WorldWide Drilling Resource®

26 AUGUST 2020 WorldWide Drilling Resource ® The South Pole Was Once a Swampy Rain Forest Adapted from Information by the Alfred Wegener Institute Researchers drilling core samples near the Pine Island Glacier in Antarctica have discovered a rain forest once existed near the South Pole. The team of researchers, led by geoscientists from the Alfred Wegener Institute (AWI), Helmholtz Centre for Polar and Marine Research, started noticing unusual colors of sediment around 88-98 feet below the ocean floor. The core samples were examined using X-ray computed tomography scans, more commonly known as CT scans. The scans revealed this vast area of glaciers and ice was once a swampy landscape where rainforests, similar to the ones found today, grew and even thrived. Amongst the sediment, Dr. Johann Klages, a geologist at the AWI, found pristinely preserved forest soil from the Cretaceous Period, including a large quan- tity of plant pollen, spores, and a dense network of roots, confirming the coast of West Antarctica was once warm and ice free. The dense network of roots spread through the entire soil layer of fine-grained clay and silt. It was so well-preserved, researchers could make out individual cell structures. The pollen and spores dis- covered in the cores were from various vascular plants and include the first rem- nants of flowering plants ever found at high Antarctic latitudes. The Cretaceous Period is not only known for its dinosaurs, it’s also known as the warmest period for the planet, but even then the Antarctic continent was at the South Pole, which means the area was subject to a four-month polar night. With no life-giving sunlight at all for a third of every year, how did plants in the rainforest grow? Researchers speculate this could only happen if there were no Antarctic ice sheets and the atmospheric carbon dioxide concentration was significantly higher than what current climate models show. “Before our study, the general assumption was that the global carbon dioxide concentration in the Cretaceous [Period] was roughly 1000 ppm (parts per million). But in our model-based experiments, it took concentration levels of 1120 to 1680 ppm to reach the average temperatures back then in the Antarctic,” explained AWI climate modeller Professor Gerrit Lohmann. So, what caused the climate to cool so dramatically to form ice sheets again? Finding that answer will be the next challenge for the international climate research community. ENV Photo of the University of Bremen’s seafloor drill rig MARUM-MeBo70, during station work right in front of the Pine Island ice shelf edge, by Karsten Gohl, Alfred Wegener Institute.