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20-year Study Observes Climate Change Induces Shift in Soil Ecosystem of Antarctic Dry Valleys


Earth Warming Shifts Ecosystems

“With climate change, some species are winners, some are losers,” explains Walter Andriuzzi, the lead author of a two-decade-long study led by Colorado State University.  The study has found that starting 2001, when a strange warm weather event occurred in the McMurdo Dry Valleys, the most common species in this desert – nematode Scottnema Iindsayae – is decreasing in population, while other species are flourishing and spreading uphill.

This shift in soil invertebrates is attributed to the increasing temperature in the region, resulting in the melting of more glaciers and permafrost. With increasing water downhill, the microbes and animals in the soil found uphill are becoming more diverse, and the consequence of which for the whole ecosystem of the region is not yet known. “In the Dry Valleys, it’s all about how they respond with warming and, most importantly, water,” says Andriuzzi.

These findings serve as a warning and awareness on how ecosystems behave in response to unusual climate events, according to scientists. “This is happening worldwide, and not just in Antarctica,” informs Andriuzzi. Scientists have also observed, for example, insects migrating uphill in the Rocky Mountains on a yearly basis, due to increasing temperatures.


Unusual Warming Events Observed

The research team’s findings in this two-decade-long study could not be observed by simply looking at average or monthly temperatures, according to Andriuzzi, who also led the field work.  “It’s a few hours or days of unusually warm weather. There are even peaks of high solar radiation that trigger ice thawing without high temperatures. That’s how climate change is happening there, and it’s already starting to impact the biological community there,” he explains.

“Until 2001, the region was not experiencing a warming trend. On the contrary, it was getting colder. But in 2001, the cooling trend stopped abruptly with an extremely warm weather event. Since then, the average temperatures are either stable or are increasing slightly. But most importantly, there have been more frequent intense weather events.”


Why in Antarctic Dry Valleys?

Shifts in communities are often very hard to predict, according to Andriuzzi, because there are so many species. “It’s easier in places like the dry valleys to isolate the effects of climate change or to isolate how one species respond to climate change in one way. It’s a natural laboratory, where some of the mechanisms that operate elsewhere can be unveiled.”

In McMurdo Dry Valleys, one of the world’s driest and coldest deserts and located in the largest region of the Antarctic continent, no plants, birds, or mammals can be found, only microbes, and microscopic soil invertebrates. The region is characterized by its harsh environment of extreme coldness, averaging below -15 degrees Celsius.

The study was conducted by sampling soil invertebrates and measurement of soil properties such as water content in three water basins located at three different elevations. In 1993, the field study was launched in the Taylor Valley, while in 2011, the researchers began studying the Miers and Garwood valleys.


[via EurekAlert!]

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