Real-time, continuously recording observatory technologies are now installed at three mid-ocean ridge locations, serving disciplines from geophysics to biology. All three observatories provide power and communications to seafloor networks of sensors, with data being transmitted to land via long-distance cables or a satellite link. Two observatories have been operating since 2010 (EMSO Açores and NEPTUNE Endeavour), and the third (OOI Axial Volcano) went online in 2015. This presentation will review the the geological and biological characteristics of these three observatory locations, their deployed observing technologies, and consider the common and unique contributions that each can make to a multi-disciplinary understanding of the interaction of tectonic, hydrothermal, oceanographic and biological processes at mid-ocean ridges. One of the challenges to using observatory technologies for the inter disciplinary study of mid-ocean ridge processes is the development of continuously-recording sensors for disciplines such as chemistry and biology that have traditionally relied on the collection of physical samples for data. We will provide examples of how biologists are using imagery combined with physical sensor data to study how hydrothermal vent organisms interact with environmental gradients, and how their activities can be modulated by environmental fluctuations. We will also consider how current and upcoming developments in physical and chemical sensors combined with the automated and remote-controlled collection of water samples will enable advances in our understanding how the properties of discharging hydrothermal fluids are influenced by microbial and physical processes below the seafloor. Finally, we will provide an update from the U.S. Ocean Observatory Initiative cabled observatory at Axial Volcano where a seafloor volcanic eruption was detected and monitored by observatory sensors earlier this year. Planned submersible and multi-beam surveys at Axial Volcano in August 2015 will provide ground-truthing for an eruption scenario that was developed from analysis of seismometer, hydrophone and temperature data.