南四湖南阳湖区河口与湖心沉积物理化性质垂向分布特征对比分析

Vertical Distribution of Sediment Physicochemical Properties at Estuary and Center of Nanyang Zone from Nansi Lake

利用沉积物柱状采样器在南四湖南阳湖区湖心和河口分别采取原位柱状沉积物,对比分析了河口与湖心沉积物理化性质垂向分布特征.结果表明,南阳湖河口区与湖心区沉积物含水率、孔隙度、粒度、有机质、总磷和氨氮的垂向分布差异明显.湖心区沉积物孔隙度、粒度、有机质、氨氮和总磷含量随深度增加逐渐减小,沉积物颗粒中值粒径由40 cm以上的19～29 μm减至40 cm以下的7.28 μm,氨氮和总磷含量分别由表层（0 ～ 10 cm均值）的137和610 mg/kg降至56和410 mg/kg（30 ～40 cm均值）.河口区沉积物理化指标在45cm以上较为接近,45 cm以下陡增.其中,有机质含量较表层增加4～6倍,河口区较湖心区沉积序列有“倒置现象”,河口泥沙沉积是导致其差异的主要原因.

Intact in situ sediment cores were collected by core sampler at estuary and center of Nanyang Zone from Nansi Lake,the vertical dis- tribution of sediment physicochemieal properties was analyzed. Results showed that the vertical distribution of sediments water content, porosity, grain size,organic matter, total phosphorus, ammonia nirtogen at estuary and center of Nanyang Zone were significantly different. Sediments porosi- ty, grain size,,organic matter, ammonia nitrogen and total phosphorus concentration in center decreased with depth, and the median diameter of sediment particle reduced from 19 -29 μm in surface 40 cm to 7.28 pan under 40 cm ,the concentration of ammonia nitrogen and total phosphorus reduced from 137 and 610 mg/kg （0 - 10 em average） to 56 and 410 mg/kg （30 -40 cm average） ,respectively. Sediment physicochemieal properties at estuary were closer in surface 45 era,and then significantly increase below 45 em,where the sediment organic matter increased about 4 to 6 times than the surface. The sedimentary sequence at estuary had ＂inversion phenomenon＂ compared with the center, and the different depositional environment may the main cause.