Studies in the Gulf of Alaska reveal marine heatwaves are disrupting the ocean's ability to store carbon, threatening a critical climate-regulating process and triggering widespread ecological damage.

October 7, 2025

Source:
MBARI
Ocean's Carbon Pump Under Stress
Recent studies from the Gulf of Alaska reveal a critical climate-regulating mechanism is faltering. Marine heatwaves are disrupting the ocean's "biological carbon pump," a natural process that sends atmospheric carbon to the deep sea for long-term storage.
This disruption means more carbon dioxide could remain near the surface or in the atmosphere, potentially accelerating global warming.
Defining Marine Heatwaves
A marine heatwave is a prolonged period of unusually high ocean temperatures, where the water temperature exceeds the 90th percentile of historical records for at least five consecutive days. These events are becoming more frequent and intense.
A Spreading Global Problem
The issue extends far beyond Alaska. According to the NOAA Physical Sciences Laboratory, as of August 2025, approximately 26% of the global ocean surface is experiencing marine heatwave conditions. The North Pacific, in particular, shows significant and persistent warming.
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Source:
ScienceDaily
Ecosystems and Circulation Disrupted
The impacts of these heatwaves are twofold, affecting both the physical movement of water and the biological communities within it.
Weakened Ocean Currents
Research published in Nature shows that heatwaves in the Gulf of Alaska have suppressed ocean circulation. Key findings include:
Altered Plankton: The heat favors smaller plankton species that are less effective at sinking. As a result, the carbon they absorb stays in the upper ocean instead of being sequestered.
Suppressed Vortices: Large, rotating water masses known as anticyclonic vortices, which are vital for nutrient and carbon transport, have been weakened.
Widespread Damage to Wildlife
The ecological consequences are already severe. The U.S. Geological Survey has documented mass die-offs of seabirds, including the Common Murre, following the 2014-2016 “Blob” heatwave. These events signal a food web in crisis, with significant implications for commercial fisheries that depend on a stable marine environment.
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Source:
e360-Yale
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