Are there water molecules in the oceans which will almost never fall down as rain?

Question

Some oceans are very deep. But is there also current (convection) deep in the ocean so that all water molecules will ones be evaporated and fall down as rain or is it very quite at the bottom so some water molecules will stay at the bottom for decades?

Answer 1

Ocean currents are a convective process, but they tend to not pull water up from the bottom to the top (heat rise and cold sink like a normal convective cell) because the heat source is predominately the sun. Some of the water doesn't just stay at the bottom for decades, but instead centuries.