作者：Peng, Y., Xie, W., Peng, Y., Zhou, C., Liu, H., Jin, Q., Zhou, Y., Kinouchi, T., Doi, H. & Xu, X.

Eutrophication-intensified cyanobacterial blooms are increasingly recognized as significant contributors to carbon emissions from shallow lakes, yet the underlying mechanisms remain poorly understood. Here, we combined basin-scale field surveys, satellite-derived floating algae index (FAI), and microcosm incubations to evaluate the effects of cyanobacterial blooms on carbon emissions and sediment carbon loss in seven shallow lakes of the middle and lower Yangtze River Basin. FAI-based analyses showed severe and spatially extensive cyanobacterial blooms, with maximum bloom coverage reaching approximately 68.8% of the lake area in Taihu and nearly complete coverage in Dianshan, while bloom intensity correlated positively with trophic level. Field observations revealed that hypereutrophic lakes with higher total nitrogen (TN), total phosphorus (TP), and organic carbon (OC) concentrations in the overlying water and sediments exhibited strongly elevated CH4 and CO2 fluxes; specifically, CH4 emissions in Taihu (248.6 mu g center dot m(-2)center dot min(-1)) exceeded those in the mesotrophic Lake Caizi (7.1 mu g center dot m(-2)center dot min(-1)) by over an order of magnitude. Furthermore, microcosm experiments demonstrated that cyanobacterial-derived labile carbon enhances the decomposition of macrophyte detritus via co-metabolic-like effect interactions: mixed cyanobacteria-plant treatments resulted in up to approximately 100% and 125% increases in CH4 and CO2 production, respectively, while sediment TOC loss exceeded theoretical expectations. These findings highlight that bloom-driven co-metabolic-like effect is a critical mechanism for amplifying carbon emissions and destabilizing sediment carbon pools in eutrophic lakes, highlighting the necessity of incorporating bloom dynamics and multi-source carbon interactions into regional and global lake carbon budgets.

富营养化加剧的蓝藻水华正日益被认为是浅水湖泊碳排放的重要贡献者，但其内在机制仍知之甚少。研究结合流域尺度野外调查、卫星反演的漂浮藻类指数（FAI）与微宇宙培养实验，评估了蓝藻水华对长江中下游流域7个浅水湖泊碳排放及沉积物碳损失的影响。基于FAI的分析显示：蓝藻水华严重且空间分布广泛——太湖最大水华覆盖面积约占湖面68.8%，淀山湖则近乎全覆盖；且水华强度与营养水平呈正相关。野外观测表明，富营养水平更高的湖泊——其上覆水与沉积物中总氮（TN）、总磷（TP）及有机碳（OC）浓度更高——表现出显著升高的CH₄与CO₂通量；具体而言，太湖CH₄排放（248.6 μg·m⁻²·min⁻¹）超过中营养的菜子湖（7.1 μg·m⁻²·min⁻¹）一个数量级以上。此外，微宇宙实验证明：蓝藻源的不稳定碳通过类共代谢效应促进挺水/沉水植物残体的分解——蓝藻—植物混合处理的CH₄与CO₂产量最高分别增加约100%与125%，且沉积物总有机碳（TOC）损失超过理论预期。这些发现凸显了水华驱动的类共代谢效应是放大富营养湖泊碳排放、动摇沉积物碳库稳定性的关键机制，并表明将水华动态与多源碳相互作用纳入区域及全球湖泊碳收支的必要性。

（来源：Journal of Hydrology 2026  DOI: 10.1016/j.jhydrol.2026.135935）