Tough Enough

Will Antarctica’s smallest residents care when the sea warms?

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Rod Budd

Antarctic microbes are a hardy bunch, usually enjoying life at -2°C, in and under the sea ice. But laboratory incubator studies have shown they can also survive at a comparatively balmy temperature of +4°C.

Microbes, particularly microalgae, are at the very base of the Antarctic food chain and there has long been concern about how they might fare in a warmer climate.

“Microalgae and bacteria make up the vast majority of the marine microbial community in the Southern Ocean,” says University of Victoria researcher Andrew Martin. “In fact, if you could extract and weigh all the life forms including seals, penguins, whales 95 per cent would be microbes.” A decline in microbes would ultimately lead to a decline in seals, penguins and whales, he says. “So, understanding vulnerability at the base of the food chain makes sense with respect to global change.”

This result of the incubator studies brings new hope that these important microbes can tolerate a warming of up to six degrees both in the Antarctic and Arctic as sea-surface temperatures increase. “However, the next challenge is to try to more accurately model the real world where there are multiple stressors on the ecosystem, such as UV radiation, pH, salinity and temperature,” Martin says. Just how extreme these extremophiles really are remains to be seen.

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