The world’s largest and oldest iceberg, A23a, has been on the move again after being stationary for several months, according to several reports. The British Antarctic Survey (BAS) has been monitoring the iceberg for quite a while now.
According to BAS, the A23a iceberg was observed a year ago by researchers on a science mission in the Weddell Sea for the BIOPOLE project. Scientists reportedly took the first photos of the moving iceberg while examining how Antarctic ecosystems and sea ice influence global ocean cycles of carbon and nutrients.
Earlier in the year, while tracking the iceberg, researchers also noted that the progress of A23a was stalled when it got trapped in a Taylor Column — a vortex of spinning water caused by ocean currents interacting with an underwater mountain.
The massive iceberg, which is double the size of London, weighs around 1 trillion tonnes is expected to continue its journey into the Southern Ocean following the Antarctic Circumpolar Current. From there it is likely to drift towards the sub-Antarctic island of South Georgia, where it will encounter warmer water, leading to potential fragmentation and melting.
According to BAS, A23a first calved from Antarctica's Filchner Ice Shelf in 1986 but remained on the seabed of the Weddell Sea for over 30 years. It wasn't until 2020 that it finally broke free, likely due to erosion or shrinkage, and began to drift northward on ocean currents, reported the Times of India.
In recent months, A23a has resumed its movement and is now approaching the warmer waters beyond Antarctic waters.
According to the TOI report, the Taylor Column served as a natural "anchor" preventing the iceberg from drifting, as ocean currents and underwater topography kept it in place. Satellite imagery from NASA and video footage from October showed the iceberg rotating clockwise within the vortex, it added.
A23a is expected to melt and break apart in warmer waters near the sub-Antarctic island of South Georgia, scientists from the BAS have said. Here, it is expected to release fresh water into the ocean, which could have significant effects on local ocean currents and marine ecosystems, stated the same TOI report.
The movement of A23a has several potential implications.
Sea Level Rise
Although there have been no immediate concerns over sea level rise related to A23a currently drifting in the Southern Ocean, scientists have touted it a potent symbol of changes being witnessed in the polar regions. According to another report, "The story of A23a is a clear reminder of the complexity and fragility of polar ecosystems, making continuous monitoring essential to better understand the future dynamics of the ocean and climate."
The phenomenon, the report adds, is not only an indication of the altering Antarctic landscape but also the impacts it would have on the global marine ecosystem and Earth’s climate. Icebergs are known to form and separate from ice shelves due to natural processes, but experts have warned that they are undergoing acceleration due to global warming.
Climatologist Alexey Kokorin has, for instance emphasised on the significance of glacier destruction in the western part of Antarctica. While speaking to Sputnik, Kokorin dubbed glacial destruction in Western Antarctica as "a crucial factor contributing to the overall rise of the ocean." The melting of the Western Antarctic Ice Sheet has the greatest potential impact on rising sea levels, he said.
Impact on Marine Ecosystems
As A23a drifts, it releases fresh water and nutrients into the surrounding waters, which can enrich marine ecosystems. Icebergs like A23a provide vital nutrients to ocean regions, fostering biodiversity and supporting various marine life forms. However, this process could also disrupt existing marine habitats, especially if A23a breaks apart in a way that alters local ocean currents and temperatures, reported the TOI.
Monitoring and Research
A23a's movement offers a unique opportunity for scientific research. Researchers are using satellites, drones, and ship-based observations to track the iceberg and study its behavior. This research provides valuable insights into the dynamics of icebergs and their impact on global climate patterns. The data gathered by the researchers is expected to improve models predicting the impact of climate change on polar regions and inform strategies for addressing future environmental challenges.
The movement of iceberg A23a, could have profound impacts on rising sea levels, marine ecosystems and global climate patterns. Understanding these dynamics is crucial for anticipating future environmental challenges and mitigating the effects of climate change.
