贵州草海沉水植物现状调查与影响因素分析

Investigation of submerged macrophytes current situation and analysis of influence factors in Caohai, Guizhou

  • 摘要: 沉水植物作为淡水湖泊水生态系统主要的初级生产者, 有机地连接湖泊水体与沉积物, 对于湖泊水生态系统健康的维持具有重要作用。为了解当前贵州草海沉水植物退化现状和原因, 本研究采用网格布点法和设置样带法分别调查了草海的沉积物理化性质和沉水植物群落, 评价了草海目前沉水植物群落时空分布格局与沉积物营养盐特征, 探究了影响沉水植物的关键环境因子, 同时通过草海种子库萌发实验评估了草海沉水植物恢复的潜力。结果发现, 草海现存包括轮藻(Charophyte sp)、穗花狐尾藻(Myriophyllum spicatum)、篦齿眼子菜(Stuckenia pectinata)、大茨藻(Najas marina)、光叶眼子菜(Potamogeton lucens)、轮叶黑藻(Hydrilla verticillata)、穿叶眼子菜(Potamogeton perfoliatus)、金鱼藻(Ceratophyllum demersum)、微齿眼子菜(Potamogeton maackianus)和单果眼子菜(Potamogeton acutifolius)在内的共10种沉水植物。草海沉水植物生物量和覆盖度均表现出明显的时空差异。沉水植物总覆盖度与水体和沉积物营养盐呈显著负相关的结果表明, 沉水植物在湖泊修复中具有削减营养盐的生态学功能, 同时过高的营养盐可能对沉水植物的生长具有负面作用。当前草海沉积物营养盐的释放可能是影响沉水植物生长的主要因素。相较于其它湖泊草海沉积物具有疏松、含水率高等特点, 对植物根系黏着力较低, 导致沉水植物较难定植和生长。松散的沉积物很容易向水体中释放可溶性营养盐, 引起藻类增殖及植物残体悬浮的遮光作用降低了水体透明度, 从而影响沉水植物的光合作用。草海具有良好的沉水植物自然恢复潜力, 但目前沉积物的高营养盐特征及其松散易悬浮的性质是制约沉水植物恢复的关键因素。本研究能为草海后续开展水生态恢复方案提供基础资料和技术参考。

     

    Abstract: Acting as the main primary producer of freshwater lake water ecosystem, submerged macrophytes organically connect lake water bodies and sediments, and play an important role in maintaining the health of lake water ecosystems. In order to understand the current degradation situation and reasons of submerged macrophytes in Caohai in Guizhou, this study investigated submerged macrophyte community and sediment physiochemical properties, and estimated the currently spatial and temporal distribution patterns of submerged macrophytes and sediment nutrient characteristics using grid point method and belt transect method, and determine the key factors that impact submerged macrophytes. In addition, Seed bank germination experiments of Caohai were conducted to estimate restoration potentiality of submerged macrophyte. Results showed that a totally current 10species of submerged macrophytes including Charophyte sp, Myriophyllum spicatum, Stuckenia pectinata, Najas marina, Potamogeton lucens, Hydrilla verticillate, Potamogeton perfoliatus, Ceratophyllum demersum, Potamogeton maackianus, Polygonum amphibium and Potamogeton acutifolius were found in Caohai. The coverage and biomass of submerged macrophyte in Caohai showed obviously seasonal and spatial variations. The significant negative correlation between the total coverage of submerged macrophytes and nutrient in water and sediment indicated that submerged macrophytes have the ecological function of reducing nutrient in lake restoration, and excessive nutrients might have negative effects on the growth of submerged macrophytes. At present, the release of nutrient from sediments in Caohai could be the main factor affecting the growth of submerged macrophytes. Compared to other lakes, surface sediment in Caohai is characterized by loosen and high moisture content, which result in submerged macrophytes are difficult to plant and germination. Meanwhile, the loosen sediment is easy to release soluble nutrient into waterbody. Photosynthesis of submerged macrophytes have been impact by water transparency decline originated from phytoplankton excessive propagation and shading of suspended plant residues. Caohai has a good potential for natural restoration of submerged macrophytes, but the higher nutrient concentration and the loosen property of sediment currently limited submerged macrophytes restoration. The study could provide theoretical basis and technical reference for the subsequent implementation of Caohai steady-state transformation control, water quality improvement and aquatic plant restoration technical scheme.

     

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