AUTHOR=Li Ding , Wang Liping , Jiang Fan , Zeng Xiang , Xu Qinzeng , Zhang Xuelei , Zheng Qiang , Shao Zongze 

TITLE=Unveiling the microbial diversity across the northern Ninety East Ridge in the Indian Ocean

JOURNAL=Frontiers in Microbiology

VOLUME=15

YEAR=2024

URL=https://www.frontiersin.org/journals/microbiology/articles/10.3389/fmicb.2024.1436735

DOI=10.3389/fmicb.2024.1436735

ISSN=1664-302X

ABSTRACT=<p>Prokaryotes play a crucial role in marine ecosystem health and drive biogeochemical processes. The northern Ninety East Ridge (NER) of the Indian Ocean, a pivotal yet understudied area for these cycles, has been the focus of our study. We employed high-throughput 16S rRNA gene sequencing to analyze 35 water samples from five stations along the ridge, categorized into three depth- and dissolved oxygen-level-based groups. Our approach uncovered a clear stratification of microbial communities, with key bioindicators such as <italic>Prochlorococcus</italic> MIT9313, Sva0996 marine group, and <italic>Candidatus Actinomarina</italic> in the upper layer; <italic>Ketobacter</italic>, <italic>Pseudophaeobacter</italic>, <italic>Nitrospina</italic>, and SAR324 clade in the middle layer; and <italic>Methylobacterium-Methylorubrum</italic>, <italic>Sphingomonas</italic>, <italic>Sphingobium</italic>, and <italic>Erythrobacter</italic> in the deep layer. <italic>Methylobacterium-Methylorubrum</italic> emerged as the most abundant bacterial genus, while <italic>Nitrosopumilaceae</italic> predominated among archaeal communities. The spatial and depth-wise distribution patterns revealed that <italic>Ketobacter</italic> was unique to the northern NER, whereas <italic>Methylobacterium-Methylorubrum</italic>, UBA10353, SAR324 clade, SAR406, Sva0996_marine_group, <italic>Candidatus Actinomarina</italic> were ubiquitous across various marine regions, exhibiting niche differentiation at the OTU level. Environmental factors, especially dissolved oxygen (DO), silicate, nitrate, and salinity, significantly influence community structure. These findings not only reveal the novelty and adaptability of the microbial ecosystem in the northern NER but also contribute to the broader understanding of marine microbial diversity and its response to environmental heterogeneity.</p>