Fungi typically spread by means of thread-like hyphae, which can form immense underground networks of mycelia, especially in forests where the fungi live in a symbiotic relationship with tree roots. Each filament is a chain of cells with hard walls made of chitin, the same substance that insects use for their exoskeleton.
When these hyphae branch and intertwine, they may form resting structures known as sclerotia. Sclerotia of modern soil-borne fungi such as Rhizoctonia look nearly identical to the disc-shaped structures found among the Reduviasporonites microfossils. Sclerotia are energy storage structures that can help fungi survive extreme conditions.
The team concluded that the loss of trees and the roots that hold soil in place led to severe topsoil erosion, which carried the sclerotia to the sea.
The researchers acknowledge that conifer forests probably suffered from other environmental stresses as a result of the long-term volcanic eruptions, which spewed carbon dioxide and methane into the atmosphere and likely destroyed some of Earth's protective ozone layer. Nevertheless, they wrote in their paper, " whatever (the) sequence of events that triggered ecosystem destabilization on land, the aggressiveness of soil-borne pathogenic fungi must have been an integral factor involved in Late Permian forest decline worldwide."
|Contact: Robert Sanders|
University of California - Berkeley