Long-term plankton studies in neotropical lakes are scarce. Here we studied plankton composition in Lake Cote, Costa Rica, twice per year from 2002 to 2018, to monitor changes after it was modified as a reservoir for hydroelectricity in 2003. Plankton variation was examined for a long-term trend and its relationship with basic limnological characteristics of the lake. Phytoplankton was sampled from the surface and with a depth-integrating sampler. Zooplankton was caught with vertical hauls, at the same station at the middle of the lake. A total of 138 taxa of microalgae occurred, most from Chlorophyta and Cyanobacteria, to which dominant species belonged; Aulacoseira granulata was also ubiquitous. A shift in dominance occurred, from Cosmarium asphaerosporum to Aphanothece cf. microscopica, and Aphanocapsa cf. delicatissima. Zooplankton included 23 species of Cladocera, Copepoda, Rotifera, and Chaoborus. Most abundant were Keratella americana, Eubosmina tubicen, and Cyclopoida; Daphnia laevis became abundant after 2007 while E. tubicen declined. There was little correspondence between both planktonic components. Plankton composition was typical of a mesotrophic to eutrophic shallow lake, but changes indicated an increase in stratification, and can be attributed to combined effects of recent warming and outflow management for hydropower production.

中文翻译：

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2002 年至 2018 年哥斯达黎加科特湖浮游生物的变化

新热带湖泊中的长期浮游生物研究很少。在这里，我们研究了哥斯达黎加科特湖的浮游生物成分，从 2002 年到 2018 年每年两次，以监测 2003 年改造为水电水库后的变化。检查了浮游生物变化的长期趋势及其与基础的关系湖的湖沼学特征。浮游植物从地表采样，并使用深度积分采样器。浮游动物在湖中央的同一个站被垂直拖运捕获。共有138个微藻类群，主要来自优势种属的绿藻门和蓝藻门；Aulacoseira granulata 也无处不在。优势发生了转变，从 Cosmarium asphaerosporum 到 Aphanothece cf。显微镜和 Aphanocapsa 参见。熟食。浮游动物包括枝角类、桡足类、轮虫类和潮虫类 23 种。最丰富的是 Keratella americana、Eubosmina tubicen 和 Cyclopoida；Daphnia laevis 在 2007 年后变得丰富，而 E. tubicen 下降。两种浮游成分之间几乎没有对应关系。浮游生物组成是典型的中营养至富营养浅湖，但变化表明分层增加，可归因于近期变暖和水电生产流出管理的综合影响。