The nitrogen reduction in eutrophic water column driven by Microcystis blooms
The nitrogen reduction in eutrophic water column driven by Microcystis blooms
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微囊藻水华导致富营养化水体中氮的减少
DOI：
10.1016/j.jhazmat.2019.121578
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发表时间：
--
影响因子：
13.6
通讯作者：
Chen Xuechu
中科院分区：
文献类型：
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作者：
Shen Yingshi;Huang Yingying;Hu Jun;Li Panpan;Zhang Chen;Li Lei;Xu Ping;Zhang Junyi;Chen Xuechu
在水华期间，溶解无机氮下降，导致氮限制的发生。目前还不清楚氮气的去向。围隔实验和批式试验表明，微囊藻水华能显著降低水体中的氮素，不同层次的微囊藻水华降低水体中氮素的关键机制不同。同化作用是表层氮还原的主要途径，而反硝化作用在沉积物-水界面和上覆水中均起重要作用。稳定氮同位素实验表明，微囊藻对沉积物-水界面硝酸盐还原效率有明显的促进作用，达到76.5%~ 84.7%。硝化作用占硝酸盐还原的63.8 ~ 67.3%，反硝化速率是DNRA速率的7.4 ~ 8.5倍。在水体中，微囊藻水华促进了暗/缺氧条件的形成，有利于反硝化。从田间采集的微囊藻聚集体表现出很大的脱氮潜力，两天内上覆水体中的TN减少了3.76 ~ 6.03 mg L− 1。本研究为微囊藻水华与水体氮还原之间的关系提供了现场证据和更深层次的认识，并进一步阐明了微囊藻对水体氮还原的强化作用。
During the bloom seasons, the dissolved inorganic nitrogen declines, which results in the occurrence of nitrogen limitation. It is unclear where the nitrogen goes. Our enclosure experiments and batch tests suggested thatMicrocystisblooms could significantly reduce the nitrogen in water bodies and the key mechanisms for the nitrogen reduction in different layers were different. The assimilation was the main pathway for nitrogen reduction in the surface layer, while denitrification played an important role both at the sediment-water interface and in the overlying water. Stable nitrogen isotope experiments showed that the nitrate reduction efficiency at sediment-water interface was enhanced byMicrocystis, reaching to 76.5∼84.7 %. Dissimilation accounted for 63.8∼67.3 % of the nitrate reduction, and the denitrification rate was 7.4∼8.5 times of DNRA rate. In the water column, theMicrocystisbloom facilitated the formation of dark/anoxic condition, which favored the denitrification. TheMicrocystisaggregates collected from the field showed a great potential in removing nitrogen, and the TN in the overly water was reduced by 3.76∼6.03 mg L−1within two days. This study provided field evidences and deeper insights into the relationship betweenMicrocystisblooms and nitrogen reduction in the whole water column and gave more details about the enhancing effects ofMicrocystison nitrogen reduction.