Soil erosion and wildfire another nail in coffin for Triassic era

Date:
March 21, 2022
Source:
Curtin University
Summary:
New research has revealed that soil erosion and wildfires
contributed to a mass extinction event 201 million years ago that
ended the Triassic era and paved the way for the rise of dinosaurs
in the Jurassic period.



FULL STORY ========================================================================== Curtin research has revealed that soil erosion and wildfires contributed
to a mass extinction event 201 million years ago that ended the Triassic
era and paved the way for the rise of dinosaurs in the Jurassic period.


==========================================================================
Lead author Curtin PhD graduate Dr Calum Peter Fox, from the WA-Organic
and Isotope Geochemistry Centre (WA-OIGC) in Curtin's School of Earth
and Planetary Sciences, said the research identified the other factors
that contributed to a combination of stresses that killed off Triassic
life and allowed the ecological expansion of dinosaurs.

"This new study adds soil erosion and wildfire activity to the list
of factors that drove this mass extinction to end the Triassic era,
building on our previous research that found a rise in levels of acid
and hydrogen sulfide in the ocean caused by rapid increases in carbon
dioxide due to a surge in volcanic activity," Dr Fox said.

"Similar to modern large-scale fire events that are driven by climate
change, periods of wildfire activity have significant impacts for
land-dwelling fauna and flora and drive environmental and ecosystem stress
that can lead to mass extinctions." Dr Fox said the team investigated
fire events 201 million years ago during the end-Triassic mass extinction event, which featured similar increases to carbon dioxide to those
witnessed in the modern-day conditions due to greenhouse gas emissions.

"By studying polycyclic aromatic hydrocarbons, which can be formed
during the incomplete combustion of organic matter, we found that soil
erosion was a more prominent terrestrial ecological stress than intensive wildfire activity during the end-Triassic mass extinction event in the
Bristol Channel of the south-west United Kingdom.

"This tells us land and marine ecosystem and environmental stresses
occurred at the same time and were likely exacerbated by soil erosion,
with fire activity likely to be more localised in other areas rather
than widespread across Europe." Co-author John Curtin Distinguished
Professor Kliti Grice, also from WA-OIGC in Curtin's School of Earth and Planetary Sciences, said modern-day soil erosion was a major cause of land degradation as it removed fertilised soil and promoted the deoxygenation
of water columns, much like the mass extinction events of the past.

"These processes certainly have implications in the modern day due
to the introduction of pollutants and pesticides," Professor Grice
said. "Observing that soil erosion had major impacts in our history and in comparing and contrasting a global record of the past, we can anticipate
the scale and duration of currently-occurring and future soil erosion
events." Further research will aim to determine the global extent of soil erosion to better understand terrestrial ecosystem stresses in the past
and to see if this is a common feature across all mass extinction events.


========================================================================== Story Source: Materials provided by Curtin_University. Original written
by Lucien Wilkinson.

Note: Content may be edited for style and length.


========================================================================== Journal Reference:
1. C.P. Fox, J.H. Whiteside, P.E. Olsen, K. Grice. Flame
out! End-Triassic
mass extinction polycyclic aromatic hydrocarbons reflect more
than just fire. Earth and Planetary Science Letters, 2022; 584:
117418 DOI: 10.1016/j.epsl.2022.117418 ==========================================================================

Link to news story: https://www.sciencedaily.com/releases/2022/03/220321103742.htm

--- up 3 weeks, 10 hours, 51 minutes
* Origin: -=> Castle Rock BBS <=- Now Husky HPT Powered! (1:317/3)