摘要
基于2009年和2010年分别在玛旁雍错和拉昂错开展的2次野外湖泊调查,本文简要报道这2个藏南内流水系湖泊的水深分布、湖水理化特征及湖泊现代沉积速率.测深结果显示玛旁雍错湖盆形状规则,深水区坡度平缓,最大水深为72.6 m;拉昂错北部为较浅的河流冲积扇,通过狭长的水道与开阔的南部湖区相连,南部湖区中心平坦,实测最深处49.03 m;根据水深数据计算的玛旁雍错和拉昂错水量分别为1.462×1010m3和5.711×109m3.玛旁雍错湖水剖面水质在垂直方向上呈现明显的分层结构,温跃层介于25～35 m之间,温度梯度为0.17℃/m,水体pH、电导率和溶解氧在温跃层具有同步变化特征;拉昂错湖水温跃层与玛旁雍错相比不明显,5～15 m间温度梯度为0.16℃/m,湖水pH与溶解氧呈反相变化,这可能与水生植物呼吸作用有关.2个湖泊湖水的主要离子组成特征除Ca2+外基本相同,拉昂错主要离子浓度约为玛旁雍错的3倍,而Ca2+则约为玛旁雍错的1/2;利用210Pb和137Cs方法对玛旁雍错和拉昂错的短岩芯进行了测试,结果表明2个湖泊近代沉积速率分别约为0.31 mm/a和0.65 mm/a.
In this paper, we reported water depth, water quality and modem sedimentation rates of Mapam Yumco and La＇ang Co, southern Tibet, based on field investigation conducted in 2009 and 2010, respectively. Bathymetric survey showed a rather regular shape of Mapam Yumco with a maximum depth of 72.6 m and fiat in the middle part of the lake. In La＇ang Co, there are shallow fluvial fans in the north part and open areas in the south, which are connected lay a narrow channel. The deepest part of La＇ang Co is 49.03 m which lies in southern basin. The water volumes of the two lakes are 1. 462 × 10^10m3 and 5. 711 ×10^9 m3 , respective- ly, according to the calculation based on water depth data. For the physicochemieal profile feature of Mapam Yumco, a thermocline existed between 25 -35 m with a temperature gradient of 0.17~C/m. Conductivity, pH and dissolved oxygen showed synchronous abrupt changes in the thermoeline. In La＇ang Co, temperature decreased abruptly between 5 - 15 m with a gradient of O. 16~C/m. Meanwhile, pH changed to weak acid condition from surface to bottom, while the dissolved oxygen changed oppositely which may caused by respiration of aquatic plants. In Mapam Yumco and La＇ang Co, major ionic composition showed similar features except Ca2 ＋ , major ions in La＇ang Co were approximately three times of Mapam Yumco in concentration, while Ca2 ＋ was only half of Ma- pam Yumco. 210Pb and 137Cs method was used to determine the modem sedimentation rates of both lakes, the results showed that it was O. 31 mm/a and 0.65 mm/a in Mapam Yumco and La＇ang Co, respectively.
出处
《湖泊科学》
EI
CAS
CSCD
北大核心
2013年第4期609-616,共8页
Journal of Lake Sciences
基金
国家自然科学基金项目(41071123
41190082)
国家重点基础研究发展计划"973"项目(2012CB956100)联合资助
关键词
水深测量
理化性质
玛旁雍错
拉昂错
现代沉积速率
青藏高原
Bathymetric survey
physieochemical feature
Mapam Yumco
La＇ang Co
modem sedimentation rate
Tibetan Plateau
