巢湖十五里河水花生生长区沉积物及间隙水中营养盐的基本特性

Sediment and Pore Water Nutrient Characteristics in Growing Zones of Alternanthera philoxeroides in the Shiwuli River,Chaohu Lake

为揭示十五里河水生植物(水花生)生长区沉积物及间隙水营养盐的基本特征,在河道上选择3个具有代表性的采样点位(SP1、SP2和SP3)和1个对照点位(SP4),采集15根沉积物柱状样,并按2 cm厚度现场分层,得到样品80个.在对沉积物TN、TP、NH4+-N、NO3--N、Fe/Al-P、Ca-P、有机质含量及间隙水TN、TP、NH4+-N、NO3--N、PO34--P浓度分析测试基础上,解析沉积物及间隙水的氮磷垂直剖面分布特征,并进行氮磷相关性分析.由间隙水氮磷剖面分布发现,水花生生长区孔隙水氮磷浓度具有大致相似的垂直变化特性;除PO34--P浓度存在差异外,不同采样点位表层沉积物-上覆水界面的营养盐源汇关系,也具有很好的一致性.研究表明,在沉积深度0～18 cm内,水花生生长区的间隙水NH4+-N和NO3--N垂直浓度剖面,基本上都可以由Origin软件提供的Exp2PMod2或Exp3P2指数函数拟合,而PO34--P则不具备这一特点,暗示着间隙水PO34--P扩散的规律性弱于NH4+-N和NO3--N.

In order to investigate the nitrogen and phosphorus characteristics of sediments and pore water in growing zones of aquatic macrophytes（Alternanthera philoxeroides）,three classic representative sampling points in the planted Alternanthera philoxeroides fields（i.e.SP1,SP2 and SP3） and one reference site in the seldom vegetation（i.e.SP4） were chosen along the Shiwuli River,pouring into Chaohu Lake.Fifteen sediment cores were collected and sliced in-situ with a thickness of 2 cm,and a total of 80 samples were obtained.In the laboratory,both the contents of TN,TP,NH＋4-N,NO-3-N,Fe/Al-P,Ca-P,organic matter in sediments and the concentrations of TN,TP,NH＋4-N,NO-3-N and PO4^3--P in pore water were measured.And then,the vertical distribution profiles were illustrated and explored,and the correlations were also analyzed for the growing zones of Alternanthera philoxeroides.Through the comparison of profiles,it found that both nitrogen and phosphorus concentrations in pore water showed a rough similarity for three vegetation fields.At the surface sediment-overlying water interface,in general,there was a good agreement on the source-sink relationship for nitrogen and phosphorus corresponding to the SP1,SP2 and SP3.Study results showed that the vertical distribution of NH＋4-N and NO-3-N in pore water within the depth of 0-18 cm could be characterized by using exponential functions such as Exp2PMod2 or Exp3P2 provided by OriginLab software,but PO4^3--P hardly ever did,implying that PO4^3--P might have a weaker regularity in solute diffusion than that of NH＋4-N and NO-3-N.