Conductivity-Temperature-Depth (CTD) observations were made from the DSSV Pressure Drop using full-depth hadal landers at sixteen of the world's trenches between 2018 and 2022. Data was collected using an SBE-49 FastCat and post-processed using the SBE Data Processing software and TEOS-10 equations. Trenches include the South Sandwich Trench, Java Trench, Tonga Trench, Kermadec Trench, New Hebrides Trench, Santa Cruz Trench, San Cristobal Trench, Mariana Trench, Yap Trench, Palau Trench, Philippine Trench, Ryukyu Trench, Izu-Ogasawara Trench, Japan Trench, Atacama Trench and the Puerto Rico Trench. The data was collected as part of the Five Deeps Expedition and the Ring of Fire Expedition to map the deepest points of the world alongside increasing our understanding of hadopelagic and trench biology and physical conditions.

CTD casts are split into the down-profile (10 dbar bins) and for the time while the CTD was on the seafloor. The latter is indicated by the word bottom in event name.