Pacific Ocean both the Water Hemisphere and the Western Hemisphere are in the Pacific Ocean. The equator subdivides it into the North Pacific Ocean and South Pacific Ocean, with two exceptions: the Galápagos and Gilbert Islands, while straddling the equator, are deemed wholly within the South Pacific. Its mean depth is . The Mariana Trench in the western North Pacific is the deepest point in the world, reaching a depth of . The western Pacific has many peripheral seas. Though the peoples of Asia and Oceania have traveled the Pacific Ocean since prehistoric times, the eastern Pacific was first sighted by Europeans
World Ocean Database Project released approximately every four years, 1998, 2001, and 2005. The most recent World Ocean Database series, WOD09, was released in September 2009. The WOD09 has more than 9 million temperature profiles and 3.6 million salinity profiles. The table shows a comparison of the number of stations by instrument type in WOD09 with previous NODC/WDC global ocean databases. Ocean profile, plankton data, and metadata are available in the World Ocean Database for 29 depth-dependent variables (physical and biochemical) and 11 instruments types: Ocean Station Data (OSD), Mechanical Bathythermograph (MBT), Expendable Bathythermograph (XBT), Conductivity, Temperature, Depth (CTD), Undulating Oceanographic Recorder (UOR), Profiling