{"id":4258,"date":"2018-01-22T17:07:27","date_gmt":"2018-01-22T23:07:27","guid":{"rendered":"https:\/\/www.wisconsin.edu\/for-wisconsin\/?post_type=campus_story&p=4258"},"modified":"2018-01-23T08:46:45","modified_gmt":"2018-01-23T14:46:45","slug":"uw-milwaukee-geologists-uncover-antarcticas-fossil-forests","status":"publish","type":"campus_story","link":"https:\/\/www.wisconsin.edu\/all-in-wisconsin\/story\/uw-milwaukee-geologists-uncover-antarcticas-fossil-forests\/","title":{"rendered":"UW-Milwaukee geologists uncover Antarctica\u2019s fossil forests"},"content":{"rendered":"
\"Photo<\/a>
Erik Gulbranson, paleoecologist and assistant professor at UWM, studies some of the fossilized trees he brought back from Antarctica. Gulbranson is returning there for further research this year. (UWM Photo\/Troye Fox)<\/figcaption><\/figure>\n

During Antarctica\u2019s summer, from late November through January, UW-Milwaukee geologists Erik Gulbranson and John Isbell climbed the McIntyre Promontory\u2019s frozen slopes in the Transantarctic Mountains. High above the ice fields, they combed the mountain\u2019s gray rocks for fossils from the continent\u2019s green, forested past.<\/p>\n

By the trip\u2019s end, the geologists had found fossil fragments of 13 trees. The discovered fossils reveal that the trees are over 260 million years old, meaning that this forest grew at the end of the Permian Period, before the first dinosaurs.<\/p>\n

\u201cPeople have known about the fossils in Antarctica since the 1910-12 Robert Falcon Scott expedition,\u201d said Gulbranson, a paleoecologist and assistant professor in UWM\u2019s Department of Geosciences. \u201cHowever, most of Antarctica is still unexplored. Sometimes, you might be the first person to ever climb a particular mountain.\u201d<\/p>\n

The time frame is exactly what they are looking for. The Permian Period ended 251 million years ago in history\u2019s greatest mass extinction, as the Earth rapidly shifted from icehouse to greenhouse conditions. More than 90 percent of species on Earth disappeared, including the polar forests. Because the Antarctic forests grew at polar latitudes where plants\u00a0can\u2019t grow today, Gulbranson believes that the trees were an extremely hearty species\u00a0and is trying to determine why they went extinct.<\/p>\n

\"Photo<\/a>
Gulbranson studies a fossil under a microscope. (UWM Photo\/Troye Fox)<\/figcaption><\/figure>\n

Isbell, a distinguished professor of geosciences at UWM, has previously studied Antarctica\u2019s Permian glacial deposits to determine how the climate changed. On this expedition, he used the rocks around the fossilized trees to determine how the fossils fit into Antarctica\u2019s geologic history.Many scientists now believe that a massive increase in atmospheric greenhouse gases, such as carbon dioxide and methane, caused the Permian-Triassic extinction. It\u2019s likely that over the course of 200,000 years \u2013 a short time, geologically speaking \u2013 volcanic eruptions in Siberia released many tons of greenhouse gases into the atmosphere.<\/p>\n

\u201cThis forest is a glimpse of life before the extinction, which can help us understand what caused the event,\u201d Gulbranson said. It can also give clues to how plants were different than today.<\/p>\n

\u00a0<\/strong>At the Permian Period\u2019s end, Antarctica was warmer and more humid than it is today. The world\u2019s continents, as we know them, were packed together in two giant landmasses \u2013 one in the north and one in the south. Antarctica was part of Gondwana, the supercontinent spanning the Southern Hemisphere that also included present-day South America, Africa, India, Australia and the Arabian Peninsula.<\/p>\n

There would have been a mixture of mosses, ferns and an extinct plant called\u00a0Glossopteris<\/em>, and it\u2019s likely that this forest stretched across the entirety of Gondwana.<\/p>\n

Watch video.<\/a><\/p>\n

Gulbranson said that the fossil forests looked different than forests today. During the Permian Period, forests were a potentially low diversity assemblage of different plant types with specific functions that affected how the entire forest responded to environmental change. This is contrast to modern high-latitude forests that display greater plant diversity.<\/p>\n

\u201cThis plant group must have been capable of surviving and thriving in a variety of environments,\u201d Gulbranson said. \u201cIt\u2019s extremely rare, even today, for a group to appear across nearly an entire hemisphere of the globe.\u201d<\/p>\n

But not even these robust forests survived the high carbon dioxide concentrations of the mass extinction.<\/p>\n

The resilient plants also must have survived through the polar extremes of perpetual light and total darkness. Even in a warmer past, the polar regions would have experienced months of darkness in winter and would have gone without sunset during the summer months.<\/p>\n

By studying the preserved tree rings, Gulbranson and colleagues have found that these trees transitioned from summer activity to winter dormancy rapidly, perhaps within a month. Modern plants make the same transition over the course of several months and also conserve water by making food during the day and resting at night. Scientists don\u2019t yet know how months of perpetual light would have affected the plants\u2019 day-and-night cycles.<\/p>\n

\u201cThere isn\u2019t anything like that today,\u201d Gulbranson said. \u201cThese trees could turn their growing cycles on and off like a light switch. We know the winter shutoff happened right away, but we don\u2019t know how active they were during the summertime and if they could force themselves into dormancy while it was still light out.\u201d<\/p>\n

He returned to the site in December and stayed through January 2018, hoping to learn more about the extinction event. He previously wasn\u2019t able to study the extinction period because of weather constraints and aircraft troubles.<\/p>\n

\u00a0<\/em>Gulbranson is going to look for deposits from the mass extinction to see if he can determine exactly how the forests responded as carbon dioxide rose.<\/p>\n

\u201cThe geologic record shows us the beginning, middle and end of climate change events,\u201d Gulbranson said. \u201cWith further study, we can better understand how greenhouse gases and climate change affect life on Earth.\u201d<\/p>\n","protected":false},"excerpt":{"rendered":"

During Antarctica\u2019s summer, from late November through January, UW-Milwaukee geologists Erik Gulbranson and John Isbell climbed the McIntyre Promontory\u2019s frozen slopes in the Transantarctic Mountains. High above the ice fields, they combed the mountain\u2019s gray rocks for fossils from the continent\u2019s green, forested past. By the trip\u2019s end, the geologists had found fossil fragments of […]<\/p>\n","protected":false},"author":15,"featured_media":4261,"comment_status":"closed","ping_status":"closed","template":"","institution":[107],"story_category":[],"class_list":["post-4258","campus_story","type-campus_story","status-publish","has-post-thumbnail","hentry","institution-uw-milwaukee"],"_links":{"self":[{"href":"https:\/\/www.wisconsin.edu\/all-in-wisconsin\/wp-json\/wp\/v2\/campus_story\/4258","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.wisconsin.edu\/all-in-wisconsin\/wp-json\/wp\/v2\/campus_story"}],"about":[{"href":"https:\/\/www.wisconsin.edu\/all-in-wisconsin\/wp-json\/wp\/v2\/types\/campus_story"}],"author":[{"embeddable":true,"href":"https:\/\/www.wisconsin.edu\/all-in-wisconsin\/wp-json\/wp\/v2\/users\/15"}],"replies":[{"embeddable":true,"href":"https:\/\/www.wisconsin.edu\/all-in-wisconsin\/wp-json\/wp\/v2\/comments?post=4258"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/www.wisconsin.edu\/all-in-wisconsin\/wp-json\/wp\/v2\/media\/4261"}],"wp:attachment":[{"href":"https:\/\/www.wisconsin.edu\/all-in-wisconsin\/wp-json\/wp\/v2\/media?parent=4258"}],"wp:term":[{"taxonomy":"institution","embeddable":true,"href":"https:\/\/www.wisconsin.edu\/all-in-wisconsin\/wp-json\/wp\/v2\/institution?post=4258"},{"taxonomy":"story_category","embeddable":true,"href":"https:\/\/www.wisconsin.edu\/all-in-wisconsin\/wp-json\/wp\/v2\/story_category?post=4258"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}