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 World Ocean Database Project The World Ocean Database Project, or WOD, is a project established by the Intergovernmental Oceanographic Commission (IOC). The project leader is Sydney Levitus who is director of the International Council for Science (ICSU) World Data Center (WDC) for Oceanography, Silver Spring. In recognition of the success of the IOC Global Oceanographic Data Archaeological and Rescue Project (GODAR project), a proposal was presented at the 16th Session of the Committee on International Oceanographic Data and Information Exchange (IODE), which was held in Lisbon, Portugal, in October–November 2000, to establish the World Ocean Database Project. This project is