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Life Sciences => Plant Sciences, Zoology & Evolution => Topic started by: thedoc on 19/01/2014 15:43:04

Title: How will penguins cope with a warming Antarctic?
Post by: thedoc on 19/01/2014 15:43:04
British Antarctic Survey researchers have seen evidence of emperor penguins searching out new breeding grounds.

Read the whole story on our  website by clicking here (http://www.thenakedscientists.com/HTML/news/news/1000419/)

  
Title: Re: How will penguins cope with a warming Antarctic?
Post by: CliffordK on 19/01/2014 18:44:34
Quote
Emperor penguins rely on the formation of ice floes around the Antarctic coastline in order to breed. These ice sheets provide easy access to the sea, so that the giant birds are able to find fish to eat while raising their young on dry land.

However, rising temperatures mean that the extent of the ice floes which form each winter is shrinking, giving the penguins less room to breed. Exceptionally warm spells during the winters of 2011 and 2012 threatened to put the penguins under exceptional pressure, as the ice floes hardly formed at all.

This just doesn't make any sense. 

The Emperor Penguin ranges around almost the entire Antarctic Continent during the SUMMER, then migrate northward for the winter.

The sea ice around Antarctica is highly variable with most of the sea ice disappearing in the summer, and reforming in the winter.  Over the last couple of decades the sea ice has generally been INCREASING around Antarctica. 

http://arctic.atmos.uiuc.edu/cryosphere/IMAGES/seaice.recent.antarctic.png
http://arctic.atmos.uiuc.edu/cryosphere/IMAGES/seaice.anomaly.antarctic.png

According to the chart, the winter 2011 sea ice was slightly below average (when the Penguins were not around), but the summer sea ice for January 2011 & December 2011 was pretty close to average.  2012, on the other hand, was at or above average for most of the year.  The current summer extent (2013/2014) is much higher than average. 

Is this only looking at a small colony of penguins on the Antarctic Peninsula? 

It is good to hear that the birds can find a path to climb the ice shelves, but not particularly surprising as the summer sea ice around Antarctica is always extremely variable, and many videos I've seen show the Penguins following each other in lines and acting in groups.

We are only looking at a few decades snapshot of ice conditions in both the Arctic and Antarctic.  It is hard to believe a species could survive extreme shifts between glacial and interglacial periods, warm and cool periods, and fluctuations of sea levels of hundreds of meters without being at least a little bit adaptable.
Title: Re: How will penguins cope with a warming Antarctic?
Post by: evan_au on 20/01/2014 09:28:19
Quote
migrate northward for the winter
I thought the emperor penguins overwintered  (http://en.wikipedia.org/wiki/Emperor_penguin#Courtship_and_breeding) within the Antarctic continent, which would be more to the south?
I know everything is backwards in the Southern Hemisphere...
Title: Re: How will penguins cope with a warming Antarctic?
Post by: CliffordK on 21/01/2014 02:12:16
Quote
migrate northward for the winter
I thought the emperor penguins overwintered  (http://en.wikipedia.org/wiki/Emperor_penguin#Courtship_and_breeding) within the Antarctic continent, which would be more to the south?
Ohhh....
I think I had migrations of different species of penguins confused.

But, we're both half right.
Apparently the males stay on the Antarctic Continent for the winter.

The females, on the other hand abandon their mates and head northward to warmer weather for the winter.  During the winter, the males are huddling together in bitter cold weather with nothing to eat.  The species is apparently well adapted to the long harsh winter conditions, although I wonder if there would be benefits of more leads and Polynyas occurring in the sea ice, perhaps allowing a shorter fasting period.

Much of the timing for the sea ice formation is based on the sun, and the very dark winters in Antarctica.  It will take major changes in the environment for all of the sea ice to go away. 

Apparently there is a relationship between Antarctic Krill, Algae, and Sea Ice.  If the sea ice was to significantly decrease, it could have a negative impact on the krill, and many species that depend on them.

Anyway, looking at the range map (https://en.wikipedia.org/wiki/File:Manchot_empereur_carte_reparition.png) for the Emperor Penguins, I'd ask why it isn't uniform around Antarctica.  Green on the map is for mating areas, red is the range.  So, the question is what is so different about Wilkes Land that there are no emperor penguin colonies?  And perhaps the same for the Antarctic Peninsula.  Of course there are Adélie Penguins in the area.  Is there competition between species?
Title: Hear this story on our show
Post by: thedoc on 21/01/2014 15:59:26
Read the whole story on our  website by clicking here (http://www.thenakedscientists.com/HTML/news/news/1000419/), or go to the podcast page (http://www.thenakedscientists.com/HTML/podcasts/naked-scientists/show/20140121/)
[chapter podcast=1000590 track=14.01.21/Naked_Scientists_Show_14.01.21_1001885.mp3](https://www.thenakedscientists.com/forum/proxy.php?request=http%3A%2F%2Fwww.thenakedscientists.com%2FHTML%2Ftypo3conf%2Fext%2Fnaksci_podcast%2Fgnome-settings-sound.gif&hash=f2b0d108dc173aeaa367f8db2e2171bd) Listen to the Story[/chapter] or [download as MP3] (http://nakeddiscovery.com/downloads/split_individual/14.01.21/Naked_Scientists_Show_14.01.21_1001885.mp3)