Different salt concentrations.
Sea water is denser, not only that, different oceans have different densities.
The movement of water when ocean and fresh water meet is called Density currents.
Objects with densities higher than water will sink. Density is the measure of how much mass is contained in a given volume, so objects with higher densities will displace less water than their own mass which causes them to sink.
The different color variations in ocean water are caused by the presence of various substances such as phytoplankton, sediments, and dissolved organic matter. These substances can absorb and scatter light, leading to different colors in the water.
Water density depends on the temperature. See this table for density.
Light bends or refracts when it goes from water to air because the speed of light is different in the two mediums due to their different densities. This change in speed causes the light to change direction.
Oil and Water
When water of different densities meet, they will initially mix together due to turbulence and movement, but eventually they will separate based on their densities, with the denser water sinking to the bottom and the lighter water rising to the top. This process is known as stratification, where layers of water form based on their density.
Within a Chemistry book that contains a section on the results of laboratory experiments that determine and define these parameters. This section may also list densities of water at different saline concentrations.
When water of different densities come in contact, they do not mix instantly due to the difference in densities. Instead, they form distinct layers with the denser water sinking below the less dense water. Over time, small-scale mixing processes may occur to eventually achieve equilibrium.
Different oils have different densities; usually a bit less than the density of water.
the presence of minerals such as sodium cholride,magnesium etc causes the difference in ocean water ....