Featured Research

from universities, journals, and other organizations

Abandoned Penguin Colonies May Help Refine Antarctic Climate Studies

Date:
December 9, 2003
Source:
National Science Foundation
Summary:
A previously unnoticed cooling trend that persisted for a millennium caused enough ice to build up in Antarctica's Ross Sea that thousands of Adelie penguins abandoned their colonies beginning about 2,000 years ago, according to newly published research.

ARLINGTON, Va. -- A previously unnoticed cooling trend that persisted for a millennium caused enough ice to build up in Antarctica's Ross Sea that thousands of Adelie penguins abandoned their colonies beginning about 2,000 years ago, according to newly published research.

Related Articles


Using radiocarbon analyses of abandoned colonies on the Victoria Land coast of the Ross Sea, scientists believe that modern, ice-free conditions developed in the region only within roughly the past 1,000 years and that the present Adelie colonies on Ross Island, which are among the most numerous in the world, are likely no more than 500 years old.

Those techniques, they say, can also help to refine our understanding of climatic change on the southernmost continent

"We think the birds left the colonies when the southern Ross Sea was completely iced over in a cooling trend that very likely covered that region for probably a thousand years," said Steven D. Emslie, of the University of North Carolina at Wilmington. "That's never been known before from other climate records."

Scientists typically use chemical signatures in marine sediments, ice cores and other natural records to piece together a picture of what the Antarctic climate looked like thousands and even millions of years ago. But those records do not provide a highly defined or detailed picture of climate over shorter geological time scales.

"The evidence from these colonies can help refine those other records," said Emslie. "They are adding a higher resolution to the climatic record in Antarctica."

The National Science Foundation (NSF) funded Emslie's work, which was published recently in the journal Marine Ecology Progress Series. NSF is an independent federal agency that supports fundamental research and education across all fields of science and engineering, with an annual budget of nearly $5 billion.

Emslie said the evidence points to four conditions that suggests penguins once nested in an area: the terrain was ice-free; there was open water close to the colony that allowed them to expend less energy to reach their food by swimming, rather than walking; a food source was close enough so that the birds were able to go out and forage to feed their chicks; and there were pebbles on a beach that the birds could use to make their nests.

If those conditions--especially the first three--change sufficiently, then the birds will abandon a colony and establish themselves elsewhere.

Emslie said data collected by his team allow him to make a strong case that Adelies abandoned the entire southern Ross Sea for almost 1,000 years, from roughly 2000 to 1000 years ago. The analysis also indicates that the large Adelie penguin colonies that now exist on Ross Island in McMurdo Sound likely were established only 500 to 600 years ago.

Emslie also noted that a "natural experiment" seems to be underway in Antarctica today that confirms the idea that Adelie populations can rapidly adapt to changing conditions. But it also helps illuminate the difficulties in interpreting the climate record.

Iceberg B-15A, an enormous piece of ice that broke away from the Ross Ice Shelf in March of 2000, has caused much more ice than usual to accumulate for a number of years in eastern McMurdo Sound, essentially cutting off large Adelie colonies at Cape Royds, Cape Crozier, and Cape Bird. Another enormous berg, called C-16 has exacerbated the ice build up.

The bergs prevented Ross Sea currents from breaking up sea ice every year, as they normally would, instead allowing the ice to accumulate and thicken and forcing the birds to travel farther to reach open water.

While the icebergs now appear to be breaking up, the numbers of breeding pairs of birds in those colonies, which already were experiencing some declines, have dropped dramatically in the past three years and, if the unusual conditions produced by the icebergs conditions persist, may cause the penguins to abandon those colonies completely.

Scientists are debating whether the existence of the huge icebergs is due to a general warming of the climate in Antarctica or simply part of some other natural process in which pieces of ice break away--or "calve"--from the Ross and other ice shelves in the same way that human fingernails break off when they reach a certain length.

But Emslie noted, paradoxically, even if the calving is due to warming, because the icebergs are causing a concentration of sea ice that could eventually cause an abandonment of penguin colonies, scientists in the future could interpret the abandonment as evidence of a cooling trend.

"I think it's a good lesson for us," he said. "Although you might think this ecosystem is relatively simple, it's apparent that it's a lot more complex than it first appears."


Story Source:

The above story is based on materials provided by National Science Foundation. Note: Materials may be edited for content and length.


Cite This Page:

National Science Foundation. "Abandoned Penguin Colonies May Help Refine Antarctic Climate Studies." ScienceDaily. ScienceDaily, 9 December 2003. <www.sciencedaily.com/releases/2003/12/031209080804.htm>.
National Science Foundation. (2003, December 9). Abandoned Penguin Colonies May Help Refine Antarctic Climate Studies. ScienceDaily. Retrieved December 22, 2014 from www.sciencedaily.com/releases/2003/12/031209080804.htm
National Science Foundation. "Abandoned Penguin Colonies May Help Refine Antarctic Climate Studies." ScienceDaily. www.sciencedaily.com/releases/2003/12/031209080804.htm (accessed December 22, 2014).

Share This


More From ScienceDaily



More Earth & Climate News

Monday, December 22, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

New Fish Species Discovered, Setting Record for World's Deepest

New Fish Species Discovered, Setting Record for World's Deepest

Buzz60 (Dec. 22, 2014) A new species of fish is discovered living five miles beneath the ocean surface, making it the deepest living fish on earth. Jen Markham has the story. Video provided by Buzz60
Powered by NewsLook.com
Raw: Lava Inches Closer to Highway

Raw: Lava Inches Closer to Highway

AP (Dec. 21, 2014) Officials have opened a new road on Hawaii's Big Island for drivers to take care of their daily needs if encroaching lava from Kilauea Volcano crosses a highway and cuts them off from the rest of the island. (Dec. 20) Video provided by AP
Powered by NewsLook.com
Could Cheap Oil Help Fix U.S. Roads?

Could Cheap Oil Help Fix U.S. Roads?

Newsy (Dec. 21, 2014) As falling oil prices boost Americans' spending power, the U.S. government is also gaining flexibility from savings on oil. Video provided by Newsy
Powered by NewsLook.com
Raw: Russian Surfers Brave Icy Cold Waters

Raw: Russian Surfers Brave Icy Cold Waters

AP (Dec. 20, 2014) Surfers in Russia's biggest port city on the Pacific Ocean, Vladivostok, were enjoying the sport on Saturday despite below freezing temperatures and icy cold waters. (Dec. 20) Video provided by AP
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:

Strange & Offbeat Stories


Plants & Animals

Earth & Climate

Fossils & Ruins

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