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Author Topic: Antarctic Ecosystems  (Read 4352 times)

wili

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Antarctic Ecosystems
« on: June 23, 2014, 06:36:04 PM »
I think we have a thread somewhere on changing sea life in the Arctic, so I thought I'd start one on the Antarctic, but include land species/ecosystems, inspired (if that's the right word) by this recent piece:

http://www.truthdig.com/report/item/icebergs_strip_away_rich_antarctic_habitat_20140623

Icebergs Strip Away Rich Antarctic Habitat

Quote
A once-rich habitat in the Antarctic has become an impoverished zone as icebergs, increasingly breaking free from the surrounding sea ice because of global warming, scour the shallow-water rocks and boulders on which a diversity of creatures cling to life.

A report in the journal Current Biology says that researchers who carried out a survey dive in 2013 at Lagoon Island, off the West Antarctic Peninsula, discovered that “no live mega or macro-fauna can be found, the first time this has been observed there, despite being regularly visited by scientific divers since 1997”.

David Barnes, of the British Antarctic Survey, and colleagues report that boulders on the seabed near the Rothera research station had once been richly encrusted with creatures that competed for living space. Now such rocks might only support a single species.

(Mods, please merge or set this in more appropriate place if this isn't it.)
« Last Edit: March 25, 2022, 09:42:27 AM by oren »
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Laurent

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Re: Antarctic ecosystems
« Reply #1 on: June 23, 2014, 07:45:09 PM »

FredBear

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Re: Antarctic ecosystems
« Reply #2 on: November 26, 2021, 01:40:34 AM »
Whaling effects:- "They calculated that before industrial whaling, these creatures would have consumed about 430 million metric tons of krill—small, shrimplike animals—every year. That’s twice as much as all the krill that now exist, and twice as much by weight as all the fish that today’s fisheries catch annually. But whales, despite their astronomical appetite, didn’t deplete the oceans in the way that humans now do."

https://www.theatlantic.com/science/archive/2021/11/whaling-whales-food-krill-iron/620604/?utm_source=pocket-newtab-global-en-GB

NotaDenier

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Re: Antarctic ecosystems
« Reply #3 on: December 05, 2021, 04:22:39 PM »
https://www.vox.com/22797395/antarctica-was-once-a-rainforest-could-it-be-again

Not far from the South Pole, more than half a mile below the ocean in a region that was once covered by ice, a layer of ancient fossils tells a surprising story about the coldest continent on Earth. Today, the South Pole records average winter temperatures of 78 degrees Fahrenheit below zero. But roughly 90 million years ago, the fossils suggest, Antarctica was as warm as Italy and covered by a green expanse of rainforest.

“That was an exciting time for Antarctica,” Johann P. Klages, a marine geologist who helped unearth the fossils, told Vox. “It was basically the last time the whole continent was covered by vegetation and probably also wildlife — dinosaurs, and all that.”

Intrepid polar scientists like Klages, who works at the Alfred Wegener Institute for Polar and Marine Research in Bremerhaven, Germany, are revealing new sides of the Antarctica we know today. In the April 2020 issue of the journal Nature, he and 39 colleagues described networks of fossilized tree roots that they pulled up from the seafloor in 2017. They’re a sign of just how much the polar climate has changed since the “supergreenhouse” of the Cretaceous period — and perhaps how much the climate could change again.

northsylvania

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Re: Antarctic ecosystems
« Reply #4 on: January 06, 2022, 06:14:18 PM »
Whaling effects:- "They calculated that before industrial whaling, these creatures would have consumed about 430 million metric tons of krill—small, shrimplike animals—every year. That’s twice as much as all the krill that now exist, and twice as much by weight as all the fish that today’s fisheries catch annually. But whales, despite their astronomical appetite, didn’t deplete the oceans in the way that humans now do."

https://www.theatlantic.com/science/archive/2021/11/whaling-whales-food-krill-iron/620604/?utm_source=pocket-newtab-global-en-GB
In line with that, I read an interesting article about Antarctic krill, how they are harvested for everything from Omega3 supplements to commercial fish food. Reportedly, new technology brought in since the 2000s has made harvesting extraordinarily efficient yet estimates of the number of krill are only based on partial counts taking place during Antarctic summer.
https://www.theearthandi.org/post/antarctic-krill-an-ecosystem-powerhouse-caught-between-humans-and-nature
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morganism

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Re: Antarctic Ecosystems
« Reply #5 on: June 07, 2022, 01:55:55 AM »
 ‘Hidden world’ of marine life discovered in Antarctic ‘river’ under ice

New Zealand scientists ‘jumping up and down’ at find during investigation of climate-induced melt of ice shelf

 Beneath a vast Antarctic ice shelf, in a cathedral-like cavern hundreds of metres high, are swarms of little shrimp-like creatures in a newly discovered underwater ecosystem that, until recently, had remained an ice-locked secret.

A team of scientists from New Zealand discovered the ecosystem 500 metres below the ice in a suspected estuary, hundreds of kilometres from the edge of the Ross Ice Shelf.

Antarctica New Zealand supported researchers from universities in Wellington, Auckland and Otago, the National Institute of Water and Atmospherics (Niwa) and Geological and Nuclear Sciences to investigate what role the estuary could play in climate-induced ice-shelf melt.

But when they drilled down through the ice and into the river, their camera was swarmed by amphipods, little creatures from the same lineage as lobsters, crabs and mites.

“For a while, we thought something was wrong with the camera, but when the focus improved, we noticed a swarm of arthropods around 5mm in size,” said Niwa’s Craig Stevens.

The project’s lead, Huw Horgan from Te Herenga Waka Victoria University of Wellington, was the first to spot the estuary, after spying a groove in the ice while studying satellite imagery of the Ross Ice Shelf.

Researchers have been aware of a network of hidden freshwater lakes and rivers below the Antarctic ice sheets for some time but they have yet to be directly surveyed, Horgan said.

“Getting to observe and sample this river was like being the first to enter a hidden world.”

Instruments had been left in the river to observe its behaviour, he said, while lab researchers would investigate what makes the water unique.

The team’s findings extended further – it had just deployed its mooring a few days before the enormous eruption of Tongan volcano Hunga Tonga-Hunga Ha’apai. The team’s instruments detected a significant pressure change as the tsunami made its way through the cavity."

https://www.theguardian.com/world/2022/jun/06/hidden-world-of-marine-life-discovered-in-antarctic-river-under-ice