Scientists make new discovery of earth’s longest runout sediment flows

These dense, fast-moving underwater flows of sediment and water carve out deep-sea canyons and transport vast amounts of sediment, organic carbon, and nutrients across the ocean floor to the deep-sea.

Until now, it has been difficult to study these flows because they can easily damage monitoring equipment placed in their path.

However, the research team has found a way to safely monitor these currents using seabed seismographs, equipment which is typically used to measure earthquakes.

Revolutionary monitoring technique

Using ocean-bottom seismographs placed outside the destructive path of the turbidity currents, the researchers were able to track the longest runout sediment flows ever recorded on Earth.

These flows travelled over 1,000 kilometres along the Congo Canyon-Channel, offshore West Africa, at speeds of up to 7.6 metres per second.

The flows lasted for more than three weeks, offering valuable new data on their speed, duration, and internal structure.

The researchers explain this new method allows them to safely observe these powerful currents in action without risking the loss of expensive equipment.

This has opened up a whole new world of understanding about how these currents behave over long distances.

Global importance

The study shows that turbidity currents play an essential role in moving organic carbon from rivers into the deep ocean, affecting unique benthic ecosystems and global carbon cycles.

Despite the large amount of seabed erosion that occurred, the front of these massive flows maintained a consistent speed and duration over long distances.

This helps the currents efficiently transport significant amounts of organic carbon, nutrients, and sediment to the ocean floor.

The team’s discovery will improve our understanding of deep-sea sediment transport processes and could help protect undersea communication cables that can be disrupted by these powerful currents.

Find out more

• This research was led by Dr Megan Baker.
• Read the full paper published in Geophysical Research Letters.
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