Nitrogen limitation affects the sinking property of Microcystis by promoting carbohydrate accumulation
Nitrogen limitation affects the sinking property of Microcystis by promoting carbohydrate accumulation
复制标题
氮限制通过促进碳水化合物积累影响微囊藻的下沉特性
DOI：
10.1016/j.chemosphere.2019.01.080
复制
发表时间：
2019
期刊：
影响因子：
8.8
通讯作者：
Xuechu Chen
中科院分区：
文献类型：
--
作者：
Ying Ying Huang;Jingjie Hong;Chengyu Liang;Gengyang Li;Lin Shen;Haichun Zhang;Xiongxing Hu;Xuechu Chen
Nitrogen limitation has been proven to inhibitMicrocystisproliferation, and the significant decline inMicrocystisblooms in late summer or autumn has been considered to be related to the nitrogen depletion in water. Sinking loss is another factor that influences the dynamics of cyanobacteria in lakes. However, to date, it is still unclear how the sinking property ofMicrocystisresponds to nitrogen availability. Our results suggest that nitrogen limitation would directly influence sinking property ofMicrocystis, through a significant increase in the specific density of cells. In the short term, carbohydrate accumulation was mainly responsible for the high specific density, showing a high correlation among the NO3−-N concentration, specific density and carbohydrate content. Furthermore, carbohydrates could rapidly accumulate after one light/dark cycle, which was mainly due to the reduction in carbohydrate consumption in the darkness under nitrogen limitation. Under nitrogen-light coupling conditions, the specific density ranged from 1.060 to 1.068, except for the treatment with high-nitrogen plus low-light, which showed the value of 1.032. More importantly, when coupled with low nitrogen, the low light did not decrease the carbohydrate content and the specific density, which implied that the sinking cells could not migrate back to the surface. Accordingly, a hypothesis was proposed that the carbohydrate accumulation induced by low nitrogen availability caused an increase in specific density, which invalidates the buoyancy regulation, and cells sink continually out of the water column. This study explores a new understanding on the disappearance mechanisms ofMicrocystisblooms in the late summer and fall.
