We are deploying a dozen pressure-temperature gauges (PTGs) around Yellowstone Lake. These measure pressure and temperature at the lake floor every few seconds. With this network, we can record the pressure variations experienced by the deep hydrothermal systems we’re targeting. The high sampling rate means we record not only seasonal variations in lake level, but also the pressure variations from waves, including both wind-driven waves with a period of a few seconds and basin-wide seiche waves with a period of several minutes. Measuring these pressures is an important part of assessing the sensitivity of the deep hydrothermal vent fields. Photos by Rob Sohn, WHOI. Work was completed under an authorized Yellowstone Research Permit.