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Polar bear sub-populations and pollution

Polar bear sub-populations and pollution

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Uploaded 21 Feb 2012 by GRID-Arendal
Year: 2010 Author: Riccardo Pravettoni, UNEP/GRID-Arendal
Description:
There are thought to be between 20,000 and 25,000 bears in the world, which occur in19 relatively discrete sub-populations, some of which are shared between nations. Topping the food chain in the Arctic, the polar bear is exposed to high levels of pollutants that are magnified with each step higher in the food web (a process known as biomagnification). Recent studies have suggested that the immune system may be weaker in polar bears with higher levels of toxic contaminants (e.g., Polychlorinated Biphenyls or PCBs). There is also evidence that the hormone system of polar bears is affected by pollution, something that may interfere with reproduction and growth. Climate change could also indirectly affect Arctic animals topping the food chain, such as the polar bear, through the secondary release of toxic contaminants have long been trapped in snow, ice and permafrost that is now melting.
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