Recent studies indicated that the algal decomposition produces particulate and dissolved organic carbon (DOC), and can enhance denitrification in eutrophic lakes. However, the effects of the living cyanobacteria on nitrogen cycling in eutrophic lakes were still an unknown question. This study explores a new underlying mechanism of nitrate removal which is driven by living Microcystis. The results suggested that living Microcystis significantly enhanced the nitrate removal at sediment-water interface, with a nitrate removal rate of 0.54 d^-1, which was 2.57 times higher than the nitrate removal rate in the treatment without the addition of Microcystis. Measurements of Chl a and Fv/Fm confirmed that Microcystis was tolerant to the dark/anoxic condition, and the recovery experiments suggested that Microcystis could survive under such stress conditions for at least seven days. Meanwhile, DOC secreted by living Microcystis reached to 4.55 mg C mg^-1 Chl a. These secretions were biodegradable hydrophilic and contained carbohydrates and proteins. Our study indicated that during blooms, sinking Microcystis cells could directly provide DOC as carbon source, then consequently enhanced the denitrification at sediment-water interface, and the interactive relationship between living cyanobacteria and permanent nitrate removal should be taken into account while studying nitrogen cycling in aquatic ecosystem.

最近的研究表明，藻类分解会产生颗粒和溶解的有机碳（DOC），并且可以增强富营养化湖泊中的反硝化作用。然而，活蓝藻对富营养化湖泊中氮循环的影响仍然是一个未知的问题。这项研究探索了一种新的潜在的硝酸盐去除机制，它是由活微囊藻引起的。结果表明，活的微囊藻显着提高了沉积物-水界面的硝酸盐去除率，硝酸盐去除率为0.54 d ^-1，是不添加微囊藻的处理中硝酸盐去除率的2.57倍。Chla和Fv / Fm的测定证实微囊藻耐黑暗/缺氧条件，恢复实验表明微囊藻在这样的压力条件下可以存活至少7天。同时，活的微囊藻分泌的DOC达到4.55 mg C mg ^-1 Chl a。这些分泌物是可生物降解的亲水性物质，并含有碳水化合物和蛋白质。我们的研究表明，在开花期间，下沉的微囊藻细胞可以直接提供DOC作为碳源，从而增强了沉积物-水界面的反硝化作用，在研究氮素循环时应考虑活蓝藻与永久性硝酸盐去除之间的相互作用关系。水生生态系统。