عربي English Türkçe اردو فارسى
Logo
Latest News
Varieties

World’s Largest Iceberg Breaks Free, Heads toward Southern Ocean

A satellite imagery of the world's largest iceberg, named A23a, seen in Antarctica, November 15, 2023. (Courtesy of European Union/Copernicus Sentinel-3/Handout via Reuters)
A satellite imagery of the world's largest iceberg, named A23a, seen in Antarctica, November 15, 2023. (Courtesy of European Union/Copernicus Sentinel-3/Handout via Reuters)
TT
TT

World’s Largest Iceberg Breaks Free, Heads toward Southern Ocean

A satellite imagery of the world's largest iceberg, named A23a, seen in Antarctica, November 15, 2023. (Courtesy of European Union/Copernicus Sentinel-3/Handout via Reuters)
A satellite imagery of the world's largest iceberg, named A23a, seen in Antarctica, November 15, 2023. (Courtesy of European Union/Copernicus Sentinel-3/Handout via Reuters)

The world's largest iceberg is on the move for the first time in more than three decades, scientists said on Friday.

At almost 4,000 square km (1,500 square miles), the Antarctic iceberg called A23a is roughly three times the size of New York City.

Since calving off West Antarctica's Filchner-Ronne Ice Shelf in 1986, the iceberg — which once hosted a Soviet research station — has largely been stranded after its base became stuck on the floor of the Weddell Sea.

Not anymore. Recent satellite images reveal that the berg, weighing nearly a trillion metric tons, is now drifting quickly past the northern tip of the Antarctic Peninsula, aided by strong winds and currents.

It's rare to see an iceberg of this size on the move, said British Antarctic Survey glaciologist Oliver Marsh, so scientists will be watching its trajectory closely.

As it gains steam, the colossal berg will likely be launched into the Antarctic Circumpolar Current. This will funnel it toward the Southern Ocean on a path known as "iceberg alley" where others of its kind can be found bobbing in dark waters.

Why the berg is making a run for it now remains to be seen.

"Over time it's probably just thinned slightly and got that little bit of extra buoyancy that's allowed it to lift off the ocean floor and get pushed by ocean currents," said Marsh. A23a is also among the world's oldest icebergs.

It's possible A23a could again become grounded at South Georgia island. That would pose a problem for Antarctica's wildlife. Millions of seals, penguins, and seabirds breed on the island and forage in the surrounding waters. Behemoth A23a could cut off such access.

In 2020, another giant iceberg, A68, stirred fears that it would collide with South Georgia, crushing marine life on the sea floor and cutting off food access. Such a catastrophe was ultimately averted when the iceberg broke up into smaller chunks — a possible end game for A23a as well.

But "an iceberg of this scale has the potential to survive for quite a long time in the Southern Ocean, even though it's much warmer, and it could make its way farther north up toward South Africa where it can disrupt shipping," said Marsh.

Most Viewed

 
 
Varieties

Animals Found Living Underground Near Deep-sea Hydrothermal Vents

Giant tubeworms on the seafloor surface at 2,500 meters water depth at the East Pacific Rise, a volcanically active ridge located where two tectonic plates meet on the floor of the Pacific Ocean in this undated photograph.CC BY-NC-SA Schmidt Ocean Institute/Handout via REUTERS
Giant tubeworms on the seafloor surface at 2,500 meters water depth at the East Pacific Rise, a volcanically active ridge located where two tectonic plates meet on the floor of the Pacific Ocean in this undated photograph.CC BY-NC-SA Schmidt Ocean Institute/Handout via REUTERS
TT
TT

Animals Found Living Underground Near Deep-sea Hydrothermal Vents

Giant tubeworms on the seafloor surface at 2,500 meters water depth at the East Pacific Rise, a volcanically active ridge located where two tectonic plates meet on the floor of the Pacific Ocean in this undated photograph.CC BY-NC-SA Schmidt Ocean Institute/Handout via REUTERS
Giant tubeworms on the seafloor surface at 2,500 meters water depth at the East Pacific Rise, a volcanically active ridge located where two tectonic plates meet on the floor of the Pacific Ocean in this undated photograph.CC BY-NC-SA Schmidt Ocean Institute/Handout via REUTERS

A deep-diving robot that chiseled into the rocky Pacific seabed at a spot where two of the immense plates comprising Earth's outer shell meet has unearthed a previously unknown realm of animal life thriving underground near hydrothermal vents.

Giant tubeworms - the world's heftiest worms - and other marine invertebrates such as snails and bristle worms were found using the remotely operated underwater vehicle SuBastian. They were living inside cavities within the Earth's crust at an ocean-floor site where the Pacific is 1.56 miles (2,515 meters) deep. All the species were previously known to have lived near such vents, but never underground, Reuters reported.

"We discovered vent animal life in the cavities of the ocean's crust. We now know that the unique hydrothermal vent ecosystem extends into the ocean's crust," said marine biologist Sabine Gollner of the Royal Netherlands Institute for Sea Research, one of the leaders of the study published this week in the journal Nature Communications.

"To our knowledge, it is the first time that animal life has been discovered in the ocean crust," Gollner added.

The exploration was conducted at the East Pacific Rise, a volcanically active ridge on the floor of the southeastern Pacific, running approximately parallel to South America's west coast. Earth's rigid outer part is divided into colossal plates that move gradually over time in a process called plate tectonics. The East Pacific Rise is located where two such plates are gradually spreading apart.

This area contains many hydrothermal vents, fissures in the seafloor situated where seawater and magma beneath the Earth's crust come together. Magma refers to molten rock that is underground, while lava refers to molten rock that reaches the surface, including the seafloor. New seafloor forms in places where magma is forced upward toward the surface at a mid-ocean ridge and cools to form volcanic rock.

The hydrothermal vents spew into the cold sea the super-heated and chemical-rich water that nourishes microorganisms.

"The warm venting fluids are rich in energy - for example, sulfide - that can be used by microbes, which form the basis of the food-chain," Gollner said.

Life flourishes around the vents - including giant tubeworms reaching lengths of 10 feet (3 meters), mussels, crabs, shrimp, fish and other organisms beautifully adapted to this extreme environment. The giant tubeworms do not eat as other animals do. Instead, bacteria residing in their body in a sack-like organ turn sulfur from the water into energy for the animal.

The researchers deployed SuBastian from the Schmidt Ocean Institute research vessel Falkortoo to the vent site deep below. The robot was equipped with arms that wielded a chisel that the researchers used to dig into the crust and uncover warm and fluid-filled cavities where the tubeworms, bristle worms and snails were spotted.

"We used a chisel to break the rock. We dug about 20 cm (8 inches). The lava plates were about 10 cm (4 inches) thick. The cavities below the lava plates were about 10 cm in height," Gollner said.

Larvae from these animals may invade these subseafloor habitats, the researchers said, in an example of connectivity between the seafloor and underground ecosystems.

"It changed our view on connectedness in the ocean," Gollner said of discovering the subsurface lair.