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 Atlas World Ocean Atlas The World Ocean Atlas (WOA) is a data product of the Ocean Climate Laboratory of the National Oceanographic Data Center (U.S.). The WOA consists of a climatology of fields of "in situ" ocean properties for the World Ocean. It was first produced in 1994 (based on the earlier "Climatological Atlas of the World Ocean"), with later editions at roughly four year intervals in 1998, 2001, 2005, 2009, and 2013. The fields that make up the WOA dataset consist of objectively-analysed global grids at 1° spatial resolution. The fields are three-dimensional, and data are typically interpolated onto 33