ABSTRACT

Allochthonous or autochthonous disturbances may change waterbodies from a clear to a turbid state, increasing the availability of nutrients and promoting blooms of harmful cyanobacteria. Submerged macrophytes may play an important role in alleviating the adverse effects of phosphorus resuspension and release from bottom sediments. We assessed the effects of allochthonous disturbances (rainfall and wind) on phosphorus release by constructing models using data from 2 shallow lakes with contrasting steady states. Using partial least squares path modeling, we examined submerged macrophytes, phytoplankton, and possible drivers of their abundance. In the clear-water lake, the concentrations of total phosphorus (TP) had the greatest direct influence on the macrophyte percentage of volume infested and phytoplankton biomass, followed by concentrations of TP in the sediment. In the turbid lake, the TP concentration in the water was the most important factor affecting phytoplankton biomass directly, followed by disturbances on TP concentration in the sediment and euphotic zone. Our models support the hypothesis that submerged macrophyte coverage acts as a stabilizing force to prevent the proliferation of cyanobacteria and stabilize the clear-water phase in semiarid lakes. However, potential mutual inhibition mechanisms between the submerged macrophyte Nitella cernua and the cyanobacterium Microcystis aeruginosa need to be better addressed for restoration purposes in lakes with shallow clear waters.

摘要

异源或自生干扰可能会使水体从透明状态变为浑浊状态，从而增加了养分的利用率并促进了有害蓝藻的繁殖。沉水植物可能在减轻磷重悬浮和从底部沉积物中释放的不利影响中起重要作用。我们通过使用来自两个具有稳定状态对比的浅湖的数据构建模型来评估异源干扰（降雨和风）对磷释放的影响。使用偏最小二乘路径模型，我们研究了淹没的大型植物，浮游植物及其丰富度的可能驱动因素。在清水湖中，总磷（TP）的浓度对大型植物侵染量和浮游植物生物量的百分比具有最大的直接影响，其次是沉积物中TP的浓度。在浑浊的湖泊中，水中的总磷浓度是直接影响浮游植物生物量的最重要因素，其次是沉积物和富营养区的总磷浓度受到干扰。我们的模型支持以下假设：淹没的大型植物覆盖物起到稳定作用，可防止蓝细菌的繁殖并稳定半干旱湖泊中的清水相。然而，淹没植物之间潜在的相互抑制机制 我们的模型支持以下假设：淹没的大型植物覆盖物起到稳定作用，可防止蓝细菌的繁殖并稳定半干旱湖泊中的清水相。然而，淹没植物之间潜在的相互抑制机制 我们的模型支持以下假设：淹没的大型植物覆盖物起到稳定作用，可防止蓝细菌的繁殖并稳定半干旱湖泊中的清水相。然而，淹没植物之间潜在的相互抑制机制在浅水清澈的湖泊中，为了恢复的目的，需要更好地解决Nitella cernua和蓝细菌铜绿微囊藻。