What is the main characteristic of ocean stratification?

The main characteristic of ocean stratification is the layering of water masses. This phenomenon occurs due to differences in temperature, salinity, and density within the ocean. Surface water, which is usually warmer and less dense, tends to float above the colder, denser water found at greater depths. This layering leads to distinct levels within the ocean, which can be categorized into different zones such as the euphotic zone, thermocline, and deep water. Stratification plays a crucial role in marine ecosystems, influencing nutrient distribution, oxygen levels, and the overall productivity of ocean habitats.

In contrast, the movement of large fish schools is not a defining feature of stratification but rather a behavioral aspect of marine life. The presence of plankton blooms relates to nutrient availability and oceanic conditions but is a consequence of stratification rather than a characteristic of it. Formation of underwater volcanoes involves geological processes related to tectonic activity and is unrelated to the stratification of the water column.