Marine Heatwaves and Carbon Transport
Marine heatwaves are changing our oceans in significant ways. New research shows that these extreme heat events disrupt the natural processes that move carbon from the ocean’s surface down to the deep sea. This slowdown puts the planet at risk by impairing one of our key methods for storing carbon.
The study, led by Mariana Bif, an assistant professor at the University of Miami, involved a collaboration with several institutions, including the Monterey Bay Aquarium Research Institute. It was published on October 6 in Nature Communications.
Bif explains, “The ocean has a biological carbon pump that typically moves carbon like a conveyor belt from the surface to deeper waters.” The research found that when marine heatwaves occur, they disrupt the plankton at the base of the ocean food web. This disruption jams the conveyor belt, preventing carbon from sinking deep where it can stay locked away for centuries.
To understand this impact, scientists used data from robotic floats and long-term ocean observation programs. They looked at how marine heatwaves from 2013-2015 and 2019-2020 affected plankton and carbon cycles.
During the 2013-2015 heatwave, photosynthetic plankton produced a lot of surface carbon. However, rather than sinking quickly to the deep ocean, this carbon got stuck around 200 meters down. In the 2019-2020 heatwave, carbon particles built up at the surface due to both plankton recycling and organic waste. These particles then lingered in the “twilight zone” of the ocean instead of diving deeper.
Different heatwaves had different effects. For instance, the increase in smaller grazers during these events slowed down the sinking process. As a result, more carbon stayed near the surface, leading to a higher chance of it returning to the atmosphere instead of being stored long-term.
“We found that not all marine heatwaves are created equal,” Bif noted. “Different plankton respond differently, affecting how the ocean sequesters carbon.” This reflects a broader understanding of the complexity of marine ecosystems and emphasizes the need for monitoring their health.
Statistics show that marine heatwaves are becoming more frequent and intense. In fact, a recent report from the National Oceanic and Atmospheric Administration (NOAA) found that the number of marine heatwave days has increased by around 50% over the last century. This trend threatens marine life, fisheries, and even our climate stability.
Experts stress the importance of studying these changes in more depth. Ken Johnson, a senior scientist at MBARI, added, “This research brings a fresh perspective to ocean monitoring, demonstrating how advanced technologies can provide a comprehensive view of how ocean processes change after extreme events.”
As our oceans continue to warm, the ability to track and understand these shifts is vital for protecting our planet’s future.
For more insights on marine studies, you can check the Nature Communications article.
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carbon cycling,Global warming,marine heatwaves,Monterey Bay Aquarium Research Institute (MBARI),ocean food webs,plankton,University of Miami
