At 5,100 meters above sea level, this settlement is the highest permanent place humans live on Earth. Oxygen levels are ...

Seals may be able to directly sense oxygen levels in their blood, an ability humans don't possess. A Scottish study reveals these marine mammals adjust their dives based on this vital parameter.

Rivers, streams, lakes, and reservoirs aren't just scenic parts of our landscape -- they're also vital engines for life on Earth. These inland waters 'breathe' oxygen, just like we do. But a new study ...

New research shows ancient tropical oceans once held more oxygen than cooler regions, reshaping where early life could ...