ITHACA, N.Y. - Researchers from Cornell University have pinpointed the source of oxygen that sustains deep sea life in the North Atlantic Ocean: the churning waters in the Labrador Sea.
The study , published in Nature Geoscience on August 17, gives heightened significance to the Labrador Sea, sandwiched between Greenland and Newfoundland. There, waters from the Atlantic Meridional Overturning Circulation (AMOC), the ocean’s major current system, turn in a gyre, and oxygen-rich surface waters mix with deeper waters. Previous research had found that the Labrador Sea has little impact on the strength of AMOC, but the study finds it plays a critical role in oxygen transport.
The research also sheds light on processes that may be helping the North Atlantic maintain its oxygen levels, as oxygen declines in oceans globally due to warming temperatures.
“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. “Our finding shows that if we’re going to understand the future, especially in the face of these deoxygenation trends, you can’t just look at the strength of AMOC, you also have to understand processes in the Labrador Sea.”
The study comes amid debate about the vulnerability of AMOC, as the current has weakened over the last 75 years. Scientists have warned that a collapse of the system could cause major disruption in weather and devastate ecosystems.
Miller, working with a large team of, used data from 60 oxygen sensors attached for the first time to moorings that run along the bottom of the Labrador and western Irminger seas.
The researchers were able to quantify the amount of oxygen the Labrador Sea waters carry, enough oxygen to sustain breathing for every person on earth for at least two months. The team found that the amount of oxygen matches estimates of the respiration rates of microbes and animals across the North Atlantic deep sea. The correlation strongly suggests deep sea life relies on the Labrador Sea, which is one of very few regions where this mixing of waters occurs.
Many questions remain about the relationship between the strength of AMOC and oxygenation processes, and what would happen if one or both were to weaken. Miller is continuing to study oxygenation in the Southern Ocean, around Antarctica, another critical region where the surface ocean connects to the deep ocean.
Funding for the study came from the National Science Foundation, the National Oceanic and Atmospheric Administration, the Canada Excellence Chair in Ocean Science and Technology and the Canada First Research Excellence Fund.
For additional information, read this Cornell Chronicle story.
Cornell University has dedicated television and audio studios available for media interviews.
-30-
Nature Geoscience