The iceberg A23a, considered the largest and oldest in the world, ran aground about 73 kilometers from the subantarctic island of South Georgia, a natural sanctuary for millions of penguins and seals. Its presence raises concerns among scientists and conservationists, who fear it could disrupt the fragile ecosystem of the region.
The A23a, with an area of approximately 3,600 square kilometers and a weight close to a trillion tons, broke off from the Filchner Antarctic ice shelf in 1986. For over 30 years, it remained stuck on the seabed of the Weddell Sea until it began to move slowly northward in 2020.
Its journey brought it to shallow waters near South Georgia, a British island also known as San Pedro. There, its massive ice mass threatens to hinder access to fishing grounds and affect the feeding of local wildlife, especially penguins, which rely on unrestricted access to the ocean for food.
Environmental Impact and Possible Scenarios
Experts warn that the presence of A23a could have both negative and positive consequences on the marine ecosystem. According to oceanographer Andrew Meijers of the British Antarctic Survey, if the iceberg remains stuck, the impact on wildlife could be minor. However, if it breaks apart, it could create dangerous obstacles for navigation and alter the migratory routes of marine species.
On the other hand, some scientists suggest that the melting of the iceberg would release essential nutrients for the ocean, which could stimulate plankton proliferation and benefit the marine food chain. Ecologist Nadine Johnston compares this phenomenon to “throwing a nutrient bomb into an empty desert,” which would lead to an increase in marine life in the region.
Ecologist Mark Belchier, an advisor to the Government of South Georgia, pointed out that if A23a fractures, the resulting fragments could pose a danger to local vessels. “Icebergs will follow the course of marine currents and could hinder access to fishing grounds,” he warned in statements to the BBC.
How this iceberg was formed.
Uncertain Outcome
Since breaking off nearly 40 years ago, A23a has shown remarkable resilience. Despite losing part of its total area, it remains one of the largest ice masses on the planet. Its final fate is uncertain: it could remain stuck for years or continue to break up and melt over time.
Professor Huw Griffiths, from a polar research vessel in Antarctica, recalls that “the fate of all icebergs is to disappear.” What remains to be seen is how this icy colossus will impact the biodiversity of South Georgia and its surroundings.
Melting and its Consequences
Icebergs are ice formations resulting from the detachment of glaciers that fall into the sea. These huge chunks of ice, formed by frost and snow, can reach kilometers in length. The top of icebergs is composed of loosely compacted snow that melts rapidly, while the submerged part is a block of hard, compact ice rounded by water erosion, which can have a lifespan of up to ten years before melting.
What few know is that detachments are much more common than believed, becoming a threat to vessels and the environment.
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