Mummified seals reveal effects of climate change in Antarctica

  • 08/02/2012

Climate change in Antarctica's Dry Valleys may affect the area more rapidly than previously expected, according to an international team of Antarctic researchers.

There has been a longstanding belief that life progresses very slowly in the harsh conditions of environments such as the Dry Valleys. In an effort to conserve the scare resources, changes in ecosystems take place over millennia.

However, the scientists have found that microbial communities in the soil undergo rapid and lasting changes in response to current environmental conditions.

The team, led by Professor Craig Cary at the University of Waikato, measured the rate at which observed biological changes occurred beneath a 250-year-old crab-eater seal carcass and at a nearby control site.

Under the carcass the soil environment changed by stabilising temperatures, elevating relative humidity and reducing ultraviolet exposure.

The scientists then transferred the mummified carcass to an untouched site to find out how quickly these changes occurred.

They tracked the changes in microbial composition and structure using community DNA fingerprinting and new sequencing techniques.

The mummy leaked nutrients into the soil and trapped moisture under it that would have normally escaped into the air. It took only two years for major changes to occur during the five year study.

Their findings have been published this week in the international online science journal Nature Communications.

"We used to think that changes in microbial change took place slowly over centuries," said Professor Cary. "But the research we've been doing indicates that the bacteria living in the soil are inherently sensitive to climate variability - minor temperature variations could lead to cascading changes in hydrology and biogeochemical cycling and could dramatically affect ecosystem function."

A recent climate change report for Antarctica predicts the continent may experience more changes as the ozone hole begins to close over the next 50 years, according to Professor Cary.

The mummified seal has now been moved back to its original location to see how the microbial communities alter once more.

He stressed the importance of continued documentation of the current biodiversity in Antarctica in an effort to predict the effects of climate change.

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source: newshub archive