For the past 40 years, the total number of Adélie Penguins, one of the most common on the Antarctic Peninsula, has been steadily declining -- or so biologists have thought. A new study led by researchers from the Woods Hole Oceanographic Institution (WHOI), however, is providing new insights on of this species of penguin. In a paper published in the journal Scientific Reports, the scientists announced the discovery of a previously unknown "supercolony" of more than 1,500,000 Adélie Penguins in the Danger Islands, a chain of remote, rocky islands off of the Antarctic Peninsula's northern tip.

The researchers found that the Danger Islands have 751,527 pairs of Adélie penguins--more than the rest of the entire  Antarctic Peninsula region combined. They include the third and fourth largest Adélie penguin colonies in the world  [Credit: Michael Polito, Louisiana State University]

"Until recently, the Danger Islands weren't known to be an important penguin habitat," says co-PI Heather Lynch, Associate Professor of Ecology & Evolution at Stony Brook University. These supercolonies have gone undetected for decades, she notes, partly because of the remoteness of the islands themselves, and partly the treacherous waters that surround them. Even in the austral summer, the nearby ocean is filled with thick sea ice, making it extremely difficult to access.

Yet in 2014, Lynch and colleague Mathew Schwaller from NASA discovered telltale guano stains in existing NASA satellite imagery of the islands, hinting at a mysteriously large number of penguins. To find out for sure, Lynch teamed with Stephanie Jenouvrier, a seabird ecologist at WHOI, Mike Polito at LSU and Tom Hart at Oxford University to arrange an expedition to the islands with the goal of counting the birds firsthand.

When the group arrived in December 2015, they found hundreds of thousands of birds nesting in the rocky soil, and immediately started to tally up their numbers by hand. The team also used a modified commercial quadcopter drone to take images of the entire island from above.

Earlier reports based on satellite data suggested that the Danger Islands could be home to several penguin "supercolonies."  However, heavy pack ice is common around the Danger Islands, even in austral summer, making difficult to access this area  to conduct a comprehensive survey [Credit: Rachael Herman, Louisiana State University, © Stony Brook University]

"The drone lets you fly in a grid over the island, taking pictures once per second. You can then stitch them together into a huge collage that shows the entire landmass in 2D and 3D," says co-PI Hanumant Singh, Professor of Mechanical and Industrial Engineering at Northeastern University, who developed the drone's imaging and navigation system. Once those massive images are available, he says, his team can use neural network software to analyze them, pixel by pixel, searching for penguin nests autonomously.

The accuracy that the drone enabled was key, says Michael Polito, coauthor from Louisiana State University and a guest investigator at WHOI. The number of penguins in the Danger Islands could provide insight not just on penguin population dynamics, but also on the effects of changing temperature and sea ice on the region's ecology.

"Not only do the Danger Islands hold the largest population of Adélie penguins on the Antarctic Peninsula, they also appear to have not suffered the population declines found along the western side of Antarctic Peninsula that are associated with recent climate change," says Polito.


Being able to get an accurate count of the birds in this supercolony offers a valuable benchmark for future change, as well, notes Jenouvrier. "The population of Adélies on the east side of the Antarctic Peninsula is different from what we see on the west side, for example. We want to understand why. Is it linked to the extended sea ice condition over there? Food availability? That's something we don't know," she says.

It will also lend valuable evidence for supporting proposed Marine Protected Areas (MPAs) near the Antarctic Peninsula, adds Mercedes Santos, from the Instituto Antártico Argentino (who is not affiliated with this study but is one of the authors of the MPA proposal) with the Commission for the Conservation of the Antarctic Marine Living Resources, an international panel that decides on the placement of MPAs. "Given that MPA proposals are based in the best available science, this publication helps to highlight the importance of this area for protection," she says.

Source: Woods Hole Oceanographic Institution [March 02, 2018]

More than 70 percent of the global King penguin population, currently forming colonies in Crozet, Kerguelen and Marion sub-Antarctic islands, may be nothing more than a memory in a matter of decades, as global warming will soon force the birds to move south, or disappear. This is the conclusion of a study published in the journal Nature Climate Change and performed by an international team of researchers.

More than 70 percent of the global King penguin population may be nothing more than a memory in a matter of decades,  as global warming will soon force the birds to move south, or disappear [Credit: Robin Cristofari]

"The main issue is that there is only a handful of islands in the Southern Ocean and not all of them are suitable to sustain large breeding colonies" says Robin Cristofari, first author of the study, from the Institut Pluridisciplinaire Hubert Curien (IPHC/CNRS/University of Strasbourg) and the Centre Scientifique de Monaco (CSM).

King penguins are in fact picky animals: in order to form a colony where they can mate, lay eggs and rear chicks over a year, they need tolerable temperature all year round, no winter sea ice around the island, and smooth beach of sand or pebbles. But, above all, they need an abundant and reliable source of food close by to feed their chicks. For millennia, this seabird has relied on the Antarctic Polar Front, an upwelling front in the Southern Ocean concentrating enormous amounts of fish on a relatively small area.

Yet, due to climate change, this area is drifting south, away from the islands where most King penguins currently live. Parents are then forced to swim farther to find food, while their progeny is waiting, fasting longer and longer on the shore. This study predicts that, for most colonies, the length of the parents' trips to get food will soon exceed the resistance to starvation of their offspring, leading to massive King penguin crashes in population size, or, hopefully, relocation.

King penguins are picky animals [Credit: Celine LeBohec]

Using the information hidden away in the penguin's genome, the research team has reconstructed the changes in the worldwide King penguin population throughout the last 50,000 years, and discovered that past climatic changes, causing shifts in marine currents, sea-ice distribution and Antarctic Polar Front location, have always been linked to critical episodes for the King penguins. However, hope is not lost yet: King penguins have already survived such crises several times (the last time was 20 thousand years ago), and they may be particularly good at it.

"Extremely low values in indices of genetic differentiation told us that all colonies are connected by a continuous exchange of individuals," says Emiliano Trucchi formerly at the University of Vienna and now at the University of Ferrara, one of the coordinator of the study. "In other words, King penguins seem to be able to move around quite a lot to find the safest breeding locations when things turn grim."

But there is a major difference this time: for the first time in the history of penguins, human activities are leading to rapid and/or irreversible changes in the Earth system, and remote areas are no exception. In addition to the strongest impact of climate change in Polar Regions, Southern Ocean is now subject to industrial fishing, and penguins may soon have a very hard time fighting for their food.

Penguins form colonies in Crozet, Kerguelen and Marion sub-Antarctic islands [Credit: Celine LeBohec]

"There are still some islands further south where King penguins may retreat," notes Celine Le Bohec (IPHC/CNRS/University of Strasbourg and CSM), leader of the programme 137 of the French Polar Institut Paul-Emile Victor within which the study was initiated, "but the competition for breeding sites and for food will be harsh, especially with the other penguin species like the Chinstrap, Gentoo or Adelie penguins, even without the fisheries. It is difficult to predict the outcome, but there will surely be losses on the way. If we want to save anything, proactive and efficient conservation efforts but, above all, coordinated global action against global warming should start now."

Source: University of Vienna [February 26, 2018]

A NASA study based on an innovative technique for crunching torrents of satellite data provides the clearest picture yet of changes in Antarctic ice flow into the ocean. The findings confirm accelerating ice losses from the West Antarctic Ice Sheet and reveal surprisingly steady rates of flow from its much larger neighbor to the east.

The flow of Antarctic ice, derived from feature tracking of Landsat imagery [Credit: NASA Earth Observatory]

The computer-vision technique crunched data from hundreds of thousands of NASA-U.S. Geological Survey Landsat satellite images to produce a high-precision picture of changes in ice-sheet motion.

The new work provides a baseline for future measurement of Antarctic ice changes and can be used to validate numerical ice sheet models that are necessary to make projections of sea level. It also opens the door to faster processing of massive amounts of data.

“We’re entering a new age,” said the study’s lead author, cryospheric researcher Alex Gardner of NASA’s Jet Propulsion Laboratory in Pasadena, California. “When I began working on this project three years ago, there was a single map of ice sheet flow that was made using data collected over 10 years, and it was revolutionary when it was published back in 2011. Now we can map ice flow over nearly the entire continent, every year. With these new data, we can begin to unravel the mechanisms by which the ice flow is speeding up or slowing down in response to changing environmental conditions.”

The innovative approach by Gardner and his international team of scientists largely confirms earlier findings, though with a few unexpected twists.

Among the most significant: a previously unmeasured acceleration of glacier flow into Antarctica’s Getz Ice Shelf, on the southwestern part of the continent -- likely a result of ice-shelf thinning.

Speeding up in the west, steady flow in the east

The research, published in the The Cryosphere, also identified the fastest speed-up of Antarctic glaciers during the seven-year study period. The glaciers feeding Marguerite Bay, on the western Antarctic Peninsula, increased their rate of flow by 1,300 to 2,600 feet (400 to 800 meters) per year, probably in response to ocean warming.

Perhaps the research team’s biggest discovery, however, was the steady flow of the East Antarctic Ice Sheet. During the study period, from 2008 to 2015, the sheet had essentially no change in its rate of ice discharge -- ice flow into the ocean. While previous research inferred a high level of stability for the ice sheet based on measurements of volume and gravitational change, the lack of any significant change in ice discharge had never been measured directly.

The study also confirmed that the flow of West Antarctica’s Thwaites and Pine Island glaciers into the ocean continues to accelerate, though the rate of acceleration is slowing.

In all, the study found an overall ice discharge for the Antarctic continent of 1,929 gigatons per year in 2015, with an uncertainty of plus or minus 40 gigatons. That represents an increase of 36 gigatons per year, plus or minus 15, since 2008. A gigaton is one billion tons.

The study found that ice flow from West Antarctica -- the Amundsen Sea sector, the Getz Ice Shelf and Marguerite Bay on the western Antarctic Peninsula -- accounted for 89 percent of the increase.

Computer vision

The science team developed software that processed hundreds of thousands of pairs of images of Antarctic glacier movement from Landsats 7 and 8, captured from 2013 to 2015.

These were compared to earlier radar satellite measurements of ice flow to reveal changes since 2008.

“We’re applying computer vision techniques that allow us to rapidly search for matching features between two images, revealing complex patterns of surface motion,” Gardner said.

Instead of researchers comparing small sets of very high-quality images from a limited region to look for subtle changes, the novelty of the new software is that it can track features across hundreds of thousands of images per year -- even those of varying quality or obscured by clouds -- over an entire continent.

“We can now automatically generate maps of ice flow annually -- a whole year -- to see what the whole continent is doing,” Gardner said.

The new Antarctic baseline should help ice sheet modelers better estimate the continent’s contribution to future sea level rise.

“We’ll be able to use this information to target field campaigns, and understand the processes causing these changes,” Gardner said. “Over the next decade, all this is going to lead to rapid improvement in our knowledge of how ice sheets respond to changes in ocean and atmospheric conditions, knowledge that will ultimately help to inform projections of sea level change.”

Author: Pat Brennan | Source: NASA [February 21, 2018]

A team of scientists, led by British Antarctic Survey (BAS), heads to Antarctica this week (14 February) to investigate a mysterious marine ecosystem that's been hidden beneath an Antarctic ice shelf for up to 120,000 years.

Larsen C ice shelf [Credit: NASA/Nathan Kurtz]

The iceberg known as A68, which is four times of London, calved off from the Larsen Ice Shelf in July 2017. The scientists will travel by ship to collect samples from the newly exposed seabed, which covers an area of around 5,818 km2. It is an urgent mission. The ecosystem that's likely been hidden beneath the ice for thousands of years may change as sunlight starts to alter the surface layers of the sea.

The international team, from nine research institutes, leaves Stanley in the Falkland Islands on 21 February to spend 3 weeks in February-March 2018 on board the BAS research ship RRS James Clark Ross. Satellite monitoring is critical for the ship to navigate through the ice-infested waters to reach this remote location.

Marine biologist Dr Katrin Linse from British Antarctic Survey is leading the mission. She says: "The calving of A68 provides us with a unique opportunity study marine life as it responds to a dramatic environmental change. It's important we get there quickly before the undersea environment changes as sunlight enters the water and new species begin to colonise. We've put together a team with a wide range of scientific skills so that we can collect as much information as possible in a short time. It's very exciting."

The team will investigate the area previously under the ice shelf by collecting seafloor animals, microbes, plankton, sediments and water samples using a range of equipment including video cameras and a special sledge pulled along the seafloor to collect tiny animals. They will also record any marine mammals and birds that might have moved into the area. Their findings will provide a picture of what life under the ice shelf was like so changes to the ecosystem can be tracked.

This newly exposed marine area is the first to benefit from an international agreement made in 2016 by the Commission for the Conservation of Antarctic Marine Living Resources (CCAMLR). This agreement designates Special Areas for Scientific Study in newly exposed marine areas following the collapse or retreat of ice shelves across the Antarctic Peninsula region. The agreement came following a European Union proposal to CCAMLR, led by British Antarctic Survey (BAS) scientists.

Professor David Vaughan, Science Director at BAS says: "The calving of A68 offers a new and unprecedented opportunity to establish an interdisciplinary scientific research programme in this climate sensitive region. Now is the time to address fundamental questions about the sustainability of polar continental shelves under climate change.

We need to be bold on this one. Larsen C is a long way south and there's lots of sea ice in the area, but this is important science, so we will try our best to get the team where they need to be."

Prof. Dr. Angelika Brandt from the Marine Zoology department is on board representing the Senckenberg Research Institute and Natural History Museum. During and after the Larsen-C expedition Brandt and collaborators will focus on biodiversity and assemblage structure assessment of the epi- and suprabenthic peracarid crustaceans and their respective colonisation in this newly developed benthic ecosystem.

While the team mobilises for the expedition, glaciologists and remote sensing specialists continue to monitor the movement of the Larsen C Ice Shelf. In December 2017, a team from University of Leeds worked on the remaining ice shelf to investigate changes in ice structure after the calving event, to be able to predict shelf stability in the future.

Source: Senckenberg Research Institute and Natural History Museum [February 13, 2018]

New research led by the University of Colorado Boulder shows that the changing topography of ice sheets in the Northern Hemisphere during the last Ice Age forced changes in the climate of Antarctica, a previously undocumented inter-polar climate change mechanism.

The chemical composition of snowflakes, such as this, can act as recorders of the climate. After they have become frozen into the ice sheets, that information can be unlocked may years later and used to tell us how the climate  was different in the past [Credit: Tyler Jones]

The new study - published in the journal Nature and co-authored by researchers at the University of Bristol, University of Washington and UC Berkeley - suggests that substantial reduction of the Laurentide Ice Sheet that covered much of present-day North America approximately 16,000 years ago resulted in significant climate variations in the tropical Pacific and in West Antarctica.

"The results demonstrate how seemingly localized effects in one part of the world may have a large impact on climate elsewhere on Earth," said Tyler Jones, a research associate in CU Boulder's Institute of Arctic and Alpine Research (INSTAAR) and the lead author of the new study.

Jones and his colleagues studied an ice core collected from the West Antarctic Ice Sheet (WAIS) in order to document historical climate. The WAIS ice core is the first climate record to preserve year-to-year climate variability continuously as far back as 30,000 years ago.

Ice Retreat in North America after the last Ice Age [Credit: T. Kostolany/WikiCommons]

"This ice core is really important because it contains long-term climate information that relates to the timescales that humans experience and remember," said Jones.

At INSTAAR's Stable Isotope Lab, the researchers slowly melted and then vaporized the ice cores for analysis using laser absorption spectroscopy, a new methodology that reveals the isotopic composition of the water. This method has improved the researchers' ability to measure climate change through ice cores, both by increasing measurement resolution and saving time.


When researchers examined the amplitude of year-to-year climate signals preserved in the WAIS core, they noticed a large, abrupt decline in the signal strength approximately 16,000 years ago. They subsequently determined that the anomaly was largely caused by the lowering of the Laurentide Ice Sheet.

"When there is a large ice sheet over North America, the circulation of the atmosphere becomes very different than today," said Jones. The new results corroborate another published research study suggesting that ice sheet changes during the same time period shifted the climate in the tropical Pacific enough to transform the terrestrial ecosystems of present-day Indonesia from a grassland savannah to a rainforest, which they remain today.

Overall, the study highlights that changes in the Earth's climate system can be linked across vast distances.

"No one has really investigated this kind of signal before. It potentially opens up new and exciting ways to think about climate data," said Jones.

Author: Trent Knoss | Source: University of Colorado at Boulder [February 05, 2017]

In a study spanning two decades, a team of researchers led by Colorado State University found declining numbers of soil fauna, nematodes and other animal species in the McMurdo Dry Valleys, one of the world's driest and coldest deserts. This discovery is attributed to climate change, which has triggered melting and thawing of ice in this desert since an uncharacteristically warm weather event in 2001.

There are no plants, birds or mammals in the McMurdo Dry Valleys, which are located in the largest region  of the Antarctic continent [Credit: Ashley Shaw]

There are no plants, birds or mammals in the McMurdo Dry Valleys, located in the largest region of the Antarctic continent. But microbes and microscopic soil invertebrates live in the harsh ecosystem, where the mean average temperature is below -15 degrees Celsius, or 5 degrees Fahrenheit.

The findings offer insight and an alarm bell on how ecosystems respond to climate change and to unusual climate events, scientists said.

"Until 2001, the region was not experiencing a warming trend," said Walter Andriuzzi, lead author of the study and a postdoctoral researcher in the Department of Biology and School of Global Environmental Sustainability.

"On the contrary, it was getting colder," he continued. "But in 2001, the cooling trend stopped abruptly with an extremely warm weather event. Since then, the average temperatures are either stable or are increasing slightly. But most importantly, there have been more frequent intense weather events."

The research team sampled soil invertebrates and measured soil properties, including water content, in three hydrological basins and at three different elevations in the region. In Taylor Valley, the field study was launched in 1993; in Miers and Garwood valleys, scientists started their work in 2011.

Andriuzzi said what the team found in this long-term study cannot be observed by looking at average or monthly temperatures.

"It's a few hours, or days of unusually warm weather," he said. "There are even peaks of high solar radiation that trigger ice thawing without high temperatures. That's how climate change is happening there, and it's already starting to impact the biological community there."

Higher temperatures have led to the decline of the nematode Scottnema lindsayae, seen here through a microscope  [Credit: Walter Andriuzzi, Colorado State University]

Higher temperatures mean more melting and thawing of ice from glaciers and permafrost, which has led to the decline of the most common species, the nematode Scottnema lindsayae. Other species are becoming more abundant and are spreading uphill. As a result, at higher elevations, the microbes and animals in the soil are becoming more diverse, with unknown consequences for the ecosystem.

"This is happening worldwide, and not just in Antarctica," said Andriuzzi, who is a researcher in the lab of University Distinguished Professor Diana Wall. In the Rocky Mountains, for instance, scientists have observed insects moving uphill on a year to year basis, due to warming temperatures.

Andriuzzi, who led field work in the McMurdo Dry Valleys, called Antarctic nematodes "remarkable creatures."

"It's amazing that they survive in these conditions," he said. The growing season only lasts a few weeks, but in the field, this microscopic animal may live 10 years.

Given what the team found, Andriuzzi said it will take time for the nematode community to recover from these disturbances.

"With climate change, some species are winners, some are losers," he said. "In the Dry Valleys it's all about how they respond to warming and, most importantly, water."

Andriuzzi said shifts in communities are often very hard to predict because there are so many species.

"It's easier in places like the dry valleys to isolate the effects of climate change, or to isolate how one species responds to climate change in one way," he said. "It's a natural laboratory, where some of the mechanisms that operate elsewhere can be unveiled."

The study is published in the journal Ecology.

Author: Mary Guiden | Source: Colorado State University [January 06, 2018]