Ocean cold as water at greater depths. Below the thermocline, water is very cold, ranging from −1 °C to 3 °C. Because this deep and cold layer contains the bulk of ocean water, the average temperature of the world ocean is 3.9 °C. If a zone undergoes dramatic changes in salinity with depth, it contains a halocline. If a zone undergoes a strong, vertical chemistry gradient with depth, it contains a chemocline. The halocline often coincides with the thermocline, and the combination produces a pronounced pycnocline. The deepest point in the ocean is the Mariana Trench, located in the Pacific Ocean
World Ocean Database Project Projects such as the completed World Ocean Circulation Experiment (WOCE) and Joint Global Ocean Flux Study (JGOFS), as well as currently active programs such as CLIVAR and Argo, (c) International Ocean Data Management Projects such as the IOC/IODE Global Oceanographic Data Archaeology and Rescue Project (GODAR), and (d) Real-time Ocean Observing Systems such as the IOC/IODE Global Temperature-Salinity Profile Project (GTSPP). All ocean data acquired by WDC Silver Spring – USA are considered as part of the WDC archive and are freely available as public domain data. The World Ocean Database was first released in 1994 and updates have been