Climate History of Northern Antarctica Revealed by Fossilized Pollen

By looking at fossilised pollen found below a hundred feet of dense rock off the coast of Northern Antarctica, researchers have been able to reconstruct a climate record for the southern continent, and determine that the last remnant of Antarctic vegetation existed on the continents northern peninsula some 12 million years ago in a tundra landscape similar to that of Patagonia.

The research was led by researchers at Rice University and Louisiana State University and appears online this week and will be featured on the cover of the July 12 issue of the Proceedings of the National Academy of Sciences.

The study contains the most detailed reconstruction of the history of the Antarctic Peninsula’s climate.

This sort of research is especially important in light of the fact that the Antarctic Peninsula was not only the last part of Antarctica to succumb to ice, but is also the currently suffering extreme shifts in climate and warming. A rapid decline of the Peninsula’s glaciers has led to widespread speculation as to how the rest of the continent’s ice sheets will react to rising temperatures.

“The best way to predict future changes in the behavior of Antarctic ice sheets and their influence on climate is to understand their past,” said Rice University marine geologist John Anderson, the study’s lead author.

55 million years ago, Antarctica was not the ice-laden behemoth it is today. It was covered in forests which were then swept underneath the layers of ice that began forming about 38 million years ago. The Antarctic Peninsula was the last past of the continent to be covered due to the fact that it stretches so far north.

This same feature is why it is the first part of Antarctica to be affected by the changing climate today.

“There’s a longstanding debate about how rapidly glaciation progressed in Antarctica,” said Sophie Warny, a Louisiana State University geologist who specializes in palynology (the study of fossilized pollen and spores) and led the palynological reconstruction. “We found that the fossil record was unambiguous; glacial expansion in the Antarctic Peninsula was a long, gradual process that was influenced by atmospheric, tectonic and oceanographic changes.”

Along with her students and colleague Rosemary Askin, Warny studied thousands of individual grains of pollen that were preserved in muddy sediments beneath the sea floor located just off the coast, and was thus able to determine the exact species of plant that had existed on the peninsula over the past 36 million years.

“The pollen record in the sedimentary layers was beautiful, both in its richness and depth,” Warny said. “It allowed us to construct a detailed picture of the rapid decline of the forests during the late Eocene — about 35 million years ago — and the widespread glaciation that took place in the middle Miocene — about 13 million years ago.”

For more information on just how the sediment was acquired from the seafloor, follow the link to the Rice University press release for a fascinating look into the process needed to drill in one of the planet’s harshest environments.

Image Source: euphro

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