On the adaptiveness of aquatic macrophyte to the sediment in Wuli Lake

Abstract

在五里湖富营养化过程中,氮、磷及有机物质在湖底沉积物中大量积累。在夏季高温、高水位期。底泥中因有机物分解耗氧强烈和溶解氧补给受阻而发生缺氧。挺水植物和浮叶植物均能适应这种底质条件;在水温低于30℃或水深小于1m的情况下,五里湖的底质条件对沉水植物生长十分有利;但在夏季,当水温超过30℃且水深远大于1m时,底泥和底层湖水中的厌氧环境会引起沉水植物烂根,故沉水植物无法在五里湖渡过夏季,成为重建水生植被的障碍。适当降低水位,开挖湖心区底泥,在沿岸带堆积造成人工浅滩,可以创造出适合水生植物生长的生境条件。;In the eutrophication process of Wuli Lake, large amount of nitrogen, phosphorous and organic matter accumulated in the sediment of the lake bottom. In summer, oxygen deficiency often occurred in the sediment and bottom water, because high temperature enhanced biochemical oxygen consumption in the sediment and water, but the high water level greatly limited oxygen supply of the bottom water and sediment. The sediment condition was suitable for emerged plant and floating-leaved plant all the time, and even favorite to submerged plant when the temperature was below 30℃ or the water depth was less than 1m. In summer season when the temperature was over 30℃ and the water depth was beyond 1m, the anaerobic condition in the sediment and bottom water could destroy the root of submerged plant and cause it floating-up. It became an obstacle for restore aquatic vegetation in Wuli Lake that submerged plant could not survive the summer. To create suitable habitat for aquatic plant in Wuli Lake, the water level should be controlled, and the fertile sediment in the center of the lake be moved to the littoral zone to make it more shallow.