Fossil Find in China Reveals Plant Life Survived the “Great Dying”

The Permian mass extinction, a cataclysmic event known as the “Great dying” that wiped out approximately 80% of life on Earth around 251.9 million years ago, may not have been as devastating for plant life as previously believed. A recent study focusing on fossil findings in China has identified a refuge where plants thrived during this period, challenging long-held assumptions about the extent of terrestrial devastation. This revelation offers new insights into the complexities of the extinction event and the resilience of plant ecosystems.

The Permian extinction coincided with the existence of the supercontinent Pangea, which was in the process of breaking apart, with most of the world’s landmass still connected and separated by shallow seas. This period was marked by extreme environmental changes, largely attributed to massive volcanic activity.

The Siberian Traps, a vast volcanic system, experienced large eruptions that dramatically increased carbon dioxide levels in the atmosphere. A 2021 study estimated that CO2 levels reached 2,500 parts per million (PPM) during this time, substantially higher than the current level of approximately 425 ppm.This surge in CO2 led to global warming and ocean acidification, causing a widespread collapse of marine ecosystems.

A Terrestrial Refuge in China

While the impact on marine life is well-documented, the effects on terrestrial ecosystems during the Permian extinction are less understood. Fossil records from this period are scarce, with only a few locations worldwide containing rock layers with well-preserved land ecosystem fossils from the end of the Permian to the beginning of the triassic period.

A new study, published in the journal *Science Advances* on Wednesday, March 12, focuses on one such location in northeastern China. The research reveals a refuge where the ecosystem remained relatively healthy despite the Great Dying. This area supported a thriving gymnosperm forest, characterized by seed-producing plants, alongside ferns that reproduced through spores.

Wan Yang, a professor of geology and geophysics at the Missouri University of Science and Technology and one of the study’s authors, stated:

at least in this place, we do not see mass extinction in plants.
Wan Yang, Missouri University of Science and Technology

This finding suggests that the impact of the Permian extinction on land may have been more nuanced than previously thought, with some areas providing refuge for plant life.

Gradual Changes, Not Sudden Extinction

The research team analyzed rock layers in Xinjiang, a region now characterized by desert landscapes. The site’s unique geological features, including layers of ash containing zircon crystals, allowed for precise dating of the rocks. Zircon contains radioactive elements, such as lead and uranium, which decay at a known rate, enabling researchers to determine the age of the rocks with greater accuracy.

The rock layers also contained spore and pollen fossils, providing valuable insights into the plant life that existed during the Permian-Triassic transition.These fossils indicate that the changes in plant species were gradual, rather than a sudden extinction followed by rapid repopulation.

Josefina Bodnar, a paleobotany expert from the National University of La Plata in Argentina, who was not involved in the study, noted that these findings align with evidence from other regions:

Land plants have many adaptations that allow them to survive this extinction. For example, they have underground structures such as roots or stems that can last for hundreds of years.In addition, seeds can also survive for a long time.
Josefina Bodnar, National University of La Plata

Bodnar’s comments highlight the inherent resilience of plants, which possess various survival mechanisms that enable them to withstand environmental stresses.

Favorable Environmental Conditions

The survival of plant life in the Xinjiang refuge might potentially be attributed to specific environmental conditions. during the Permian period, the area was characterized by a damp habitat with numerous lakes and rivers, located a few hundred miles from the coast. Similarly, other plant refuges, such as those found in Argentina, were situated at high latitudes, away from the extreme temperatures near the equator.

The study also revealed that the climate in Xinjiang became slightly drier during the Permian-Triassic transition, but not to the extent that it caused widespread deforestation. This suggests that the environmental changes in the refuge were not as severe as in other regions, allowing plant life to persist.

Devin Hoffman, a paleontology researcher from University College London, who was not involved in the study, explained the potential reasons for this localized survival:

On land, you can still avoid some of the impact. Everything is basically pushed towards the poles and coastal, but on land, there is a possibility to survive.
Devin Hoffman, University College London

Hoffman’s comments underscore the idea that terrestrial environments offered more opportunities for survival compared to the uniformly acidified oceans.

Re-evaluating the “Great Dying”

The findings from this study have sparked debate about the appropriateness of the term “Great Dying” when considering the impact on terrestrial ecosystems. Robert Gastaldo, Professor of Emeritus Geology from Colby College, who has collaborated with Wan Yang but was not involved in this particular study, suggests a different outlook:

I prefer to call it a crisis on land, not extinction.
Robert Gastaldo, Colby College

gastaldo’s viewpoint reflects the growing recognition that the Permian extinction’s effects varied across different environments, with plant life demonstrating a remarkable capacity for survival in certain regions.

Lessons for the Future

The Permian mass extinction holds notable relevance to contemporary climate change concerns. The event was triggered by a surge in greenhouse gases, mirroring the current situation caused by human activities.While the scale of the Permian event was far more extreme, with complete melting of polar ice and a potential sea-level rise of up to 70 meters, studying this ancient disaster can provide valuable insights into the potential consequences of unchecked carbon emissions.

Gastaldo emphasizes the importance of studying past extinction events:

This planet has experienced it.The planet’s memory is stored in rock records.And we can learn from the rocks about what will happen to the earth under this extreme condition.
Robert Gastaldo,Colby College

By examining the geological record,scientists can gain a better understanding of the Earth’s response to extreme climate conditions and inform strategies for mitigating the impacts of current and future climate change.

Conclusion

The revelation of a plant refuge in China during the Permian mass extinction challenges the notion that the “Great Dying” was uniformly devastating across all ecosystems. The resilience of plant life in this region, coupled with evidence from other locations, highlights the complexity of the extinction event and the importance of considering regional variations. By studying these ancient events, scientists can gain valuable insights into the Earth’s capacity to respond to extreme environmental changes and inform strategies for addressing the challenges of modern climate change.