Wednesday, April 05, 2006

Penguins have to rush sex - 'quicky' is the new norm


Apparently, the Southern Hemisphere is not immune to global warming either, though most of the research has been done in the North, probably due to socio-political reasons - that is where the rich countries tend to be located.

However, several recent papers look at the effects of climate change on Antarctica. Just like in the Arctic, where polar bears are drowning when they try to swim between ever more distant pieces of floating ice, the same thing is happening in the Antarctica, negatively affecting the birds that nest there.

First, Warming signs mount up in Antarctica (the paper is: Significant Warming of the Antarctic Winter Troposphere) looks at the ice melting in the Antarctica.

The ice is breaking. This makes it more and more difficult for populations of penguins and other birds to travel between their feeding grounds and their nesting grounds. There are clear evolutionary consequences as the populations are getting more fragmented: Penguin evolution linked to shifting icebergs (Microevolution and mega-icebergs in the Antarctic).

Now, in the latest paper - Mating march of the penguins slows down - (not online on PNAS yet) this change in the ice forces the birds to remain at the feeding grounds longer in order to fulfill their metabolic needs. They need to stock up on all the calories for the long period of fasting while they court, mate, nest, lay and incubate the eggs and raise the hatchlings. So, they are arriving at their breeding sites late and starting the whole reproductive effort later.

In the extremes of polar regions, there is only a very narrow window of opportunity, during the super-short summer, to successfully raise hatchlings. Exact timing is crucial, especially for smaller animals (elephant seals don't seem to care - they are completely unsynchronized with the planet and breed every 9 months) and for migratory species.

In penguins, the climate change is placing their metabolic needs and the survival needs of their offspring in conflict, similarly to the situation in the Northern Hemisphere. How much longer can this go on until the window of opportunity for reproduction is completely closed?

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