Huge London-sized iceberg breaks off Antarctica’s main ice shelf

Two of the world’s largest icebergs, including one the size of London and an even larger one, are being monitored by British scientists.

The huge A81, which is about the size of the capital of England, broke away from the Antarctic ice shelf in late January and was recently photographed from the air for the first time.

At 135km long and 25km wide, it’s the largest floating iceberg on the planet – about the size of the English county of Cornwall – and heading for the gap between the British overseas territories of Falklands and South Georgia.

There are fears that the glacier could move east towards South Georgia and get stuck in the shallow waters of its continental shelf, or possibly head towards nearby islets known as Shag Rocks. In both of these areas, this can cause problems for local wildlife and people.

If an iceberg sinks to the shallow seabed in this region, it could destroy fauna throughout the seafloor and disrupt ocean currents and foraging routes for local wildlife.

In addition to the environmental impact, icebergs in the South Georgia region can pose a great risk to local ships.

Huge icebergs like these two can take decades to melt and disappear, so they will remain a potential threat for some time to come. A81 (that’s what it was called) is the second large iceberg in the region in two years. It is expected to follow in the footsteps of previous icebergs carried by the strong Antarctic coastal current to the west.

Professor Geraint Tarling, Head of the Ecosystems Team at BAS: “An iceberg of this size will have a big impact on the ocean ecosystems that support the rich diversity of marine life found in this Antarctic region. These consequences can be both positive and negative. On the plus side, as the iceberg melts, many nutrients are released that can help grow microscopic plants like phytoplankton. The downside is that melting on such a large scale releases large amounts of fresh water into the ocean, reducing salinity and making the waters unsuitable for many of the phytoplankton and zooplankton species that feed on them. These effects can then cascade down the food web to fish, birds, seals and whales.”

Christina DENISYUK.