Díaz-Torres Osiris, de Anda José, Lugo-Melchor Ofelia Yadira, Pacheco Adriana, Orozco-Nunnelly Danielle A, Shear Harvey, Senés-Guerrero Carolina, Gradilla-Hernández Misael Sebastián
Centro de Investigación y Asistencia en Tecnología y Diseño del Estado de Jalisco, A.C., Unidad de Servicios Analiticos y Metrologicos, Guadalajara, Mexico.
Departamento de Tecnologia Ambiental, Centro de Investigación y Asistencia en Tecnología y Diseño del Estado de Jalisco, A.C., Zapopan, Mexico.
Front Microbiol. 2021 Mar 9;12:617151. doi: 10.3389/fmicb.2021.617151. eCollection 2021.
Lake Cajititlán is a small, shallow, subtropical lake located in an endorheic basin in western Mexico. It is characterized by a strong seasonality of climate with pronounced wet and dry seasons and has been classified as a hypereutrophic lake. This eutrophication was driven by improperly treated sewage discharges from four municipal wastewater treatment plants (WWTPs) and by excessive agricultural activities, including the overuse of fertilizers that reach the lake through surface runoff during the rainy season. This nutrient rich runoff has caused algal blooms, which have led to anoxic or hypoxic conditions, resulting in large-scale fish deaths that have occurred during or immediately after the rainy season. This study investigated the changes in the phytoplankton community in Lake Cajititlán during the rainy season and the association between these changes and the physicochemical water quality and environmental parameters measured in the lake's basin. and were the dominant genera of the cyanobacterial community, while the Chlorophyceae, Chrysophyceae, and Trebouxiophyceae classes dominated the microalgae community. However, the results showed a significant temporal shift in the phytoplankton communities in Lake Cajititlán induced by the rainy season. The findings of this study suggest that significant climatic variations cause high seasonal surface runoff and rapid changes in the water quality (Chlorophyll-, DO, NH , and NO ) and in variations in the composition of the phytoplankton community. Finally, an alternation between phosphorus and nitrogen limitation was observed in Lake Cajititlán during the rainy season, clearly correlating to the presence of when the lake was limited by phosphorus and to the presence of when the lake was limited by nitrogen. The evidence presented in this study supports the idea that the death of fish in Lake Cajititlán could be mainly caused by anoxia, caused by rapid changes in water quality during the rainy season. Based on our review of the literature, this is the first study on the phytoplankton community in a subtropical lake during the rainy season using high throughput 16S rRNA and 18S rRNA amplicon sequencing.
卡希蒂特兰湖是一个小型、浅水的亚热带湖泊，位于墨西哥西部的一个内流盆地。其特点是气候季节性强烈，干湿季节分明，已被归类为富营养化湖泊。这种富营养化是由四个城市污水处理厂未经妥善处理的污水排放以及过度的农业活动导致的，包括在雨季通过地表径流进入湖泊的化肥过度使用。这种富含营养的径流导致了藻类大量繁殖，进而造成缺氧或低氧状况，导致在雨季期间或雨季刚结束后发生大规模鱼类死亡。本研究调查了雨季期间卡希蒂特兰湖浮游植物群落的变化，以及这些变化与在该湖流域测量的物理化学水质和环境参数之间的关联。 和 是蓝藻群落的优势属，而绿藻纲、金藻纲和小球藻纲则在微藻群落中占主导地位。然而，结果显示雨季导致卡希蒂特兰湖浮游植物群落发生了显著的时间变化。本研究结果表明，显著的气候变化导致季节性地表径流增加，水质（叶绿素 - 、溶解氧、氨氮和硝态氮）迅速变化，浮游植物群落组成也发生变化。最后，在雨季期间卡希蒂特兰湖观察到磷限制和氮限制之间的交替，当湖泊受磷限制时明显与 的存在相关，当湖泊受氮限制时与 的存在相关。本研究提供的证据支持了卡希蒂特兰湖鱼类死亡可能主要是由雨季期间水质迅速变化导致的缺氧引起的这一观点。基于我们对文献的综述，这是首次利用高通量16S rRNA和18S rRNA扩增子测序对亚热带湖泊雨季期间的浮游植物群落进行的研究。
