内蒙古中部达里湖沉积物粒度及营养盐垂直变化特征

The Vertical Variation Characteristics of Grain Size and Nutrients of Sediments in Dali Lake, Central Inner Mongolia

中文关键词:  达里湖  沉积物  TP  TN  OM  粒度

英文关键词::Dali Lake  Sediment  TP  TN  OM  Granularity封面图片:查波错 查波错亦称“扎布措”,意为“岩石湖”,位于西藏自治区改则县东北180 km,地理坐标北纬33°19′20″~33°23′40″,东经84°09′00″~84°14′00″,海拔4 505 m。湖滨有天然牧场,常有野牦牛,藏羚羊等野生动物出没。 查波错为盐湖地表卤水矿床,湖水即是含矿卤水  西部较宽,达7.7 km,向东变窄,仅1.2 km  面积为39.96 km²,形状略似一只摆尾的蝌蚪,湖水较浅,最深可达2.1 m,周边湖水一般为0.4 m～0.9 m。湖水中Li⁺,B₂O₃平均含量分别为158.31 mg/L,847.51 mg/L。 (中国科学院青海盐湖研究所 杨 波)

中文摘要:

      通过对达里湖湖中心柱状沉积岩芯总氮(TN)、总磷(TP)、有机质(OM)和粒度指标的测试与分析,探讨其垂向分布特征及影响因素。结果表明,营养盐TN、TP和OM的含量分别为2.12~3.71 g/kg、0.48~0.74 g/kg和4.71%~7.97%,平均值分别为2.98 g/kg、0.64 g/kg和6.29%。1832~1941年,TN、TP和OM含量较为稳定且含量较低；1941~1965年,TN和TP含量不同程度上先增加后减小,OM含量呈减小趋势；1965~2011年,TN、TP和OM含量整体上表现为增加趋势。沉积物中C/N值显示有机质及营养盐的主要来源为浮游动植物,沉积物粒级组成以粘土为主。沉积物中OM与TN和TP极显著相关,说明沉积物中氮主要以有机氮的形式存在,有机质与磷的生物地球化学循环也有相当紧密的关联；TN与TP表现出极显著相关性,说明沉积物氮、磷在沉积行为上有一定的相似性。沉积物中TN、TP和有机质与粒径小于4 μm的颗粒正相关,与其它粒径的颗粒负相关。

英文摘要:

      :The vertical distribution and influencing factors were examined in combination with TN,TP,OM and particle size which was from the middle part of Dali Nor’s columnar sediment. The TP,TN and OM in sediments range from 2.12 g·kg-1to 3.71 g·kg-1 ,0.48 g·kg-1to 0.74 g·kg-1 and 4.71 g·kg-1 to 7.97 g·kg-1 with an average of 2.98 g·kg-1 ,0.64 g·kg-1and 6.29 g·kg-1 respectively.During 1832-1941, the TP,TN and OM with a lower content and kept a nearly even trend.During 1941-1965, the TN and TP concentration presented a trend of first increasing then decreasing, OM content showed a trend of decrease.During 1965-2011,the concentration of TN,TP and OM presented a trend of increasing in total.The C/N ratio in sediment explain the zooplankton and phytoplankton are the main source of the nutrients and organic matter. Primary composition of grain size of sediment is clay.The OM,TN and TP in sediment shows a significant correlation. It means the organic nitrogen was the mainly nitrogen forms in sediment. The biogeochemical cycles of phosphorus and the sediment organic matter has a greatly correlation.The deposition behavior between the sediment phosphorus and nitrogen are similar since the TN and TP has positive correlation. TN, TP and OM in sediment presented on positive correlation with grain which the diameter is less than 4 μm, but revealed the negative correlation with grains which have other diameters.