巢湖十五里河沉积物氮磷形态分布及生物有效性

为了解巢湖十五里河底泥氮磷形态分布规律及生物有效性,在河道上采集7个柱状样,按10 cm厚度分层,共得样品41个.采用化学提取方法,获得氨氮(NH4+-N)、硝酸盐氮(NO3--N)、易交换态磷(Ex-P)、铝结合态磷(Al-P)、铁结合态磷(Fe-P)、闭蓄态磷(Oc-P)、钙结合态磷(Ca-P)、碎屑磷(De-P)和有机磷(Or-P)等各形态氮磷及总氮(TN)和总磷(TP)含量,进而对各形态氮和磷的空间分布特征及相关性进行分析,并评估氮磷的生物有效性.结果表明,十五里河沉积物中各形态氮磷在纵向和垂直方向上表现出一定的规律性,且主要氮磷形态之间还具有显著的相关性.此外,在0～10、10～20、20～30、30～40、40～50和50～60cm等沉积深度,生物有效性氮(NH4+-N与NO3--N两者之和)占TN的质量分数分别为8.17%、11.88%、7.99%、8.44%、8.97%和20.06%,生物有效性磷(Ex-P、Al-P、Fe-P三者之和)占TP的质量分数分别为50.18%、49.12%、42.41%、34.11%、32.71%和39.55%.

Distribution and Bioavailability of Nitrogen and Phosphorus Species in the Sediments from Shiwuli Stream in Lake Chaohu

In order to learn the distribution and bioavailability of nitrogen (N) and phosphorus (P) species in the sediments of Shiwuli Stream, pouring into Lake Chaohu, seven sediment cores were collected along the stream, and then a total of 41 samples for the sediment cores were sliced in-situ with a thickness of 10 cm. The contents of ammonia nitrogen (NH₄⁺-N), nitrate nitrogen (NO₃^--N), exchangeable P (Ex-P), Al-bound P (Al-P), Fe-bound P (Fe-P), occluded P (Oc-P), Ca-bound P (Ca-P), detrital apatite P (De-P), organic P (Or-P) as well as total nitrogen (TN) and total phosphorus (TP) were measured by chemical extraction methods. The researches on spatial distribution, correlation and bioavailability of nitrogen and phosphorus species were conducted according to the analyzed data. The results show that the spatial distribution of nitrogen and phosphorus species contents in the sediments of Shiwuli Stream is characterized by some regularity, and notable correlations between the major nitrogen and phosphorus forms are displayed as well. Generally, in the sediment layers of 0-10 cm, 10-20 cm, 20-30 cm, 30-40 cm, 40-50 cm and 50-60 cm, the average ratios of bio-available nitrogen content (the sum of NH₄⁺-N and NO₃^--N) to TN are 8.17%, 11.88%, 7.99%, 8.44%, 8.97% and 20.06%, respectively, while the mean ratios of bio-available phosphorus content (the sum of Ex-P, Al-P and Fe-P) to TP are 50.18%, 49.12%, 42.41%, 34.11%, 32.71% and 39.55%, respectively.