Insights into the impact of melting mega-icebergs with robotic gliders
The vast, icy expanse of the Southern Ocean has long been shrouded in mystery, its secrets hidden beneath layers of freezing water and colossal ice formations. But now, a team of intrepid scientists has embarked on a groundbreaking mission to unravel the mysteries lurking beneath the surface.
Imagine being aboard the RRS James Cook, surrounded by nothing but frigid waters and towering icebergs as far as the eye can see. This was the reality for researchers from the British Antarctic Survey (BAS) and the National Oceanography Centre (NOC) as they set out to explore one of the world’s largest icebergs, A-68a, near South Georgia.
Gathering data in such extreme conditions is no easy feat. Large icebergs like A-68a move unpredictably, making it challenging for traditional research vessels to get up close. However, armed with cutting-edge robotic gliders, the team dove headfirst into this icy realm, collecting vital information on everything from salinity and temperature to chlorophyll levels and optical backscatter.
“We think this is the first time measurements have been made so close to an iceberg – so it’s really ground-breaking stuff! It was just really exciting to see the data come back and see how the ocean was changing so drastically.” ~ Natasha Lucas
As they delved deeper into their research, a remarkable discovery emerged. The melting process at the base of these massive ice structures was not only reshaping the physical landscape but also triggering a cascade of events that rippled across the ecosystem. Known as basal melting, this phenomenon eroded a crucial layer of “Winter Water,” disrupting established barriers between surface and deep-sea environments.
By breaching this natural divide, nutrient-rich waters surged upwards, carrying essential elements like iron and silica from the melting iceberg. These nutrients acted as catalysts for primary productivity, fueling a thriving ecosystem teeming with life in an otherwise desolate seascape.
Natasha Lucas, a pioneering physical oceanographer leading this expedition, shared her awe at witnessing these transformative processes firsthand. Despite facing numerous challenges – including losing one glider and battling against A-68a’s unpredictable movements – Lucas and her team emerged triumphant after 17 days with a trove of invaluable data that shed light on Earth’s delicate balance.
“This ultimately impacts how much heat and carbon is exchanged between our ocean and atmosphere.” ~ Natasha Lucas
But their journey didn’t end there. Since A-68a’s dramatic calving in 2021, more behemoth icebergs have drifted towards South Georgia, including A-23a which recently grounded on its continental shelf. Researchers aboard RRS Sir David Attenborough seized this opportunity during BIOPOLE 2 science mission to gather samples from A-23a for further analysis back in their UK laboratories.
In their landmark study published in Nature Geoscience – “Giant iceberg meltwater increases upper-ocean stratification and vertical mixing” – Natasha Lucas et al., unraveled key insights shaping our understanding of climate change’s intricate web within Antarctica’s frozen domain.
Embark on this extraordinary scientific voyage where every turn reveals new wonders hidden beneath polar waters; where each discovery brings us closer to deciphering nature’s cryptic language written in ice.
Leave feedback about this