Leg 3 Fini!

An impressionist-style portrait of a giant rattail obscured by the high-temperature vent fluid the Jason temperature probe is measuring at Diva vent in the International District vent field. Credit: UW/NSF-OOI/WHOI, Dive J2-1546, V23.

September 4-6, 2023: In spite of weather delays, the objectives of Leg 3 were accomplished. Two of the Leg 3 dives took place at International District, surrounded by hydrothermal vents and chemosynthetic animal communities. The team deployed a RAS/PPS sampler which collects fluid and DNA samples from the vents, specifically a vent known as “Tiny Towers”. This same vent, and the cap that the RAS/PPS samples from, is observed year-round by a digital still camera. The third instrument deployed at International District (the Hydrothermal Vent Fluid Temperature and Resistivity sensor) samples the temperature and chemical properties of the hydrothermal vent fluid. Vent fluid is extremely acidic (low pH), and resistivity is an analogue for chlorinity, a way of measuring how salty the fluid is compared to background seawater. Lots more details including live video are available here.