初春苦草腐解过程中营养盐释放过程及规律

采用室内模拟方法研究初春温度条件下苦草在腐解过程中碳、氮和磷的释放过程,研究沉水植物衰亡过程中营养盐的释放规律.结果表明,在初春温度条件下,苦草迅速腐解,向水体释放大量碳、氮和磷.随着时间的推移,苦草向水体释放的磷大部分沉积进入底泥,而氮则是部分沉积进入底泥,部分以气体形式移出水体.苦草腐烂分解产生的厌氧条件和大量有机碳的供给促进了水体反硝化作用并加快氮素移出水体.较大的生物残留量会引起水体缺氧,同时产生大量营养盐,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.

Process and Law of Nutrient Release During Decomposition of Submerged Macrophytes ( Vallisneria natans) in Early Spring

Processes of nutrients(nutrient salts,N and P) releasing from decaying submerged macrophytes(Vallisneria natans) at the temperature of an early spring were simulated in laboratory to study laws of the nutrient release.Results show that the rapidly decaying plant released a lot of nutrients(C,N and P) into the water at the temperature of an early spring.With the time going by,most of the phosphorus released from the plant settled down into the sediment,whereas only part of the nitrogen went down and part escaped out of the water as gas.The anaerobic condition resulting from decomposition of the plant and the supply of large amounts of organic carbon promoted denitrification in the waterbody,thus accelerating escape of N out of the water.A large amount of plant residues resulted in oxygen deficiency of the water and release of large amounts of nutrients,thus leading to deterioration of water quality.It is,therefore,advisable to harvest the aquatic plant to reduce residue biomass in the waterbody.