An estimated 150,000 Adelie penguins living in Antarctica have died after a huge iceberg the size of Luxemburg became lodged near their colony. The grounding of the colossal iceberg in Cape Denison in Commonwealth Bay left the colony effectively landlocked.

This meant the mid-sized penguins, that range from 46cm-71 cm (18in-28in), had to trek 60km to the sea to feed on their favoured krill. Their habitat used to sit on the edge of a large expanse of open water but in 2010 a massive iceberg measuring 2,900km sq became lodged in the bay, rendering the colony of Penguins landlocked.

In the last five years the colony was dwindled in size, as the perilous journey has claimed the lives of 150,000 of the penguins, according to research carried out by the Climate Change Research Centre at Australia's University of New South Wales. And scientists warned that the colony is set to disappear in just 20 years unless the sea ice breaks up or the iceberg, named B09B, becomes dislodged.

Researchers in an article in Antarctic Science said: "The arrival of iceberg B09B in Commonwealth Bay, East Antarctica, and subsequent fast ice expansion has dramatically increased the distance Adélie penguins breeding at Cape Denison must travel in search of food.

"The Cape Denison population could be extirpated within 20 years unless B09B relocates or the now perennial fast ice within the bay breaks out. This has provided a natural experiment to investigate the impact of iceberg stranding events and sea ice expansion along the East Antarctic coast."

But all is not lost, a study of another colony of Adelie penguins located just 8km from the coast of Commonwealth Bay is thriving, the researchers said. And new findings from other studies suggest that between the last ice age through to 1,000 years ago, some species of penguins have benefited from climate warming and retreating ice.

Professor Chris Turney, who led the expedition, told the Morning Herald that penguin numbers had been recorded for 100 years at Cape Denison. "It's eerily silent now," he said. "The ones that we saw at Cape Denison were incredibly docile, lethargic, almost unaware of your existence. The ones that are surviving are clearly struggling.

"They can barely survive themselves, let alone hatch the next generation. We saw lots of dead birds on the ground it's just heartbreaking to see."