-Modern oceanography began with the Challenger Expedition between 1872 and 1876. It was the first expedition organized specifically to gather data on a wide range of ocean features, including ocean temperatures seawater chemistry, currents, marine life, and the geology of the seafloor.
- discoveries was one of the deepest parts of the ocean -- the Marianas Trench in the western Pacific, where the seafloor is 26,850 feet, or more than 4 miles deep (8,200 meters). The deepest place in all the oceans is near where the Challenger took its sounding. It is now called the Challenger Deep and it is 37,800 feet deep (11,524 meters). The expedition also revealed the first broad outline of the shape of the ocean basin, including a rise in the middle of the Atlantic Ocean that we now know is the Mid-Atlantic Ridge. Scientists compiled the first systematic plots of currents and temperatures in the oceans