Iceberg Scour Affects Biodiversity

Jul 17, 2008
Large red sea spider (Arthropoda pcynogonida) walking over white hydroid at 25 m. Antarctic sea spiders can be up to 500mm across and have up to 12 legs. (Simon Brockington @ British Antarctic Survey)

Antarctic worms, sea spiders, urchins and other marine creatures living in near-shore shallow habitats are regularly pounded by icebergs. New data suggests this environment along the Antarctic Peninsula is going to get hit more frequently. This is due to an increase in the number of icebergs scouring the seabed as a result of shrinking winter sea ice. The results are published this week in the journal Science.

Scientists from the British Antarctic Survey (BAS) show how the rate of iceberg scouring on the West Antarctic Peninsula seabed is affected by the duration of winter sea ice, which has dramatically declined (in space and time) in the region over the last few decades due to climate warming. This increase in iceberg disturbance on the seabed, where the majority of all Antarctic life occurs (80%), could have severe effects on the marine creatures living as deep as 500m underwater.

Lead author, Dr Dan Smale from BAS, says: "It has been suggested previously that iceberg disturbance rates may be controlled by the formation of winter sea ice, but nobody's been able to go out and measure it before. We were surprised to see how strong the relationship between the two factors is. During years with a long sea ice season of eight months or so, the disturbance rates were really low, whereas in poor sea ice years the seabed was pounded by ice for most of the year. This is because icebergs are locked into position by winter sea ice, so they are not free to get pushed around by winds and tides until they crash into the seabed."

By using grids of small concrete markers on the seabed at three different depths for five years, BAS SCUBA divers were able to determine the frequency of iceberg scour by counting the number of damaged or destroyed markers annually.

Ice disturbance has been recognised as a driving force in the structure of the Antarctic seabed animal communities. Iceberg scouring damages areas of the seabed creating space for a high diversity of animals to use. However, an increase in iceberg scour with the seabed would affect the type and number of marine creatures found on the seabed and may cause changes in the distributions of key species.

Source: British Antarctic Survey

Explore further: Food shortages could be most critical world issue by mid-century

add to favorites email to friend print save as pdf

Related Stories

The Isthmus of Panama: Out of the Deep Earth

Apr 01, 2014

As dates in geologic history go, the formation of the slender land bridge that joins South America and North America is a red-letter one. More than once over the past 100 million years, the two great landmasses ...

Geoscientists back from expedition to Labrador Sea

Jul 22, 2009

Scientists from the Alfred Wegener Institute have researched the geology of the seabed in the Labrador Sea on board of the research vessel Maria S. Merian. They have studied the so-called Eirik Drift at the ...

Pine Island Glacier sensitive to climatic variability

Jan 02, 2014

A new study published in Science this month suggests the thinning of Pine Island Glacier in West Antarctica is much more susceptible to climatic and ocean variability than at first thought. Observations by a team of scient ...

Recommended for you

China says massive area of its soil polluted

7 hours ago

A huge area of China's soil covering more than twice the size of Spain is estimated to be polluted, the government said Thursday, announcing findings of a survey previously kept secret.

User comments : 2

Adjust slider to filter visible comments by rank

Display comments: newest first

zevkirsh
2 / 5 (4) Jul 17, 2008
what a life!. sonds like living in a video game.
mikiwud
1.2 / 5 (6) Jul 17, 2008
If the sea ice is shrinking surely there would be less and/or smaller icebergs.Also data shows that Antarctic sea ice is increasing anyway.All this (whatever) has been going on for millennia atleast with no lasting effects,ill or otherwise.

More news stories

There's something ancient in the icebox

Glaciers are commonly thought to work like a belt sander. As they move over the land they scrape off everything—vegetation, soil, and even the top layer of bedrock. So scientists were greatly surprised ...

Clean air: Fewer sources for self-cleaning

Up to now, HONO, also known as nitrous acid, was considered one of the most important sources of hydroxyl radicals (OH), which are regarded as the detergent of the atmosphere, allowing the air to clean itself. ...

Turning off depression in the brain

Scientists have traced vulnerability to depression-like behaviors in mice to out-of-balance electrical activity inside neurons of the brain's reward circuit and experimentally reversed it – but there's ...