沉水植物黑藻腐解过程中营养盐释放过程

为探究沉水植物衰亡过程中营养盐的释放规律,采用黑藻(Hydrilla verticillata Royle)作为研究用沉水植物,在实验室内模拟了黑藻在初春温度下腐解过程中的主要营养盐碳、氮、磷的释放过程.结果表明:黑藻在试验初期迅速腐解,该过程中向水体释放大量碳(81.31%)、氮(81.62%)、磷(85.94%).但随着时间的推移,黑藻向水体释放的磷大部分沉积进入底泥,而氮有部分沉积进入底泥,同时有部分以气体形式移出水体.黑藻腐烂分解产生的厌氧条件以及高TOC供给促进水体反硝化作用加快氮素移出水体.但是较大生物残留量会引起水体缺氧,植物残体分解加剧,导致水质严重恶化,因此需要适时收割水生植物来控制水体残留生物量.

Nutrient release process during decomposition of submerged macrophytes (Hydrilla verticillata Royle)

The decaying process of submerged macrophytes (Hydrilla verticillata) was simulated in laboratory. Results showed that the plant decayed rapidly and released a lot of nutrients C (81.31%), N(81.62 %) and P (85.94%) into the water at the beginning of experiment. After a period of time, most of the phosphorus and part of nitrogen was released into sediment, whereas part of nitrogen escaped out of the water as gas. The decomposition of plant released large amounts of organic carbon making the water anaerobic. Both of the anaerobic conditions resulted from decomposition and high TOC supply are benefitial to nitrogen removal by denitrification. However, the larger biomass residues of submerged plants should be controlled to avoid secondary pollution caused by excessive decomposition of submerged plants.