Examinando por Autor "Cornejo-D'Ottone, Marcela"

Mostrando 1 - 2 de 2
  • Miniatura
    Ítem
    Energetic convergence drives metabolic adaptation in lirima chilean high-altitude hydrothermal system
    (Springer Nature, 2025) Paquis, Pablo; Pardo Esté, Coral; Tapia, Joseline; Florez, July Z; Pérez, Vilma; Molina, Verónica; Cornejo-D'Ottone, Marcela; Pérez, Pablo A; Harrod, Chris; Jeffrey, Wade H; Calabrese, Sergio; Quatrini, Paola; Tassi, Franco; Hengst, Martha B
    High-altitude hydrothermal systems provide laboratories for understanding microbial adaptation to extreme conditions. Here we investigated thermodynamic controls on metabolic transitions in Lirima hydrothermal system (Chile, 4000 meters above sea level) calculating affinities of competing carbon and sulfur reactions across pools (53-75 degrees C). Through geochemistry, numerical thermodynamic modeling, and stable isotope analysis, we identify Energetic Convergence Nodes where chemical affinities of competing pathways become equal. Calculations reveal hydrogenotrophic and carboxydotrophic methanogenesis converge with sulfate reduction at 63-64 degrees C. This corresponds with responses: carbon isotopes shift from -17.2 parts per thousand to -27.7 parts per thousand, sulfur isotopes from -20.5 parts per thousand to -9.1 parts per thousand, and carbon-to-sulfur ratios drop from similar to 10 to <1, indicating transition from carbon to sulfur-dominated metabolism. Microbial activity collapses at this temperature, while metagenomics validates both pathways. Independent analysis confirms convergence at 63-64 degrees C, establishing Energetic Convergence Nodes as predictive frameworks for metabolic boundaries with applications for early Earth biogeochemistry and extraterrestrial biosignature detection.
  • Miniatura
    Ítem
    Peatland Pond Microbiome and Biogeochemical Responses to Solar Radiation Extremes in a High-Altitude Wetland, Salar de Huasco, Chile
    (MDPI, 2025) Eissler, Yoanna; Yanez-Montalvo, Alfredo; Celis-Pla, Paula S. M; Cornejo-D'Ottone, Marcela; Trabal, Andres; Dorador, Cristina; Piccini, Claudia; Falcon, Luisa I; Romero, Carlos; Aguilar-Munoz, Polette; Molina, Veronica
    High-altitude wetland holds unique peatland ponds subjected to extreme diel environmental condition changes. Herein, we evaluate the response of photoautotrophic and nitrification activities and compare it with bacteria and archaea composition shifts in sediment and water changes during key hours of the day. Results indicate the presence of photo-inhibition, including ammonia oxidizers, but a high recovery of photosynthetic activities in the microbial mat and of potential specific functional groups towards the afternoon. The microbial community was composed of 45 phyla, mainly proteobacteria from Alpha-, Delta-, and Gammaproteobacteria and Bacteroidota in the water and sediments, and these later groups were notoriously enriched during the afternoon. The microbial community composition changes were associated with chlorophyll a, nutrients, and greenhouse gases reservoir variability, including methane potential release towards the atmosphere at hours of high radiation. Peatland pond microbial communities and their biogeochemical contribution change in a complex interplay coupled by time to environmental conditions predominantly driven by the extreme solar radiation.