A bi-directional Data link into the Deep Sea — The DOMEST Project

Publisher Summary This chapter describes the different aspects of the DOMEST project, a bi-directional data link into the deep sea. In recent time, still cameras or digital video cameras are used for monitoring particle fluxes in the ocean. In most cases, these devices are operating autonomously—that is, they are programmed on the ship and deployed in the ocean afterwards. There is a substantial demand to implement bi-directional communication techniques in open ocean moorings to check the correct operation of the devices and to control and to get real-time data from the deployed instruments. This was the initial idea for the project DOMEST, which deals with data communication in the ocean and measuring techniques for high-resolution particle transport into the deep sea. To establish the data link from the atmosphere into the ocean as fast as possible, the SBU mooting has been placed 0.5 miles near the MSU mooting. The surface buoy operates as a relay station for the coupling of acoustic underwater link and satellite based atmospheric link. Technology installed on the buoy is an acoustic underwater modem, on-board digital controller, a OrbComm satellite telemetry, and a small weather station. The underwater acoustic telemetry system works very reliable and has been tested within lateral distances up to 3.5 km and a maximum water depth of 3600 m. Communication rates were found to be strongly dependent on distances, the angle of transmission, and on physical water conditions, such as the depth of thermocline and seasonal variations in plankton content.