This includes essential supplies, snacks, any equipment they want and even the air they’ll need to breathe ... the heliox gas gives crews of deep sea submarines a better blood oxygen saturation ...

Scientists discover creatures living beneath the bottom of the sea Scientists discover creatures ... a rare view of a manta ray courtship ritual deep in the sea See a rare view of a manta ray ...

While all that is very cool, there’s one downside to riding in a deep sea submarine ... they want and even the air they’ll need to breathe. When it comes to taking enough air for a trip ...