Antarctic marine life threatened by crab invasion

A A A

An army of shell-crushing crabs is poised to invade parts of the Antarctic Ocean that were off limits to the crustaceans for millions of years because of the intensely cold water.

Scientists believe that, as global warming causes sea temperatures in the region to rise, the unique shallow-water habitat of the Antarctic Peninsula will be transformed by the mass arrival of killer crabs.

Crabs are one of the top predators of the seabed but their enforced absence from the cold waters of the Antarctic has created an unusual community of shelled creatures that could disappear once the crabs invade, scientists said yesterday.

"The crabs are on the doorstep," said Sven Thatje of the National Oceanography Centre at Southampton University.

"Rapidly rising sea temperatures off the Antarctic Peninsula are creating conditions that favour the return of shell-crushing predators after an absence of tens of millions of years," Dr Thatje told the American Association for the Advancement of Science.

Sea-surface temperatures off the western Antarctic Peninsula have risen by 1C over the past 50 years, more than double the global average.

"Crab populations have already become established in deeper, slightly warmer waters. It is only a matter of time before they expand to shallow Antarctic habitats and radically alter community structure," he said.

Marine life on the Antarctic seabed is a rare combination of giant sea spiders, marine pillbugs and bottom-dwelling fish with antifreeze in their bloodstream to prevent them from freezing solid.

In the absence of crabs and other fast-moving predators, such as sharks and rays, the main seabed predators are slow-moving sea stars and giant, floppy ribbon worms. "Crabs cannot flush magnesium out of their blood, so when they are already moving slowly because of the cold, the magnesium makes them pass out and die," Dr Thatje said.

Clams, snails and other animals with hard skeletons have evolved into rare forms that are part of an unusual food web.

"Antarctic marine communities look like primeval communities from hundreds of millions of years ago because modern predators such as crabs and fish are missing," said Rich Aronson of the Dauphin Island Sea Laboratory in Alabama. An invasion of crabs could completely change the habitat, and "that would be a tragic loss for biodiversity in one of the last truly wild places on earth".

Suggested Topics
Have you tried new the Independent Digital Edition apps?
  • Get to the point
Latest stories from i100
Have you tried new the Independent Digital Edition apps?
iJobs Job Widget
iJobs General

Ashdown Group: Data Scientist - London - £50,000 + bonus

£35000 - £50000 per annum + generous bonus: Ashdown Group: Business Analytics ...

Ashdown Group: IT Project Coordinator (Software Development) - Kingston

£45000 - £50000 per annum: Ashdown Group: IT Project Coordinator (Software Dev...

Ashdown Group: Editor-in-chief - Financial Services - City, London

£60000 - £70000 per annum + benefits : Ashdown Group: A highly successful, glo...

Ashdown Group: Junior Application Support Analyst - Fluent German Speaker

£25000 - £30000 per annum + benefits: Ashdown Group: A global leader operating...

Day In a Page

General Election 2015: Ed Miliband's unlikely journey from hapless geek to heart-throb

Miliband's unlikely journey from hapless geek to heart-throb

He was meant to be Labour's biggest handicap - but has become almost an asset
General Election 2015: A guide to the smaller parties, from the the National Health Action Party to the Church of the Militant Elvis Party

On the margins

From Militant Elvis to Women's Equality: a guide to the underdogs standing in the election
Amr Darrag: Ex-Muslim Brotherhood minister in exile still believes Egypt's military regime can be replaced with 'moderate' Islamic rule

'This is the battle of young Egypt for the future of our country'

Ex-Muslim Brotherhood minister Amr Darrag still believes the opposition can rid Egypt of its military regime and replace it with 'moderate' Islamic rule, he tells Robert Fisk
Why patients must rely less on doctors: Improving our own health is the 'blockbuster drug of the century'

Why patients must rely less on doctors

Improving our own health is the 'blockbuster drug of the century'
Sarah Lucas is the perfect artist to represent Britain at the Venice Biennale

Flesh in Venice

Sarah Lucas has filled the British pavilion at the Venice Biennale with slinky cats and casts of her female friends' private parts. It makes you proud to be a woman, says Karen Wright
11 best anti-ageing day creams

11 best anti-ageing day creams

Slow down the ageing process with one of these high-performance, hardworking anti-agers
Juventus 2 Real Madrid 1: Five things we learnt, including Iker Casillas is past it and Carlos Tevez remains effective

Juventus vs Real Madrid

Five things we learnt from the Italian's Champions League first leg win over the Spanish giants
Ashes 2015: Test series looks a lost cause for England... whoever takes over as ECB director of cricket

Ashes series looks a lost cause for England...

Whoever takes over as ECB director of cricket, says Stephen Brenkley
Fishing for votes with Nigel Farage: The Ukip leader shows how he can work an audience as he casts his line to the disaffected of Grimsby

Fishing is on Nigel Farage's mind

Ukip leader casts a line to the disaffected
Who is bombing whom in the Middle East? It's amazing they don't all hit each other

Who is bombing whom in the Middle East?

Robert Fisk untangles the countries and factions
China's influence on fashion: At the top of the game both creatively and commercially

China's influence on fashion

At the top of the game both creatively and commercially
Lord O’Donnell: Former cabinet secretary on the election and life away from the levers of power

The man known as GOD has a reputation for getting the job done

Lord O'Donnell's three principles of rule
Rainbow shades: It's all bright on the night

Rainbow shades

It's all bright on the night
'It was first time I had ever tasted chocolate. I kept a piece, and when Amsterdam was liberated, I gave it to the first Allied soldier I saw'

Bread from heaven

Dutch survivors thank RAF for World War II drop that saved millions
Britain will be 'run for the wealthy and powerful' if Tories retain power - Labour

How 'the Axe' helped Labour

UK will be 'run for the wealthy and powerful' if Tories retain power