On Frozen Ground

January 27, 2010

Dr. Vladimir Romanovsky, director of the Permafrost Laboratory at the University of Alaska, Fairbanks, conducts permafrost research on the North Slope of Alaska. Photo: courtesy Dr. Romanovsky

By Marcy Davis

Scientists have long known the importance of permafrost, a layer of frozen soil in circumpolar regions that is one of the first victims of a warming climate. For more than 50 years, researchers have dropped temperature sensors into boreholes at various depths all around the world to track the state of the permafrost. But much of this data remains isolated and unpublished, inaccessible to anyone hoping to track global temperature change.

But if Dr. Vladimir Romanovsky, director of the Permafrost Laboratory at the University of Alaska, Fairbanks, Geophysical Institute, has his way, an international collaboration between the United States and Russia could produce the first international permafrost network. Call it the Cold Cooperation, the scientific opposite of the Cold War.

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As one of 35 National Science Foundation-supported Arctic Observing Network (AON) projects, Romanovsky’s work will integrate 80 Alaskan borehole sites—locations where researchers study permafrost, with about 160 Russian borehole sites. This initial step will provide the baseline temperature estimates necessary to evaluate future rates of change, according to Romanovsky.

“Permafrost data is beneficial to any ecological or carbon cycle study,” said Romanovsky. “Providing our data to other studies is important. In turn, we want to know about ecosystems, and have to be able to take into account hydrology and vegetation changes. Establishing this network will facilitate better communication and data sharing.”

Improved Modeling

In addition, the network will make permafrost data more available to climate modelers, which should improve researchers’ abilities to predict and understand the interaction between permafrost and climate.

Permafrost

Permafrost, defined as any earth material at or below 0°C for two or more consecutive years typically forms in the Arctic, subarctic, Antarctica, and in high alpine regions. It can vary in extent and thickness, and the largest area of continuous permafrost underlies the Tibetan Plateau in China with an area totaling 2.5 million square kilometers, more than twice the size of Alaska. Eastern Siberia holds the record for thickest permafrost at 1400 meters.

Domestically, permafrost in the Rocky Mountains of North America is laterally discontinuous, or patchy, with thicknesses ranging from less than one to several meters. Where temperatures are consistently colder, the permafrost is thicker.

Along Alaska’s North Slope, permafrost is continuous except under big lakes and rivers, which do not freeze completely to the bottom in winter; water acts as a source of heat to the ground below. At Prudhoe Bay, permafrost is 660 m thick. In Alaska’s interior, permafrost is discontinuous, found mostly in stands of black spruce and in low valleys where moss and peat are prevalent; Aspen groves and south-facing slopes rarely have permafrost.

Changes To Frozen Ground

Romanovsky has observed temperature changes in Alaskan permafrost, but added that interpreting those changes is difficult. Natural oscillations that last multiple decades show the same patterns; researchers need more time to understand whether or not their results result from longer-term, global climate change.

“The cycle seems on an upward trend,” he said. “What we see could be global warming, or could just be a longer natural oscillation. What are interesting are the hemispherical similarities between Alaska and Russia. Models can help explain past temperatures and future projections regionally and globally. So, we need to keep making measurements.”

Threats To Permafrost

One of the biggest concerns about warming permafrost is that greenhouse gases such as methane now sequestered in permafrost may be released back into the atmosphere, thereby creating a positive feedback for future climate warming. Another worry stems from the potential impacts of thawing permafrost on the communities, which could include localized but important changes in ecosystems and infrastructure.

Romanovsky says, “We are seeing changes in permafrost, but they are slowly evolving changes. There could be dangers for people who live in permafrost regions so they should be aware of the problem, but should not panic. Instead, we need to focus on mitigation, and working together. We have some ways to tackle these problems, but it takes time and money.”

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There Comes the Sun

January 26, 2010

Crescent Moon over Summit Station. Photo: Bill McCormick

January 25, 2010

Kip Rithner wrote:

Hello Summiteers,
Exciting times! I hope everyone’s doing well on the world’s roof—I imagine you’re looking forward to sunshine and getting out of Summit after the Phase III team arrives around February 2.

Speaking of sun, I hope you’ll keep the field notes blog in mind when you enjoy the sunrise on January 27th. I’d love to post a picture of you enjoying the spectacle. This time always makes me think of the Beatles song. What do you think of?

Summit manager wrote:

Hi Kip,

Yes, we’ll surely be taking photos if the weather allows.  Here’s the forecast that we just received:

“Thursday:  Cloudy and maybe light snow at times. Still risk of fog and southwesterly winds about 05-15kt and temperatures unchanged or slightly warmer.”

Karl Newyear
Summit Station Manager
Winter 2009-10 Phase II

Kip Rithner wrote:

Booooo!  Maybe it’ll clear a bit, though.

Summit Manager wrote:

Hi Kip,

This is the best forecast we’ve seen in weeks!


The Arctic Food Chain: Mercury and Polar Bears

January 26, 2010

A recent study found that polar bears predating 1950 that ate a phytoplankton-based diet have higher concentrations of mercury in their systems than bears that eat diets based from the ice algae food web. Photo: Jerzy Strzelecki

The looming threat of melting sea ice has raised awareness about climate change’s impact on polar bears, an endangered species. Also relevant—and less studied—is how changes to the earth—and melting sea ice—could affect the species’ diet. 

Which may be why a recent study in the December issue of the journal Polar Research that establishes two different primary food webs for polar bears and documents surprisingly higher mercury levels in bears that eat from one specific web garnered interest from both the scientific community and science journalists. 

Mercury concentrations can be poisonous to humans and other members of the food chain; currently scientists do not know what levels of mercury are dangerous to polar bears. 

(Note: mercury is not a greenhouse gas, nor is it associated directly with global warming. However, high concentrations of mercury in polar bears is significant to scientists for complex reasons outlined below.) 

Diet Details 

 The study confirmed that polar bears got their food from two primary food webs: 

Phytoplankton-based, which begins with single-celled plants inhabiting the top layer of the ocean 

Ice algae-based, which begins with microscopic plants living within and below the sea ice 

The research went further, analyzing mercury concentrations in the bears’ fur. 

They found that polar bears chowing down on the phytoplankton-based food chain, which originates in the open ocean in the absence of sea ice, had greater concentrations of mercury in their bodies than bears whose diet traced back to the ice algae. 

Dr. Joel Blum, principal investigator, collects snow samples to test for mercury concentrations near Barrow, AK. Photo: Joel Blum

Mercury Investigations 

One of the study’s authors, Joel Blum, the John D MacArthur Professor of Geological Sciences, and Professor of Ecology at the University of Michigan, said the findings are significant as scientists strive to learn more about mercury, an inorganic element whose presence in the atmosphere has tripled since the industrial revolution. 

“Very little is known about how mercury moves around the globe,” said Blum. “But we know humans have increased the amount of mercury in the environment.” 

Mercury can stay in the atmosphere for up to a year and travel to far reaches of the globe, and scientists have documented a considerable amount of mercury deposited in the Arctic. Studying the bears provides important background data on earlier mercury levels, Blum said. 

Factory emissions are a major source of mercury pollution. Photo: courtesy Air Resources Laboratory, NOAA

Museum Bears 

Blum and his colleagues analyzed mercury concentrations in polar bears that predated 1950, before the major influx of mercury from coal-burning power plants and other industrial activities that send mercury into the atmosphere. 

Specifically, they analyzed the late-19th- and early-20th-century polar bear hair for the chemical signatures of nitrogen isotopes, carbon isotopes, and mercury concentrations, looking back in time to a period before man-caused mercury emissions escalated. 

“We know that due to human inputs mercury distribution in the Arctic is currently heterogeneous (multi-faceted and complex), so we decided to take a step back and understand the fundamental processes, pre-1950,” said Blum. 

Phytoplankton Diets = High Mercury Concentrations 

 The discovery that bears that eat on the phytoplankton food chain have significantly higher mercury concentrations suggests that as sea ice melts and bears eat more phytoplankton-based diets, their mercury concentrations could increase, said Blum. 

Moving Through The Food Web 

 And, he added, if concentrations of mercury are increasing in polar bears, which are at the top of the food chain, “this is an indication that they are also increasing lower in the arctic food chain.” 

That means human populations that rely on subsistence hunting could also be experiencing an increase of mercury exposure as well. 

How Mercury Becomes Poison 

 Relatively harmless in its inorganic state, mercury becomes extremely poisonous to humans when it is converted into methylmercury and passed up the food chain. 

Mercury in its methylated state is considered by many to be “public enemy number one,” said Blum. Its prevalence in the Arctic and potential to spread through the food chain is a very real concern and could be exacerbated by climate change. 

Recent discoveries about mercury’s biochemical properties have unlocked mysteries about the element and enabled scientists to probe deeper into the question of how a relatively inert element (mercury) can transform into a menacing poison. 

Scientists know that at times there can be extremely high concentrations of mercury in the Arctic snow pack and are working to understand where it is coming from and what unique chemical reactions take place in the Arctic that lead to rapid deposition of mercury from the atmosphere to the snowpack. 

Next Steps 

  

Sunrise on the flats near Barrow. Blum and his colleagues hope to better understand how mercury travels to and deposits in the Arctic. Photo: Joel Blum

Now that his team better understands the Arctic food web, pre-1950, the logical next step would be to examine mercury levels and nitrogen and carbon isotopes in bears from 1950 to present day, he said. 

In addition, much remains to be understood regarding mercury in the Arctic. Specifically, scientists want to better understand where it comes from, how it travels to northern latitudes, what mechanisms cause it to be deposited, and where it is converted to methylmercury. 

“We want to better understand what’s going on in the arctic mercury cycle, to see if we can help mitigate the problem,” said Blum.  —Rachel Walker


Arctic Stories: New Multi-Media Web site

January 21, 2010

Not your typical office. A research building at Barrow, AK. Photo courtesy Arctic Stories

We’re pleased to welcome Arctic Stories, the brainchild of Purdue University atmospheric chemist Paul Shepson, to the online effort to educate and inform people about arctic research and life. (In 2009, we supported Shepson and others working at Barrow, Alaska, on an international study called OASIS. Shepson headed an NSF-funded study of halogen chemistry.)

With children’s book author Peter Lourie, Shepson has built a multi-faceted Web site with NSF funding to present information on the science, wildlife, climate, and people of the Arctic.

The site features video interviews with natives and researchers like polar bear researcher Steven C. Amstrup of the USGS. It also showcases compelling photographs, and links to science institutions. In short, it’s another fantastic resource for following the ongoing work in the Arctic.

This is helpful as the public strives to understand the myriad messages about climate change, research, and more. With news stories reporting that the Arctic is warming twice as quickly as the rest of the planet, that sea ice is melting, and that species are losing habitat and nourishment, sites like Arctic Ice and ours aim to inform readers about the efforts being made to understand the science behind the phenomena.

The science is complex, designed to measure and help us understand changes in the atmosphere, land, plants and animals, human societies and water in the Arctic. To advance these goals, scientists conduct fieldwork in some of the most extreme environments on Earth–and their experiences are often as compelling as their data.

We encourage readers to check out Arctic Ice as they follow their curiosity about work in the far north.


Surviving the Break-up

January 19, 2010

Scientific and traditional expertise find mutual benefit in sea-ice study

By Marcy Davis

Walk on water: PI Hajo Eicken at the Barrow sea ice mass balance site in June 2008, during the melt season. All photos courtesy Matt Druckenmiller

Unlike most other solids on Earth, ice floats. As water freezes, it expands to include lots of airy pockets, which means that ice is less dense as a solid than as a liquid. Fresh water ice is relatively dense and impervious while sea ice, ice that freezes directly from mineral-rich ocean water, develops interconnected sand-to-finger-sized channels that help control its decay during warm months. Through the Seasonal Ice Zone Observing Network (SIZONET), one of about 35 National Science Foundation-funded projects in the Arctic Observing Network, Hajo Eicken, research associate Chris Petrich, and graduate student Matthew Druckenmiller (all from University of Alaska, Fairbanks, UAF), study the small-scale properties contributing to the formation and disintegration of arctic coastal sea ice. In addition to gaining a better understanding of the role of sea ice in the global climate system, Eicken’s team hopes to help coastal communities which rely on sea ice–like Barrow, Alaska–by forecasting break-up, the time of year when seasonal ice begins to melt.

Off the village of Barrow, BASC employee Michael Donovan navigates a boat to a grounded ice foe in July 2008 so that Matt Druckenmiller can take an ice core.

Off the village of Barrow, BASC employee Michael Donovan navigates a boat to a grounded ice foe in July 2008 so that Matt Druckenmiller can take an ice core.

“Sea ice provides many animals, humans included, a surface on which to live, travel, and hunt. We want to understand how sea ice decays from a materials perspective,” explains Eicken. “We also want this information to be useful to local communities for whom break-up is important for hunting and whaling. We spend time trying to understand how people in Barrow use the sea ice in their daily life so that we can define and redefine our models and projections for how the ice will behave.”

Eicken’s group studies the seasonal sea-ice zone, which includes land-fast ice (ice that freezes to the coastal shoreline) and drift ice (ice that floats on the water surface). In contrast to multiyear ice, which does not melt in the summer, seasonal ice builds up during winter months and melts in summer months. This means that seasonal ice is far less stable. From a human perspective, then, break-up can be dangerous because how the ice melts varies from year to year and progresses over the season.

UAF sea ice team conducting ice thickness measurements and ridge surveys in the landfast ice near Barrow in June 2007.

Break-up begins with melting on the sea-ice surface. If the meltwater is retained, it pools on the surface. Because of the darker color, the ice surface ponds absorb heat and create a positive feedback for even more melting.

“We study seasonal ice rather than multiyear ice because we understand far less about seasonal ice. The forces which control breakup are highly variable – sunshine and warmer temperatures, tides, and storms all contribute, but to what degree remains less clear. But from a Search and Rescue perspective, it is very important to the Barrow community to have as much information as possible during break-up, especially since the coastal land-fast ice and ice drifts have become much more unstable over the last 20 years,” Eicken says.

Chris Petrich and BASC Bear Guard Herman Ahsoak measuring level ice thickness near a grounded ridge in June 2007.

Eicken, Petrich and Druckenmiller use satellite data to map ice conditions along the coastline near Barrow where locals use established ice trails for hunting and whaling during break-up. Although satellite data provides a decent regional picture, the relatively low resolution equates to substantial real-life discrepancy. In addition to field campaigns aimed at measuring temperature and albedo of ice surface ponds and ice thickness, indigenous ice expert and ex whaling captain Joe Levitt provides daily ice observations to help integrate and ground-truth satellite and field data or break-up forecasts.

These are especially useful to local communities during spring whaling season, when hunters establish camps on the sea ice. “Matt [Druckenmiller] created maps showing ice thickness along whaling trails on the land-fast ice off Barrow. These maps have proven useful for the community who might have as many as 200 people spread out over a 20-mile area or more during whaling season. This is a big safety issue for them,” says Eicken. “We’re posting satellite and radar images along with sea ice trail maps on the Internet and holding workshops with folks in Barrow both to educate them about how to use these data as well as to help us refine our forecasting models.”

The sea ice trail maps give Barrow-area whalers important information about ice thickness around their sea-ice trails.


Changing Climate, Changing Patterns: An Occasional Series on the Impacts of Warming Temperatures

January 15, 2010

Arctic Ground Squirrels

A male arctic ground squirrel emerges from his den in the spring near Alaska's Toolik Field Station after a long and cold hibernation. All photos courtesy Loren Buck

To the naked eye, the abundant arctic ground squirrels near Toolik Field Station, Alaska, simply disappear as the summer slips away. They burrow into nests a meter deep and settle in for a long, cold “sleep” entombed in a virtual ice cave.

Yet their ability to survive such extreme temperatures has long fascinated scientists, and a team of collaborators with NSF funds is studying how hibernating arctic squirrels regulate their temperature and what they use to fuel their bodies (i.e. fats, proteins, carbohydrates).

Using advanced genetic analysis, which will be conducted on captive squirrels in labs at the universities of Fairbanks and Anchorage, the team aims to understand which genes are activated during hibernation in response to temperature changes.

“We already know that hibernating squirrels switch metabolic fuels they draw from based on the ambient temperature,” said Loren Buck, principal investigator and associate professor of biology at the University of Alaska in Anchorage. “Now we want to see how this is accomplished by analyzing which genes are regulated at different stages of hibernation.”

What Genes Tell Us

Made of strands of DNA, genes provide instructions for making proteins, large and complex molecules that perform a number of functions. Proteins provide cell structure, carry out almost all of the cell’s chemical reactions, and act as cell messengers.

Buck’s work with arctic squirrels seeks to understand—at specificity previously not possible because the genetic technology didn’t exist—how the body responds genetically to extreme temperatures.

Buck said the research results could have important biomedical implications. Scientists have long used data on hibernating animals in models for cerebral ischemia (reduced blood flow to the brain), traumatic head injury and hypothermia, and his results could yield important information.

“We have already established that the squirrels switch metabolic fuels in response to changes in ambient temperatures,” said Buck. “Now the question is to understand the mechanism by which they adjust and alter their metabolism.”

In The Lab

In the lab, Buck and his team have a group of squirrels in simulated hibernating conditions with varying temperatures. They monitor the animals’ core body temperatures and the amount of work the hibernating squirrels have to do to keep from freezing.

Not surprisingly, when it isn’t extremely cold, the squirrels work less. For instance, at 2+ degrees C the squirrel body temperature is also about +2 degrees C. However, when the temperature plummets to – 10 degrees C, the animals become “thermogenic” (heat producing) to maintain a core body temp of -2.9 degrees C.

The researchers use genetic analysis known as quantitative real time PCR to identify which reserves (proteins, carbohydrates, etc.) the squirrels rely on at those extreme temperatures.

When the animals are at torpor, a stage of hibernation, their core temperature is the same as the ambient temperature. For instance, when the ground temp is 0 degrees C, so is the squirrels’ core temperature. At this phase, the squirrels rely on fats to fuel their metabolism.

But when ambient temperatures decrease below the level at which squirrels can survive (-2.9 degrees C), the bodies rely on proteins and carbohydrates to keep from freezing.

To analyze the genetic information, researchers euthanize squirrels at various points of their hibernation to study which genes are expressed.

In The Field

Well before hibernation, Buck and a graduate student set up a trapping grid near Toolik Field Station to capture squirrels for lab experiments.

Buck and his team spend time in the field monitoring the squirrels and capturing animals for the labs. They collect data that can be correlated with the genetic experiments.

Temperature loggers have been in place at the squirrel hibernating sites near Toolik since 1993, providing a 17-year picture of ground temperatures. Buck said data from the metabolic study can be correlated with temperature data to study a potential link between environmental temperature and overwinter body mass.

Squirrels as Study Subjects

In addition to the ground temperature loggers, he and his crew have implanted about 100 loggers into squirrels on the North Slope to better understand the biological response to the environment.

“As we collected these data, there was more emphasis on climate change and the need to investigate its impacts on vertebrates,” said Buck. “To get the physiological data it takes a cooperative species with a short enough life span.”

Arctic squirrels are ideal because they don’t move around a lot, are large enough to carry implanted loggers (unlike, say, voles), don’t migrate out of the Arctic when conditions get bad, and are easy to recapture, which allows scientists to retrieve almost 80 percent of the data loggers each year.

Lab members Oivind Toien, Robert Fridinger, and Fanziska Kohl take a break after placing a telemetry receiving station to track tagged squirrels near Toolik Field Station.

Interdisciplinary Studies

Finally, this National Science Foundation-supported research provides an opportunity to train undergraduate and graduate students and post-doctoral fellows in arctic biology and climate change biology, said Buck. Many of his graduate students would be unlikely to leave the lab bench in normal conditions.

However their ventures into the field provide them with more experience and a better understanding of climate science, he said. This insight has been emphasized recently among universities and the NSF in an effort to coordinate research efforts with academics who have a variety of skills.

“The researchers of tomorrow must be far more interdisciplinary in scope, and these types of research projects provide great opportunities,” he said. —Rachel Walker


For the Gearheads Amongst Us

January 12, 2010

10 a.m.
Dear Tracy,
If I posted one or two of these pictures on our blog, would people who are mechanically inclined find them interesting? If so, which pictures tell the best story, in your opinion? I know I’m looking at the Case Quadtrac tractor–one of the GrIT monsters–and I know Larry Levin and Russ Howes are up in Thule overhauling the axle housing.  But dude, what am I really looking at.

All photos: Larry Levin

10:15 a.m.
Kip–

This rather extensive bit of work is really just to get at an oil leak that is buried well back in the drive train of the machine. It may simply be that the bolts need to be re-torqued, but first you’ve got to get to them – some disassembly required. Not only do we need to address it to ensure reliable operation, but we cannot be dripping oil out on the ice cap for reasons of environmental stewardship.

However, rather than dwell on some obscure mechanical detail that no one would really care about, I would emphasize four points of greater general interest:

1. It’s a big tractor with big components. Note that the boys are using a forklift to move the track and carrier assembly in/out. This is NOT like working on your compact car – nor even a big truck. This is HEAVY equipment.

2. The work is being done SAFELY. There is a primary lift point as well as two redundant jack stands. This is important on a 60,000 lb machine. If it were to fall, Larry and Russ would be just two more oil stains on the floor.

3. They are working inside the heated, well-lit garage at Thule, courtesy of the US Air Force and Greenland Contractors. Both entities have been very accommodating in supporting GrIT and other projects. This COOPERATION should get some recognition.

4. Don’t try this at home. Our people are PROFESSIONALS. Between them, Russ and Larry probably have in excess of 50 years of experience as mechanics. That they both have numerous other job responsibilities but can also get down in the trenches to get their hands greasy as needs dictate is a distinguishing characteristic of many PFS staff, and perhaps not always adequately recognized.

I don’t know if CH2 safety folks or the entities in Thule will see the blog post, but if so, it will make their hearts swell with pride. That’s my take.
 
With generous support from the US Air Force  and Greenland Contractors, the GrIT team will head out from Thule Air Base in March. Bound for NEEM and Summit with a load of fuel, they will continue sled configuration and snow strength experiments as they seek the perfect Greenland inland traverse configuration. Stay tuned!