青海尕海盐湖初级生产力特点

１９９７ 年夏季对青海尕海盐湖的生态系统进行了初步研究． 初级生产力研究结果表明：（１） 水域毛初级产氧量平均值为３ ．２７３ｇ ｍ －２ｄ－１ ，其中底栖藻类占７０．９９％ ，底栖藻类单位面积毛初级生产力是浮游植物的２．４５倍．（２） 水域初级生产力构成格局为：由沿岸到湖心区，随着水深的逐步增大，底栖藻类初级生产力逐步减少，浮游植物初级生产力逐渐占主导地位． 前者所占的比例在０．５５ ｍ 水深时为９７．７２ ％ ，在大于１３．０ ｍ 水深后即降至０．０ ％ ．（３）与国际有关文献相比，尕海盐湖初级生产力较低

THE PRIMARY PRODUCTIVITY IN THE GAHAI SALT LAKE,QINGHAI

The primary productivity of benthic algae and phytoplankton in the Gahai Salt Lake (Qinghai-Xizang Plateau) was studied in summer, 1997. The results indicated: 1. The average gross primary production in the lake was 3.273gm -2 d -1 , of which 70.99% was made by benthic algae. The primary production of benthic algae was 2.45 times higher than that of phytoplankton. 2. The distribution pattern of the primary production showed that the phytoplankton productivity in water column increased gradually from littoral zone to limnetic zone, while benthic algae productivity decreased. 97.72% of benthic algae production was made in the shallow area of 0.55m deep, but 0.0% in the deep area of 13.5m. 3. The level of primary productivity in the Gahai Salt Lake was much lower than that of most salt lakes in the world. The Gahai Salt Lake is one of oligotrophic lakes on the Qinghai-Xizang Plateau.