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Gulf of Mexico blue hole harbors high levels of novel microbial lineages

February 21, 2021

Exploration of oxygen-depleted marine environments has consistently revealed novel microbial taxa and metabolic capabilities that expand our understanding of microbial evolution and ecology. Marine blue holes are shallow karst formations characterized by low oxygen and high organic matter content. They are logistically challenging to sample, and thus our understanding of their biogeochemistry and microbial ecology is limited. We present a metagenomic and geochemical characterization of Amberjack Hole on the Florida continental shelf (Gulf of Mexico). Dissolved oxygen became depleted at the hole’s rim (32 m water depth), remained low but detectable in an intermediate hypoxic zone (40–75 m), and then increased to a secondary peak before falling below detection in the bottom layer (80–110 m), concomitant with increases in nutrients, dissolved iron, and a series of sequentially more reduced sulfur species. Microbial communities in the bottom layer contained heretofore undocumented levels of the recently discovered phylum Woesearchaeota (up to 58% of the community), along with lineages in the bacterial Candidate Phyla Radiation (CPR). Thirty-one high-quality metagenome-assembled genomes (MAGs) showed extensive biochemical capabilities for sulfur and nitrogen cycling, as well as for resisting and respiring arsenic. One uncharacterized gene associated with a CPR lineage differentiated hypoxic from anoxic zone communities. Overall, microbial communities and geochemical profiles were stable across two sampling dates in the spring and fall of 2019. The blue hole habitat is a natural marine laboratory that provides opportunities for sampling taxa with under-characterized but potentially important roles in redox-stratified microbial processes.

Citation Information

Publication Year 2021
Title Gulf of Mexico blue hole harbors high levels of novel microbial lineages
DOI 10.1038/s41396-021-00917-x
Authors N.V. Patin, Z.A. Dietrich, A. Stancil, M. Quinan, J.S. Beckler, E. R. Hall, J Culter, Christopher G. Smith, Martial Taillefert, F.J. Stewart
Publication Type Article
Publication Subtype Journal Article
Series Title Interational Society of Microbial Ecology (ISME) Journal
Index ID 70218643
Record Source USGS Publications Warehouse
USGS Organization St. Petersburg Coastal and Marine Science Center