Monday, July 11, 2016

Update: Climate Change May Shrink Adélie Penguin Range By End of Century

penguin and chicks on rocks
July 8, 2016

Climate has influenced the distribution patterns of Adélie penguins across Antarctica for millions of years. The geologic record tells us that as glaciers expanded and covered Adélie breeding habitats with ice, penguins in the region abandoned their colonies. When the glaciers melted during warming periods, the Adélie penguins were able to return to their rocky breeding grounds.

Now, a NASA-funded study by University of Delaware scientists and colleagues at other institutions reports that this warming may no longer be beneficial for Adélie penguins. In a paper published June 29 in the journal Scientific Reports, the researchers project that approximately 30 percent of current Adélie colonies may be in decline by 2060, and approximately 60 percent of the present population might be dwindling by 2099. They also found the penguins at more southerly sites in Antarctica may be less affected by climate change.

space perspective of Antarctica with data overlay
This graphic shows changes to the suitability of Adélie penguin breeding areas.
Credits: NASA's Goddard Space Flight Center

The study results suggest that changes in climate, particularly sustained periods of warmer than usual sea surface temperatures, are detrimental to Adélie penguins. While the specific mechanisms for this relationship remain unknown the study focuses attention on areas where climate change is likely to create a high frequency of unsuitable conditions during the 21st century.

“It is only in recent decades that we know Adélie penguins population declines are associated with warming, which suggests that many regions of Antarctica have warmed too much and that further warming is no longer positive for the species,” said the paper’s lead author, Megan Cimino, who earned her doctoral degree at University of Delaware in May and is now a postdoctoral scholar at Scripps Institute of Oceanography in La Jolla, California.

The Adélie penguin is a species that breeds across the entire Antarctic continent. The penguins are experiencing population declines along the West Antarctic Peninsula, which is one of the most rapidly warming places on Earth. Conversely, Adélie populations in other areas of Antarctica where the climate is stable or even cooling remain steady or are increasing.

The researchers’ objective was to understand the effects of climate change on Antarctic Adélie penguin colonies. The study, funded through the NASA Biodiversity program, used satellite data and global climate model projections to understand current and future population trends on a continental scale. They analyzed satellite observations from 1981 to 2010 of sea ice concentration and bare rock locations, as penguins need ice- and snow-free terrain with pebbles to make their nests. The scientists also took into account data from previous studies that had used satellite imagery to detect the presence or absence of penguin populations. Finally, the team also analyzed sea surface temperature data, which, together with bare rock and sea ice, was used as an indicator of the quality of penguins’ nesting habitats.

“From other studies that used actual ground counts -- people going and physically counting penguins -- and from high-resolution satellite imagery, we have global estimates of Adélie penguin breeding locations, meaning where they are present and where they are absent, throughout the entire Southern Ocean. We also have estimates of population size and how their populations have changed over last few decades,” said Cimino. “We used all these data to run habitat suitability models.”

“When we combined this data with satellite information and future climate projections of sea surface temperature and sea ice, we can look at past and future changes in Adélie penguin habitat suitability,” Cimino said. "Satellite data allowed me to look at all Adélie penguin habitats throughout the entire Southern Ocean and over multiple decades, which otherwise would not be possible using data solely collected on land or by ship."

By analyzing past satellite observations, the researchers examined the number of years from 1981 to 2010 that had novel or unusual climate  —when sea surface or ice temperatures deviated from average— during the Adélie penguin chick-rearing period and then used an ensemble of global climate models to make predictions about Adélie penguin habitat suitability from 2011 to 2099. The team validated the models with documented population trends.

space perspective of Antarctica with data overlay
This graphic shows changes to the status of Adélie penguin colonies.
Credits: NASA's Goddard Space Flight Center

According to Cimino, the southern regions of the West Antarctic Peninsula, associated islands and northern regions of the Peninsula, which are already experiencing population declines, are projected to experience the greatest frequency of unusual climate this century due to warm sea surface temperatures. This suggests that warm sea surface temperatures may cause a decrease in the suitability of chick-rearing habitats at northerly latitudes.

“Penguin colonies near Palmer Station on the West Antarctic Peninsula have declined by at least 80 percent since the 1970s,” Cimino said. “Within this region we saw the most novel climate years compared to the rest of the continent. This means the most years with warmer than normal sea surface temperature. These two things seem to be happening in the West Antarctic Peninsula at a higher rate than in other areas during the same time period.”

By contrast, the study also suggests several refugia—areas of relatively unaltered climate—may exist in continental Antarctica beyond 2099, which would buffer a species-wide decline. Understanding how these refugia operate is critical to understanding the future of this species.

“The Cape Adare region of the Ross Sea is home to the earliest known penguin occupation and has the largest known Adélie penguin rookery in the world,” Cimino said. “Though the climate there is expected to warm a bit, it looks like it could be a refugia in the future, and if you look back over geologic time it was likely a refuge in the past,”

The researchers reported that climate change impacts on penguins in the Antarctic will likely be highly site-specific based on regional climate trends, and that a southward contraction in the range of Adélie penguins is likely over the next century.

“Studies like this are important because they focus our attention on areas where a species is most vulnerable to change,” concluded Cimino. “The results can have implications for other species that live in the area and for other ecosystem processes.”
Karen B. Roberts (University of Delaware)
adapted by Maria-Jose Viñas, NASA’s Earth Science News Team
Last Updated: July 8, 2016
Editor: Karl Hille

Friday, July 8, 2016

Penguins on world’s smelliest island in danger as volcano erupts, covering them in ash

A chinstrap penguin moulting on Zavodovski Island in the south Atlantic 
A chinstrap penguin moulting on Zavodovski Island in the south Atlantic  Credit: Pete Bucktrout, British Antarctic Survey 
Penguins on a remote British island are in danger of being wiped out after a volcano erupted, showering them in ash.
The British Antarctic Survey (BAS) has warned that 1.3 million birds on Zavodovski Island are threatened by the natural disaster, which has covered the island in toxic smoke and sent ash raining down over half the landmass.
The island, which is part of the British Overseas Territory of South Georgia & the South Sandwich Islands in the southern Atlantic Ocean, is home to more than one million chinstrap penguins, the largest colony in the world, as well as 180,000 macaroni penguins, notable for the yellow plume on their heads.
Conservationists are concerned because the chinstrap penguins are moulting, shedding their old feathers for new, which means they cannot leave the island to find safety. During moulting, penguins lose their insulation and waterproofing so they have to stay out of the water.
Mount Curry on Zavodovski Island has been erupting since March 
Mount Curry on Zavodovski Island has been erupting since March  Credit: British Antarctic Survey 
The BAS is planning an expedition later in the year to check on how the ash has affected the colony.
“As the images were captured during the moult period for the chinstraps, the consequences could be very significant,” said Mike Dunn, a penguin ecologist from BAS.
“When the penguins return to breed later in the year, it will be interesting to see what impact this event has on their numbers.”
A group of chinstrap penguins 
The chinstrap penguins cannot leave the island because they are moulting Credit: Alamy 
Zavodovski Island is the most northerly of the South Sandwich Islands, a remote uninhabited archipelago of islands in the Sub Antarctic.
The island is known as the smelliest place on Earth because of the sulphuric air that emanates from the volcano. It has features including Stench Point, Acrid Point, Pungent Point, Reek Point and Noxious Bluff.
It is the first time that Zavodovski Island has been witnessed erupting, although there is evidence that it erupted in the 1970s, possibly in the 1980s and as late as 2012.
A satellite image of Zavodovski Island 
The eruption has covered half the island in ash Credit: Peter Fretwell, British Antarctic Survey 
Photos taken by fishing boats in the area show the main volcanic vent is on the western side of the island, but the prevailing wind is blowing the smoke and ash to the east, and depositing much of it on the lower slopes of the volcano where the chinstraps live in great numbers.
Mount Curry on Zavodovski Island first began erupting in March and grew more active following a 7.2 magnitude earthquake last month. Satellite imagery has confirmed that a second volcano, Mount Sourabaya on Bristol Island to the south, is also now erupting.
A chinstrap penguin 
The island is  is home to more than one million chinstrap penguins Credit: Alamy 
Dr Peter Fretwell, a geographer from BAS who was involved in the remapping of the archipelago, said: “We don’t know what impact the ash will have on the penguins. If it has been heavy and widespread it may have a serious effect on the population.
“It’s impossible to say, but two scientific expeditions are scheduled to visit the region from later this year and will try to assess the impact of the eruption.”
Chinstrap penguins are one of the brush-tailed penguin species common around the Antarctic Peninsula and Scotia Sea. The penguins are named after the distinctive strap under their beaks. Their bodies are around 70cm long and stand around 50cm high. Zavodovski Island is one of the world’s largest colonies of penguins.
A chinstrap penguin  moulting 
The island holds the largest colony of chinstrap penguins, named for the distinctive mark under their beaks  Credit: Pete Bucktrout, British Antarctic Survey  

King penguins keep an ear out for predators

Society for Experimental Biology
Credit: Tessa van Walsum
Sleeping king penguins react differently to the sounds of predators than to non-predators and other sounds, when they are sleeping on the beach. Research carried out at the University of Roehampton, UK, has revealed that even asleep, these penguins can distinguish between dangerous and benign sounds.

Both adult and juvenile king penguins are prey to large predators like orcas and giant petrels. Even huge non-predator elephant seals can crush penguins to death with their bulky passage. In an environment like this, king penguins who are exhausted after long diving sessions must constantly keep an ear out for incoming threats.

PhD student Tessa Abigail van Walsum explains: "When we played single tones to sleeping penguins, they woke up with little reaction. However, playing them the calls of orcas or skuas caused them to wake up and flee."

Penguins also had strong reactions to some non-predator sounds, reports Ms van Walsum: "The sounds of approaching elephant seals rang big alarm bells for the penguins. Interestingly too, a recording of simple white noise had an unexpectedly strong effect, likely because it sounds much like an incoming wave on the beach." Notably, playing them the sound of unfamiliar predators, such as a dog's growl, got little reaction when they awoke.

The ability of these birds to respond differently upon waking up suggests that they might sleep with just one half of their brain, while keeping close watch with the other half similar to some migratory birds - essentially 'keeping an eye open'.

This research helps us to understand the survival strategies of king penguins in their natural habitats. In line with this, the research group would also like to test the sleeping behaviours of these birds at sea, as Ms van Walsum explains: "Presumably, king penguins sleep at sea when they are on long diving expeditions, so it will be fascinating to discover how they stay alert in that environment."

King penguin response video can be seen at the following link:

Saturday, July 2, 2016

Antarctica Is Warming Quickly, And That’s Bad News For Penguin Colonies

CREDIT: Flickr/Marie and Alistair Knock
An Adelie penguin surveys the landscape from a rock slope on Petermann Island, Antarctica

About a third of Adelie penguin colonies in Antarctica could disappear in the next four decades due to human-caused global warming, a figure that could balloon to more than half by the end of the century, a new study published Wednesday found.

Published in Scientific Reports, the study projects dramatic colony losses by 2060 as global warming affects nesting and potentially the penguins’ food supply of krill and fish. “With these numbers it’s important to note that we are talking about 30 percent of the current Adelie colonies … not the population. For example, there are about 200 Adelie colonies, but within those colonies, there [are] millions of penguins,” Megan Cimino, lead author and postdoctoral scholar at Scripps Institute of Oceanography, told ThinkProgress.

Characterized by a white halo around the eyes, Adelie penguins are fast-swimming predators that breed on the coasts of the southernmost continent of the planet. As of 2014 there were some 3.79 million breeding pairs of Adelie penguin, according to Audubon.

Like other penguin species, Adelie penguins have historically benefited from some warming, which allows better access to rock breeding grounds and the ocean for foraging. However, Cimino and colleagues at the University of Delaware report that warming benefits may have a tipping point. “It is only in recent decades that we know Adelie penguins’ population declines are associated with warming, which suggests that many regions of Antarctica have warmed too much and that further warming is no longer positive for the species,” she said.
The poles are warming faster than most of the planet. For Antarctica, that means rapid ice melt at increased rates. The Antarctic Peninsula north of the continent has warmed some 2.5 degrees Celsius — 4.5 degrees Fahrenheit — since 1950, according to the National Science and Ice Data Center (NSIDC). Meanwhile, the West Antarctic Ice Sheet is losing mass, likely due to warmer water deep in the ocean near the coast. The NSIDC reports that some stations in East Antarctica show some cooling, but that in general Antarctica is warming up. According to a 2015 study, ice shelves in West Antarctica have lost some 18 percent of their volume over the last two decades.

West Antarctica is seeing dramatic ice loss particularly the Antarctic Peninsula and Pine Island regions. Ice loss culprits include the loss off buttressing ice shelves, wind, and a sub-shelf channel that allows warm water to intrude below the ice.
West Antarctica is seeing dramatic ice loss particularly the Antarctic Peninsula and Pine Island regions. Ice loss culprits include the loss off buttressing ice shelves, wind, and a sub-shelf channel that allows warm water to intrude below the ice.

Funded through the NASA Biological Biodiversity research program, the University of Delaware study is based on 30 years of satellite observations of Adelie penguin colonies. Researchers examined the number of years from 1981 through 2010 that endured unusual climate during the chick-rearing period. They then used these observations and combined them with climate models to project habitat suitability from 2011 through 2099. Cimino said scientists know sea surface temperature and sea ice concentration affect Adelie survival, but the exact dynamic of how that happens is unclear. So far it's known that climate change can affect penguins’ nesting sites and food. For example, precipitation and snowmelt can cause flooding that drowns eggs and small chicks.

According to the study, late 20th-century climate warming along the West Antarctic Peninsula coincides with Adelie population declines, while stable or cooling conditions in the rest of the continent generally cause stable or increasing populations. Indeed, population improvement has been ongoing in East Antarctica, where Adelie penguins almost doubled over the past 30 years, according to a 2015 Australian Antarctic Division study.

So there is a glimmer of hope for the Adelie penguin. Since the effects of global warming will likely be site-specific, some parts of Antarctica will remain suitable for penguins, Cimino said. This means Adelie penguins might in the coming years march to these buffers zones for survival. The Capa Adare region in East Antarctica, home to the earliest known penguin colony, is one of these areas.
"Though the climate there is expected to warm a bit, it looks like it could be a [refuge] in the future, and if you look back over geologic time, it was likely a refuge in the past," she said.