Density is one of the most important physical properties of ocean water because it influences the movement, structure, and circulation of the world's oceans. The density of seawater depends mainly on temperature, salinity, and pressure. Cold water is denser than warm water, high-salinity water is denser than low-salinity water, and increasing pressure with depth also contributes to greater density. These variations in density control vertical and horizontal water movements, affecting marine ecosystems, climate, and oceanic processes. The significance of ocean water density lies primarily in its role in thermohaline circulation, often referred to as the global ocean conveyor belt. Differences in density cause water masses to sink or rise, creating deep ocean currents that transport heat, nutrients, dissolved oxygen, and carbon dioxide across the globe. This circulation helps regulate Earth's climate by redistributing heat from tropical to polar regions. Dense, cold water formed in polar regions sinks to the ocean floor and slowly flows toward lower latitudes, while warmer surface waters move poleward to replace it. Density also plays a vital role in the formation and stability of ocean layers. Water masses with different densities tend to remain separated, producing stratification. Stable stratification restricts vertical mixing, whereas unstable conditions promote mixing of surface and deeper