The Amazon floodplains are complex systems influenced by the annual hydrological regime with an effect on the structuring of physical, chemical and biological processes. Thus, we evaluated the relationship of environmental factors with the composition and variation of functional groups based on morphology (MBFG) during the hydrological year in an Amazonian floodplain lake, with monthly sampling (2013 to 2014). We used analysis of variance (ANOVA) and Kruskal–Wallis to show differences in physicochemical variables between hydroperiods. We performed permutation analysis of variance (PERMANOVA) to assess the dissimilarity of morphofunctional groups between hydroperiods and also of environmental data between the months of the study and RDA redundancy analysis to assess the relationship between MBFGs and environmental data. It was registered 101 taxa distributed in eight taxonomic categories and was grouped into 5 MBFGs (III, IV, V, VI and VII), with Chlorophyceae (31 taxa) and Cyanobacteria (27 taxas) with the higher number of taxa. Furthermore, there was a dominance of Cyanobacteria in the total biovolume, which form blooms (MBFGs III and VII) during the periods of falling and low water in lake, influenced mainly by the reduction in the availability of light and an increase in temperature. In another scenario, the dominance of MBFGs V and VI occurred during periods of rising and high water with association with carbon compounds, rainfall, SRP and NO₂. Thus, our results demonstrate that the availability of light, the concentration of nutrients and temperature were the most important variables for the morphofunctional structuring of phytoplankton in aquatic system.

亚马逊河漫滩是受年度水文状况影响的复杂系统，影响物理、化学和生物过程的结构。因此，我们通过每月采样（2013 年至 2014 年）评估了亚马逊河漫滩湖水文年基于形态学 (MBFG) 的环境因素与功能组的组成和变化的关系。我们使用方差分析 (ANOVA) 和 Kruskal-Wallis 来显示水周期之间物理化学变量的差异。我们进行了方差置换分析 (PERMANOVA) 以评估水周期之间形态官能团的差异以及研究月份之间的环境数据和 RDA 冗余分析以评估 MBFG 与环境数据之间的关系。它注册了 101 个分类群，分布在 8 个分类学类别中，分为 5 个 MBFG（III、IV、V、VI 和 VII），其中绿藻门（31 个分类群）和蓝藻门（27 个分类群）的分类群数量较多。此外，蓝藻在总生物量中占主导地位，在湖泊下降和低水期间形成水华（MBFG III和VII），主要受光照减少和温度升高的影响。在另一种情况下，MBFG V 和 VI 的主导地位发生在与碳化合物、降雨、SRP 和 NO 相关的上升和高水位期间 蓝藻在总生物量中占主导地位，在湖泊下降和低水期间形成水华（MBFG III和VII），主要受光照减少和温度升高的影响。在另一种情况下，MBFG V 和 VI 的主导地位发生在与碳化合物、降雨、SRP 和 NO 相关的上升和高水位期间 蓝藻在总生物体积中占主导地位，在湖水下降和低水期间形成水华（MBFG III和VII），主要受光照减少和温度升高的影响。在另一种情况下，MBFG V 和 VI 的主导地位发生在与碳化合物、降雨、SRP 和 NO 相关的上升和高水位期间₂ . 因此，我们的研究结果表明，光的有效性、养分浓度和温度是水生系统中浮游植物形态功能结构的最重要变量。