Antarctic Albatross Displays Shift In Breeding Habits

Wandering albatross: Credit: Wikipedia

A new study of the wandering albatross – one of the largest birds on Earth – has shown that some of the birds are breeding earlier in the season compared with 30 years ago. Reporting online this month (April) in the journal Oikos, a British team of scientists describe how they studied the breeding habits of the wandering albatross on the sub-Antarctic island of South Georgia. They have discovered that because some birds are now laying their eggs earlier, the laying date for the population is an average of 2.2 days earlier than before. The researchers say the reasons for this change are unclear. Lead author Dr Sue Lewis at the University of Edinburgh's School of Biological Sciences said, "Our results are surprising. Every year we can determine when the birds return to the island after migration, and the exact day they lay their egg. We knew that some birds were laying earlier – those who were older or had recently changed partner - but now we see that those which haven't bred successfully in the past are also laying earlier, and these birds are effectively driving this trend in earlier laying". The researchers studied over 30 years of data from birds located near the British Antarctic Survey's research station on Bird Island (part of South Georgia). Nest sites were monitored daily during the pre-laying, laying, hatching and fledging periods to document breeding patterns. Numbers of wandering albatrosses on South Georgia have been steadily declining largely because the birds swallow baited hooks on longlines set by fishing vessels, and are dragged under and drown. Despite a recent increase in breeding success over the last 20 years, the number of birds at Bird Island has fallen by over 50% since the 1960s, from 1700 to only 800 breeding pairs. British Antarctic Survey bird ecologist Dr Richard Phillips, also an author on the paper said, "This work is important for understanding more about the behaviour of these charismatic and threatened birds. In the Indian Ocean, an increase in the intensity of westerly winds has resulted in a shift in feeding distribution of wandering albatrosses. It is possible that earlier breeding in some females at South Georgia is a consequence of environmental change, but at the moment we are not sure if this is related to weather, a change in oceanographic conditions or food availability to which only some birds are responding." This research is a collaboration between the University of Edinburgh and British Antarctic Survey and was funded by the Natural Environment Research Council (NERC). Contacts and sources: Athena Dinar, British Antarctic Survey. Source: Nano Patents And Innovations

Read More........→October 13, 2013

Methane levels remain very high around the globe

The image above shows methane levels over 1950 in yellow for both hemispheres, on the morning of August 8, 2013. The highest peak recorded was 2428 ppb at 367 mb. The highest mean was 1822 ppb at 469 mb. See also the image below for an overview of recent methane levels. for interactive version, see

Methane levels keep rising rapidly The situation is very worrying, especially since there's a huge amount of methane in the northern part of Asia and Europe, much of it bordering on the Arctic. This methane will trap a lot of heat there at a time when the melting season is still going strong. On the Southern Hemisphere, there's a huge amount of methane recorded over Antarctica. That has been going on for quite some time, but the high levels of methane over the oceans on the Southern Hemisphere have only shown up recently. They could be caused by one or more methane hydrates getting destabilized in the ocean between Antarctica and South America. Source: Arctic News

Read More........→August 10, 2013

Antarctica Melting Much Faster Than Expected, See Timelapse Imagery

Credit: The University of Texas at Austin, Institute for Geophysics.

For the first time, scientists have documented an acceleration in the melt rate of permafrost, or ground ice, in a section of Antarctica where the ice had been considered stable. The melt rates are comparable with the Arctic, where accelerated melting of permafrost has become a regularly recurring phenomenon, and the change could offer a preview of melting permafrost in other parts of a warming Antarctic continent. Research team member Jim O'Connor of the USGS inspects a block of ice calved off the Garwood Valley ice cliff.Tracking data from Garwood Valley in the McMurdo Dry Valleys region of Antarctica, Joseph Levy, a research associate at The University of Texas at Austin’s Institute for Geophysics, shows that melt rates accelerated consistently from 2001 to 2012, rising to about 10 times the valley’s historical average for the present geologic epoch, as documented in the July 24 edition of Scientific Reports. Scientists had previously considered the region’s ground ice to be in equilibrium, meaning its seasonal melting and refreezing did not, over time, diminish the valley’s overall mass of ground ice. Instead, Levy documented through LIDAR and time-lapse photography a rapid retreat of ground ice in Garwood Valley, similar to the lower rates of permafrost melt observed in the coastal Arctic and Tibet. Garwood Valley lies within the McMurdo Dry Valleys region of Antarctica.“The big tell here is that the ice is vanishing — it’s melting faster each time we measure,” said Levy, who noted that there are no signs in the geologic record that the valley’s ground ice has retreated similarly in the past. “This is a dramatic shift from recent history.” Ground ice is more prevalent in the Arctic than in Antarctica, where glaciers and ice sheets dominate the landscape. In contrast to glaciers and ice sheets, which sit on the ground, ground ice sits in the ground, mixed with frozen soil or buried under layers of sediment. Antarctica’s Dry Valleys contain some of the continent’s largest stretches of ground ice, along the coast of the Ross Sea. After Levy and colleagues noted visible effects of ground ice retreat in Garwood Valley, they began to monitor the valley, combining time-lapse photography and weather-station data at 15-minute intervals to create a detailed view of the conditions under which the ice, a relict from the last ice age, is being lost. Rising temperatures do not account for the increased melting in Garwood Valley. The Dry Valleys overall experienced a well-documented cooling trend from 1986 to 2000, followed by stabilized temperatures to present. Rather, Levy and his co-authors attribute the melting to an increase in radiation from sunlight stemming from changes in weather patterns that have resulted in an increase in the amount of sunlight reaching the ground. Timelapse imagery of ice loss in Garwood Valley, Nov. 2010 to Jan. 2012. The period represents the start and end of one summer season (Nov. 2010-Jan. 2011) followed by the end of the next season (Jan. 2012). The views were generated with biannual LiDAR scans of the valley. Sunlight tends to bounce off the white, reflective surfaces of glaciers and ice sheets, but the darker surfaces of dirty ground ice can absorb greater amounts of solar radiation. Thick layers of sediment tend to insulate deeply buried ground ice from sunlight and inhibit melting. But thin sediment layers have the opposite effect, effectively cooking the nearby ice and accelerating melt rates. As the ground ice melts, the frozen landscape sinks and buckles, creating what scientists describe as “retrogressive thaw slumps.” An acceleration in the prevalence of such slumps has been well documented in the Arctic and other permafrost regions, but not in Antarctica. Levy’s research shows that even under the stable temperature conditions of the Dry Valleys, recent increases in sunlight are leading to Arctic-like slump conditions. If Antarctica warms as predicted during the coming century, the melting and slumping could become that much more dramatic as warmer air temperatures combine with sunlight-driven melting to thaw ground ice even more quickly. Ground ice is not the major component of Antarctica’s vast reserves of frozen water, but there are major expanses of ground ice in the Dry Valleys, the Antarctic Peninsula and the continent’s ice-free islands. Garwood Valley could tell the story of what will happen in these “coastal thaw zones,” says Levy. “There's a lot of buried ice in these low-elevation coastal regions, and it is primed to melt.” Co-authors on the paper were Andrew Fountain of Portland State University, James Dickson and James Head of Brown University, Marianne Okal of UNAVCO, David Marchant of Boston University and Jaclyn Watters of The University of Texas at Austin. The research was supported by a grant from the National Science Foundation. Contacts and sources: Joseph LevyUniversity of Texas Institute for Geophysics, Jackson School of Geosciences. Souce: Nano Patents And Innovations

Read More........→July 30, 2013

CryoSat maps largest-ever flood beneath Antarctica

Site of crater

ESA’s CryoSat satellite has found a vast crater in Antarctica’s icy surface. Scientists believe the crater was left behind when a lake lying under about 3 km of ice suddenly drained. Far below the thick ice sheet that covers Antarctica, there are lakes of fresh water without a direct connection to the ocean. These lakes are of great interest to scientists who are trying to understand water transport and ice dynamics beneath the frozen Antarctic surface – but this information is not easy to obtain. One method is to drill holes through kilometres of ice to the water – a difficult endeavour in the harsh conditions of the polar regions. But instead of looking down towards the ice, a team of European scientists is looking to the sky to improve our understanding of subglacial water and its transport. By combining new measurements acquired by CryoSat with older data from NASA’s ICESat satellite, the team has mapped the large crater left behind by a lake, and even determined the scale of the flood that formed it. From 2007 to 2008, six cubic kilometres of water – about the same amount that is stored in Scotland’s Loch Ness – drained from

3D view

the lake, making it the largest event  of its kind ever recorded. That amount of water equals a tenth of the melting that occurs beneath Antarctica each year. Since the end of 2008, the lake appears to be refilling but six times slower than it drained. It could take decades to reform. The study, published recently in Geophysical Research Letters, highlights CryoSat’s unique capacity to map changes in Antarctica’s subglacial lakes in 3D, and sheds new light on events at the base of the ice sheet. CryoSat carries a radar altimeter that can ‘see’ through clouds and in the dark, providing continuous measurements over areas like Antarctica that are prone to bad weather and long periods of darkness. The radar can measure

ESA's ice mission CryoSat

both the area and depth of ice craters in high resolution, allowing scientists to calculate its volume accurately. “Thanks to CryoSat, we can now see fine details that were not apparent in older satellite data records,” said Dr Malcolm McMillan from the UK’s University of Leeds and lead author of the study ‘Three-dimensional mapping by CryoSat-2 of subglacial lake volume changes’. With every subglacial lake, there is hope of finding prehistoric marine life. The rapid draining and apparent refilling of this lake, however, suggests this was not the first time water has drained from the lake. “It seems likely that the flood water – and any microbes or sediments it contained – has been flushed into the Southern Ocean, making it difficult to imagine that life in this particular lake has evolved in isolation,” said Prof. Andrew Shepherd, a co-author of the study. About 400 lakes have been discovered at the base of the Antarctic ice sheet. When they drain, they disrupt subglacial habitats and can cause the ice above to slide more quickly into the sea. Source: Orbiter.ch Space News

Read More........→July 21, 2013

Beneath Antarctic Ice: Vast Canal System Found

In a development that will help predict potential sea level rise from the Antarctic ice sheet, scientists from The University of Texas at Austin’s Institute for Geophysics have used an innovation in radar analysis to accurately image the vast subglacial water system under West Antarctica’s Thwaites Glacier. They have detected a swamp-like canal system beneath the ice that is several times as large as Florida’s Everglades. Figure showing the transition from swamp-like water to stream-like water beneath Thwaites Glacier, West Antarctica. The findings, as described this week in the Proceedings of the National Academy of Sciences, use new observational techniques to address long-standing questions about subglacial water under Thwaites, a Florida-sized outlet glacier in the Amundsen Sea Embayment considered a key factor in projections of global sea level rise. On its own, Thwaites contains enough fresh water to raise oceans by about a meter, and it is a critical gateway to the majority of West Antarctica’s potential sea level contribution of about 5 meters. The new observations suggest the dynamics of the subglacial water system may be as important as well recognized ocean influences in predicting the fate of Thwaites Glacier. Without an accurate characterization of the bodies of water deep under Thwaites, scientists have offered competing theories about their existence and organization, especially in the rapidly changing region where the glacier meets the ocean. Using an innovation in airborne ice-penetrating radar analysis developed by lead author Dusty Schroeder, a doctoral candidate at the Institute for Geophysics, the Texas team shows that Thwaites’ subglacial water system consists of a swamp-like canal system several times as large as Florida’s Everglades lying under the deep interior of the ice sheet, shifting to a series of mainly stream-like channels downstream as the glacier approaches the ocean. Scientists have attempted to use ice-penetrating radar to characterize subglacial water for many years, but technical challenges related to the effects of ice temperature on radar made it difficult to confirm the extent and organization of these water systems. Schroeder’s technique looking at the geometry of reflections solves this problem, because the temperature of the ice does not affect the angular distribution of radar energy. “Looking from side angles, we found that distributed patches of water had a radar signature that was reliably distinct from stream-like channels,” said Schroeder. He compared the radar signature to light glinting off the surface of many small interconnected ponds when viewed out of an airplane window. Distinguishing subglacial swamps from streams is important because of their contrasting effect on the movement of glacial ice. Swamp-like formations tend to lubricate the ice above them whereas streams, which conduct water more efficiently, are likely to cause the base of the ice to stick between the streams. (The effect is similar to the way rain grooves on a tire can help prevent a car from hydroplaning on a wet road.) As a result of this change in slipperiness, the glacier’s massive conveyor belt of ice piles up at the zone where the subglacial water system transitions from swamps to streams. This transition forms a stability point along a subglacial ridge that holds the massive glacier on the Antarctic continent. “This is where ocean and ice sheet are at war, on that sticking point, and eventually one of them is going to win,” said co-author Don Blankenship, a senior research scientist from the Institute for Geophysics. Cartoon representations (above) and radar images (below) of the distinct swamp-like and stream-like water systems observed beneath Thwaites Glacier, West Antarctica. Observations of the subglacial stream-and-swamp dynamic and the sub-ice topography suggest that Thwaites Glacier is stable in the short term, holding its current position on the continent. However, the large pile of ice that has built up in the transition zone could rapidly collapse if undermined by the ocean warming or changes to the water system. “Like many systems, the ice can be stabilized until some external factor causes it to jump its stability point,” said Blankenship. “We now understand both how the water system is organized and where that dynamic is playing itself out. Our challenge is to begin to understand the timing and processes that will be involved when that stability is breched.” Current models predicting the fate of the glacier do not yet account for these dynamic, subglacial processes. The findings rely on radar data acquired during airborne geophysical surveys over West Antarctica by the Institute for Geophysics, with operational support from the National Science Foundation. The analysis was enabled through intensive supercomputing supported by the university’s Texas Advanced Computing Center. The research was funded through grants from the National Science Foundation and NASA, with additional support from both the Vetlesen Foundation and the Institute for Geophysics, which is a research unit of the university’s Jackson School of Geosciences. Contacts and sources: University of Texas Institute for Geophysics. Source: Nano Patents And Innovations, Image: flickr.com

Read More........→July 13, 2013