Thursday, April 26, 2012
Saturday, April 14, 2012
Twice as Many Emperor Penguins as Thought in Antarctica, First-Ever Penguin Count from Space Shows
ScienceDaily (Apr. 13, 2012)
— A new study using satellite mapping technology reveals there are
twice as many emperor penguins in Antarctica than previously thought.
The results provide an important benchmark for monitoring the impact of
environmental change on the population of this iconic bird, which breeds
in remote areas that are very difficult to study because they often are
inaccessible with temperatures as low as -58 degrees Fahrenheit.
Using a technique known as pan-sharpening to increase the resolution of the satellite imagery, the science teams were able to differentiate between birds, ice, shadow and penguin poo or guano. They then used ground counts and aerial photography to calibrate the analysis.
Lead author and geographer Peter Fretwell at British Antarctic Survey (BAS), which is funded by the U.K.'s Natural Environment Research Council, explains, "We are delighted to be able to locate and identify such a large number of emperor penguins. We counted 595,000 birds, which is almost double the previous estimates of 270,000-350,000 birds. This is the first comprehensive census of a species taken from space."
On the ice, emperor penguins with their black and white plumage stand out against the snow and colonies are clearly visible on satellite imagery. This allowed the team to analyze 44 emperor penguin colonies around the coast of Antarctica, and seven previously unknown colonies.
"The methods we used are an enormous step forward in Antarctic ecology because we can conduct research safely and efficiently with little environmental impact, and determine estimates of an entire penguin population, said co-author Michelle LaRue from the University of Minnesota and funded by the U.S. National Science Foundation (NSF).
"The implications of this study are far-reaching: we now have a cost-effective way to apply our methods to other poorly-understood species in the Antarctic, to strengthen on-going field research, and to provide accurate information for international conservation efforts."
NSF manages the U.S. Antarctic Program through which it coordinates all U.S. scientific research on the southernmost continent and aboard ships in the Southern Ocean as well as related logistics support.
Co-author and BAS biologist Phil Trathan noted, "Current research suggests that emperor penguin colonies will be seriously affected by climate change. An accurate continent-wide census that can be easily repeated on a regular basis will help us monitor more accurately the impacts of future change on this iconic species."
Scientists are concerned that in some regions of Antarctica, earlier spring warming is leading to loss of sea ice habitat for emperor penguins, making their northerly colonies more vulnerable to further climate change.
Trathan continued, "Whilst current research leads us to expect important declines in the number of emperor penguins over the next century, the effects of warming around Antarctica are regional and uneven. In the future, we anticipate that the more southerly colonies should remain, making these important sites for further research and protection."
This research is a collaboration between BAS, University of Minnesota/NSF, Scripps Institution of Oceanography and the Australian Antarctic Division.
Story Source:
The above story is reprinted from materials provided by National Science Foundation.
Note: Materials may be edited for content and length. For further information, please contact the source cited above.
Journal Reference:
- Peter T. Fretwell, Michelle A. LaRue, Paul Morin, Gerald L. Kooyman, Barbara Wienecke, Norman Ratcliffe, Adrian J. Fox, Andrew H. Fleming, Claire Porter, Phil N. Trathan. An Emperor Penguin Population Estimate: The First Global, Synoptic Survey of a Species from Space. PLoS ONE, 2012; 7 (4): e33751 DOI: 10.1371/journal.pone.0033751
Tuesday, April 10, 2012
Endangered Species: Penguins, Ice Caps, and Arctic Monitors
U.S. News & World Report
Scientific stations that track ecological changes increasingly survive on "bare-bones" budgetsThe temperatures are warming and the ice is melting--as is the funding for scientific stations that monitor the long-term health of arctic ecosystems.
Measuring melting glaciers and ice caused by global climate change is easy--NASA and NOAA have satellites for that. But measuring the changing climate's impact on local ecosystems is much harder, requiring manned monitoring sites around the world, a much more expensive proposition. With Washington trying to reign in the national budget, the 26 Long Term Ecological Research (or LTER) sites set up around the United States and Antarctica are becoming an increasingly endangered species.
Going forward, "we're funded on a bare-bones basis," says Andrew Fountain, a professor at Portland State University and author of a report released Friday on the importance of sites that measure the ecological impact of ice melts. "We do have funding, but it's always quite limited. I don't think we need another space program to solve this, but having consistent, reliable funding is important for these long-term studies."
The LTER program was created in 1980 by the National Science Foundation--its research is ongoing, but some studies can take decades, especially in polar regions where year-round monitoring can be difficult.
"It has required decades of coordinated observations to document significant change and to uncover the mechanisms linking climate forcing to ecosystem responses," according to Fountain's paper. "The simple logistics of polar regions make them more expensive."
[Read Study: Global Warming is Real]
While the National Science Foundation's budget has remained relatively flat, and even increased by 2.5 percent from 2011 to 2012, some lawmakers have proposed deep cuts to the agency. The journal BioScience had a special section where scientists in LTER outlined some of the discoveries made by these sites, in hopes their importance would be recognized.
Among those findings: Populations of certain penguin species in Antarctica have declined by 80 percent since 1975, wolverines can't breed unless they have sufficient snow to make caves in, and the American pika, a mouse-like creature that lives in the Rocky Mountains, has had its habitat nearly destroyed.
Measuring the environmental impact on disappearing mammal populations isn't too tough, but scientists have reason to believe microbial and krill populations in the polar regions have declined. That creates "cascading upward effects," Fountain says. That may have caused a decline in the penguin population, which can affect larger sea mammals.
[Read Poll: Republicans Coming Around on Global Warming]
"We don't understand really how everything works together--we can't say 'here are the changes, here are the parts of the systems that will change,'" Fountain says. "That's why these long-term ecological sites are important, to maintain monitoring. We need more data."
Charles Driscoll, a Syracuse University professor who studied their importance, said in a statement that LTER sites create "a crucial bridge between the scientific community and society."
"LTER datasets and experiments help inform local- to national-scale decisions regarding climate change, pollution, fire, land conversion, and other pressing environmental challenges," he said.
source
Wednesday, April 4, 2012
Bus-Size Dinosaurs, Fuzzy as Chicks
Brian Choo
An artist’s impression of
Yutyrannus huali, a giant, previously unrecognized dinosaur. The name of
the species means “beautiful feathered tyrant.”
By JOHN NOBLE WILFORD
Published: April 4, 2012
Fossils discovered in northeastern China of a giant, previously
unrecognized dinosaur show that it is the largest known feathered
animal, living or extinct, scientists report.
Although several species of dinosaurs with feathers have already been
uncovered in the rich fossil beds of Liaoning Province, the three
largely complete 125-million-year-old specimens are by far the largest.
The adult was at least 30 feet long and weighed a ton and a half, about
40 times the heft of Beipiaosaurus, the largest previously known
feathered dinosaur. The two juveniles were a mere half ton each.
The new species was a distant relative of Tyrannosaurus rex, the mighty
predator that lived 60 million years later, at the end of the dinosaur
era. The scaly T. rex apparently did not go in for feathers.
In an article in the journal Nature, published online Wednesday, Chinese
and Canadian paleontologists said the discovery provided the first
“direct evidence for the presence of extensively feathered gigantic
dinosaurs” and offered “new insights into early feather evolution.”
Xing Xu of the Institute of Vertebrate Paleontology and
Paleoanthropology in Beijing, who was the lead author of the paper, said
in a statement that it was “possible that feathers were much more
widespread, at least among meat-eating dinosaurs, than most scientists
would have guessed even a few years ago.”
Dr. Xu said the feathers were simple filaments, more like the fuzzy down
of a modern baby chick than the stiff plumes of an adult bird. Such
insubstantial feathers, not to mention the animal’s huge size, would
have made flight impossible. The feathers’ most important function was
probably as insulation.
The species has been named Yutyrannus huali, which means “beautiful
feathered tyrant” in a combination of Latin and Mandarin.
Mark A. Norell, a curator of paleontology at the American Museum of
Natural History in Manhattan, who had no part in the research, said the
findings were significant because they swept aside a longstanding
argument that perhaps dinosaurs had feathers only when they were small
and shed them as they grew.
Corwin Sullivan, a Canadian paleontologist affiliated with the Beijing
institute and an author of the report, noted that the idea of primitive
feathers for insulation was not new.
“However, large-bodied animals typically can retain heat quite easily,
and actually have more of a potential problem with overheating,” Dr.
Sullivan said. “That makes Yutyrannus, which is large and downright
shaggy, a bit of a surprise.”
The researchers suggested that the climate might have been cooler when
this feathered giant lived than it was when T. rex roamed in the late
Cretaceous period. Not necessarily, said Dr. Norell, who pointed out
that large, hairy mammals like giraffes and wildebeest, perhaps
analogous to feathered dinosaurs, live today in hot latitudes.
Another possible explanation, offered by the authors of the journal
article, is that the feathers were not widely distributed over the
dinosaurs’ bodies, and so their function as display plumage cannot be
ruled out. Yet the researchers noted several times that the feather
covering was extensive and “densely packed,” resembling some recent
discoveries of fossil birds “that undoubtedly had plumage covering most
of the body.”
“This is a great time to be a dinosaur paleontologist,” said Dr. Norell,
whose research concentrates on fossils from China and the Gobi Desert
of Mongolia. “The feathered dinosaurs show how the whole conception of
dinosaurs has really changed in the last 15 years.”