Couple of explanations. 1) The sun warms the upper layer of water. 2) The suns warmth doesn't reach much below 20 or so feet 3) In most cases, the water circulates from bottom to top and back down again - the cold water rises and gets warmer as it does, the warm water falls and gets colder.
The coldest water in the ocean is the bottom of the ocean.
The ocean floor
On The Ocean Bottom.
Cold water always sinks.
The opposite of bottom would be the top, so the oceans surface is the opposite of the ocean floor/bottom.
The Arctic Ocean is the coldest as well as the smallest ocean.
the coldest ocean in the world is the Arctic Ocean
What is the 3rd coldest ocean
Cold water sinks, while warm water rises.
sea floor
The sea floor, or sea bed.
A spiny-skinned invertebrate that lives on the ocean bottom floor is called a sea urchin.