Kong Lingrui, Feng Yiming, Zheng Ru, Wu Xiaogang, Mao Yimin, Sun Jingqi, Liu Sitong
College of Environmental Sciences and Engineering, Peking University, Beijing, PR China.
Key Laboratory of Water and Sediment Sciences, Ministry of Education, Peking University, Beijing, PR China.
Nat Commun. 2025 May 31;16(1):5078. doi: 10.1038/s41467-025-60327-x.
The trace concentration of H in most ecosystems after the Earth's oxidation has long caused the neglect of hydrogenotrophic denitrification for nitrogen loss. Here, we find that the interspecies hydrogen transfer between cyanobacteria and symbiotic bacteria within cyanobacterial aggregates is an undiscovered pathway for nitrogen loss. Cyanobacteria in aggregates can actively generate H under the diel cycle as an electron donor for neighboring hydrogenotrophic denitrifiers. The hydrogenotrophic denitrification in engineered cyanobacterial aggregates accounts for a nitrogen removal rate of 3.47 ± 0.42 mmol l day. This value is nearly 50% of the heterotrophic denitrification rate, which far exceeds the general concept of the trace role. We find that H-evolving cyanobacteria and hydrogenotrophic denitrifiers coexist in 84% of the 63 globally distributed cyanobacterial aggregates, where bloom colonies and phototrophic mats from hot springs are identified as potential hotspots. We suggest that interspecies hydrogen transfer within cyanobacterial aggregates is possibly responsible for the excessive nitrogen loss rate during cyanobacterial blooms where cyanobacterial aggregates persist.
在地球氧化之后，大多数生态系统中氢的痕量浓度长期以来导致人们忽视了氢营养型反硝化作用对氮损失的影响。在此，我们发现蓝藻聚集体内蓝藻与共生细菌之间的种间氢转移是一条未被发现的氮损失途径。聚集体中的蓝藻在昼夜循环中能够主动产生氢气，作为邻近氢营养型反硝化细菌的电子供体。工程化蓝藻聚集体中的氢营养型反硝化作用导致的氮去除率为3.47±0.42 mmol·l⁻¹·d⁻¹。该值接近异养反硝化率的50%，远远超过了其痕量作用的一般概念。我们发现，在全球分布的63个蓝藻聚集体中，84%存在产氢蓝藻与氢营养型反硝化细菌共存的情况，其中来自温泉的水华菌落和光合生物垫被确定为潜在热点。我们认为，在蓝藻聚集体持续存在的蓝藻水华期间，种间氢转移可能是导致过高氮损失率的原因。
