Greenland Seaweed Forests Trap Carbon in Deep Ocean

Scientists just mapped an underwater carbon-trapping system that could change how we fight climate change, and it's been working quietly beneath coastal waters all along.

An international research team tracked 8,000 seaweed rafts off southwest Greenland using satellites and ocean monitors. They discovered something remarkable: offshore currents carry these massive seaweeds hundreds of kilometers from shore before cold surface waters pull them deep underwater.

The seaweed, called macroalgae, absorbs huge amounts of carbon dioxide from the atmosphere as it grows. When it sinks, it carries that carbon to the deep ocean where it stays locked away for at least a century.

Scientists from Germany, Portugal, Saudi Arabia, Denmark and the UK collaborated on the groundbreaking study. They used satellite imagery, computer models and ocean current tracking devices to follow the seaweed's journey for the first time.

Previous research estimated between 4 million and 44 million tonnes of seaweed-derived carbon sink into ocean depths up to 200 meters each year. This new tracking data confirms these coastal forests play a much bigger role in storing carbon than scientists realized.

"Our findings illustrate a tangible oceanic conveyor belt that links thriving coastal macroalgal forests with the deep ocean's carbon reservoir," said Professor Ana Queirós, marine climate change ecologist at Plymouth Marine Laboratory. She leads climate change research at the lab and helped design the tracking system.

The Ripple Effect

This discovery means protecting and expanding coastal seaweed forests could become a powerful natural climate solution. Unlike human-made carbon capture technology that costs billions, these underwater forests do the work for free.

The research also helps scientists understand where else this natural carbon transport might be happening. Coastal waters around the world likely host similar seaweed conveyor belts moving carbon from the atmosphere to safe storage in the deep ocean.

Recognizing these natural pathways changes how we value coastal ecosystems. Every thriving seaweed forest represents a working carbon capture system that's been operating long before humans understood climate change.

The findings give climate scientists a clearer picture of Earth's carbon cycle and where natural solutions already exist. Sometimes the best technology is the one nature designed millions of years ago.