Just below the surface layer at Ruby volcano, a slightly deeper, more concentrated particle anomaly was detected by a light scattering sensor (LSS) on the CTD (an instrument that measures conductivity, temperature, and depth). We also have a sensor that detects changes in the chemical composition of the seawater (the EH sensor). The voltage from this sensor decreases when the CTD package is towed through hydrothermal plumes because of the types of chemicals within the plumes. This sensor also showed an anomaly at the same time we saw the increased particles just beneath the surface layer, giving us an additional indication the signal was, indeed, hydrothermal. Image courtesy of Submarine Ring of Fire 2006 Exploration, NOAA Vents Program
