Sprecher
Beschreibung
Malformed pteridophyte spores occur abundantly in conjunction with the end-Triassic mass-extinction (ETME), ~201.6 million years ago, one of the ‘Big Five’ mass-extinction events of the past 500 million years. Based on high concentrations of sedimentary mercury (Hg) in beds that contain abundant malformed spores, it has been hypothesized that volcanogenic Hg-emission from large-scale volcanism in the Central Atlantic Magmatic Province exerted stress on standing and pioneering vegetation, causing malfunctions in meiosis. Here, we provide strong evidence for anomalously high Hg among the plant survivors of the ETME using synchrotron X-ray fluorescence scanning of the earliest Jurassic fossil fern Phlebopteris angustiloba from southern Germany. P. angustiloba is a member of the Matoniaceae, which produced malformed spores within the Deltoidospora-Concavisporites complex that are common in the same beds that contain the fern fossils. Comparative XRF and XANES synchrotron-scanning of extant ferns growing in high-mercury environments in Slovenia, Slovakia, and the Czech Republic, suggest that ferns can tolerate elevated Hg-levels and store it in their placentas with the help of sulfurous compounds.