Fungal event and palynological record of ecological crisis and recovery across the Permian-Triassic boundary

Abstract

The end of the Permian Period was marked by the most severe mass extinction in the geologic record. Detailed quantitative study of pollen and spores from shallow-marine deposits spanning the Permian-Triassic (P-Tr) boundary in Israel reveals a sequence of palynological-ecological stages reflecting a major crisis among land plants. The disappearance of the gymnosperm-dominated palynoflora of the Late Permian Lueckisporites virkkiae Zone is recorded at a claystone horizon containing almost exclusively abundant fungal remains and carbonized terrestrial plant debris. This ''fungal spike'' is followed by a zone dominated by marine acritarchs and a succession showing ecological recovery with abundant lycopod spores and eventual reappearance of bisaccate gymnosperm pollen in the Early Triassic. The latest Permian proliferation of fungi is recognizable worldwide and can be correlated with other paleontological and geochemical markers of a global ecological disaster.

Extinction and recovery patterns of the vegetation across the Cretaceous–Palaeogene boundary — a tool for unravelling the causes of the end-Permian mass-extinction

“…Herbaceous vegetation probably recovered within a few months to years of the Chicxulub impact. In contrast, the PermianTriassic fungal spike may have spanned 25-54 ka (Eshet et al, 1995). Similar durations (10-30 ka) have been calculated for intervals representing marine ecosystem collapse at the Permian-Triassic boundary .…”

“…Disparate studies have reported abundant fungal remains at the Permian-Triassic boundary in both marine and terrestrial successions (Eshet et al, 1995;Retallack, 1995;Utting and Piasecki, 1995;Visscher et al, 1996;Looy et al, 2001;Steiner et al, 2003; Table 2). However, some workers regard these fossils (Reduviasporonites and its synonyms) as algal affiliates based on morphological and biochemical characteristics (Afonin et al, 2001;Foster et al, 2002).…”

“…However, some workers regard these fossils (Reduviasporonites and its synonyms) as algal affiliates based on morphological and biochemical characteristics (Afonin et al, 2001;Foster et al, 2002). In several places, including Israel and the Karoo Basin, South Africa, the floristic extinction and Reduviasporonites spike are coincident with the top of the Dicynodon Zone, which is marked by the last occurrence of a range of therapsid reptiles (Eshet et al, 1995;Kitching, 1995;Steiner et al, 2003).…”

Life in the end-Permian dead zone

“…The low spore͞pollen ratio confirms a limited role of herbaceous lycopsids and ferns. Although underrepresented in the percentage diagram, the consistent presence of fungal remains (Reduviasporonites) points to excessive decomposition of woody plant tissue (29,30) and͞or pathogenic fungal infection (14). Parallel to the disappearance of marine invertebrate macrofauna, palynological data at the top of the Schuchert Dal Formation indicate a conspicuous dominance decline among woody plants (Fig.…”

“…In conjunction with the end-Permian ecological crisis, extinction among dominant gymnosperms appears to be a global event that dramatically affected terrestrial ecosystems. Justified by worldwide changes in vegetation structure and soil characteristics, as well as by strongly increased fungal activity, dieback of woody vegetation caused an unparalleled loss of standing biomass irrespective of floral provinciality and climatic zonation (29)(30)(31)(32)(33)(34). However, because of the condensed or otherwise incomplete nature of most end-Permian palynological records, vegetation development at the climax of ecological crisis could be inferred only in very general terms.…”