An international team of researchers, led by British Antarctic Survey (BAS), is setting out to discover how glacier calving around Antarctica can trigger powerful underwater tsunamis.
When icebergs break off glacier fronts and fall into the ocean (a process called calving) they can create powerful underwater tsunamis. These hidden waves, often several metres in height, cause powerful bursts of ocean mixing, where different layers of water get churned together. This process strongly mixes heat, oxygen and nutrients between different depths, and is critical for marine life and climate regulation in the region.
This mixing was previously thought to be primarily driven by wind, tides and heat loss at the ocean surface. However, initial calculations suggest underwater tsunamis play a significant role in polar oceans, rivalling the effect of wind-driven mixing in certain locations, and having a bigger impact than tides in redistributing heat in the ocean.
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Underwater tsunamis, and the resulting mixing, could have significant implications for the Southern Ocean and beyond. Increased ocean mixing could draw more warm water up from the deeper parts of the ocean, speeding up the melting of the Antarctic Ice Sheet which would raise sea levels around the world. It can also change how nutrients are distributed in the ocean, which would affect the growth of phytoplankton (the “grass of the sea”), with consequences for the rest of the ocean food chain.
“Antarctica remains one of the most mysterious places on Earth, and we’re constantly discovering previously unknown processes that are shaping our planet. What makes this research so important is that everything in Antarctica is connected – ice, ocean and atmosphere – and those connections reach all the way back to our doorsteps. Rising sea levels, shifting weather patterns, these are Antarctic processes playing out in our lives.”
A key question going forward is understanding whether the current warming climate might increase how often these calving and tsunami events occur, and how strong they are. By learning more about this phenomenon, scientists will refine the ocean models that predict how climate will change in the future.
Retired, living in the Scottish Borders after living most of my life in cities in England. I can now indulge my interest in all aspects of living close to nature in a wild landscape. I live on what was once the Iapetus Ocean which took millions of years to travel from the Southern Hemisphere to here in the Northern Hemisphere. That set me thinking and questioning and seeking answers.
In 1998 I co-wrote Millennium Countdown (US)/ A Business Guide to the Year 2000 (UK) see https://www.abebooks.co.uk/products/isbn/9780749427917
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