Download this episode.

Arctic Slush

CCGS Amundsen

This fall, Dr. David Barber and his colleagues were cruising the western Arctic Ocean in the icebreaker/research ship CCGS Amundsen to study multi-year sea ice, the kind that has formed the permanent ice cap in the Arctic for hundreds of thousands of years. They were guided by satellite observations that suggested that solid ice was present throughout this part of the Arctic. What they saw instead was something Dr. Barber says he's never observed before - broken, slushy, decayed ice with a thin veneer of harder ice over it, which their ship pushed through as if it wasn't there. This new kind of ice had fooled the satellites, and suggests that the permanent Arctic ice cover is in even more trouble than had been previously thought.

Listen to this segment:

Related Links

Geophysical Research Letters (paper not yet available as of broadcast)
University of Manitoba News
Dr Barber's web page
Dr. Barber previously on Quirks & Quarks, Nov. 24, 2007

The Poop on Mammoths

Sediment cores from Appleman Lake, Indiana - courtesy Jacquelyn Gill

Around 15,000 years ago, North America was home to a wide variety of giant mammals, including mammoths, mastodons and giant ground sloths. But by 10,000 years ago, these megafauna were gone. The causes for this extinction were thought to be a combination of early human hunters, changes in vegetation, massive forest fires or possibly even a meteor strike. But new research by Phd candidate Jacquelyn Gill, from the Department of Geography at the University of Wisconsin, Madison, suggests something different. From the sediment of a lake-bottom, Gill examined spores left over from the fungi that grow in dung, and compared them to other indicators of that time period. The result was a new theory. Some of the events previously thought to have caused the megafauna extinction, such as changes to the environment, were actually the result of the extinction.

Listen to this segment:

Related Links

Paper in Science
Release from University of Wisconsin
Not Exactly Rocket Science blog

Pipefish Dads

Male broad-nosed pipefish, Gry Sagebakken, University of Gothenburg

In the broad-nosed pipefish world, it is the male who gets pregnant. After he fertilizes as many as 100 of the female's eggs, he takes them into a brood pouch on his tail, then shelters them until he hatches them several weeks later. But, some of the embryos mysteriously disappear during that brooding period. New research done by Gry Sagebakken, a Phd student from the Zoology Department at the University of Gothenburg in Sweden, has produced an answer. Through blood vessels in the brood pouch, the male cannibalizes some of his own embryos to give himself a boost of nutrition.

Listen to this:

Related Links

Paper in Proceedings of the Royal Society B
News release from the University of Gothenburg
Not Exactly Rocket Science Blog
Gry Sagenbakken's web page
CBC News story

Taking Leave of the MAPLEs

Inside MAPLE-2 - AECL

When news first spread in December 2007 that the Chalk River reactor -- the world's biggest single supplier of medical isotopes -- might be closed for much longer than expected, the world held its breath. Diagnostic tests for cancer and heart disease were put on hold while radiologists scrambled to find new supplies. But, ironically, an alternative source for the production of medical isotopes was sitting idle, just down the road from the aging Chalk River reactor.

MAPLE 1 and MAPLE 2 are two completely new reactors, the only ones in the world built specifically to produce medical isotopes. A single MAPLE reactor can supply all the isotopes the world currently needs; with the second MAPLE as a backup. There's just one problem: the MAPLEs have never been given the official go-ahead. And chances are, they never will. Instead, it looks like these two nuclear reactors, which cost Canadian taxpayers millions of dollars, will just be left in the bush to rot. (MAPLE stands for Multipurpose Applied Physics Lattice Experiment).

Toronto science journalist and Quirks contributor, Alison Motluk, prepared this documentary on the controversy, and spoke with the following people:

• Linda Keen is the former president of the Canadian Nuclear Safety Commission. She says her team could not let the project go ahead until AECL understood why the PCR, (the power coefficient of reactivity), part of the MAPLE's safety plan, did not come out as predicted.
• Fred Boyd, a retired physicist who has worked in nuclear regulation, as well as with AECL and in policymaking, says the discrepancy between what the physicists predicted about the PCR and what the reactor produced is not a safety issue. He believes the reactors should be brought online.
• Jatin Nathwani, an engineer who has worked in the nuclear industry and now heads the Waterloo Institute for Sustainable Energy, at the University of Waterloo, still believes in the MAPLE reactors, and thinks it makes no sense to abandon them after so much time and money has been spent.

Listen to this segment:

Related Links

Atomic Energy of Canada, Limited
Canadian Nuclear Safety Commission
MAPLE technology
AECL position on MAPLE
Defence of MAPLE from former manager on the project (pdf)
Story from CBC News

Theme music bed copyright Raphaël Gluckstein.
Creative Commons License by-nc-nd-2.0