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Putting Your Best Tusk Forward: Narwhals and Climate Research

Posted by on Jun 20, 2017 in All Posts, Featured Posts, Science | 0 comments

Putting Your Best Tusk Forward: Narwhals and Climate Research

Spread the News:ShareIn 1576, Queen Elizabeth I paid the equivalent of half a million dollars for a unicorn horn, which she believed could neutralize poison. Of course, it wasn’t a unicorn horn at all, but a narwhal tusk, remarkable in its own right. Today, over 440 years later, narwhals continue to surprise and attract attention. A recent paper in Biology Letters by Kristin Laidre et al. examined narwhal visits to glacial fronts in West Greenland. “We don’t fully understand the relation between narwhals and glaciers,” professor Mads Heide-Jørgensen of the Greenland Institute of Natural Resources told GlacierHub. Laidre added, “Narwhals in places like the Canadian Arctic, for example, have limited access to glacial habitat. However, in Greenland, most narwhals are close to glaciers in summer because Greenland is so glaciated, and there are glaciers along the entire coastline.” It has long been observed that narwhals visit glacial fronts in the summer and autumn, but it is unknown why they seek out this habitat. “Glaciers are productive regions,” commented Laidre. “They attract prey, there’s upwelling and nutrient cycling, and sometimes even osmotic shock to small invertebrates which attracts fish… We hope future studies will help us understand this, but we don’t know exactly why they go there.” Belugas, the “sister species” to the narwhal, also favor freshwater habitat in the summer, seeking out shallow water estuaries. To begin answering this question, Laidre took a novel approach, forming an international, cross-disciplinary team that included scientists from the U.S., Denmark, and the U.K. “The idea was to get biologists and glaciologists to collaborate and share data in an interdisciplinary way,” Laidre said. The team evaluated which glacial characteristics draw narwhals by collecting data from 15 satellite-tagged whales and following their movements through the fjords of Melville Bay in West Greenland. The narwhals demonstrated three preferences: they spent more time at glaciers that discharge a fresher, rather than siltier melt; they preferred slower-flowing glaciers, which are more stable and calve less; and they favored thicker glacial fronts, perhaps because they maximize access to freshwater. Sea ice also provides important habitat for narwhals. “All narwhal populations winter, and some even summer, in dense sea ice concentrations,” said Heide-Jørgensen. In summer, narwhals spend time in the high Arctic where ice has receded, and in fall, the ocean freezes solid, pushing the narwhals away from shore, Laidre explained. “They swim away from the forming ice and move offshore, where they overwinter in dense ice cover with cracks so they can breathe. Narwhals are highly associated with sea ice, perhaps the most of all whales,” he said. Heide-Jørgensen indicated that narwhals will seek out the sea ice when it decreases in coverage rather than wintering in open water. “Reduction of sea ice therefore implies a reduction in habitat, and this will again introduce a reduction in prey base or carrying capacity. In short, less sea ice means less narwhal habitat and eventually less narwhals,” he said. Laidre agreed that “changes in sea ice and the marine ecosystem will likely be the most important factor” to the future of narwhals as climate changes. Since 1979, sea ice freeze-up has occurred almost a month later in Baffin Bay and Melville Bay, where this study took place, and glaciers, of course, are retreating. But far from being simple victims of global warming, narwhals can aid in the collection of data that can help mitigate climate change. In 2005 and 2007, Laidre took advantage of narwhals’ capacity for deep dives and tendency to winter in sea ice, outfitting narwhals with temperature and depth sensors. Narwhals regularly dive over 1,700 meters to...

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Roundup: A Shrinking Lake, a Deepening Lake, and Ice below Sea Level

Posted by on Jun 19, 2017 in All Posts, Featured Posts, News, Roundup, Science | 0 comments

Roundup: A Shrinking Lake, a Deepening Lake, and Ice below Sea Level

Spread the News:ShareGlacial Retreat Shrinks Yukon’s Largest Lake From CBC News: “Kluane MLA Wade Istchenko says receding water levels on Kluane Lake are posing a problem for his constituents — and he wants the government to respond. The lake level first dropped last year, after the Kaskawulsh Glacier retreated so much that its meltwater abruptly switched direction, away from Kluane Lake. Researchers have blamed climate change for the geologic phenomenon referred to as ‘river piracy’.” You can read more about how Istchenko proposes the legislature respond here.   Spillway Lake in Nepal Deepens From Water: “Since the 1950s, many debris-covered glaciers in the Nepalese Himalaya have developed large terminal moraine-dammed supraglacial lakes, which grow through expansion and deepening on the surface of a glacier. As temperatures continue to rise and lakes continue to grow in area and volume, they pose a flooding risk to the Sherpa villages down-valley.” Learn more about how the Ngozumpa Glacier’s terminal lake is growing here.   Melting an Ice Sheet from Below From Nature: “Because the East Antarctic Ice Sheet seems so cold and isolated, researchers thought that it had been stable in the past and was unlikely to change in the future — a stark contrast to the much smaller West Antarctic Ice Sheet, which has raised alarms because many of its glaciers are rapidly retreating. In the past few years, however, “almost everything we thought we knew about East Antarctica has turned out to be wrong”, says Tas van Ommen, a glaciologist at the Australian Antarctic Division in Kingston, near Hobart. By flying across the continent on planes with instruments that probe beneath the ice, his team found that a large fraction of East Antarctica is well below sea level, which makes it more vulnerable to the warming ocean than previously thought. The researchers also uncovered clues that the massive Totten glacier, which holds about as much ice as West Antarctica, has repeatedly shrunk and grown in the past — another sign that it could retreat in the future.” Read more about uncertainty in the East Antarctic here.     Spread the...

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Photo Friday: A Look at Wolverine Glacier

Posted by on Jun 16, 2017 in All Posts, Featured Posts, Images, Science | 0 comments

Photo Friday: A Look at Wolverine Glacier

Spread the News:ShareWolverine Glacier is a valley glacier with maritime climate and high precipitation rates situated in the coastal mountains of Alaska’s Kenai Peninsula. This glacier has been named a “reference glacier” by the World Glacier Monitoring Service because it has been monitored and observed since 1965/66. A majority of the U.S. government’s climate research is taken from 50 years of glacier studies from the United States Geological Survey (USGS). Scientists first decided to take measurements of Wolverine Glacier’s surface mass balance in 1966, using these measurements, as well as local meteorology and runoff data, to estimate glacier-wide mass balances, according to USGS. This data, which makes up the longest continuous set of mass-balance data in North America, allows scientists to better understand glacier dynamics and hydrology, as well as the glaciers’ response to climate change. As temperatures rise, the retreat of glaciers in Alaska is contributing to global sea-level rise. The Wolverine Glacier has been experiencing more variability in winter temperatures, and scientists are continuing to evaluate how glaciers like the Wolverine respond to climate change. Take a look at GlacierHub’s collection of images from Wolverine Glacier.           Spread the...

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Abuzz with Opportunity: Drone Research in the Antarctic

Posted by on Jun 15, 2017 in All Posts, Featured Posts, Science | 0 comments

Abuzz with Opportunity: Drone Research in the Antarctic

Spread the News:ShareSummer in the Western Antarctic Peninsula brings long days, short nights, and a burst of life and activity. Penguins attend to the drama of colony life, seals alternate between hunting and sunning on ice flows, and humpback whales swim by, admired by tourists from the decks of cruise ships. The warmth of the summer sun causes glaciers to calve, creating new icebergs. Now, there’s a new kid on the block— hovering above the glacial landscapes and wildlife, you can sometimes spot an unmanned aerial vehicle (UAV), or drone, helping researchers study animals in new ways. A recent Cambridge University Press publication by David Leary assessed the regulatory response to UAVs by the Antarctic scientific and tourism communities. The Antarctic is new territory for drone researchers and forbidden ground for tourists. In 2014, as both recreation and scientific drone usage in the United States were ramping up, the National Science Foundation prohibited research drones until the agency could address environmental and safety concerns and establish a set of best practices for deployment in Antarctica. The International Association of Antarctic Tour Operators (IAATO) banned drones for the same reasons during the 2015/16 and 2016/17 seasons. Nations outside the U.S. have been leading the charge on Antarctic drone research, and the initial results have been promising. A 2014 project by the Japanese National Institute of Polar Research used UAVs to take aerial photos and magnetic data of Deception and Livingston Islands, collecting data on glacial recession with much lower risk than comes with traditional, manned aircraft. A study by the Warsaw University of Technology and Norwegian National Center for Research and Development outfitted drones with remote sensing technology to gather baseline data on glacial retreat, flora distribution, and whale and seal populations. Professor David Johnston of the Duke University Marine Lab is at the forefront of U.S.-based Antarctic drone research. After receiving a small facility grant from NSF about two years ago, Johnston used the funds to renovate an old building, purchase aircraft and computing infrastructure, and start dreaming up new research questions involving drones. The technology is “changing faster than anything I’ve ever seen,” marveled Johnston. “In the last couple of years, our aircraft can now fly twice as long, the resolution is almost double, and the cost has come way down.” Johnston’s team was first able to fly their aircraft around the Western Antarctic Peninsula on a research cruise in January and February 2017, and they hit the skies running. The team collected footage that allowed them to efficiently count seals and penguins, used photogrammetry techniques to measure humpback whale size, and photographed the process of “bubble netting,” a foraging technique in which the whales work together to concentrate prey into high-density aggregations. “That was one of the more epic things we were able to capture on the trip,” said Johnston. “We can study the timing of bubble burst, the width of the nets, and translate beautiful images into deeply quantitative data.” Johnston is working to demonstrate the value of this technology to research partners in the Palmer Long-Term Ecological Research Station. He anticipates a future of on-demand aerial surveys and remote sensing, and a huge range of applications that include looking at vegetation growth and using a thermal camera to study glacial ground flow. Though there has been concern about UAVs disturbing animals, Johnston believes they are actually among the best practices for wildlife research. “Whales, seals, and sea turtles don’t know drones are there— We can do our measurements in ways that are less risky and noisy. It’s better than sending people through penguin colonies, approaching...

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Polar Bears and Ringed Seals: A Relationship in Transition

Posted by on Jun 14, 2017 in All Posts, Featured Posts, Science | 0 comments

Polar Bears and Ringed Seals: A Relationship in Transition

Spread the News:ShareAlong the tidal glacier fronts of Svalbard, an archipelago halfway between Norway and the North Pole, polar bears have changed their hunting practices. A recent study published in the Journal of Animal Ecology indicates the new behavior is a response to rapidly disappearing sea ice. Charmain Hamilton and other researchers from the Norwegian Polar Institute mapped changes in the spatial overlap between coastal polar bears and their primary prey, ringed seals, to better understand how the bears are responding to climate change. The results don’t bode well for the long-term survival of polar bear populations: as sea ice continues to shrink in area, ringed seals—calorie-rich prey that are high in fat— have become increasingly difficult to catch during the summer and autumn. The bears are now finding sources of sustenance elsewhere: in the archipelago’s thriving bird colonies. The Arctic is warming at a rate three times the global average, and the sea ice in the Svalbard region is experiencing a faster rate of decline than in other Arctic areas. As Charmain Hamilton reported in an interview with GlacierHub, the findings could demonstrate what the future holds for the top predator elsewhere. “The changes that we are currently seeing in Svalbard are likely to spread to other Arctic areas over the coming decades,” she said. Svalbard’s polar bears exhibit one of two annual movement patterns: some follow the sea ice as it retreats northward during the summer, while others stay local, inhabiting coastal areas throughout the year. Both groups of bears depend on sea ice as a platform to hunt ringed seals. Given a rapid decline of sea-ice levels that began in 2006, Hamilton and other researchers wanted to know if the coastal bears were still hunting ringed seals under the deteriorating conditions. The researchers compared satellite tracking data for both polar bears and ringed seals from the periods 2002-2004 and 2010-2013 to assess whether the predator-prey dynamic had shifted. The data was analyzed according to season, with researchers paying careful attention to the dynamics of spring, summer and autumn. In spring, access to fat-rich ringed seals is critical, particularly for mothers weakened from nourishing their young in winter dens. The study shows that coastal polar bears continued to spend the same amount of time near tidal glacier fronts in spring as they did when sea ice was more abundant. The authors conclude that the declines in sea ice in Svalbard have not yet reached the stage at which bears must find alternative hunting methods during the spring. This could help to explain why cub production is not currently declining. However, during summer and autumn, bears are spending less time in the areas around tidal glacier fronts. The study shows a significant decrease in the amount of time bears spent within 5 km of glacier fronts and a sharp increase in the distances they traveled in search of food per day. The ringed seals, on the other hand, have remained near the glacier fronts. As Hamilton reported to GlacierHub, “The reduced spatial overlap between polar bears and ringed seals during the summer indicates that the reductions in sea ice have made it much more difficult for polar bears to hunt their primary prey during this season.” As sea ice recedes, ringed seals are increasingly relying on calved pieces of glacier ice as shelters and resting places. Since these pieces of calved ice are no longer connected to land-fast ice, polar bears can no longer walk up to the seals or wait by their breathing holes, but have to attack from the water. This involves swimming surreptitiously up to seals resting on calved...

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Asia’s High Glaciers Protect Communities from Drought

Posted by on Jun 13, 2017 in All Posts, Featured Posts, Science | 0 comments

Asia’s High Glaciers Protect Communities from Drought

Spread the News:ShareA recent study in Nature by Hamish Pritchard, a glaciologist at Cambridge University and researcher for the British Antarctic Survey, shows that the high mountains of Asia, including the Himalayas, the Hindu Kush, and Karakoram, are being greatly affected by global warming. In some areas of the Himalayan region, for example, temperatures have risen faster than the global average. From 1982 to 2006, the average annual mean temperature in the region increased by 1.5 °C, with an average increase of .06 °C per year, according to UNEP. Even though studies on the high mountains of Asia are incomplete, it is believed that the mountains will lose half of their ice in the next 30 years. This glacial loss has consequences for Asia as the glaciers provide an important ecosystem service to 800 million people by acting as a regional buffer against drought and providing summer meltwater to rivers and aquifers. If the glaciers in the eastern and central Himalayas disappear by 2035, the ecosystem service protecting against drought would be lost. Despite the fact that glaciers can promote drought resiliency, the surrounding areas would be particularly vulnerable to water scarcity because the glaciers will not supply enough meltwater to maintain the rivers and streams at adequate levels. Lack of water could lead to devastating food shortages and malnutrition, further impacting the economy and public health. Based on a projected estimate of glacier area in 2050, it is thought that declining water availability will eventually threaten some 70 million people with food insecurity. Droughts in the Himalayan region have already resulted in more than 6 million deaths over the past century. Glacier loss would only add to drought-related water stress in the region, impacting a surrounding 136 million people. In an interview with GlacierHub, Pritchard explained, “Without these glaciers, particularly in the Indus and Aral, droughts would be substantially worse in summer than they are now, and that could be enough to drive conflict and migration, which becomes a regional and potentially global issue. It could result in social instability, conflict, and migrations of populations.” According to Pritchard’s research, the high mountains of Asia supply 23 cubic kilometers of water downstream every summer. If the glaciers were to vanish, the amount of water during the summer would decrease by 38 percent in the upper Indus basin on average and up to 58 percent in drought conditions. The loss of summer meltwater would have its greatest effects on the municipal and industrial needs of Pakistan, Tajikistan, Turkmenistan, Uzbekistan and Kyrgyzstan, with water stress being classified as medium to extremely high. For example, the Indus River, which has one of the world’s largest irrigation networks, is Pakistan’s primary source of freshwater. About 90 percent of Pakistan’s agriculture depends on the river and much of the world’s cotton comes from the Indus River Valley. Additionally, decreased meltwater would further affect upstream countries such as Kyrgyzstan, Tajikistan and Nepal that rely on hydropower. The Toktogul hydropower plant and four smaller plants downstream produce almost 80 percent of Kyrgyzstan’s electricity. Pritchard presents data that show how much the glacier meltwater contributes to different regions within Asia during drought. Some areas, such as the Aral Sea, rely exclusively on the glacier water during the drought months. The glaciers provide meltwater when rainfall is minimal or nonexistent under drought conditions because glaciers store precipitation for decades to centuries as ice, which then flows to lower altitudes when melting in the summer. Twila Moon, a postdoctoral research associate at the U.S. National Snow and Ice Data Centre in Boulder, Colorado, recently discussed the consequences of global...

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