Structural design and development of a water transfer sample

Abstract Understanding rare suspended particulate matter (including planktonic microorganisms) in the deep ocean is important but difficult to sample, for which we deigned a large-sized in-situ water sampler (200-1000L), i.e., a large volume water transfer system sampler. The system comprises of a deep-ocean pump, a filtering device, data acquisition and control devices, a supporting frame, a power supply component, a connecting mechanism, and a flow meter, etc. The filtering device integrates membranes for three-graded filtration at 0.22, 1, and 5μm, and an additional membrane aperture upon the need. The control device adopts two working modes: depth trigger and time trigger. The system can be added with a CTD and a fluorescence meter, etc. In addition, for a stationed site survey, several sets (such as 3 sets) of the system can be fixed at an interval on the suspension cable to work at different depths simultaneously. The system can be applied for high-level multi-layer filtration to obtain suspended particles. The system has been applied in several marine expeditions. The development of this system provides an ideal tool for deep-ocean in-situ sampling technology in China. The applications of the large volume water transfer system sampler for in-situ sampling in deep-ocean have been launched for a few times. Some interesting phenomena have been discovered and the advantages of in situ sampling are proved.