12 Guaymas Basin and Gulf of California Subsurface Systems and Energy Applications

This session will present subsurface research in the Gulf of California, especially IODP Expedition 385 to Guaymas Basin that explored the linkages between tectonics, magmatism, sedimentation, hydrothermalism, carbon cycling, and microbial life. Merged sessions: Subsurface Research  in Guaymas Basin and the Gulf of California and Energy Resources and Economic Development in Baja California: Fossil, Renewable, and Transition Minerals.

Wednesday, 22 April 2026
1:30 PM - 5:30 PM
LMH, Isla Carmen

Comparative Subsurface Microbial Community Patterns Across Sediment Cores From the Guaymas and Pescadero Basins, Gulf of California

Paper number: 12-7
Program: Technical Sessions
Time: 3:05 PM – 3:20 PM

Authors

Abstract

Hydrothermal basins of the Gulf of California are extreme deep-sea environments where fluid–sediment interactions generate steep physicochemical gradients that structure subsurface microbial communities. The Guaymas and Pescadero basins are geochemically distinct hydrothermal systems separated by approximately 400 km, providing a natural framework to examine how environmental heterogeneity influences microbial community structure and inferred metabolic potential in deep-sea sediments.

In this study, we evaluate how environmental variability in hydrothermally influenced sediments shapes microbial community composition and inferred functional potential within and between two representative hydrothermal basins of the Gulf of California. Sediment push cores collected in 2021 from the Guaymas Basin (RR22, R/V Roger Revelle) and the Pescadero Basin (FK210922, R/V Falkor) were analyzed using 16S rRNA gene amplicon sequencing (V4–V5) and X-ray fluorescence (XRF) of sediment elemental composition. Subsamples from multiple sediment horizons (0–22 cmbsf) enabled comparison of depth-related taxonomic patterns and inferred metabolic potential across sediment horizons and across hydrothermal basins.

Broad comparisons of microbial community composition indicate that the Guaymas and Pescadero basins share dominant microbial groups, while exhibiting basin-specific differences in the relative contribution of bacterial and archaeal communities. These patterns underscore the value of comparative subsurface studies for understanding microbial diversity in extreme deep-sea hydrothermal systems.

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

doi: 10.1130/abs/2026CD-411050

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