Functional profiling of coastal microbial mats from the Yucatan Peninsula: methane, nitrogen and sulfur metabolism

Methane, sulfur, and nitrogen metabolism are key processes in microbial mats that directly regulate greenhouse gas emissions, nutrient availability, and ecosystem productivity. Previous studies have identified microbial mats along the coastline of the Yucatan Peninsula, revealing a diverse array of microbial macrostructures associated with mangrove ecosystems. However, a metagenomic analysis for the understanding of these metabolisms is not yet available. This study aimed to explore the functional diversity of microbial mats in coastal lagoons of the Yucatan Peninsula, focusing on methane, nitrogen, and sulfur metabolism, through shotgun sequencing. Results indicated that methanogenic communities were dominated by Methanosarcina , and that the main pathway was acetoclastic, whereas the methanotrophic communities were dominated by Methylobacterium . Flat mats from Ría Lagartos and Progreso presented greater potential for methane oxidation, whereas pustular mats from Progreso and floating mats from Sisal presented greater potential for methane production. Sulfur-related microorganisms (3.11–4.23%) were dominated by Desulfosarcina and Pseudodesulfovibrio . Total gene counts revealed a greater potential for dissimilatory sulfate reduction and sulfate oxidation in flat mats from Ría Lagartos, whereas assimilatory sulfate reduction metabolism predominated in the other mats. Nitrogen-related communities were highly abundant (21.8–28.8%), dominated by Streptomyces and Pseudomonas . Total gene count revealed greater potential for nitrogen fixation and nitrification in mats from Progreso, whereas mats from Ría Lagartos and Sisal presented a greater potential for denitrification, implying higher N₂O emissions. These findings underscore the functional heterogeneity of microbial mats and their influence on greenhouse gas dynamics and nutrient cycling in coastal ecosystems on the Yucatan Peninsula.