@nautiluslive: During the NA171 expedition, #ROVHercules explored the Hafa Adai Vent Field in the Mariana back-arc: the first visit to this extraordinary site since its discovery in 2016. Co-Lead Scientist Bill Chadwick explains how different the site looks from the last time he saw it, a visual example of the region’s ongoing hydrothermal and volcanic activity. Hot vent fluids from these chimneys include metals leeched from seafloor rocks, giving it the distinctive black color and earning the name “black smokers.” #NautilusLive #oceanexploration #hydrothermalvents #deepseachemistry