The Violet Crown Cup, Sarcosphaera coronaria, is a nicely coloured spring mushroom. In earlier days, the mushroom was considered edible, but several poisonings were reported in the early 20th century. The reason for the sporadic toxicity of S. coronaria is still unknown. The presence of arsenic could be a possible explanation, since Crown Cups can take up high amounts of this toxic element. Arsenic concentration and speciation were investigated in S. coronaria with inductively coupled plasma mass spectrometry (ICPMS) and HPLC coupled to ICPMS and revealed incredible maximum values of 0.9 % As (dry mass). Most of it was present in the form of methylarsonic acid (MA), a less toxic form of this element. However, low concentrations of the highly toxic methylarsonous acid (MA [III]) were also detected. The amounts were too low to pose an acute risk for consumers but the concentration of MA (III) significantly increased during simulated gastric digestion. We could not unambiguously identify arsenic as the toxic constituent of S. coronaria but we demonstrated that the extremely toxic MA (III) can be formed under certain circumstances, which should be carefully investigated in the future. This international research was conducted in co-operation of two Czech Academy of Sciences institutes (Institute of Geology, Nuclear Physics Institute) and the Austrian University of Graz.

Insect borings, unique in the fossil record, were found in fossil wood from a thin lignite seam of lowermost Cretaceous age, exposed in cliffs of the southwestern shore of the Isle of Bornholm (Denmark). The find consists of six thin, roughly parallel, short passages connected with a remnant of a long straight tunnel running along a mechanically-induced fissure just below the wood surface. This find is not fully analogous with the presently most common feeding insect borings as the passages are situated in an oblique fissure of the wood sample (instead of the usual position below the bark). Nevertheless, the best modern analogues of the borings found in Bornholm still come from the insect forestry pests such as the Scolytidae (bark beetles). The find shows that ecological predecessors of bark beetles probably first inhabited random mechanic cracks; later, they occupied the most devastating niche at the boundary between the bark and the wood. More in the paper (Journal Ichnos).

Long-lasting work of a team of authors dealing with the territory of Bohemian-Saxonian Switzerland was completed in spring this year. It materialized into a book under the editorship of RNDr. Zuzana Vařilová, PhD. of the Municipal Museum of Ústí nad Labem. With its 576 pages, the book represents the most extensive publication ever written on the geology of this region. Scientists of the Institute of Geology of the Czech Academy of Sciences are the leading authors of chapters Geology, Tectonics and Geomorphology. Presentation of the book with the whole team of authors will take place at Ústí nad Labem on September 24.

A paper recently published in the Earth Science Reviews journal deals with dating of zircons from folded marine sediments on the edges of oceanic plates (i.e., in accretionary wedges). A comparison of data from different sites provided a more precise interpretation of source rocks for these parts of oceanic crust. This study, performed in close cooperation with Faculty of Science of Charles University (J. Žák, J. Hajná) and co-authored by M. Svojtka and L. Ackerman of the Institute of Geology CAS, introduces a new concept of the dependence of zircon ages on the distance from source rocks. It considerably contributes to the understanding of sedimentary and tectonic processes affecting oceanic crust during its evolution.