Antarctic has seen widespread change in last 50 years, moss study reveals

"This gives us a much clearer idea of the scale over which these changes are occurring," says lead author Matthew Amesbury of the University of Exeter. "Previously, we had only identified such a response in a single location at the far south of the Antarctic Peninsula, but now we know that moss banks are responding to recent climate change across the whole of the Peninsula."

The Antarctic Peninsula is known to have been one of the most rapidly warming regions on Earth. Annual temperatures there have crept up about 0.5°C each decade since the 1950s. The researchers realized they could learn a lot about how rising temperatures have affected the ecology of the Peninsula by studying core samples taken from moss banks established more than 150 years ago.

In the new study, the researchers added an additional three sites and five cores to their earlier sample. Those sites include three Antarctic islands (Elephant Island, Ardley Island, and Green Island) where the deepest and oldest moss banks grow, representing a 600-kilometer transect along the Peninsula.

Careful analysis of those five cores going back 150 years showed increased biological activity as the Peninsula has warmed in the last 50 years. Those findings suggest that the Peninsula is undergoing fundamental and widespread change. Amesbury noted that the consistency of changes in the moss samples taken from different parts of the Peninsula was particularly striking.

There's more to come, the researchers say. The sensitivity of mosses' rate of growth in response to past temperature increases suggests that terrestrial ecosystems of the Antarctic Peninsula will continue to experience rapid change with future warming.

"Temperature increases over roughly the past half century on the Antarctic Peninsula have had a dramatic effect on moss banks growing in the region, with rapid increases in growth rates and microbial activity," says Dan Charman, who led the research in Exeter. "If this continues, and with increasing amounts of ice-free land from continued glacier retreat, the Antarctic Peninsula will be a much greener place in the future."

The researchers say they'll continue to examine core records stretching back in time over thousands of years. Their goal is to explore the impact of climate change on terrestrial ecosystems before humans began heating things up.