Oceanography, also called oceanology or marine science, is a huge science considered a branch of the Earth sciences. Oceanography is an interdisciplinary science that uses insights from biology, chemistry, geology, meteorology, and physics to analyze ocean currents, marine ecosystems, ocean storms, waves, ocean plate tectonics, and features of the ocean floor, including exotic biomes such as cold seeps and hydrothermal vents. Modern oceanography began in the 1760s with science-minded explorers such as British James Cook and the French Antoine de Bougainville, who included oceanographic observations in reports of their journeys.
Oceanography is divided into four general categories: biological oceanography (marine oceanography), the study of marine biota and their interactions; chemical oceanography (marine chemistry), which studies the chemistry of the oceans, both past and present, and the way it interacts with the atmosphere and the carbon cycle; geological oceanography (marine geology), which studies the gelological makeup of the ocean floor, including the motion and interaction of various oceanic tectonic plates; and physical oceanography (marine physics), studying the physics of the oceans, including the complex ways that light, sound, and radio waves traverse the ocean. Oceanography is also heavily used in ocean engineering, commercial or scientific ventures involving the construction of oil platforms, ships, harbors, and maybe in the future, floating cities.
Many of the important initial discoveries in oceanography occurred in the mid-19th century. The first modern sounding (exploration with reflecting sound waves) of the deep ocean was conducted by Sir James Clark Ross. Charles Darwin, famous for coming up with the theory of evolution, published some of the first papers on reefs and atolls in the 1830s. The continental shelves, sharp drop-offs usually occurring 80 km (50 mi) offshore worldwide, were discovered in 1850. The presence of continental shelves was eventually used to support theories of continental drift.
Some of the most innovative oceanographical work since WWII has been conducted by deep-sea submersibles, like the famous Alvin, which has been in operation since 1964. Using these submersibles, oceanographers have explored the wreckage of the Titanic, discovered sea floor biomes completely independent of the Sun's light, and reached the lowest point on the Earth's surface, the Challenger Deep in the Marianas Trench of the west Pacific.