Loihi Seamount is a model system for mid-plate hotspot magmatism. The newest volcano in the Hawaiian Seamount Chain, it is located ~15 km off the southeast corner of the island of Hawaii. Low-temperature vents emitting fluids up to ~70˚C dominate hydrothermal activity at Loihi, and contain elevated levels of Fe, CO2
. Loihi Seamount is an ideal site for studying subsurface crustal microbes because its chemistry is so well known, with plenty of background information from multiple samplings available from each site.
We are performing Option 1 sequencing (24 samples of V4V5 amplicon sequencing) of subsurface fluid samples and microbial mats sampled directly above the venting fluids to further our understanding of subsurface microbial populations in a low sulfide, high iron hydrothermal environment. These experiments will also allow us to determine the extent of interaction between microbial communities in subsurface diffuse fluids and seafloor microbial mats.
We will test the following hypotheses: 1. The subsurface microbial communities in the Hiolo area and Spillway area have different compositions that are related to local fluid chemistry 2. The dominant species in microbial mats at Loihi Seamount are seeded by subsurface populations present in diffuse flow fluids. It is likely that the dominant mat species are present but not dominant in the subsurface, and bloom in the transition zone at the seafloor where warm, reduced anoxic fluids mingle with cool, oxic seawater.