Mobile mud layer underneath the desiccated maar lake of Rincón de Parangueo and insights into its microbial fingerprints

  • Janet Sánchez-Sánchez Posgrado en Ciencias de la Tierra, Centro de Geociencias, Universidad Nacional Autónoma de México, Blvd. Juriquilla, 3001, 76230, Juriquilla, Querétaro, Mexico.
  • Mariano Cerca Centro de Geociencias, Universidad Nacional Autónoma de México, Blvd. Juriquilla, 3001, 76230, Juriquilla, Querétaro, Mexico.
  • Rocío J Alcántara-Hernández Instituto de Geología, Universidad Nacional Autónoma de México, Ciudad Universitaria, Av. Universidad 3000, Del. Coyoacán, 04510, Mexico City, Mexico.
  • José Jorge Aranda-Gómez Centro de Geociencias, Universidad Nacional Autónoma de México, Blvd. Juriquilla, 3001, 76230, Juriquilla, Querétaro, Mexico.
  • Dora Carreón-Freyre Centro de Geociencias, Universidad Nacional Autónoma de México, Blvd. Juriquilla, 3001, 76230, Juriquilla, Querétaro, Mexico.
  • Carlos Lozano-Flores Departamento de Biología del Desarrollo y Neurofisiología, Instituto de Neurobiología, Universidad Nacional Autónoma de México, Querétaro, Mexico.
  • Israel Muñoz-Velasco Facultad de Ciencias, Universidad Nacional Autónoma de México, Apdo. Postal 70-407, Cd. Universitaria, 04510, Mexico City, Mexico.
  • Gilles Levresse Centro de Geociencias, Universidad Nacional Autónoma de México, Blvd. Juriquilla, 3001, 76230, Juriquilla, Querétaro, Mexico.
  • Alfredo Varela-Echavarría Departamento de Biología del Desarrollo y Neurofisiología, Instituto de Neurobiología, Universidad Nacional Autónoma de México, Querétaro, Mexico.
Keywords: saturated mud, microbiology, mud injection domes, maar cráter, lake

Abstract

We surveyed a subsurface layer of saturated mobile mud and its microbial fingerprints below the desiccated bottom of a maar lake at Rincón de Parangueo (RP), Mexico. A multi-scale approach was followed using geological fieldwork, coring of the sediments, ground penetrating radar survey, physico-chemical characterization including X-ray diffraction and scanning electron microscope, and high-throughput DNA sequencing methods. The mobile mud is an organic-rich silty clay, with high values of alkalinity, volumetric water content and conductivity. Mud mobility has been attributed to overpressure caused by disequilibrium compaction of sediments related to active subsidence and pore overpressure produced by an input of groundwater and gas content in the sediments and resulted in a diverse set of structures related to mud tectonics such as injection domes and fluid seeps through fractures. Extraction and sequencing of sedimentary environmental DNA in the mud layer were performed for Bacteria and Archaea. Despite the small number of samples obtained, the microbial fingerprint from the sedimentary environmental DNA at subsurface shares similarities with the microbial communities identified on the crater surface. Additionally, we identify the DNA of specific methanogenic microorganisms in the mud, such as Bathyarchaeia, Methanomassiliicoccales, and Methanobacteriales, and we speculate on their probable role in gas production and pore overpressure in the mud layer. The underground mud at Rincón de Parangueo represents a geologically dynamic environment with conditions that are favorable for the thriving of microbial communities.

Published
2021-11-24
Section
Articles