Factors to change two alternative systems, macrophyte-rich macrophyte-free in shallow lakes

我们调查了水生植物，水质，浮游植物生物量和物种组成在三个浅水湖泊不同水平的植被覆盖度和营养盐浓度在钏路摩尔在2000年8月。菱可以在各种营养水平下生存。它形成了一个环境，具有更陡峭的消光，更高浓度的溶解有机碳（DOC），更低浓度的溶解氧（DO）的底部附近，和更低浓度的硝酸盐+亚硝酸盐，和可溶性活性磷（SRP）。两栖蓼群落的pH值较高，底层溶解氧没有下降。叶绿素a与限制性营养盐（当TN：TP ≥ 10时为TP，当TN：TP < 10时为TN/10）的关系在有沉水植被和无沉水植被的湖泊之间存在显著差异。在一定营养水平下，有沉水植物的水体中叶绿素a浓度显著低于无沉水植物的水体。对应分析表明，不同站位浮游植物群落结构的差异主要是由有无沉水植物引起的，有沉水植物的湖泊中浮游植物种类的排序最好用TN、叶绿素、pH和SRP的环境梯度来解释

We investigated aquatic macrophytes, water quality, and phytoplankton biomass and species composition in three shallow lakes with different levels of vegetation coverage and nutrient concentrations in Kushiro Moor during August 2000. Trapa japonica can live at a wide range of nutrient levels. It forms an environment with a steeper extinction of light, higher concentrations of dissolved organic carbon (DOC), lower concentrations of dissolved oxygen (DO) near the bottom, and lower concentrations of nitrate + nitrite, and soluble reactive phosphorus (SRP). The pH was much higher In a Polygonum amphibium community, and the DO near the bottom did not drop. The relationship between chlorophyll a and the limiting nutrient (TP when TN : TP 【greater than or equal】 10, and TN/10 when TN : TP < 10) significantly differed between lakes with and without submerged vegetation. The chlorophyll a concentrations at a given nutrient level were significantly lower in water with submerged macrophytes than in water without them. Correspondence analysis showed that the difference in phytoplankton community structure among sites is due largely to the presence or absence of submerged macrophytes, and the ordination of phytoplankton species in the lakes with submerged macrophytes is best explained by environmental gradients of TN, chlorophyll, pH, and SRP