中文摘要：

采用物理改良措施覆沙和底质疏松,对南四湖湿地沉积物-水微界面氧化还原状况及间隙水营养盐垂向分布特征的影响进行了研究.结果表明,改良措施能够有效地改善沉积物的物理结构及氧气的垂向分布.在沉积物-水界面附近,覆沙和底质疏松均能显著提高界面处氧化层的厚度,覆沙效果最佳.随着剖面深度的增加,间隙水中NH4＋和可溶性PO43-浓度呈指数关系增长,改良措施能有效降低间隙水中PO43-的含量,轻度底质疏松的效果最佳,差异显著（P〈0.05）.而界面以下NO3-和氧气浓度呈指数关系下降,在沉积物中10cm以下时营养盐接近一个常数,在4mm以下溶解氧接近0.对剖面沉积物不同形态的磷组分进行统计检验表明,改良措施能有效提高表层沉积物中NH4Cl-P及BD-P（铁磷）的含量.

英文摘要：

Investigation was carried out to evaluate the impact of physical amelioration treatments（fine sand covered and sediment loosened） on the sediments and pore water in Lake Nansi wetland in China.Oxygen microprofiles near sediment-water interface and the vertical distribution of pore-water nutrients（PO43-,NH4＋,NO3-and NO2-） in the uppermost sediment were determined.The treatments could effectively improve sediment physical structure（i.e.water content,porosity et al.） and oxygen depth-distribution.The oxic zone thickness at sediment-overlying water interface was significantly widened in fine sand covered and loosened sediments treatments compared with those in-situ sediments treatment（P 0.05）,and the oxygen furthermost penetrations were determined in fine-sand covered treatment.The NH4＋ and PO43-distribution in the vertical profile exhibited a nearly exponential increase and a NO3-decrease with depth in 10 cm surface sediment,indicating an approximate constant concentration below 10 cm depth.Otherwise,dissolved oxygen sharply deceased with depth at the water-sediment surface and arrived near zero mg/L at the 4 mm depth.All treatments could decrease PO43-concentration in pore water,and the lowest interstitial PO43-concentration was found in slightly loosened sediment treatments（P 0.05）.Also,NH4Cl-extractable PO43-and bicarbonate dithionite（BD）-extractable PO43-contents increased significantly in slightly loosened sediment treatment,especially in surface.