Rhynie Basin and its nature at the time of deposition of the cherts which host its famous fossils. There follows an introduction to the development of the half-graben in which the cherts and host sediments were deposited, the palaeoenvironment this represented and the taphonomy of the fossils themselves. We subsequently provide an overview of the mineralization and geochemistry of the deposit, and then the fossils found within the Rhynie chert. These include: six plant genera, which continue to provide significant insights into the evolution of life on land; a range of different fungi, with recent work starting to probe plant - fungus interactions; lichens, amoebae and a range of unicellular eukaryotes and prokaryotes (algae and cyanobacteria); and finally a range of both aquatic and terrestrial arthropods. Through continued study coupled with methodological advances, Rhynie fossils will continue to provide unique insights into early life on land.

Gatchell, M., 2020. A new take on circumstellar carbon chemistry. Nature Astronomy 4, 21-22.

https://doi.org/10.1038/s41550-019-0925-6 For years, much of our understanding of the formation of circumstellar aromatic molecules has been based on laboratory flame studies. Now, results acquired using a novel experimental technique suggest that circumstellar aromatics might not be formed under the conditions we thought they were.

Gautier, T., Danger, G., Mousis, O., Duvernay, F., Vuitton, V., Flandinet, L., Thissen, R., Orthous-Daunay, F.R., Ruf, A., Chiavassa, T., d'Hendecourt, L.S., 2020. Laboratory experiments to unveil the molecular reactivity occurring during the processing of ices in the protosolar nebula. Earth and Planetary Science Letters 531, 116011.

http://www.sciencedirect.com/science/article/pii/S0012821X19307034 Using laboratory experiments, we investigate the role of photo and thermal degradation in the possible complexification mechanisms of organic matter that may originate from interstellar ices prior to, or during the formation of the Solar System. We perform High Resolution Orbitrap Mass Spectrometry on organic residues formed from the photo- and thermochemical alterations of Interstellar Medium (ISM) dirty ice laboratory analogues. We probe, at the molecular level, the possible effects within the protosolar nebula on the composition and structure of these organic refractory materials obtained from an initial ice composition representative of astrophysical ices. We show that nitrogen incorporation, by competing with the carbon, has a strong influence on the final composition of the residue. NH rich ices lead to a group of unsaturated molecules 3 in the final residue, while H O rich ices lead to saturated ones. Finally, we observe and discuss the strong effect 2 of UV irradiation on the decarboxylation on organic matter and discuss potential implications of this result for the protosolar nebula.

Gdara, I., Zrafi, I., Balducci, C., Cecinato, A., Ghrabi, A., 2020. First investigation of seasonal concentration behaviors and sources assessment of aliphatic hydrocarbon in waters and sediments from Wadi El Bey, Tunisia. Archives of Environmental Contamination and Toxicology 78, 1-19.

https://doi.org/10.1007/s00244-019-00669-y The contents, composition profiles, and sources of aliphatic hydrocarbons were examined in surface sediment and water samples collected from Wadi El Bey, in Tunisia, during different year seasons in 14 stations receiving domestic effluent, industrial discharge, and agricultural drainage wastes. The target substances were analyzed by gas chromatography coupled with mass spectrometric detection (GC/MS). Total concentrations of n n n -alkanes ( -C - -C ) ranged from 0.08 ± 0.01 to 18.14 ± 0.1 µg/L in waters and 0.22 ± 0.04 to 31.9 ± 24.6 14 38 µg/g in sediments, while total aliphatic fraction ranged from 0.08 ± 0.01 to 196 ± 140 µg/L in waters and 0.22 ± 0.04 to 1977 ± 1219 µg/g in sediments, which means that almost all sites were affected by hydrocarbon contents in sediments exceeding the recommended limit (100 µg/g). Various diagnostic indices (ADIs) were n used to identify the hydrocarbon sources, namely the concentration ratios of individual compounds ( - n n n n n C /pristane, -C /phytane, pristane/phytane, -C / -C , -C / -C ) as well as cumulative quantities (Carbon 17 18 29 17 31 19 n Preference Index, natural -alkanes ratio, terrigenous/aquatic compounds ratio, unresolved complex mixture