Assalamu alaikum warahmatullah.
The ocean is made up of 60 different chemical elements that give it its salty taste. The main ingrients, chlorine, sodium, sulphate, magnesium, calcium, and potassium, come mostly from river sediments and are dumped into the ocean.
The temperature of the water differs according to the intensity of the sun’s rays hitting it. The surface of water is warmer than that at a great depth.
The colours that make up sunlight are absorbed in different ways by water particles. Red yellow and orange cannot penetrate (go in) more than a few feet below the surface of the water. But blue can penetrate more than 800 feet. That is why the ocean appears blue.
Sometimes water looks green. That is because it contains lots of little tiny plants called phytoplankton. Water puts pressure on the human body. The deeper we go the greater the pressure. The black sea and the yellow sea got their names from the colour of sediment floating in their water and lying on their beds.
Source: Tell me what book.
I hope you found this information useful inshallah!