strongly suspected to participate in buildings blocks biomineralization that self-assembles in a process that could be affected by a chelating agent. These degradation products are similar to aurosomes structures revealed 50 y ago in vivo after gold salt therapy. Overall, we bring to light steps in the lifecycle of gold nanoparticles in which cellular pathways are partially shared with ionic gold, revealing a common gold metabolism.

Balseiro, D., Powell, M.G., 2019. Carbonate collapse and the late Paleozoic ice age marine biodiversity crisis. Geology 48, 118-122.

https://doi.org/10.1130/G46858.1 The late Paleozoic ice age (LPIA) was characterized by persistently low diversity of marine invertebrates following a second-order mass extinction. Here, we used a data set of North American (paleotropical) fossil occurrences of brachiopod, bivalve, and coral genera from the Paleobiology Database, combined with lithologic data from Macrostrat, to demonstrate that low diversity was caused by the collapse of carbonate environments during the LPIA. After dividing the data by lithology, low diversity was evident only in carbonate environments, whereas diversity within siliciclastic environments actually increased during the LPIA, after a brief decline in the Serpukhovian (late Mississippian). Diversity patterns closely matched respective changes in the volume of carbonate and siliciclastic rocks. The contrasting patterns observed in the two environments suggest that habitat loss was a direct cause of changes in diversity, because other factors, such as temperature, would have affected genera in both environments. Acausal relationship is also supported by the finding that diversity remained high in carbonate refugia (carbonate beds within majority-siliciclastic formations) until the ∼ Bashkirian, postdating the onset of icehouse conditions by 8 m.y. Our results provide a unifying, mechanistic explanation for the distinctive characteristics of the biotic impact, including its disproportionate effect on the tropical marine invertebrate fauna, prolonged recovery from extinction, low macroevolutionary rates during the recovery interval, and regional differences in its expression.

Banda, J.F., Lu, Y., Hao, C., Pei, L., Du, Z., Zhang, Y., Wei, P., Dong, H., 2020. The effects of salinity and pH on microbial community diversity and distribution pattern in the brines of soda lakes in Badain Jaran Desert, China. Geomicrobiology Journal 37, 1-12.

https://doi.org/10.1080/01490451.2019.1654568 The Badain Jaran Desert (BJD) is characterized by extremely arid conditions. Counterintuitively, this arid region has over 100 permanent lakes. To date, only a few studies have characterized microbial community in these lakes. Our investigation sampled five lakes with salinity (2.1?397.33 g/L) and pH (9.69?10.83) gradients, of which one was low salinity (< 3.0 g/L), three were moderately saline (50?250 g/L) and the other one was hypersaline (>250.0 g/L). Using high-throughput sequencing of 16S rRNA genes, we noted a significant difference in microbial communities inhabiting the different alkali-saline lakes. Generally, bacteria were predominant in the low and moderately saline lakes, while archaea were dominant in the hypersaline lake. The low salinity lake exhibited the highest microbial diversity, dominated by Burkholderia and Halomonas. Spiribacter and Halomonas dominated the moderately saline lakes, while Halohasta and Halosimplex dominated the hypersaline lake. pH was a primary driver of microbial richness, whereas salinity was the predominant factor controlling microbial community composition. Therefore, both pH and salinity shaped the haloalkaliphilic community in the soda lakes. Furthermore, it was found that many haloalkaliphiles such as Spiribacter and Halomonas survived beyond their pH and salinity limits, suggesting that there could be more new species in these soda lakes.

Bang, S., Lee, Y.I., 2020. Darriwilian carbon isotope stratigraphy in the Taebaeksan Basin, Korea and its implications for Middle Ordovician paleoceanography. Palaeogeography, Palaeoclimatology, Palaeoecology 541, 109534.

http://www.sciencedirect.com/science/article/pii/S0031018219303979