Featured Research

from universities, journals, and other organizations

Polar ecosystems acutely vulnerable to sunlight-driven tipping points

Date:
July 31, 2013
Source:
University of New South Wales
Summary:
Slight changes in the timing of the annual loss of sea-ice in polar regions could have dire consequences for polar ecosystems, by allowing a lot more sunlight to reach the sea floor. The research predicts biodiversity on some areas of the polar seabed could be reduced by as much as one third within decades, as the poles warm.

Fan worms (turquoise) and sponges (orange) under the sea ice in Antarctica near Casey Station.
Credit: Graeme Clark

Slight changes in the timing of the annual loss of sea-ice in polar regions could have dire consequences for polar ecosystems, by allowing a lot more sunlight to reach the sea floor.

The research by scientists at UNSW and the Australian Antarctic Division predicts that biodiversity on some areas of the polar seabed could be reduced by as much as one third within decades, as the poles warm.

The study, Light-driven tipping points in polar ecosystems, will be published in the journal Global Change Biology.

Dr Graeme Clark, of the UNSW School of Biological, Earth and Environmental Sciences, says the team's research shows that polar ecosystems may be even more sensitive to climate change than previously thought.

"Even a slight shift in the date of the annual sea-ice departure could cause a tipping point, leading to widespread ecosystem shifts. On the Antarctic coast this may cause unique, invertebrate-dominated communities that are adapted to the dark conditions to be replaced by algal beds, which thrive on light, significantly reducing biodiversity," Dr Clark says.

The invertebrates lost could include sponges, moss animals, sea squirts and worms. These animals perform important functions such as filtering of water and recycling of nutrients and provide a food source for fish and other creatures.

"This is a prime example of the large-scale ecological impacts that humans can impose through global warming -- even in places as remote as Antarctica," says UNSW team member, Associate Professor Emma Johnston.

"Our modelling shows that recent changes in ice and snow cover at the poles have already transformed the amount of light reaching large areas of the Arctic and Antarctic annually."

For the study, the team deployed light meters on the sea floor at seven sites near Casey Station in Antarctica, at depths of up to 10 metres. They used cameras to photograph the coast at midday every day for two and a half years, to determine sea-ice cover.

They determined the growth rates of Antarctic algae in the lab in different light conditions, and conducted experiments in Antarctic waters to test the sensitivity of algae to available light. They also surveyed species living on sub-tidal boulders, to see how communities varied with ice cover.

Tipping points are events where small changes in environmental conditions cause rapid and extensive ecological change.

The amount of sunlight reaching the poles is highly dependent on the seasons because Earth's tilt causes the sun to be above the horizon for considerably longer during summer than winter, and the lower solar angle during winter increases reflectance from the water surface.

"Early melt that brings the date of sea-ice loss closer to midsummer will cause an exponential increase in the amount of sunlight reaching some areas per year," says Dr Clark.


Story Source:

The above story is based on materials provided by University of New South Wales. Note: Materials may be edited for content and length.


Journal Reference:

  1. Graeme F. Clark, Jonathan S. Stark, Emma L. Johnston, John W. Runcie, Paul M. Goldsworthy, Ben Raymond, Martin J. Riddle. Light-driven tipping points in polar ecosystems. Global Change Biology, 2013; DOI: 10.1111/gcb.12337

Cite This Page:

University of New South Wales. "Polar ecosystems acutely vulnerable to sunlight-driven tipping points." ScienceDaily. ScienceDaily, 31 July 2013. <www.sciencedaily.com/releases/2013/07/130731093919.htm>.
University of New South Wales. (2013, July 31). Polar ecosystems acutely vulnerable to sunlight-driven tipping points. ScienceDaily. Retrieved September 17, 2014 from www.sciencedaily.com/releases/2013/07/130731093919.htm
University of New South Wales. "Polar ecosystems acutely vulnerable to sunlight-driven tipping points." ScienceDaily. www.sciencedaily.com/releases/2013/07/130731093919.htm (accessed September 17, 2014).

Share This



More Earth & Climate News

Wednesday, September 17, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Raw: Scientists Examine Colossal Squid

Raw: Scientists Examine Colossal Squid

AP (Sep. 16, 2014) Squid experts in New Zealand thawed and examined an unusual catch on Tuesday: a colossal squid. It was captured in Antarctica's remote Ross Sea in December last year and has been frozen for eight months. (Sept. 16) Video provided by AP
Powered by NewsLook.com
Man Floats for 31 Hours in Gulf Waters

Man Floats for 31 Hours in Gulf Waters

AP (Sep. 16, 2014) A Texas man is lucky to be alive after he and three others floated for more than a day in the Gulf of Mexico when their boat sank during a fishing trip. (Sept. 16) Video provided by AP
Powered by NewsLook.com
Researchers Explore Shipwrecks Off Calif. Coast

Researchers Explore Shipwrecks Off Calif. Coast

AP (Sep. 16, 2014) Federal researchers are exploring more than a dozen underwater sites where they believe ships sank in the treacherous waters west of San Francisco in the decades following the Gold Rush. (Sept. 16) Video provided by AP
Powered by NewsLook.com
Isolated N. Korea Asks For International Help With Volcano

Isolated N. Korea Asks For International Help With Volcano

Newsy (Sep. 16, 2014) Mount Paektu volcano in North Korea is showing signs of life and there's not much known about it. Video provided by Newsy
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:

Breaking News:
from the past week

In Other News

... from NewsDaily.com

Science News

Health News

Environment News

    Technology News



    Save/Print:
    Share:

    Free Subscriptions


    Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

    Get Social & Mobile


    Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

    Have Feedback?


    Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
    Mobile: iPhone Android Web
    Follow: Facebook Twitter Google+
    Subscribe: RSS Feeds Email Newsletters
    Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins