Research progress on microbial diversity in seafloor hydrothermal chimneys

Seafloor hydrothermal vents serve as crucial conduits for material and energy exchange between the Earth's interior and the ocean, with their geological background playing a pivotal role in determining the chemical composition of the expelled fluid. Hydrothermal chimney stands as a quintessential structural and ecological unit within submarine hydrothermal vents, housing a diverse array of microbial groups with varying physiological functions. These microorganisms can use the chemical imbalance between high-temperature hydrothermal solution and low-temperature seawater or through weathering of various sulfide minerals to obtain the energy necessary to maintain their metabolism, and they are selectively distributed in various ecological niches in the chimney body along big environmental gradients of temperature, pH, Eh, and reducing compound concentration. Through high-throughput sequencing and omics analysis, it has been revealed that the nutrient metabolism types driving microbial life processes within the chimney encompass sulfur oxidation, sulfur reduction, methane oxidation, methane production, hydrogen nutrition, iron oxidation, nitrification and denitrification, and various other chemoautotrophic metabolic pathways, which suggests their potential significance in shaping the global element cycle. This paper provides a comprehensive and systematic overview of the microbiomes present in hydrothermal chimneys worldwide, including their distribution characteristics and variation patterns, contributing to the comprehensive and systematic understanding on hydrothermal microbial survival strategies, environmental adaptation mechanisms, and geochemical cycles involving hydrothermal microorganisms.