The ocean has a salt concentration of approximately 3.5%. The addition of salt in the water makes its density higher in comparison to freshwater. Higher density means that things submerged will in turn be more boyant. An increased boyancy helps to support the body weight of larger animals such as whales that would collapse under their own weight on land. 

The freezing point of salt water is lower than that of pure water due to a phenomenon called freezing point depression. This happens because adding salt (or any solute) to water disrupts the ability of water molecules to form the organized, crystalline structure of ice. when salt water freezes it goes through a process called brine rejection where the salts are expelled as they do not fit in the crystalline structure of ice. 

The concentration of salt in the ocean also allows for the increased absorption and storage of heat. Additionally factors such as the Ocean's large surface area, Ocean currents and Thermal stratification (layers of different temperatures) all account for the ocean's great ability to absorb heat.

Water is often called the universal solvent because it can dissolve more substances than any other liquid. This ability comes from its unique chemical structure: water molecules have a polar arrangement, with a slightly positive charge on the hydrogen atoms and a slightly negative charge on the oxygen atom. This polarity allows water to interact with various ions and molecules, breaking them apart and allowing them to mix or dissolve in water