Bacterial Dynamics and Their Influence on the Biogeochemical Cycles in a Subtropical Hypereutrophic Lake During the Rainy Season

Osiris Díaz-Torres; Ofelia Yadira Lugo-Melchor; José de Anda; Adriana Pacheco; Carlos Yebra-Montes; Misael Sebastián Gradilla-Hernández; Carolina Senés-Guerrero

doi:10.3389/fmicb.2022.832477

Bacterial Dynamics and Their Influence on the Biogeochemical Cycles in a Subtropical Hypereutrophic Lake During the Rainy Season

Front Microbiol. 2022 Apr 5:13:832477. doi: 10.3389/fmicb.2022.832477. eCollection 2022.

Authors

Osiris Díaz-Torres¹, Ofelia Yadira Lugo-Melchor¹, José de Anda², Adriana Pacheco³, Carlos Yebra-Montes⁴, Misael Sebastián Gradilla-Hernández⁵, Carolina Senés-Guerrero⁵

Affiliations

¹ Centro de Investigación y Asistencia en Tecnología y Diseño del Estado de Jalisco, A.C., Unidad de Servicios Analiticos y Metrologicos, Guadalajara, Mexico.
² Departamento de Tecnologia Ambiental, Centro de Investigación y Asistencia en Tecnología y Diseño del Estado de Jalisco, A.C., Zapopan, Mexico.
³ Tecnologico de Monterrey, Escuela de Ingenieria y Ciencias, Monterrey, Mexico.
⁴ ENES- León, Universidad Nacional Autónoma de Mexico, León, Mexico.
⁵ Tecnologico de Monterrey, Escuela de Ingenieria y Ciencias, Zapopan, Mexico.

Abstract

Lakes in subtropical regions are highly susceptible to eutrophication due to the heavy rainfall, which causes significant runoff of pollutants (e.g., nutrients) to reach surface waters, altering the water quality and influencing the microbial communities that regulate the biogeochemical cycles within these ecosystems. Lake Cajititlán is a shallow, subtropical, and endorheic lake in western Mexico. Nutrient pollution from agricultural activity and wastewater discharge have affected the lake's water quality, leading the reservoir to a hypereutrophic state, resulting in episodes of fish mortality during the rainy season. This study investigated the temporal dynamics of bacterial communities within Lake Cajititlán and their genes associated with the nitrogen, phosphorus, sulfur, and carbon biogeochemical cycles during the rainy season, as well as the influences of physicochemical and environmental variables on such dynamics. Significant temporal variations were observed in the composition of bacterial communities, of which Flavobacterium and Pseudomonas were the dominant genera. The climatological parameters that were most correlated with the bacterial communities and their functional profiles were pH, DO, ORP, turbidity, TN, EC, NH₄ ⁺, and NO₃ ^-. The bacterial communities displayed variations in their functional composition for nitrogen, phosphorus, and sulfur metabolisms during the sampling months. The bacterial communities within the lake are highly susceptible to nutrient loads and low DO levels during the rainy season. Bacterial communities had a higher relative abundance of genes associated with denitrification, nitrogen fixation, assimilatory sulfate reduction, cysteine, SOX system, and all phosphorus metabolic pathways. The results obtained here enrich our understanding of the bidirectional interactions between bacterial communities and major biogeochemical processes in eutrophic subtropical lakes.

Keywords: 16S rRNA gene sequencing; bacterial communities; fuctional properties; hypereutrophic lake; physicochemical and environmental parameters; subtropical lake.