New research shows that mercury pollution from volcanism caused prolonged ecological disturbances and plant stress for over a million years following the end-
Persistent Environmental Stress From Mercury Pollution
An international team of scientists from the Netherlands, China, Denmark, Britain, and the Czech Republic analyzed sediments from Northern Germany, which span the uppermost Triassic to lower
The Role of Ferns in Post-Extinction Recovery
The study shows that ferns replaced trees across vast regions in response to extreme environmental changes, such as heat stress and increased monsoonal rains. Despite widespread deforestation, ferns thrived and adapted, displaying a unique tolerance to mercury. However, the ferns were subjected to recurring stress from mercury pollution for up to 2 million years after the extinction event, affecting their spore development.
Long-Term Effects of Mercury and Climate Variability
Bos and his team uncovered four additional episodes of high mercury concentrations corresponding to the long eccentricity cycle, a major variation in Earth’s orbit. These periods triggered repeated forest diebacks and allowed pioneer ferns to spread, with fern spore malformations indicating ongoing mercury poisoning from environmental factors other than volcanism, such as soil erosion and photochemical reduction. These findings illustrate a complex, extended period of ecological disturbance lasting over a million years after the initial volcanic events.
Reference: “Climate-forced Hg-remobilization associated with fern mutagenesis in the aftermath of the end-Triassic extinction” by Remco Bos, Wang Zheng, Sofie Lindström, Hamed Sanei, Irene Waajen, Isabel M. Fendley, Tamsin A. Mather, Yang Wang, Jan Rohovec, Tomáš Navrátil, Appy Sluijs and Bas van de Schootbrugge, 27 April 2024, Nature Communications.
DOI: 10.1038/s41467-024-47922-0