Radio Script
2003

Researchers John Smol and Kathleen Ruhland say a warmer northern climate is causing changes in the kinds of algae living in Canada's Arctic lakes. (Courtesy Queen's University)

Warmer Arctic Hosts New Plants
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INTRO: Scientists amassed a lot of evidence that indicates the Arctic is getting warmer. They've measured melting glaciers, witnessed a rise in air temperature and calculated the loss of polar sea ice. Now scientists say the ecology of freshwater lakes in the far north is changing as well. As Doug Schneider reports in this week's Arctic Science Journeys Radio, a change in microscopic plants found in Arctic lakes offers fresh proof that the global climate is getting warmer.

STORY: Scientists studying lakes in Northern Canada have found the remains of microscopic plants more commonly found in warmer climates. That these plants are showing up so far north is a clear sign that northern latitudes have become warmer.

Click image to view larger version. (Courtesy Queen's University)

John Smol is a biologist at Queen's University in Kingston, Ontario. He and his colleagues studied the fossilized remains of diatoms in sediment samples gathered from 50 lakes in Canada's Northwest Territories. Diatoms are a form of algae. They use minerals in the water to encase themselves in a glass-like shell.

For each lake, Smol and his colleagues compared diatoms preserved in the top, most recent sediment layer with those from the bottom layer dating back to a time before global industrialization.

Diatoms buried about 30 centimeters into the sediment date back about 200 years. Smol says they typically were kinds better suited for colder climates. However, Smol says diatoms found at the surface of sediment cores were of a type that prefer warm water.

Smol says this shift in the basis of the food web could indicate bigger changes for the lakes themselves.

SMOL: "If the diatoms are changing, it means that probably the entire ecosystem is changing. Some of these lakes, quite possibly, are getting warmer; it's possible that fish, for example, or other species that used to live farther south, will be able to move into these lakes, and they'll totally start changing these systems after many thousands of years of being one type of system."

Smol also says the remains of these tiny plants are a sign that even larger-scale changes are occurring in the global climate.

SMOL: "I think this is adding more evidence that the climate is changing and it's related to, at least partially, to greenhouse gas emissions. We really have to take greenhouse gas-induced changes as a significant factor. We don't want to say all these changes are due to greenhouse warming, but I think the evidence is constantly piling in that we are seeing significant changes in climate."

Smol says he wasn't surprised to discover these changes in Canada's lakes. He says the Arctic is where some of the earliest and strongest signs of global warming have been observed.

Help this week comes from Earthwatch Radio at the University of Wisconsin Sea Grant Institute. This is Arctic Science Journeys Radio, a production of the Alaska Sea Grant Program at the University of Alaska Fairbanks School of Fisheries and Ocean Sciences. I'm Doug Schneider.

Thanks to the following individual for help preparing this script:

John P. Smol, Professor of Paleolimnology
Department of Biology
Assessment and Research Lab
Paleoecological Environmental
Queen's University
116 Barrie St.
Kingston, Ontario K7L 3N6
Canada
Phone: 613-533-6147
Email: smolj@biology.queensu.ca

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Related websites

Fifty Arctic Lakes Show Dramatic Effects of Climate Warming

John Smol web site

Earthwatch Radio

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