A mobile seabed detecting system for the seawater-sediment interface is developed and introduced in this paper, which can conduct mobile monitoring and on-site sampling, and realize chemical analysis of the fluid in submarine methane leakage areas. The functions of the mobile detecting system are verified by a sets of laboratory tests, which can conduct in-situ detecting and sampling (pore water and sediment) under 4500 m water depth. The proposed detecting platform can provide important technical support for evaluating and detecting the environmental impacts of the methane leakage area and cold seeps.
Methane seepage is closely related to gas hydrate resources and can cause complex ecological effects (Phrampus, BJ, 2012). It has important resource and environmental research significance. As the gate for methane seepage to the ocean, the seawater-sediment interface is the area where the physical, chemical and biological characteristics of the ocean change the most. The rising methane undergoes a series of biogeochemical reactions at this interface, which significantly changes the marine environment (Michaelis, W,2002). The interface is the best carrier for methane seepage research. International research on methane seepage on this interface is mainly based on fixed-point long-term monitoring (Santschi, P, 1990), but the detection of regional methane seepage is relatively blank (Feng, D, 2018). The reason is that the mobile detection and high-fidelity sampling technology of this interface are relatively scarce, and the related fluid testing technology It is also relatively weak, which limits the in-depth study of the evolution of the geological environment system in the methane seepage area (Himmler, T, 2013). The earliest mobile underwater detection platform developed in the world is the Detroit Rover of the United States, which can last up to 6 months under the sea (Faure, K,2010). The Phoenix mobile detection platform developed by Japan has a diving depth of up to 8178m (Liang, Q, 2017). Compared with the current ROV system, the underwater mobile detection platform can realize flexible and convenient mobile detection (Tryon, MD, 1999). At present, there are few researches on mobile detection platforms that can be used on the seabed. Therefore, the development of a mobile detection platform equipped with various sensors such as methane, carbon dioxide, dissolved oxygen, temperature and salt depth, and fidelity sampling system and testing technology for the seawater-sediment interface, in-depth understanding of regional methane seepage flux and its impact on the ocean The environmental impact mechanism can make up for the blank of ocean exploration technology and provide important support for cold spring research and environmental monitoring of hydrate trial mining (Leifera, I, 2005).
