The Research On Technology Of The Deep-Sea Stratified Sampling

Deep sea is a dark and oligotrophic environment with high-pressure and low temperature. Gas components in deep seawater reflect deep-sea resource reserves to a certain extent. The trace of abnormal distribution of gas concentrations in the seawater helps to identify the submarine hydrothermal activity and look for Marine resources such as gas hydrate. Deep sea is also a treasure trove of natural medicines, including very specific biological structures, genes, metabolic regulation mechanisms and metabolites which the above-ground biomasses do not have. These are important sources to develop new biologically active substances. So it is of great importance to sample deep-sea resource.The thesis is based on the gas-tight water sampling system developed by Zhejiang University. Firstly, a floating self-locking mechanism of which the structure is simple was designed to improve the capability of resist pressure and tightness. Laboratory experiments and sea trials indicated that the pressure-resistance and gas tightness of the sampler was improved dramatically by the floating self-locking mechanisms. The sampler with self-locking mechanism provides the necessary technical support for the exploration and analysis of deep-sea resources. Secondly, two types design principles of multi-channel reversing valve were elaborated. The sealing performance of multi-channel reversing valve with planar seal was analyzed, and it came to the conclusion that its seal ability was proportional to the external load of seal surface and the torque for turning was also proportional to the external load of the distributors. For the multi-channel reversing valve with clearance seal, the cross-contamination caused by the tap between the valve core and valve body was analyzed with related theories and flow field, and the advantages and disadvantages of the two types of deep-sea stratified sampling system for micro-organisms based on these valves were discussed. In the end, a communication circuit was designed to solve the communication problems between the upper computer and the lower computer when the deep-sea microbial stratified sampler is integrated into the gas-tight water sampling systems. It provides us with technical reference for equipping Conductivity, Temperature, and Pressure Recorder (CTD) with types of samplers to sample.