7-4 Beyond Bacteria: Exploring Microeukaryote Diversity and Function within Microniches of the Eastern Tropical North Pacific Oxygen Minimum Zone

Session: Earth Life Sciences across the Cordillera (Posters)

Poster Booth No.: 10

Presenting Author:

Sofia FONSECA YEPEZ

Authors:

FONSECA YEPEZ, Sofia¹, GARCIA DE LEON, Francisco Javier², VAZQUEZ ROSAS LANDA, Mirna³, MENDOZA PORTILLO, Verónica⁴, VALDIVIA CARRILLO, Tania⁵

(1) Centro de Investigaciones Biologicas del Noroeste, La Paz, Baja California Sur, Mexico, (2) Planeación Ambiental y Conservación, Centro de Investigaciones Biológicas del Noroeste, La Paz, Baja California Sur, Mexico, (3) Instituto de Ciencias del Mar y Limnología, UNAM, Ciudad de México, Mexico, (4) Instituto de Ciencias del Mar y Limnología, UNAM, Ciudad México, Mexico, (5) Ecología Pesquera, Centro de Investigaciones Biológicas de Noroeste, La Paz, Baja California Sur, Mexico,

Abstract:

The Eastern Tropical North Pacific (ETNP) contains the largest Oxygen Minimum Zone (OMZ) on the planet. These zones are of global importance due to their impact on biogeochemical cycles, particularly the nitrogen cycle, where they cause substantial losses of fixed nitrogen and the emission of greenhouse gases. Within these regions, microorganisms represent the predominant life forms, and their metabolic activities determine the direction of biogeochemical fluxes under oxygen-deficient conditions. While bacteria in OMZs have been extensively studied using advanced genomic techniques, such as shotgun metagenomics, the assembly of communities and diversity of microbial eukaryotes remain an underexplored but crucial component for understanding the dynamics of the ocean microbiome. This study presents a meta-analysis of free-living and particle-associated microbial eukaryote communities in the OMZ. Microbial eukaryotic data were retrieved from GenBank (Bioproyect PRJNA632347 and PRJNA254808) through a specialized workflow designed to filter eukaryotic sequences from previously published ETNP ocean samples. The analyzed sequences were originally generated through shotgun metagenomics.

Our workflow identifies microbial eukaryotic sequences by detecting potentially homologous proteins, while also generating data for a comprehensive assessment of diversity indices. This research is part of an ongoing master’s thesis project. Preliminary findings reveal distinct microbial eukaryote assemblages, with notable differences in community composition and abundance between free-living and particle-associated groups. Currently, both the general taxonomic characteristics and the functional traits of the identified proteins are undergoing further analysis. These initial results contribute to a more holistic understanding of the role of eukaryotes in the microniches and biogeochemical dynamics of marine anoxic zones.

Geological Society of America Abstracts with Programs. Vol. 58, No. 3, 2026

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