The Atlantic Ocean, a vast body of water, spans between the Americas to the west and Europe and Africa to the east. It extends from the Arctic Ocean in the north to the Southern Ocean near Antarctica. Its depth reveals a complex and fascinating underwater world.
The Average Depth of the Atlantic Ocean
The Atlantic Ocean has an average depth of approximately 3,646 meters (11,962 feet), including its dependent seas. While this average provides a general understanding, the actual depth varies considerably across the ocean basin. The Atlantic is the second-largest ocean globally, contributing significantly to Earth’s oceanic volume.
Geological Features Influencing Atlantic Depth
The varied depths of the Atlantic Ocean are shaped by prominent geological features on its seafloor. A major influence is the Mid-Atlantic Ridge, an immense underwater mountain range that runs down the center of the ocean. This ridge is a site of active seafloor spreading, where tectonic plates pull apart and new oceanic crust forms, creating a complex topography. It separates the Atlantic into two large troughs, with depths in these basins typically ranging between 3,700 and 5,500 meters (12,000 and 18,000 feet).
Shallower areas include continental shelves, gently sloping platforms extending from landmasses into the ocean. These shelves are relatively shallow, often averaging around 200 meters (660 feet) in depth before descending to deeper regions. Beyond the continental margins, vast, flat, and deep abyssal plains stretch across the ocean floor. These diverse features contribute to the Atlantic’s overall average depth.
Measuring Ocean Depths
Scientists employ various methods to measure ocean depths, a field known as bathymetry. The primary technique is sonar technology, or echo sounding, which uses sound waves transmitted from ships. These sound waves travel through the water, reflect off the seafloor, and return to the ship, with the time taken for the echo to return indicating the depth. Multibeam echosounders, a type of sonar, send out rapid sound waves in a fan-like pattern to scan wider areas of the ocean floor.
Satellite technology also contributes to mapping larger seafloor features by detecting subtle variations in sea surface height. These variations are caused by the gravitational pull of underwater topography, allowing satellites to infer the presence of mountains and valleys on the ocean floor. While sonar provides highly detailed local measurements, satellites offer a broader perspective for mapping extensive oceanic regions.
The Atlantic’s Extreme Depths and Shallowness
The Atlantic Ocean contains points of extreme depth and shallowness that contrast with its average measurement. The deepest known point is the Milwaukee Deep, located within the Puerto Rico Trench, north of the island of Puerto Rico. This submarine depression reaches an approximate depth of 8,380 meters (27,493 feet). The Puerto Rico Trench is about 1,750 kilometers (1,090 miles) long and results from tectonic plate interactions.
In contrast, the Atlantic also features notably shallow areas. Continental shelves, extending from land, are generally shallow, with some coastal regions being less than 100 meters deep. Specific shallow features exist, such as the Gorringe Ridge, located between the Azores and Gibraltar, where some peaks are just 20 to 33 meters (66 to 108 feet) below sea level. These extremes highlight the complex and varied topography beneath the Atlantic’s surface.