2017 – RV "Kexue 3" –– Water samples were collected at the Challenger Deep from 11 layers of the Mariana Trench in March 2017. Seawater samples from 4 to 4,000 m were collected by Niskin Bottles mounted to a Seabird SBE25 CTDs; whereas water samples at depths from 6,050 m to 8,320 m were collected by a self-designed acoustic-controlled full ocean depth water samplers. In this study, scientists studied the RNA of pico- and nano-plankton from the surface to the hadal zone.