Abnormal pollen grains: an outcome of deteriorating atmospheric conditions around the Permian–Triassic boundary

Abstract

Records of abnormal gymnosperm pollen morphotypes from coeval localities in Russia and NW China provide independent and unique evidence of deteriorating atmospheric conditions at the close of the Permian. Although at similar palaeolatitude, the Vologda region of European Russia and the Junggar Basin of Xinjiang Province, China, were thousands of kilometres apart and on different tectonic plates. The co-occurrence of the megaspore Otynisporites eotriassicus Fuglewicz 1977 , and its restricted distribution elsewhere in marine sections with either Late Permian ammonoids or the basal Triassic conodont marker Hindeodus parvus , confirms the age range, and correlation of the Russian and NW Chinese sections. In three Chinese sections, rapid changes in carbon isotopic (δ 13 C org ) composition of between 4 and 10‰ occur over the intervals showing abnormal pollen. These patterns reflect bioclastic facies contributions responding to local environmental changes. They are nevertheless coincident with global perturbations in the atmosphere, caused by extensive volcanic activity around the Permian–Triassic boundary.

Aberrant Classopollis pollen reveals evidence for unreduced (2 n ) pollen in the conifer family Cheirolepidiaceae during the Triassic–Jurassic transition

“…WGD events may have lowered extinction risks during mass extinction events, such as at the Cretaceous-Paleogene boundary some 65 Ma [47]. We suggest that similar to aberrant lycophyte spores [48] and conifer pollen [49], during the end-Permian mass extinction aberrant Classopollis pollen may indicate environmental mutagenesis during the end-Triassic mass extinction. Extensive volcanism of the Central Atlantic magmatic province during the Triassic-Jurassic transition is generally viewed as a trigger mechanism of this global biotic crisis by extreme climate transitions [50].…”

Disrupted continental environments around the Devonian-Carboniferous Boundary: introduction of the tener event

“…Living plants produce a small percentage of pollen grains considered to be abnormal and not viable as part of a natural variation (Pozhidaev, 2000). Higher percentages of abnormal forms (>3% after Foster & Afonin, 2005) cannot be explained by natural variation and it requires external mutagen factors. Such factor are basically environmental (hydric stress, high temperature, increased CO2 atmospheric content; Mulcahy, 1981;Koti et al, 2005), pollution (heavy metal, acid rain; Visscher et al, 2004;Foster & Afonin, 2005) and UV-B radiation (stratospheric ozone destruction).…”

“…Higher percentages of abnormal forms (>3% after Foster & Afonin, 2005) cannot be explained by natural variation and it requires external mutagen factors. Such factor are basically environmental (hydric stress, high temperature, increased CO2 atmospheric content; Mulcahy, 1981;Koti et al, 2005), pollution (heavy metal, acid rain; Visscher et al, 2004;Foster & Afonin, 2005) and UV-B radiation (stratospheric ozone destruction). Filipiak & Racki (2010) invoked the volcanic activity as a potential source of mutation leading to an abnormal palynological association in the uppermost Famennian from the Holy Cross Mountains.…”

Advanced morphology and behaviour of extinct earwig-like cockroaches (Blattida: Fuziidae fam. nov.)

“…This species is important in several respects: it represents further evidence for decreasing variability of respective species over time (Vršanský 2000;Webster 2007) and also for occurrence of first mass animal deformations representing mutations (Vršanský 2004(Vršanský , 2005) -phenomena recently observed in the paleobotanical record as well (Krassilov 2003;Visscher et al 2004;Foster & Afonin 2005).…”