Abstract:
Whole-lake microalgal biomass surveys were carried out in Lake Balaton to investigate the seasonal, spatial, and temporal changes of benthic algae, as well as to identify the drivers of the phytobenthos. Phytobenthos was controlled mainly by light: the highest benthic algal biomass was in the shallow littoral region characterized by large grain size (sand) with good light availability but lower nutrient content in the sediment. During the investigated period, phytoplankton biomass showed a significant decrease in almost the entire lake. At the same time, the biomass of benthic algae increased significantly in the eastern areas, increasing the contribution of total lake microalgae biomass (from 20 % to 27 %). Benthic algal biomass increase can be explained by the better light supply, owing to the artificially maintained high water level which greatly mitigates water mixing. The decrease in planktonic algal biomass could be attributed to increased zooplankton grazing, which is otherwise negatively affected by mixing. As a result of the high water level, the trophic structure of the lake has been rearranged in recent decades with a shift from the planktonic life form to the benthic one while the nutrient supply has largely remained unchanged.
摘要:
在巴拉顿湖进行了全湖微藻生物量调查,以调查季节性,空间,和底栖藻类的时间变化,以及确定植物底栖动物的驱动因素。植物底栖动物主要受光控制:底栖藻类生物量最高的是在浅海沿岸地区,其特征是粒径大(沙子),光线利用率好,但沉积物中的养分含量较低。在调查期间,浮游植物生物量在几乎整个湖泊中显示出显着下降。同时,东部地区底栖藻类的生物量显著增加,增加总湖泊微藻生物量的贡献(从20%增加到27%)。底栖藻类生物量的增加可以解释为更好的光供应,由于人工维持高水位,大大减轻了水的混合。浮游藻类生物量的减少可能归因于浮游动物放牧的增加,否则会受到混合的负面影响。由于水位过高,近几十年来,湖泊的营养结构已经重新布置,从浮游生命形式转变为底栖生命形式,而营养供应基本保持不变。