[Reading Science] Amazing Analysis Results of 250 Million-Year-Old Pollen

International Joint Research Team "UV Filter Components Found in Late Permian Pollen"
"Actual Evidence Found Supporting Existing 'Volcanic Eruption Theory' Related to Earth's Mass Extinction"

[Asia Economy Reporter Kim Bong-su] One of the causes of the Permian-Triassic mass extinction event 250 million years ago was a deadly surge in ultraviolet radiation, according to a new study. This supports the existing theory that attributes the extinction to increased carbon dioxide from massive volcanic eruptions, ozone layer depletion, and global warming.

An international research team composed of scholars from the University of Nottingham in the UK, China, and Germany published this paper on the 6th in the international academic journal Science Advances. The team claimed this after analyzing pollen preserved in rocks formed 250 million years ago and identifying a type of UV-blocking compound.

Dinosaur Extinction

The mass extinction at the end of the Permian period about 250 million years ago was so severe that it wiped out 80% of all species living on land and in the sea at that time. The cause was triggered by a massive volcanic eruption in what is now the Siberian region. The volcanic eruption caused a large increase in carbon dioxide, ozone layer collapse, and a greenhouse effect, leading to the annihilation of many organisms.

The research team developed a new technique using laser beams to analyze the components of microscopic molecules such as pollen grains less than half the thickness of a human hair, which they applied in this study. The pollen used for component analysis was found in rocks collected from southern Tibet. Plants require sunlight for photosynthesis but must also block harmful ultraviolet (UV-B) radiation. To do this, plants produce a chemical structure that acts as a kind of sunscreen, dissipating the high-energy wavelengths of UV-B and preventing it from penetrating internal tissues. UV-B has a wavelength range of 280?315 nm and is absorbed by ozone, but when the ozone layer is depleted, excessive UV-B reaches the surface, causing serious effects on humans such as skin cancer and cataracts. It is also harmful to plants and plankton.

Pollen from 250 million years ago discovered in southern Tibet by an international joint research team. Photo by University of Nottingham, UK website

The results of this study add credibility to the existing theory about the cause of the mass extinction at the end of the Permian period 250 million years ago. In other words, the mass extinction process proceeded as follows: massive volcanic eruptions → massive carbon dioxide emissions and ozone layer destruction → rapid temperature rise and climate change → extinction of 80% of species. The study confirmed evidence of ozone layer destruction. It suggests that plants evolved to produce these UV-blocking compounds to survive the deadly surge of UV-B radiation during the late Permian.

The research team also found a link between the surge in UV-B and changes in plant chemical structures that caused the mass extinction of insect ecosystems. The team pointed out, "Plant tissues exposed to large amounts of ultraviolet radiation are difficult for herbivores to consume and digest. Because the nitrogen content in plant leaves is low, insects that feed on leaves do not receive sufficient nutrients, which can explain the sharp decline in insect populations during the mass extinction period."