The Labrador Sea Is the Hidden Oxygen Pipeline for the Deep North Atlantic

Researchers from Cornell University have identified the Labrador Sea, tucked between Greenland and Newfoundland, as the primary oxygen source sustaining deep-sea life across a vast stretch of the North Atlantic. The study, published in Nature Geoscience on August 17, 2026, found that the sea exports enough oxygen to meet the biological needs of ecosystems far beyond its own waters.

In the Labrador Sea, waters from the Atlantic Meridional Overturning Circulation (AMOC), the ocean's major current system, turn in a gyre where oxygen-rich surface water mixes with deeper water. Earlier research had found the Labrador Sea has little effect on the overall strength of AMOC, but the new study shows it plays a critical role in carrying oxygen into the deep ocean.

"We found that the Labrador Sea exports enough oxygen to meet the biological need across a vast part of the deep North Atlantic Ocean, so it's very likely crucial to sustain these deep-sea ecosystems," said first author Una Miller, assistant professor of earth and atmospheric sciences at Cornell. The team attached 60 oxygen sensors to seafloor moorings in the Labrador and western Irminger seas, the first sustained multi-year measurements of their kind, and used machine learning to fill gaps in the data.

In most of the ocean, water layers at different temperatures and densities do not mix, so oxygen from the air largely stays near the surface. But in the Labrador Sea, currents become colder and denser and sink, carrying oxygen and carbon into the deep Atlantic as the lower limb of AMOC.

The researchers calculated that Labrador Sea waters carry more than 27 teramoles of oxygen into the deep ocean each year, enough to sustain human breathing for everyone on Earth for at least two months. That amount matches the estimated respiration rates of microbes and animals across the North Atlantic deep sea, a match the team says strongly suggests deep-sea life depends on the Labrador Sea.