The overall goal of the project is to monitor environmental parameters (temperature, pressure, seismicity) at the Logatchev Hydrothermal Field over a longer period of time (1 year or longer) to provide a basic data set for all long-term investigations of biological communities and for all studies of the hydrothermal plume, its sources and its development over time. One focus of temperature monitoring effort will be to assess the low temperature diffuse outflow from fissures and fractures. In addition a probe will be developed to measure temperatures at selected locations and transmit them in real-time to guide ROV operational decisions. The deployment and recovery of all instruments (with exception of the water column profiling loggers) depends entirely on the availability of a deep sea ROV or submersible, which avoids the need for expensive release systems. The proposed technical development will provide the basic instrumentation for monitoring other submarine hydrothermal fields for all members of the SPP 1144.