Originally posted on the BAS website

15 January, 2026 Press releases

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.  

This newly discovered phenomenon was observed by chance when researchers aboard BAS’ previous research ship, RRS James Clark Ross, collected ocean data before, during and after a calving event during an expedition to Antarctica. Now, scientists are at Rothera Research Station, on the Antarctic Peninsula, and on board the UK’s polar research ship RRS Sir David Attenborough to learn more about underwater tsunamis. 

Professor Michael Meredith, an oceanographer at BAS, is leading the research. He said: 

“We want to learn what creates underwater tsunamis, how they work, and what impact they have – do different types of calving cause differences in the tsunami? Do the different conditions in each season change how the tsunamis form? What does the mixing that they cause do to the polar climate and ecosystems?”  

Using satellites, remote cameras, drones and underwater robots, the team will collect data from glacier fronts, including locations too dangerous for researchers to go. They will develop and apply deep-learning algorithms to analyse satellite data, and computer simulations to model how these tsunamis are generated and spread. From this, the researchers will assess the impacts of these intense bursts of mixing on ocean temperature, nutrients and marine productivity – all of which are critical to our climate and ecosystems.  

Dr Alexander Brearley is an oceanographer at BAS who studies ocean mixing. He is currently at Rothera Research Station using an autonomous underwater vehicle to study the front of the nearby Sheldon Glacier. He said: 

“Our team is deploying a range of cutting-edge air, land-based and ocean technology to understand individual glacier calving events at unprecedented resolution and detail, and the impact the tsunamis that are generated have on the ocean. This includes high-quality imagery of the front of the glacier in real-time, ocean moorings with instruments to study the individual waves generated by calving, and underwater autonomous vehicles to document the physical and biological impacts of these underwater tsunamis.”

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. 

Professor Kate Hendry is a chemical oceanographer at BAS. She said: 

“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. 

The POLOMINTS project is a collaboration led by British Antarctic Survey, and includes the Scottish Association for Marine Science, the University of Southampton, the University of Leeds, the National Oceanography Centre, the University of Exeter, and Bangor University. International partners are from the Scripps Institution of Oceanography (USA), the Institute of Geophysics of the Polish Academy of Sciences (Poland), the University of Delaware, and Tufts University (both USA). 

POLOMINTS is funded by the Natural Environment Research Council (nerc.ac.uk) 

Originally posted on the BAS website

29 July, 2024 Arctic

You might imagine glaciers as vast, cold, and lifeless rivers of ice, but they’re far more dynamic and alive than we once thought. Kate Hendry, polar oceanographer at British Antarctic Survey is currently working in the Arctic. Below, she shares some insights from her recent research on these frozen rivers, and their impact on our oceans.

Glaciers – vast rivers of ice that flow from ice caps and ice sheets – were once thought to be inert environments, too cold for biology or for chemical reactions to occur. In the past two decades, scientists have discovered that glaciers are teeming with diverse microorganisms and are hotspots for biogeochemical weathering—chemical processes that release essential elements into the environment. As glaciers flow, they grind the underlying rock into a fine “flour,” and the unique chemistry of the waters beneath these ice sheets leads to the formation of new, highly reactive materials. This glacial flour can release nutrients into the environment, acting as a significant source of precious elements for coastal marine ecosystems. While glacial flour has the potential to fertilize crops, it can also harbour toxic metals. We are just beginning to unravel the intricate web of interactions among these elements as they travel downstream.

Unveiling the role of silicon

One key nutrient we’re focusing on in our new project, Silicon Cycling in Glaciated Environments (SiCLING), is silicon. Every living organism needs silicon in small amounts, but some, like plants and diatoms (a type of algae), need larger quantities to build their silica-based structures. Glacial flour is rich in reactive detritus that dissolves, releasing biologically available silicon. This means it could be a vital nutrient source for crops and coastal marine systems deficient in silicon.

Through SiCLING, we’re investigating how silicon in glacial flour and fjord sediments is released, interacts with other elements like iron, and changes with global warming and accelerated ice melting.

Our journey begins in Ny-Ålesund, northern Svalbard, in the land of the polar bear. Here, we’re sampling water, flour, and sediments from Kongsfjorden near the UK Arctic Research Station. Using small boats, we collect samples and process them in the station’s labs. Many analyses will be done back in the UK, where we’ll use cutting-edge imaging and geochemical fingerprinting to understand silicon’s interactions with other elements. With all the data we gather, we’ll use new modeling methods to calculate how much silicon glaciers in Svalbard release.

Later this year, we will continue our fieldwork adventure by comparing our Arctic findings to coastal environments off the West Antarctic Peninsula.

Meet the team

I am proud to lead the SiCLING project as the Deputy Science Leader of the Polar Oceans Team at the British Antarctic Survey. Joining me in Ny-Ålesund are Nathan Callaghan from the UK Centre for Ecology and Hydrology and Katie Howe from Dauphin Island Sea Lab, USA. Nathan is working on river chemistry and fluxes, and Katie is joining us as an expert in isotope uptake experiments. Our team also includes Rhiannon Jones and Siobhán Foden from BAS, and Helen Williams, and Helena Pryer from the University of Cambridge.

We’re thrilled to share our progress with you as we delve deeper into the fascinating world of glacial biogeochemistry. If you’re curious to learn more about our findings on silicon and glaciers, check out our latest paper: Detrital input sustains diatom production off a glaciated Arctic coast.