(Sydney Morning Herald online)
Scientists get scoop on whale waste
Jim O'Rourke
January 2, 2011
IF A whale breaks wind in the Southern Ocean and no one is around to hear it, does it make a sound?
This philosophical riddle could have been contemplated by Australian scientists while they collected whale waste as part of a study to determine if it could help "fertilise" the ocean and make it more productive.
Scientists from the Australian Antarctic Division, based in Hobart, have been testing the hypothesis that enormous amounts of iron excreted by whales is akin to liquid manure.
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This fertiliser helps phytoplankton grow, which in turn helps support a wide number of marine species including those eaten by humans.
Whales take the iron into their systems by eating huge quantities of krill, a shrimp-like crustacean. But because whales produce blubber rather than muscle, they don't need iron in their diet – so it passes out in their excrement.
In the days before industrial whaling there were millions of the mammals in the waters around Antarctica in the summer providing the iron to keep the ecosystem productive.
But molecular biologist Simon Jarman, with the Australian Antarctic Division, said now that whale populations have dropped to levels of just 2 to 3 per cent of former numbers, there is not enough iron in the Southern Ocean. "Removing whales from the ecosystem has probably made the whole ecosystem less productive," Dr Jarman said. "We know there used to be a lot more fish."
To test their theories the scientists had to find areas where whales were feeding, and then be ready with a fine mesh net to scoop up the faeces.
"They will defecate eventually," Dr Jarman said. "You can notice it fairly easily, it's a big event.
"It could be as much as half a tonne in one go, but no one has ever been actually able to measure it."
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