This occurs because the Earth is tilted on an axis.
at mid ocean ridges
New crust is created as the plates are drawn apart.
Magma is extruded as lava at the mid-ocean ridges when they are pulled apart.
at the bottom of the ocean
Mid-Ocean Trench
For the same reason they are in no other ocean, there is no requirement for them.
because they arent in an endangered sea/ocean
at mid ocean ridges
An Ocean Apart - 2004 was released on: USA: 15 October 2004
The cast of An Ocean Apart - 1988 includes: David Dimbleby as Himself, Presenter
The Indian Ocean, as the Strait of Malacca joins the Indian Ocean to the Pacific, and Somalia has a coastline on the Indian Ocean. Apart from that they are a few thousand miles apart.
Siberia
Africa and Ireland are a long way apart, and are not exactly separated by a sea. To travel from Ireland to Africa by water, you would go through part of the Atlantic Ocean.
New crust is created as the plates are drawn apart.
Because as tectonic plates move away from each other, the ocean floor spreads apart and fills the gap.
Magma is extruded as lava at the mid-ocean ridges when they are pulled apart.
New ocean crust is formed at mid-ocean ridges where tectonic plates are diverging (spreading apart).