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Author Topic: What's new in Antarctica ?  (Read 128646 times)

b_lumenkraft

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Re: What's new in Antarctica ?
« Reply #450 on: February 15, 2019, 06:21:39 PM »
Damn! :-\

vox_mundi

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Re: What's new in Antarctica ?
« Reply #451 on: February 16, 2019, 06:53:17 PM »
More Trophic Cascade Collapse ...

Tiny Invertebrates Spell Big Trouble for Southern Ocean Fish
https://phys.org/news/2019-02-nutritious-diet-southern-ocean-fish.html

Like collapsing ice shelves, the surge of barrel-bodied salps in the Southern Ocean tells us that other life forms in Antarctica and its surrounding waters are in decline. Blooms of a gelatinous plankton, known as salp, have been identified in waters south of 60°S, in the Indian Sector of the Southern Ocean, by researcher Paige Kelly

... "In the Southern Ocean, waters south of 60°S are typically full of Antarctic krill, which are a crucial food source for mammals and fish," says Paige, a Ph.D. student at the Institute for Marine and Antarctic Studies and Antarctic Climate and Ecosystems Cooperative Research Centre.

"The presence of salps so far south means that these mammals and fish might have to eat salps instead of krill. And this could have serious consequences for the ecosystem."

The consumption of these East Antarctic salps—which contain less than one third of the calories and protein of krill—could change the weight, reproduction and behaviour of commercially fished species that prefer to feed on krill.

When salps are abundant, Antarctic krill are scarce. Krill are a keystone species here. Everything eats them directly or indirectly. Penguins, baleen whales, seals, seabirds and fish, even krill eat krill. No krill, no Antarctica.

Since the 1970s krill populations have dropped by as much as 70 per cent in their most critical habitat, the southwest Atlantic sector of the Southern Ocean. Krill, especially juveniles, depend on sea ice subsurface matrix of brine channels and crevices, a microcosm of life where innumerable plankton live, feed and hide from predators. Summer krill abundance is correlated with the extent of the previous winter's sea ice.



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Dutch Scientists Probing Mystery of Mass Bird Deaths
https://phys.org/news/2019-02-dutch-scientists-probing-mystery-mass.html

... Why, for example, are only guillemots dying all along the Dutch coastline? Leopold said he has received no similar reports from Belgium or Germany. "They are pretty robust birds," he said, but now, dead birds are washing up "in their thousands"

"That's pointing out that there is something wrong at sea, and that's alarming."
“There are three classes of people: those who see. Those who see when they are shown. Those who do not see.” ― Leonardo da Vinci

Insensible before the wave so soon released by callous fate. Affected most, they understand the least, and understanding, when it comes, invariably arrives too late

maga

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Re: What's new in Antarctica ?
« Reply #452 on: February 19, 2019, 10:45:12 PM »
I just want to draw some attention to a future calving in East Antarctica. I don't know the name of the ice shelf but it's the one directly west of Roi Baudouin Ice Shelf. Big calvings in this area seem to be rather rare.

maga

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Re: What's new in Antarctica ?
« Reply #453 on: February 19, 2019, 10:59:28 PM »
Also a very interesting region to watch is around the southern part of the Wilkins Ice Shelf (and its neighbours). The cracks in the picture (Beethoven Peninsula at bottom) will eventually help to break up Wilkins Ice Shelf completely within the next years.

vox_mundi

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Re: What's new in Antarctica ?
« Reply #454 on: March 05, 2019, 06:37:35 AM »
Mystery of Green Icebergs May Be Solved
https://m.phys.org/news/2019-03-mystery-green-icebergs.html

... Pure ice is blue because ice absorbs more red light than blue light. Most icebergs appear white or blue when floating in seawater, but since the early 1900s explorers and sailors have reported seeing peculiar green icebergs around certain parts of Antarctica.

The green icebergs have been a curiosity to scientists for decades, but now glaciologists report in a new study that they suspect iron oxides in rock dust from Antarctica's mainland are turning some icebergs green. They formulated the new theory after Australian researchers discovered large amounts of iron in East Antarctica's Amery Ice Shelf. Watch a video of the new findings here.



Open Access: Stephen G. Warren et al, Green Icebergs Revisited, Journal of Geophysical Research: Oceans (2019)
“There are three classes of people: those who see. Those who see when they are shown. Those who do not see.” ― Leonardo da Vinci

Insensible before the wave so soon released by callous fate. Affected most, they understand the least, and understanding, when it comes, invariably arrives too late