A depth that is equivalent to one atmosphere in the ocean is equal to how many feet (meters) in seawater and freshwater?

One atmosphere of pressure is approximately equivalent to the pressure exerted by a column of water 33 feet (10 meters) deep in seawater, and about 34 feet (10.4 meters) deep in freshwater. This difference arises due to the varying densities of seawater and freshwater.

Seawater is denser than freshwater because of the dissolved salts it contains, leading to a greater weight of seawater per unit volume. As a result, less depth in seawater is required to reach the same pressure as in freshwater. Thus, at a depth of 33 feet, you experience one atmosphere of pressure in seawater, while it takes slightly more depth in freshwater—around 34 feet—to experience the same pressure.

Understanding this difference is crucial for divers, as it affects how they plan their dives and manage pressure-related issues such as buoyancy and decompression. Therefore, the correct answer reflects the accurate relationship between depth and pressure for both types of water.