Long term seafloor observatory for deep sea research

The last decade has showed that there is a great interest in physical, biological, geophysical and chemical processes of deep sea research. A wide variety of monitoring systems have developed and used to perform the surveying, sampling, and manipulation tasks to quantitative oceanographic science. In most cases, in-situ results are likely to be less biased, compared to the methods of bringing the samples to the surface of the ship. On the other hand, it is required for a scientist to understand the long term vibration both in time scale and spatial scale. The field observatory is a self-contained system that not only can operate autonomously under water for a long period (1 month to 1 year), but also have the capability to cover temporal changes. We reported the design work of GeoVent (Geochemistry, Oceanographic and hydrothermal Vent Observations), a seabed observatory developed in China. This system consists of power supply, data acquisition and control unit, and multi sensors can automatically operate under potentially hazardous conditions. An acoustic modem is attached to allow the system to send the data back to the surface in real time. A detailed description of the prototype of GeoVent is presented. It is shown that it is an ideal tool for deep ocean science, by combining the different sensor packages. The capabilities and limitation of the in situ observation methods are also discussed.