Mansano A S, Hisatugo K F, Leite M A, Luzia A P, Regali-Seleghim M H
Departamento de Ecologia e Biologia Evolutiva, Universidade Federal de São Carlos - UFSCar, Rod. Washington Luis, Km 235, CEP 13564-905, São Carlos, SP, Brazil.
Braz J Biol. 2013 May;73(2):321-30. doi: 10.1590/S1519-69842013000200012.
The seasonal variation of the protozooplanktonic community (ciliates and testate amoebae) was studied in a tropical oligotrophic reservoir in Brazil, which was under the influence of two contrasting climatic seasons (rainy/warm and dry/cold). The aim of this study was to evaluate the effect of these climatic changes on physical, chemical and biological variables in the dynamic of this community. The highest mean density of total protozoans occurred in the rainy/warm season (5683.2 ind L-1), while the lowest was in the dry/cold (2016.0 ind L-1). Considering the seasonal variations, the protozoan groups that are truly planktonic, such as the oligotrichs (Spirotrichea), predominated in the dry season, whereas during the rainy season, due to the material input and resuspension of sediment, sessile protozoans of the Peritrichia group were the most important ones. The dominant protozoans were Urotricha globosa, Cothurnia annulata, Pseudodifflugia sp. and Halteria grandinella. The highest densities of H. grandinella were associated with more oxygenated and transparent water conditions, while the highest densities of C. annulata occurred in sites with high turbidity, pH and trophic state index (TSI). The study demonstrated that density and composition of protozooplanktonic species and groups of the reservoir suffered seasonal variation due to the environmental variables (mainly temperature, turbidity, water transparency, dissolved oxygen and TSI) and the biological variables (e.g. morphological characteristics, eating habits and escape strategies from predation of the species).
在巴西一个热带贫营养水库中研究了原生浮游动物群落（纤毛虫和有壳变形虫）的季节变化，该水库受两个对比鲜明的气候季节（雨季/温暖和旱季/寒冷）的影响。本研究的目的是评估这些气候变化对该群落动态中物理、化学和生物变量的影响。原生动物总数的最高平均密度出现在雨季/温暖季节（5683.2个/L），而最低密度出现在旱季/寒冷季节（2016.0个/L）。考虑到季节变化，真正浮游的原生动物类群，如寡毛类（旋毛亚纲），在旱季占主导地位，而在雨季，由于物质输入和沉积物再悬浮，缘毛类的固着原生动物是最重要的。优势原生动物有球形尾草履虫、环颈钟虫、伪砂壳虫属和大型弹跳虫。大型弹跳虫的最高密度与含氧量更高和水更清澈的条件相关，而环颈钟虫的最高密度出现在浊度、pH值和营养状态指数（TSI）较高的位点。研究表明，由于环境变量（主要是温度、浊度、水透明度、溶解氧和TSI）和生物变量（如物种的形态特征、饮食习惯和逃避捕食的策略），水库中浮游原生动物物种和类群的密度和组成存在季节变化。
