Development of visual survey tools for seafloor observations and sampling

The ATIS (Abyss Twisted-pair Imaging System) and FITS (Fiber-optical Instrumentation Towed System) were developed for real-time observing on the sea floor around the gas hydrate seeps, while the V-corer (Video-guided multi-corer) was for effective sediment collection. Considering that the CTD (Conductivity, Temperature, and Depth) winch is a standard equipment on most of the research vessels, the ATIS was designed to be operated using a 2 cores twisted-pair CTD cable that is able to transmit live video and digital data over a range of 8 km. Therefore, the ATIS is portable and is readily operated on most of the research vessels; however, it suffers from the limited amount of battery-life and low communication bandwidth. On contrast, the FITS contains a surface power source and uses a fiber-optic cable as its backbone so that the FITS has nearly unlimited endurance and supports connection bandwidth of several gigabits per second. With unlimited power and high bandwidth budget, the FITS is able to carry more sensors and instruments than the ATIS for seafloor exploration. With the same power and communication architectures as the ATIS, the V-corer is developed to provide visual information of the experimental sites to the scientists such that a prompt and accurate decision can be made for collecting sediment samples. The V-corer, as opposed to conventional blind corers, equipped with a real-time HD camera and lightings, uplinks the live video to the surface vessel. This function improves the efficiency of sediment collection significantly because the operators can avoid hard seafloor which is highly risky for the coring device. Since 2013, the ATIS, FITS and V-corer have made 105 dives covering over 270 km of tracks and having a total of 256 hours dive duration off the southwest and northeast Taiwan, in which the deepest dive is 2630 m.