Abstract The impact of the development of cascade reservoirs on the biogenic substance cycle is an important scientific issue for the future sustainable development of the Lancang-Mekong River. The vertical distribution of phosphorus (P) fractions of Xiaowan (XW) and Nuozhadu (NZD) Reservoir sediment in Lancang River were studied to better understand the environment influence of cascade deep reservoir for the first time. The results showed that the P concentration in the overlying water and the P content in sediment of the upstream XW Reservoir was higher than that of the downstream NZD Reservoir, but the P bio-availability (BAP) in sediment were lower than that of the NZD Reservoir. The sediment of the XW Reservoir showed low BAP content and high inert P content. In the contrast, the sediment of the NZD Reservoir showed high BAP content and low inert P content. The P in the sediment of the two reservoirs has totally different control factors, which indicates that the biogenic substance cycles mechanisms of two reservoirs are significantly different under the influence of the cascade reservoir. The less sediment source of downstream reservoir highlights the role of regional sediment in turn. The biogenic substance of the regional sediment plays an important role in the downstream reservoir sediment.

中文翻译：

---

从磷组分看梯级水库建设对澜沧江沉积物生物物质循环的影响

摘要 梯级水库的开发对生物物质循环的影响是澜沧江-湄公河未来可持续发展的重要科学问题。首次研究了澜沧江小湾（XW）和糯扎渡（NZD）水库沉积物磷（P）组分的垂直分布，以更好地了解梯级深水库对环境的影响。结果表明，上游XW水库上覆水中P浓度和沉积物中P含量高于下游NZD水库，但沉积物中P生物有效性（BAP）低于NZD水库。XW 水库沉积物 BAP 含量低，惰性 P 含量高。相比之下，新西兰元水库的沉积物显示出高 BAP 含量和低惰性 P 含量。两个水库底泥中P的控制因子完全不同，说明在梯级水库的影响下，两个水库的生物物质循环机制存在显着差异。下游水库泥沙来源较少，反过来突出了区域泥沙的作用。区域沉积物的生物成因物质在下游水库沉积物中起着重要作用。下游水库泥沙来源较少，反过来突出了区域泥沙的作用。区域沉积物的生物成因物质在下游水库沉积物中起着重要作用。下游水库泥沙来源较少，反过来突出了区域泥沙的作用。区域沉积物的生物物质在下游水库沉积物中起着重要作用。