以内蒙古高原的达里诺尔湖为研究对象,对其在冰封期湖水不同相态下总氮(TN)、总磷(TP)浓度以及氢、氧同位素比值的分布特征和定量关系进行初步研究.结果表明:1)在冰封期,达里诺尔湖水体中营养盐的平均浓度相对较高,已远超过国家V类水质标准.水体中TN、TP浓度均大于其在对应冰体中的浓度,均值分别是对应冰体中的9.91、3.11倍,说明低温冷冻过程对达里诺尔湖水体中的氮、磷具有浓缩效应.而通过与非冰封期的对比发现,湖冰的排氮效应强于磷.2)冰封期由于结冰过程中同位素热力学分馏明显,加之贡格尔河的人流补给,使得达里诺尔湖冰体中的氢、氧同位素比值远高于水体中的比值,同时,随冰层的加深,同位素逐渐偏重.3)冰封期达里诺尔湖水体及冰体中,同位素比值与营养盐浓度均呈显著负相关,水体的相关性较冰体要好,在冰层中,随着冰层的加深相关性越明显.利用SPSS统计软件分析发现同位素比值与营养盐浓度的相关关系显著,水体中最大相关系数达到0.991,冰体中达到0.988;氢同位素(D)与TN、TP浓度的关系式分别为:TN=-0.28258D-6.0083和TP=-0.08058D-1.2395,这为研究湖泊营养盐的时空变化规律提供新的手段和理论.
This study aims at understanding the distribution characteristic and the correlativity of total nitrogen ( TN), total phos- phorus (TP) , hydrogen isotope ( D ) and oxygen isotope ( 18 O) in ice layer and water during the freeze-up period in Lake Dalinuoer of Inner Mongolia. The results show that : 1 ) The Lake Dalinuoer water with high content of nutrient is even worse than the fifth lev- el of water quality( Chinese standard) during freeze-up period. The concentrations of TN and TP in water are higher than those of in ice layer above the water during the freeze-up period. They are 9.91 times and 3.11 times in water higher than those of the ice layer, respectively. It is caused by the process of concentration effect on nitrogen and phosphorus when the lake water freezes up. It can be found that the interception content of nitrogen is relatively higher than phosphorus in the ice layer,comparing with the un- frozen period, 2 ) The effect of thermodynamic isotope fractionation and the inflow supplies of Gongger River together make that iso- tope content in ice much larger in water during freeze-up period. The isotope content is increasing from the top ice to the bottom one. 3 ) The content of isotopic and nutrient appeares significantly negative correlation during the freeze-up period. The correlation relationship in water is stronger than that in ice, and bottom ice stronger than the top one. It was found that the closest correlation coefficients is 0. 991 in lake water, and 0. 988 in ice, calculated by SPSS software. The quantitative relationship between the con- tent of isotope and nutrient ( eg. the relationship function : TN = - 0. 2825 δD - 6. 0083 and TP = - 0. 0805 8D - 1. 2395 ) will provide a new method for studying temporal and spatial variation of nutrient content in the lake.