.48±7.60、-6.78±5.87、-7.15±8.68和-14.04±14.39 mol m yr，低/中添加水平和高添加水平之间存在显著差异。
添加HCO增加了水中、大型植物和整个系统中的碳储量，对碳沉积储量的影响最小。我们的研究为理解水生生态系统的碳汇能力提供了有价值的见解，并阐明了在系统尺度上驱动这些过程的潜在机制。
