Showing posts with label antarctica. Show all posts
Showing posts with label antarctica. Show all posts
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linda
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Time-lapse video of penguin colonies shows challenges of snow and cold.
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Two penguin rookeries in Antarctica appear in time-lapse over the course of a year. The footage was shot by researchers from the Zoological Society of London and the University of Oxford:
The first colony on the video is of gentoo penguins at Brown Bluff on the Antarctic Peninsula... Penguins come and go, then mostly go. The whiteout of winter snows buries the camera. The snow melts, penguins return to establish nests as new snow falls and melts.
The second colony in the video is of king penguins at the much more populated Salisbury Plain on South Georgia Island, where about 200,000 birds gather to nest... You can see that as winter approaches, and as the parents go off to fish for them, the brown woolly chicks huddle together for warmth in groups known as crèches.
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Two penguin rookeries in Antarctica appear in time-lapse over the course of a year. The footage was shot by researchers from the Zoological Society of London and the University of Oxford:
By adapting existing camera technology and using time-lapse photography, we are trialling the development of a new monitoring array for the southern polar region. By monitoring remotely, we hope to be able to ask new questions about the response of Antarctic penguins to their changing world.
Cameras capture daily images of the movements of the penguins, allowing us to collect data on the timings of penguin life cycles at different locations, such as their time of arrival to breed and chick fledging.
The first colony on the video is of gentoo penguins at Brown Bluff on the Antarctic Peninsula... Penguins come and go, then mostly go. The whiteout of winter snows buries the camera. The snow melts, penguins return to establish nests as new snow falls and melts.
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| Gentoo penguins with chicks. Credit: Liam Quinn via Wikimedia Commons. |
The second colony in the video is of king penguins at the much more populated Salisbury Plain on South Georgia Island, where about 200,000 birds gather to nest... You can see that as winter approaches, and as the parents go off to fish for them, the brown woolly chicks huddle together for warmth in groups known as crèches.
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| King penguins with chicks. Credit: Ben Tubby via Wikimedia Commons. |
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linda
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| Gentoo penguin and chick. Credit: © Julia Whitty. |
There are big changes underway in penguin colonies in the Antarctic Peninsula.
Why? First up, it's one of the fastest warming regions on Earth.
And we know that a warming climate can shift the phenology—the timing of annually recurring lifecycle events like migrations and flowering—of species.
Phenological shifts can leads to "trophic mismatches." That is, where interacting species fall out of sync.
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| Caribou. Credit: NPS. |
For instance, a study in Proceedings of the Royal Society B showed a trophic mismatch between caribou (whose seasonal migration to summer calving ranges is cued by changes in day length) and the plants they feed on in their summer ranges (whose growing season is cued by local temperatures).
Trophic mismatches are increasingly likely in a warming world, especially among migratory species that have no way to know the schedule is speeding up hundreds or thousands of miles away.
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| Adélie penguin and chick. Credit: © Heather Lynch. |
A new paper in MEPS (Marine Ecology Progress Series) takes an interesting look at another aspect of phenological change—the possible effects on species that breed (and compete) together.
Specifically on three penguins on the Antarctic Peninsula: Adélie, chinstrap, and gentoo.
Adélies and chinstraps migrate to their breeding colonies. The gentoo is resident year round.
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| Warming in Antarctica in degrees C per year between 1981-2007.Credit: NASA Earth Observatory, image by Robert Simmon, based on data from Joey Comiso, GSFC. |
You can probably already hypothesize a dynamic among these three species competing for breeding space and to some extent food resources in a rapidly warming area.
The authors of the MEPS paper investigated changes in clutch initiation dates (the date the first egg is laid) of the three species in the Western Antarctic Peninsula (WAP)—that's the pointy bit at the upper left of the map, above.
The results were striking. From the paper:
We found that clutch initiation was most significantly correlated with October air temperatures such that all 3 species advanced clutch initiation to varying degrees in warmer years. Gentoo penguins were able to advance [clutch initiation dates] almost twice as much (3.2 d°C−1) as Adélie (1.7 d°C−1) and chinstrap penguins (1.8 d°C−1).
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| Chinstrap penguins and chicks. Credit: Hannes Grobe/AWI via Wikimedia Commons. |
What jumps out here is that resident gentoos, who are already on the breeding ground, appear able to accurately judge the advancing spring dates and lay earlier. And this may be the reason, at least in part, as to why Adélies and chinstraps are suffering population declines and gentoos are thriving in the WAP:
- Adélies declining in 18 of 24 surveyed breeding sites
- Chinstraps declining at 16 of 29 surveyed breeding sites
- Gentoos increasing at 32 of 45 surveyed breeding sites
Those numbers are forthcoming in another paper from some of this same team.
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| Heather Lynch counting gentoo penguins at Port Lockroy, Antarctica. Credit: © Julia Whitty. |
BTW, I first wrote about two of these researchers—Heather Lynch and Ron Naveen—in my Mother Jones article March of the Tourists a while back.
The papers:
- Heather J. Lynch, William F. Fagan, Ron Naveen, Susan G. Trivelpiece, Wayne Z. Trivelpiece. Differential advancement of breeding phenology in response to climate may alter staggered breeding among sympatric pygoscelid penguins. MEPS. DOI:10.3354/meps09252.09252
- Eric Post and Mads C Forchhammer. Climate change reduces reproductive success of an Arctic herbivore through trophic mismatch. Phil. Trans. R. Soc. B. DOI:10.1098/rstb.2007.2207
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linda
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| Bear Glacier, Alaska. Via. |
A new paper in Nature calculates that total global ice mass lost from Greenland, Antarctica, and all Earth's glaciers and ice caps between 2003 and 2010 was about 4.3 trillion tons (1,000 cubic miles).
That's enough melted ice to drive up global sea level by 0.5 inches (12 millimeters).
And that's enough water to cover the US to 1.5 feet deep (0.5 meters deep).
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| Glacier melt tunnel. Credit: Dook Cook | DougAK via Flickr. |
The research was based on satellite measurements of ice loss from all Earth's land ice collected over eight years—with attention paid to rarely-observed glaciers and ice caps outside of Greenland and Antarctica.
The findings:
- About a quarter of the average annual ice loss came from glaciers and ice caps outside of Greenland and Antarctica (roughly 148 billion tons, or 39 cubic miles).
- Ice loss from Greenland and Antarctica and their peripheral ice caps and glaciers averaged 385 billion tons (100 cubic miles) a year.
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| Glacier Bay, Alaska. Credit: NPS. |
Traditional estimates of Earth's ice caps and glaciers have been made using ground measurements from only a few hundred of the roughly 200,000 glaciers worldwide.
This video explains some of those traditional ground-based measurement techniques.
This video describes how the GRACE satellite measurements work.
One positive finding of the satellite study was that ice loss from high the high Asian ranges—from the Himalaya, Pamir, and Tien Shan mountains—was only about 4 billion tons of ice a year. Previous ground-based estimates ranged as high as 50 billion tons a year.
From NASA News:
"This study finds that the world's small glaciers and ice caps in places like Alaska, South America and the Himalayas contribute about 0.02 inches per year to sea level rise," said Tom Wagner, cryosphere program scientist at NASA Headquarters in Washington. "While this is lower than previous estimates, it confirms that ice is being lost from around the globe, with just a few areas in precarious balance. The results sharpen our view of land-ice melting, which poses the biggest, most threatening factor in future sea level rise."
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| Bering Glacier, Alaska. Credit: NASA. |
The paper:
- Thomas Jacob, John Wahr, W. Tad Pfeffer & Sean Swenson. Recent contributions of glaciers and ice caps to sea level rise. Nature. DOI:10.1038/nature10847
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| Ship wake. Credit: Yosemite James via Flickr. |
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| Offshore wind farm wakes. Via. |
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| South Georgia Island cloud wake. Credit: NASA. |
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| Island wakes, Canary Islands. Via Flickr. |
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| Aircraft turbulence wake. Via. |
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| Ship track wakes in the clouds, North Pacific. Credit: NASA. |
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| Comet wake. Credit: NASA via. |
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| Bioluminescent dolphin wakes. Credit: Ammonite via National Geographic. |
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| Icebreaker wake. Via. |
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| Iceberg wake. Via Wikimedia Commons. |
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| Crabeater seal wakes, Southern Ocean. Credit: Steve Nicol via. |
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| Penguin wake. Via. |
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| Ship bow-wake with bow-riding dolphins. Via. |
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| Von Karman vortices, Aletian Islands. Credit: USGS. |
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| Sea turtle wake. Credit: Rosa Say via Flickr. |
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| Sea turtle wake. Via RedBubble. |
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| Surf wake. Via. |
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| Antarctic fur seal (right), Weddell seal (left), Penguin Island, South Shetland Islands, Antarctica. Credit: © Julia Whitty. |
How do you assess the health of a marine invertebrate—namely Antarctic krill—when there's no historical baseline to measure it against?
In an intriguing piece of detective work reported in PLoS ONE a team of researchers from China and the US turned to analyzing old seal hairs to determine changes in abundance of krill in the past century.
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| Antarctic krill. Credit: Uwe Kils via Wikimedia Commons. |
Antarctic krill, Euphausia superba, is a keystone species in the Southern Ocean and the primary consumer in a foodweb supporting fish, penguins, seabirds, seals, and whales.
They school in swarms of up to of 30,000 individuals per cubic meter and are perhaps the most abundant animal on Earth, with a total biomass estimated at ~379 million metric tons.
In the video below (starting at 00:01), you can see humpback whales bubble feeding on krill in Antarctic waters.
There's evidence of a decline in krill biomass in parts of Antarctica in the past 30 years—but when did it begin?
To look deeper into history, the authors analyzed core samples from lake sediments near an Antarctic fur seal colony on King George Island in the South Shetland Islands off the Antarctic Peninsula.They dated the fur in the cores via stable carbon (δ13C) in the samples. They inferred the abundance of krill in the seals' diet via the nitrogen (δ15N) isotopes in the fur. From the paper:
Since Antarctic fur seals feed preferentially on krill, the variation of [nitrogen] in seal hair indicates a change in the proportion of krill in the seal's diets and thus the krill availability in local seawater.
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| Antarctic krill grazing on algae living on the underside of sea ice. Credit: Uwe Kils via Wikimedia Commons. |
Their results indicate that krill began to decline in the diet of fur seals in this part of Antarctica nearly a century ago. That time frame correlates with increasing sea surface temperatures and dwindling sea ice. (See my post Life Inside the Sea Ice more about the relationship between krill and sea ice.)
From the PLoS ONE paper:
In this region for the past decades, the sea ice shows a decline trend, and this is in coincidence with the decline trend in krill populations. Like the seal [nitrogen] values, the sea surface temperature anomaly in Southern Ocean (50°S) also shows an obvious increasing trend for the 20th century, and the significant correlation between them... suggests that the inferred decreasing krill population is linked with warming ocean and declining sea ice extent.
The paper:
- Relative Changes in Krill Abundance Inferred from Antarctic Fur Seal.PLoS ONE. 2011.DOI:10.1371/journal.pone.0027331.
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| 1657. Jan Janssonius. Dutch. Showing hints of southern coastlines labelled 'Terra Australis Incognita.' |
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| 1714. French. Guillaume de L'Isle. Antarctica empty. |
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| 1739. Philippe Buache. French. Showing two Antarctic land masses, New Zealand connected to Antarctica, and Australia connected to New Guinea. |
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| 1777. Thomas Bowen. British. Showing the 'Track of his Majesty's Sloop Resolution in Search of a Southern Continent.' |
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| 1818. John Pinkerton. US. Antarctica missing again. |
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| 1855. J. H. Colton. US. Showing partially sketched details of the 'Southern Regions.' |
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| 1894. Scottish. Real features getting named, including ocean currents. |
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| 1912. German. From Stielers Handatlas. Suddenly, details. |
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| 1920s. Showing 'unexplored regions,' focus on expedition routes. |
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| 1922. John Bartholomew. UK. Limited but exquisite detail. |
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| 1934. US. Focusing on the Byrd Expedition. |
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| 1972. H.C. Berann. US. Showing Antarctica in context with the seafloor. |
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| 2006. UK. Showing Antarctica without the ice. |
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| 2006. Dave Pape. Stitched satellite view. |
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In case in the middle of an ordinary dry Wednesday you've forgotten how extraordinary is our ocean planet, here are a few watery reminders.
The Blue Ocean in RED from Howard Hall on Vimeo.
(Squid, possibly the bigfin reef squid, Sepioteuthis lessoniana. Credit:Nhobgood at Wikimedia Commons.)
MAYO / MAY from Rafa Herrero Massieu on Vimeo.
(Giant anemone, Condylactis gigantea. Credit:Nhobgood via Wikimedia Commons.)
Antarctica from Darek Sepiolo on Vimeo.
(Kelp. Credit: FASTILY via Wikimedia Commons.)
This new product released by Google Earth and developed by oceanographers at Columbia's Lamont-Doherty Earth Observatory promises a dynamic look through darkness to the seafloor. I confess, the extinct filmmaker in me wants to get my hands on this video and edit in some heft. But you can see how cool the perspectives are—how the new layers make Google Earth more oceanlike.
