Recent
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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e360-Yale
A Dangerous Climate Feedback Loop
When the ocean stores less carbon, it loses some of its capacity to buffer the planet from climate change. This creates a concerning feedback loop that could intensify warming trends.
Amplifying Global Warming
Less carbon sinking to the deep sea means more CO₂ remains in the upper ocean and atmosphere. This reduction in the planet's natural carbon sequestration service leaves humanity facing an even greater challenge in stabilizing the climate.
"The failure of carbon to reach deep layers could mean more CO₂ remains in the atmosphere or upper ocean, amplifying global warming," one of the key findings highlights.
The Urgent Need for Observation
Researchers stress that the findings underscore an urgent need for continuous and collaborative ocean observation. Tracking these complex changes is essential for understanding their full impact and developing effective climate adaptation strategies. The ongoing monitoring by agencies like NOAA provides critical data for forecasting and responding to these events.
How do marine heatwaves impact the ocean's ability to store carbon?
They alter plankton communities, favoring smaller species that don't sink efficiently. This prevents organic matter from carrying carbon to the deep ocean for long-term storage, effectively weakening the ocean's 'biological carbon pump.'
What are the long-term effects of marine heatwaves on ocean ecosystems?
How do marine heatwaves affect commercial fisheries in the Gulf of Alaska?
What measures can be taken to mitigate the effects of marine heatwaves?
How do marine heatwaves influence climate feedbacks?
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