Microbial Community Structure and Diversity Across Whale Fall, Submarine Canyon, and Submarine Fan Sites in Deep Sea Marine Sediments

Deep-sea ecosystems are essential to global carbon cycling, with microbes driving key biogeochemical processes. In this study, we investigated microbial community structure and diversity across whale fall and submarine canyon sites in Monterey Bay, California, and bathypelagic sediments sites. Twenty sediment cores (extending 15 to 18 cm below seafloor, cmbsf) were collected from five sites at depths ranging from 633 to 3,562 meters. Our results indicate that biological dissimilarity increases with geographical distance, even over small spatial scales (2–50 cm), with rare microbial populations significantly contributing to dissimilarity among replicated samples. Bacterial community dissimilarities were greater across 15 cm vertical depth of the core(s) than over 150 km horizontally. Several key taxa exhibited significant variation (Mann-Whitney U Test, p < 0.01) in relative abundance between surface (0-6 cmbsf) and deeper (>6 cmbsf) horizons. Sediment surface horizons were dominated by Bacteroidota, Gammaproteobacteria, and Verrucomicrobiota, while deeper horizons were characterized by Chloroflexi, Acidobacteriota, Zixibacteria, Spirochaetota, and Caldatribacteriota. Notably, whale-fall sites, where a detrital whale was deposited approximately a decade or more ago, showed that the biosphere characteristic of deeper sediments depths occurs at shallower depths than in non-whale-fall sites located 90 m away, indicating enhanced microbial development. These findings provide insights into microbial diversity in deep-sea sediments.

Presentation Preference: Oral

Primary Presenter: Yu-Chen Ling, Marine Biological Laboratory (lchacol@gmail.com)

Authors:

Yu-Chen Ling, Marine Biological Laboratory  (lchacol@gmail.com)

Rachel Harbeitner, University of California Santa Cruz  (rharbeit@ucsc.edu)

Theo Krueger, GEOMAR Helmholtz Centre for Ocean Research Kiel  (theokrueger.marbio@gmail.com)

Sebastian Sudek, Monterey Bay Aquarium Research Institute  (ssudek@mbari.org)

Sujung Lim, California Institute of Technology  (sjnglim@gmail.com)

Victoria Orphan, California Institute of Technology  (vorphan@caltech.edu)

Alexandra Worden, Marine Biological Laboratory  (azworden@mbl.edu)