North Atlantic Deep Water be detected by its high salinity, high oxygen content, nutrient minima, high C/C, and chlorofluorocarbons (CFCs). CFCs are anthropogenic substances that enter the surface of the ocean from gas exchange with the atmosphere. This distinct composition allows its path to be traced as it mixes with Circumpolar Deep Water (CDW), which in turn fills the deep Indian Ocean and part of the South Pacific. NADW and its formation is essential to the Atlantic Meridional Overturning Circulation (AMOC), which is responsible for transporting large amounts of water, heat, salt, carbon, nutrients and other substances from the Tropical Atlantic to the Mid
Challenger Deep of ± On 31 May 2009 the United States sent the "Nereus" hybrid remotely operated vehicle (HROV) to the Challenger Deep. Nereus thus became the first vehicle to reach the Mariana Trench since 1998 and the deepest-diving vehicle then in operation. Project manager and developer Andy Bowen heralded the achievement as "the start of a new era in ocean exploration". "Nereus", unlike "Kaikō", did not need to be powered or controlled by a cable connected to a ship on the ocean surface. "Nereus" spent over 10 hours at the bottom of the Challenger Deep and measured a depth of at