Friday, March 23, 2012

Penguin “emissions” acidify air over Antarctic site

22 March 2012
Posted by kramsayer
Researchers have identified the source of a spike of atmospheric acidity over an Antarctic site - penguin poop. (Credit: Flickr user Chadica,

After some scientific sleuthing, researchers have tracked down the cause of a mysterious spike in atmospheric acidity over an Antarctic site made famous by the documentary March of the Penguins. The culprit? Penguin poop. It turns out penguins who live in the area could be responsible for acidity levels in December 2010 that were four times higher than levels observed during Southern Hemisphere summers back to 1997.

The Adélie penguins that inhabit the area (think of the wise-cracking group from Happy Feet) produce tons of guano, according to atmospheric scientist Anne-Mathilde Thierry. Literally, their output is about one metric ton (2,205 pounds) per day, explained the Ph.D. student at the Institut Pluridisciplinaire Hubert Curien in Strasbourg, France, and co-author of a new study revealing the unexpected effect of that pronounced penguin production.

The study will be published next week in the Journal of Geophysical Research-Atmospheres, a publication of the American Geophysical Union.

Previous scientific investigations of the atmosphere over this coastal area, known as Dumont d’Urville, have detected releases of oxygenated volatile organic compounds (OVOCs), which cause acidity and which were traced back to natural marine processes in the nearby ocean. However, Michel Legrand of the Laboratoire de Glaciologie et Géophysique de l’Environnement in Grenoble, France, lead author of the new study, and his colleagues found that the compounds, called alkenes, released by the marine processes in December 2010 were insufficient to make up all the OVOCs – and therefore all the acid – present. OVOCs, in general, are easily vaporized chemicals such as acetic acid, acetaldehyde, and acetone. They form through both natural and human-induced processes, including the burning of vegetation, vehicle exhaust, and natural plant emissions, but are short-lived in the atmosphere.

Stumped trying to explain the December OVOC spike, Legrand discussed the puzzle with Thierry. Soon their conversation turned to penguin guano and bacterial activity in the soils that guano eventually becomes. When alkenes released by the decomposing penguin guano were taken into account, the increased levels of acidity made more sense. More alkenes reacting with ozone molecules meant more OVOCs being produced, which would lead to more atmospheric acidity.
Noting that there had been unusually mild weather in December 2010 that sped up decomposition of guano into alkenes, they “started to consider that penguins could have something to do with the increase in atmospheric acidity,” Thierry explained.

“It had to be the penguins! So we took samples of both fresh and old guano so that the chemists could do some more analyses,” she said.

It turns out getting sample supplies of penguin guano for testing was not too difficult. “When you study penguins, you tend to get guano on your clothes during a typical day of work – so it wasn’t much of a trouble to get the fresh guano samples,” Thierry said.

While the acidity over Dumont d’Urville was remarkable enough to prompt a scientific investigation, it isn’t enough to set off environmental or ecological alarms, Legrand said.

Large amounts of OVOCs can affect the atmosphere’s ability to cleanse itself, but the increased quantities of acids in this case are too small to cause harm. “At the local scale, the high concentrations of acetic acid make this acid dominant compared to other acidic species,” noted Legrand. Yet, “I don’t think the species emitted by penguin colonies have a significant detrimental effect,” he added.

For a break from the science of it, check out Sea World San Diego’s penguin cam.

Legrand, M., Gros, V., Preunkert, S., Sarda-Estève, R., Thierry, A., Pepy, G., & Jourdain, B. (2012). A reassessment of the budget of formic and acetic acids in the boundary layer at Dumont d’Urville (coastal Antarctica): The role of penguin emissions on the budget of several oxygenated volatile organic compounds Journal of Geophysical Research DOI: 10.1029/2011JD017102

Thursday, March 22, 2012

Warming Antarctic Brings Changes to Penguin Breeding Cycles

Chinstrap penguins at Bailey Head, Deception Island in the Antarctic Peninsula. (Credit: Photograph by Ron Naveen ©2011)
ScienceDaily (Mar. 21, 2012) — Three penguin species that share the Western Antarctic Peninsula for breeding grounds have been affected in different ways by the higher temperatures brought on by global warming, according to Stony Brook University Ecology and Evolution Assistant Professor Heather Lynch and colleagues. The work by Lynch and her team is contained in three papers that have been published online in Polar Biology, Ecology and Marine Ecology Progress Series (MEPS).

Lynch and her colleagues used a combination of field work and, increasingly, satellite imagery to track colonies of three penguin species -- Adélie, chinstrap and gentoo. The Adélie and chinstrap migrate to the peninsula to breed, while the gentoo are year-round residents.

The Antarctic is considered one of the world's most rapidly warming regions. Warmer temperatures move up the breeding cycle, causing the penguins to lay their eggs earlier. The resident gentoo population is able to adapt more quickly and advance their "clutch initiation" by almost twice as much as the other species. Lynch believes this may allow them to better compete for the best nesting space. The Adélie and chinstrap are unaware of the local conditions until they arrive to breed and have not been able to advance their breeding cycles as rapidly.

In addition, the gentoo prefer areas with less sea ice, and have been able to migrate further south into the Antarctic as the sea ice shrinks. The chinstrap and Adélie species rely more heavily on the abundance of Antarctic krill, which require sea ice for their lifecycle.

The result -- the gentoo numbers are increasing while the other two species have noticeably dwindling populations on the Antarctic Peninsula.

Professor Lynch will speak about her research and advances in the use of satellite imagery to track penguin populations as part of "Polar Climate Change Research: A Workshop for Educators" at the Charles B. Wang Center at Stony Brook University on April 10-11, 2012. The workshop, sponsored by the joint BNL-SBU Center for Impacts of Regional Climate Change (CIRCC), is designed to give high school science teachers the tools they need to teach about climate change in the Polar regions.

Story Source:
The above story is reprinted from materials provided by Stony Brook University, via Newswise.
Note: Materials may be edited for content and length. For further information, please contact the source cited above.

Journal References:
  1. Heather J. Lynch, Ron Naveen, Philip N. Trathan, William F. Fagan. Spatially integrated assessment reveals widespread changes in penguin populations on the Antarctic Peninsula. Ecology, 2012; : 120117073021007 DOI: 10.1890/11-1588.1
  2. HJ Lynch, WF Fagan, R Naveen, SG Trivelpiece, WZ Trivelpiece. Differential advancement of breeding phenology in response to climate may alter staggered breeding among sympatric pygoscelid penguins. Marine Ecology Progress Series, 2011; DOI: 10.3354/meps09252
  3. Heather J. Lynch, Richard White, Andrew D. Black, Ron Naveen. Detection, differentiation, and abundance estimation of penguin species by high-resolution satellite imagery. Polar Biology, 2012; DOI: 10.1007/s00300-011-1138-3

Stony Brook University (2012, March 21). Warming Antarctic brings changes to penguin breeding cycles. ScienceDaily. Retrieved March 22, 2012, from source

Friday, March 9, 2012

Iridescent, Feathered Dinosaur Offers Fresh Evidence That Feathers Evolved to Attract Mates

Microraptor fossil. (Credit: Image courtesy of University of Texas at Austin)

ScienceDaily (Mar. 8, 2012) — A team of American and Chinese researchers has revealed the detailed feather pattern and color of Microraptor, a pigeon-sized, four-winged dinosaur that lived about 120 million years ago. A new specimen shows the dinosaur had a glossy iridescent sheen and that its tail was narrow and adorned with a pair of streamer feathers, suggesting the importance of display in the early evolution of feathers, as presented in the March 9 edition of the journal Science.

The research was conducted by scientists at the Beijing Museum of Natural History, Peking University, The University of Texas at Austin, the University of Akron, and the American Museum of Natural History.

By comparing the patterns of pigment-containing organelles from a Microraptor fossil with those in modern birds, the scientists determined the dinosaur's plumage was iridescent with a glossy sheen like the feathers of a crow. The new fossil is the earliest record of iridescent color in feathers.
A new reconstruction of the dinosaur will help scientists approach the controversy of how dinosaurs began the transition to flight.

Since it was discovered as the first four-winged dinosaur in 2003, Microraptor has been at the center of questions about the evolution of feathers and flight. A number of scientists have proposed aerodynamic functions for various feathery features such as its tail, forewing shape and hind limbs, going so far as to place Microraptor models in wind tunnels and launch them from catapults. Once thought to be a broad, teardrop-shaped surface or with a shape more like that of a paper airplane meant to help generate lift, Microraptor's tail fan is actually much narrower with two elongate feathers off of its tip. The researchers believe the tail feathering may have been ornamental and probably evolved for courtship and other social interactions and not as an adaptation for flight.
"Most aspects of early dinosaur feathering continue to be interpreted as fundamentally aerodynamic, optimized for some aspect of aerial locomotion," said Julia Clarke, one of the paper's co-authors and an associate professor of paleontology at The University of Texas at Austin's Jackson School of Geosciences. "Some of these structures were clearly ancestral characteristics that arose for other functions and stuck around, while others may be linked to display behaviors or signaling of mate quality. Feather features were surely shaped by early locomotor styles. But, as any birder will tell you, feather colors and shapes may also be tied with complex behavioral repertoires and, if anything, may be costly in terms of aerodynamics."

"Modern birds use their feathers for many different things, ranging from flight to thermoregulation to mate-attracting displays," said Matt Shawkey, a co-author and associate professor of biology at the University of Akron. "Iridescence is widespread in modern birds and is frequently used in displays. Our evidence that Microraptor was largely iridescent thus suggests that feathers were important for display even relatively early in their evolution."

The scientists deduced Microraptor was iridescent when Shawkey discovered that in the most common iridescent feathers, arrays of pigment-bearing organelles called melanosomes were uniquely narrow.

Information on feather color of a variety of dinosaurs has recently come to light, since the first color map of an extinct dinosaur showed black and white spangles, red coloration and gray body color in a species called Anchiornis in 2010. Based on the new data from Microraptor and these other finds, a complex color repertoire that includes iridescence is probably ancestral to a group of dinosaurs called Paraves that originated at least 140 million years ago and includes dinosaurs such as Velociraptor as well as Archaeopteryx, Anchiornis and living birds.

"This study gives us an unprecedented glimpse at what this animal looked like when it was alive," said Mark Norell, co-author and chair of the American Museum of Natural History's Division of Paleontology. Clarke, Norell and the AMNH team, also including Mick Ellison and Rui Pei, worked closely re-analyzing the bony anatomy and digital overlays of the feathering in the new specimen and eight previously described Microraptor specimens to come up with their new view of the animal.
The researchers studied feathering, melanosome shape and density from a Microraptor fossil working closely with collaborators Quanguo Li, Ke-Qin Gao and Meng Qingjin at the Beijing Museum of Natural History. The samples and preservation of melanosomes were assessed by Jakob Vinther and compared with a database of melanosomes from a variety of modern birds assembled by Shawkey and Liliana D'Alba at the University of Akron.

The feather color displayed by many modern birds is produced partially by arrays of melanosomes, about a hundred of which can fit across a human hair. Generally found in a round or cigar-like shape, a melanosome's structure is constant for a given color. After a breakthrough by Vinther in 2009, paleontologists have started analyzing the shape of melanosomes in well-preserved fossilized feather imprints. By comparing these patterns with those in living birds, scientists can infer the color of dinosaurs that lived many millions of years ago. Iridescence arises when the narrow melanosomes are organized in stacked layers.

The research was funded by the National Science Foundation, the Air Force Office of Scientific Research, the Natural Science Foundation of China, the Beijing Municipal Bureau of Human Resources, and the Beijing Academy of Science and Technology.

Story Source:
The above story is reprinted from materials provided by University of Texas at Austin.
Note: Materials may be edited for content and length. For further information, please contact the source cited above.

Journal Reference:
  1. Q. Li, K.-Q. Gao, Q. Meng, J. A. Clarke, M. D. Shawkey, L. D'Alba, R. Pei, M. Ellison, M. A. Norell, J. Vinther. Reconstruction of Microraptor and the Evolution of Iridescent Plumage. Science, 2012; 335 (6073): 1215 DOI: 10.1126/science.1213780

University of Texas at Austin (2012, March 8). Iridescent, feathered dinosaur offers fresh evidence that feathers evolved to attract mates. ScienceDaily. Retrieved March 9, 2012, from ­­ /releases/2012/03/120308143159.htm

Saturday, March 3, 2012

Penguins' food goes south

Posted on: 03 Mar 2012

Climate change warming the sea surface is separating breeding King Penguins from their main food sources, a new study shows.

King Penguins are the top avian fish consumers in the southern oceans, and their feeding ranges, habits and behaviour have been widely studied in this context for decades. However, overall seabird populations in the Antarctic's catchment have been changing for at least the last three decades and demographic modelling suggests that there will be radical changes over the next 100 years. The polar regions have been warming at a  faster rate than more temperate and tropical areas, and most scientific predictions are that this will continue over the rest of the century.

The Crozet Islands' King Penguins number well over one million individuals, far and away the largest population in the world and not currently viewed as being under any conservation threat. The population has been studied fairly comprehensively since the early 1960s and, though the population increased up to the 1990s, since 1994 there has been a notable decline. A particular long-term breeding dataset from Possession Islands in the archipelago was used to understand and model the habitat the penguins use during incubation and brooding, and to predict how the warming of the southern oceans would affect the distribution of this habitat, so important for the penguins continued survival.

The study's data confirmed that sea surface temperature controls the areas that are productive for King Penguin foraging during incubation and brooding, and that the penguins mostly use the colder pelagic waters of the polar air mass front, tracking these as they fluctuate between 300-500 km south of their colony. Models derived from the long-term data predict that the optimum feeding zones will shift south by about 400 km by 2100, and that therefore feeding during the early stages of the breeding cycle will become a significant challenge in the near future.

Clearly, the penguins reliance on the fish species that congregate around the polar front will mean that birds already under pressure from breeding will have to expend more energy swimming further  to collect more food over a shorter time period, a handicap compounded as the front moves gradually southwards over the course of the summer, anyway.

Demographic studies already indicate that breeding success declines during warmer summers in the Crozet Islands, but this may not necessarily be the case at other on Kerguelen and Heard islands, which are not as affected by the warming surface temperatures due to the shallower seas around them reducing the amount of annual temperature variation. Also, not enough is known about the responses of the major fish prey species involved to the changing surface temperatures to fully predict their movements, though fish have certainly changed their distribution in other parts of the world because of this.

However, the 21st century is not looking good for the Crozet Island populations unless they are able to evolve new foraging strategies or move to alternative breeding sites over time.

Péron, C, Weimerskirch, H and Bost, C-A. 2012. Projected poleward shift of king penguins (Aptenodytes patagonicus) foraging range at the Crozet Islands, southern Indian Ocean. Proceedings of the Royal Society B: doi: 10.1098/rspb.2011.2705.

Penguin fossils offer 'chance of a lifetime'

The scientist behind the exciting discovery of two unknown species of penguin in the Waitaki Valley says the area provides unique fossils that help bring history to life.

A report published this week by Daniel Ksepka, of North Carolina State University, has revealed previously unknown fossilised species Kairuku Grebneffi and Kairuku Waitaki, that were discovered in the Waitaki 20 years ago.

The revelation has caused excitement in the international science community.
More remarkable is the penguins are believed to have stood 1.3m tall – 30cm taller than their nearest modern-day descendant, the emperor penguin, of Antarctica.

It weighed at least 60kg, which is 50 per cent heavier than the emperor.

Otago University geology professor Ewan Fordyce first came across the fossilised bones in a cliff in the Waihao Valley near Waimate in 1977 while on a field trip looking for whale and dolphin fossils.
He was a PhD student at the time.
"It was the broken end of a leg bone and I thought, `that looks different'.

"Then I realised the species was bigger than expected. We knew this was something big.
"We've had a succession of other finds since then," he said.

The latest was last December with discoveries in the Duntroon area.

The well-preserved fossils allowed scientists to rebuild the bird and form a "clear description".
"I thought we really should bring in one of the leading people [so in 2009] I invited Dr Ksepka to come over here and work with me on the material."

Dr Ksepka was able to help in rebuilding the fossils.

Students at the university had also helped with the project for their theses.
Dr Fordyce said the Waitaki Valley was ideal for excavating fossils as the limestone geology of the area aided preservation.
Remains of large penguins had been found in other areas of New Zealand and overseas but were not as complete as the fossils found in the Waitaki Valley.

It was "very, very satisfying" to have been part of the discovery, he said.
"It tells us that penguins were different in the past.

"Why were they bigger and why did they disappear? As far as why they disappeared we really don't know.

"It could have been, for example, climate change. It could have been the appearance of some new predator. There are a variety of options.

"Those questions that we can't easily answer, they're the thing that drives our research."
He said the large size of the seabird would have meant it could swim further and dive deeper than modern penguin species.

At least four individual Kairuku penguins are known. The fossils recovered from the Waitaki Valley are now displayed in the Geology Museum.

Remains of "giant" penguins were first recovered from New Zealand as long ago as the 1840s, but there were no reasonably complete specimens.

Dr Fordyce said the finds were very exciting for penguin biologists and provided a significant boost to what was known internationally about the history of penguins.

Finding such specimens offered the "chance of a lifetime" to better understand extinct penguins that lived before the earliest fossils of modern species more than 15 million years ago.
"For the first time we have been able to publish really clear evidence about the body size and proportions of these older penguins."

The diversity of species and the penguin's unique physique had made the reconstruction difficult.
"Kairuku was an elegant bird by penguin standards, with a slender body and long flippers, but short, thick legs and feet," Dr Ksepka said.

The researchers rebuilt size and proportions from two main fossils, using the skeleton of an existing king penguin as a model.

Dr Ksepka hoped that the rebuilding of Kairuku would give other palaentologists more information about other fossils found in that area, as well as add to the knowledge about giant penguin species.
- © Fairfax NZ News