Strange new discovery reveals UV radiation played a role in mass extinctions
#Strange #discovery #reveals #radiation #played #role #mass #extinctions Welcome to Alaska Green Light Blog, here is the new story we have for you today:
A new discovery of sunscreen-like chemicals in fossil plants shows UV radiation played a role in mass extinctions.
New research has found that pollen preserved in rocks 250 million years old contains compounds that act like sunscreens. These are produced by plants to protect them from harmful ultraviolet (UV-B) radiation. The results suggest that a UV-B pulse played an important role in the late Permian mass extinction.
Scientists from the University of Nottingham, China, Germany and the UK, led by Professor Liu Feng of the Nanjing Institute of Geology and Palaeontology, have developed a new method to detect sunscreen-like compounds from plants in fossil pollen grains. The research was published today (January 6, 2023) in the journal Science Advances.
The late Permian extinction event (250 million years ago) is the most severe of the five major extinction events, with the loss of ~80% of marine and terrestrial species. This catastrophic loss of biodiversity was in response to a paleoclimatic emergency triggered by the emplacement of a continental-scale volcanic eruption covering much of present-day Siberia. Volcanic activity caused huge amounts of carbon trapped in the Earth’s interior to be released into the atmosphere, leading to widespread greenhouse warming. Accompanying this global warming event was a collapse of the Earth’s ozone layer. This theory is supported by the abundance of malformed spores and pollen grains, which indicate the influence of mutagenic UV radiation.
Professor Barry Lomax from the University of Nottingham explains: “Plants need sunlight for photosynthesis, but they need to protect themselves, and particularly their pollen, from the harmful effects of UVB radiation. To do this, plants load the outer walls of pollen grains with compounds that act like sunscreens to protect the vulnerable cells and ensure successful reproduction.”
Professor Liu Feng adds: “We developed a method to detect these phenolic compounds in fossil pollen grains from Tibet and found much higher concentrations in these grains produced during the mass extinction and peak phase of volcanic activity.”
Elevated levels of UV-B can have even more far-reaching and longer-lasting effects throughout the Earth system. Recent modeling studies have shown that increased UV-B stress reduces plant biomass and terrestrial carbon storage, which would exacerbate global warming. The increased concentration of phenolic compounds also makes plant tissues less easily digested, making a hostile environment even more challenging for herbivores.
dr Summarizing the group’s findings, Wes Fraser of Oxford Brookes University commented: “Volcanism of such catastrophic proportions affects all aspects of the Earth system, from direct chemical changes in the atmosphere, to changes in carbon sequestration rates, to reductions in the volume of nutrient Food sources available for animals.”
Reference: “Dying in the Sun: Direct Evidence for Increased UV-B Radiation in Late Permian Mass Extinctions,” 6 January 2023, Science Advances.