Forest cover and runoff are influenced by freezing temperatures at the end of the Paleozoic Ice Age, study finds

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New research by Baylor University biology doctoral student William J. Matthaeus and biology professor Joseph White, Ph.D., examines how frost intolerance of plants has affected forest cover and hydrology in the During the Pennsylvanian Period, approximately 340-285 million years ago during the Paleozoic Era, proposing improvements to climate projections for the past and future with data on plant function.

This highly interdisciplinary and collaborative project included Baylor postdoctoral researcher in geology, Jon Richey, as well as climatologists, geologists and paleobotanists from several other American and European institutions.

The study, published in Proceedings of the National Academy of Sciences, suggests that plant freezing would have limited the geographic distribution of forest cover across the Pangea supercontinent. During this time, there were glacial-interglacial cycles and prolonged periods of low temperatures. Depending on the physiology limits of frost tolerant plants, minimum freezing temperatures likely limited the ability of tree plants to survive.

“Plants can tell us things about when and where they grew because plants have basic needs, much like people do. But because plants cannot move around to get what they have. need, they have to build their ‘bodies’ to function well for where they grow, “said Matthaeus.” For this reason, plant fossils contain information about how these plants function, but also about the conditions under which they were confronted even 300 million years ago. “

Low forest cover has increased surface runoff of freshwater and sediment in some areas. Frost-induced runoff changed dramatically between ice ages and interglacials across Pangea, and may have resulted in location-specific differences in the levels of minerals, sediment, organic matter, and nutrients in the runoff. freshwater in riparian, riparian and coastal marine environments.

The researchers combined climate modeling and ecosystem process modeling to simulate tree vegetation at the end of the Paleozoic Ice Age. Since existing global climate modeling projections do not take into account the differences in plant functional traits between contemporary and Paleozoic plants, the researchers used plant trait data derived from fossils to simulate global ecosystem processes.

“Even with the limited sample of the fossil record used here, clues to the impact of freezing on 300 million year old plant communities are evident. We combine fossil inference about plant function with modeling of the plant. global climate to bring Earth to life.These are an essential couple of disciplines to put together the puzzle of natural history, ”said Matthaeus.

Global climate modeling showed freezing temperatures to be near global and probably a limiting factor in the distribution of forest cover, even in subjects. Less than 25% of the non-glacial land that could support vegetation remained above the freezing point year round. The researchers suggest that widespread and repeated exposure of plants to freezing temperatures during the Pennsylvanian influenced the evolution of notable aspects of plant physiology in the later Paleozoic.

“Climate models are typically used to study average temperature trends over monthly or longer time scales in the Earth’s past. However, this approach ignores the extreme temperatures which are known to be critical for the functioning and survival of plants today. A new aspect of this study is that we are focusing on the model-simulated daily temperature changes that plants likely endured during the Pennsylvanian, ”said Sophia I. Macarewich, co-author and doctoral student in paleoclimatology and scientific computation at the University of Michigan.

Incorporating fossil-derived paleobotanical data into deep-time climate modeling can improve projections and understanding of past Earth systems, as well as contribute to future models of climate change, the authors say.

“Further development of these methods can serve as a bridge to understand the foundations of global ecosystems through Earth’s ancient past. By understanding how things have worked throughout natural history, we have a better chance of understand our own future, ”said Matthaeus.

White sees the study as strengthening Baylor as a leader in the field, especially with regard to doctoral studies and academic achievement.

“Mr. Matthaeus’ success can be attributed to his inherently inquisitive mind and exceptional computer skills which, along with his university degrees in evolutionary biology and mathematics, provided him with a mind prepared to succeed in solving such a difficult question.” , did he declare. “He is also extremely cultured and has benefited from direct interaction with experts in the discipline, many of whom are his co-authors, in addition to the mentorship of other Baylor professors such as paleobotanist Dr Dan Peppe, associate professor of geosciences, and Dr. Bernd Zechmann, director and associate research professor at the Center for Microscopy and Imaging. ”


The first forest fires testify to the expansion of ancient trees


More information:
William J. Matthaeus et al, Frost tolerance influenced forest cover and hydrology during the Pennsylvanian, Proceedings of the National Academy of Sciences (2021). DOI: 10.1073 / pnas.2025227118

Provided by Baylor University

Quote: Study reveals that forest cover and runoff are influenced by freezing temperatures during the Late Paleozoic Ice Age (2021, October 15) retrieved October 16, 2021 from https://phys.org/news/2021 -10-forest-runoff-temperatures-late-paleozoic .html

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