Ocean Eddies Play Minor Role in Carbon Transport, Study Finds

Ocean Eddies and the Biological Carbon Pump

The biological carbon pump is a critical oceanic process that moves carbon from the surface to deeper waters, helping maintain the ocean’s capacity to absorb atmospheric carbon dioxide. Among the mechanisms driving this pump are eddies—small-scale, circular water currents generated by physical instabilities in the ocean.

Eddies’ Role in Carbon Transport: A Global Analysis

Previous studies suggested that eddies might play a significant role in carbon subduction, but the lack of global data left this question unresolved. Now, researchers have used a worldwide network of remote sensors to capture eddy-driven carbon transport in action.

The team, led by Keutgen De Greef, analyzed data from 941 autonomous Argo floats collected between 2010 and 2024. Their findings indicate that eddies contribute less than 5% of the total organic carbon transported by the biological carbon pump, making them a secondary factor in ocean carbon flows.

Key Findings from the Study

• Carbon Export Estimates: The eddy subduction pump exports approximately 0.05 petagrams (50 million metric tons) of carbon per year from the ocean surface.
• Hot Spots Identified: Carbon subduction hot spots were found in the mid- to high latitudes of the Southern Ocean and the subpolar North Atlantic, with a strong seasonal peak in spring.
• Mechanisms Revealed: The study identified a correlation between eddy kinetic energy and physical subduction events, where surface waters sink below the mixed layer.

Study Limitations and Future Research

While the research provides valuable insights, it also highlights data gaps in regions such as the Pacific, South Atlantic, and southern Indian Ocean. These areas may have underestimated contributions due to sparse data collection.

The Argo floats used in the study measure particulate carbon levels but cannot effectively capture dissolved organic carbon, meaning some carbon export may be overlooked. However, the authors suggest that these limitations likely do not significantly alter the overall estimate of biological carbon subduction, given the minimal role of eddies in the process.

Expert Perspective

"The eddy subduction pump carries less than 5% of the overall organic carbon transported by the biological carbon pump, meaning it’s of secondary importance to understanding ocean carbon flows."

—Keutgen De Greef et al., Global Biogeochemical Cycles

Citation and Publication Details

This study was published in Global Biogeochemical Cycles on April 17, 2026, with the DOI: 10.1029/2025GB008912. The research was conducted by Keutgen De Greef and colleagues, with additional commentary provided by Science Writer Nathaniel Scharping.

© 2026. American Geophysical Union (AGU). Text is licensed under CC BY-NC-ND 3.0. Images are subject to copyright unless otherwise noted.