Alfred-Wegener-Institut/J. McKay
–
The polar regions of the Eocene were green and fertile.
–
Nationalgeographic.co.id – plant fossils dating from 55 to 40 million years ago during time Eocene reveal details about warmer and wetter climates in the past. This condition means that there is palm trees at the North and South Poles. While most of the arid lands such as in Australia are fertile and green.
The plant fossils were collected over decades by paleobotanist David Greenwood from Australia. Some are so well preserved that it is hard to believe they are millions of years old.
By focusing on the morphological and taxonomic features of 12 different flora, the researchers developed a more detailed view of what climate and productivity were like in the ancient Eocene greenhouse world. The research report has been published in Paleoceanography and Paleoclimatology with the title “Plant Proxy Evidence for High Rainfall and Productivity in the Eocene of Australia” recently.
The fossils hold details about the ancient world in which they developed. Greenwood and the research team included climate model and research scientist David Hutchinson, of the University of New South Wales, and paleobotanist The University of Connecticut’s Department of Geosciences, Tammo Reichgelt, has begun the process of gathering evidence to study it.
Reichgelt and co-authors looked for evidence of differences in rainfall and crop productivity between past and present. Because different plants thrive under certain conditions, plant fossils can indicate the type of environment in which they lived.
Contributed photo
–
These are organically preserved leaves that have been mummified for about 45 million years.
–
Reichgelt explained that morphological methods depend on the fact that the leaves of angiosperms, or flowering plants, generally have strategies to respond to climate. “For example, if a plant has large leaves and is left in the sun and doesn’t get enough water, it begins to shrivel and die from excessive evaporation,” Reichgelt said in a University of Connecticut media release.
“Plants with large leaves also lose heat to their surroundings. Finding large leaf fossils means that it’s very likely that these plants did not grow in an environment that was too dry or too cold for excessive evaporation or sensible heat loss to occur.”
These characteristics, he continued, and morphological features that can be associated with the environment can be measured. We can compare fossils with modern flora around the world and find the closest analogy.
The second approach is taxonomy. “If you climb a mountain, the taxonomic composition of the flora changes. Lower down, there may be deciduous forests dominated by maple and beech and as you go further up the mountain you see more spruce and spruce forests,” says Reichgelt. .
“Finding fossils of beech and maple trees therefore likely means a warmer climate than if we were to find fir and fir fossils.”
According to him, the climatic preferences of such plant groups can be used to quantitatively reconstruct the ancient climate in which a group of plants in a fossil assemblage grew. The results suggest that the Eocene climate would be very different from the climate of modern Australia.
Adobe Stock
–
Dry today, Australia was once covered by dense forests, according to new research.
–
To maintain a lush green landscape, the continent needs a steady supply of rainfall. Warmth means more evaporation, and more rainfall is available to move into the interior of the Australian continent.
Higher levels of carbon dioxide in the atmosphere at the time, 1,500 to 2,000 parts per million, also contributed to fertility through a process called carbon fertilization. Reichgelt explained that with the abundance of CO2, plants basically formed land at that time.
Also Read: What are the Forests of Pangea like? Plant Fossils Be The Witness
Also Read: Before it was frozen and covered in ice, Antarctica was full of rainforests
Also Read: What Would the Earth Be Without Modern Humans? Here is the Explanation of the Experts
“South Australia appears to be largely forested, with primary productivity similar to that of seasonal forest, not dissimilar to that of New England today,” Reichgelt said.
In the summer, he explains, today’s Northern Hemisphere, there are major changes in the carbon cycle. That’s because a lot of carbon dioxide is pulled in due to primary productivity in the vast forests that are in the great belt around 40 to 60 degrees north.
Whereas in the Southern Hemisphere, there is no such landmass that exists at the same latitude today. But Australia during the Eocene occupied 40 degrees to 60 degrees south.
“As a result, there will be large landmasses that are very productive during the Southern Hemisphere summer, pulling carbon, more than what Australia is doing today because it’s mostly arid,” he said.
PROMOTED CONTENT
Featured Videos
–
