Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Abandoned Penguin Colonies May Help Refine Antarctic Climate Studies

08.12.2003


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.

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."

Peter West | NSF

More articles from Earth Sciences:

nachricht A promising target in the quest for a 1-million-year-old Antarctic ice core
24.05.2018 | University of Washington

nachricht Tropical Peat Swamps: Restoration of Endangered Carbon Reservoirs
24.05.2018 | Leibniz-Zentrum für Marine Tropenforschung (ZMT)

All articles from Earth Sciences >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Powerful IT security for the car of the future – research alliance develops new approaches

The more electronics steer, accelerate and brake cars, the more important it is to protect them against cyber-attacks. That is why 15 partners from industry and academia will work together over the next three years on new approaches to IT security in self-driving cars. The joint project goes by the name Security For Connected, Autonomous Cars (SecForCARs) and has funding of €7.2 million from the German Federal Ministry of Education and Research. Infineon is leading the project.

Vehicles already offer diverse communication interfaces and more and more automated functions, such as distance and lane-keeping assist systems. At the same...

Im Focus: Molecular switch will facilitate the development of pioneering electro-optical devices

A research team led by physicists at the Technical University of Munich (TUM) has developed molecular nanoswitches that can be toggled between two structurally different states using an applied voltage. They can serve as the basis for a pioneering class of devices that could replace silicon-based components with organic molecules.

The development of new electronic technologies drives the incessant reduction of functional component sizes. In the context of an international collaborative...

Im Focus: LZH showcases laser material processing of tomorrow at the LASYS 2018

At the LASYS 2018, from June 5th to 7th, the Laser Zentrum Hannover e.V. (LZH) will be showcasing processes for the laser material processing of tomorrow in hall 4 at stand 4E75. With blown bomb shells the LZH will present first results of a research project on civil security.

At this year's LASYS, the LZH will exhibit light-based processes such as cutting, welding, ablation and structuring as well as additive manufacturing for...

Im Focus: Self-illuminating pixels for a new display generation

There are videos on the internet that can make one marvel at technology. For example, a smartphone is casually bent around the arm or a thin-film display is rolled in all directions and with almost every diameter. From the user's point of view, this looks fantastic. From a professional point of view, however, the question arises: Is that already possible?

At Display Week 2018, scientists from the Fraunhofer Institute for Applied Polymer Research IAP will be demonstrating today’s technological possibilities and...

Im Focus: Explanation for puzzling quantum oscillations has been found

So-called quantum many-body scars allow quantum systems to stay out of equilibrium much longer, explaining experiment | Study published in Nature Physics

Recently, researchers from Harvard and MIT succeeded in trapping a record 53 atoms and individually controlling their quantum state, realizing what is called a...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

12th COMPAMED Spring Convention: Innovative manufacturing processes of modern implants

28.05.2018 | Event News

In focus: Climate adapted plants

25.05.2018 | Event News

Save the date: Forum European Neuroscience – 07-11 July 2018 in Berlin, Germany

02.05.2018 | Event News

 
Latest News

International Workshop Sees Central Role for Solar in Transforming the World Energy Economy

28.05.2018 | Seminars Workshops

Cognitive Power Electronics 4.0 is gaining momentum

28.05.2018 | Trade Fair News

Organic light-emitting diodes become brighter and more durable

28.05.2018 | Physics and Astronomy

VideoLinks
Science & Research
Overview of more VideoLinks >>>