and often branching. On the basis of the available data obtained from cultivation and genomics, and reasoned interpretations of the existing literature, we propose a hypothetical model for eukaryogenesis, termed the 3 entangle - engulf - endogenize (also known as E ) model.

Iyer, J., Chen, X., Carroll, S.A., 2020. Impact of chemical and mechanical processes on leakage from damaged wells in CO storage sites. Environmental Science &Technology 54, 1196-1203. 2

https://doi.org/10.1021/acs.est.9b05039 The perceived risk of CO leakage through wells has been considered a potential limitation to commercial scale 2 deployment of geologic CO storage. However, chemical and mechanical alteration of cement can reduce the 2 permeability of leakage pathways. We conducted 100s of simulations spanning realistic operating conditions and well-damage characteristics to understand (1) under what conditions and time frames do fractures seal and (2) for fractures that do not seal, how quickly and to what extent is the permeability reduced. For the conditions simulated, fractures with apertures in the tens of microns seal while those greater than hundreds of microns may exhibit long- term leakage. Fractures with apertures between 10 and 500 μm took a few days to a couple of ye ars to seal. For non-sealing fractures mechanical deformation of altered asperities can rapidly reduce permeability. A sealing criterion was developed to relate fracture aperture with the cemented length required for self-sealing. Longer cemented intervals can seal large fractures; however, they take longer to seal and leak larger volumes before sealing. While the results presented here are subject to uncertainties, the manuscript provides a framework in which a model can be used to quantitatively answer questions regarding well integrity to facilitate decision making.

Jacquemot, P., Viennet, J.-C., Bernard, S., Le Guillou, C., Rigaud, B., Delbes, L., Georgelin, T., Jaber, M., 2019. vice versa The degradation of organic compounds impacts the crystallization of clay minerals and . Scientific Reports 9, 20251.

https://doi.org/10.1038/s41598-019-56756-6 Expanding our capabilities to unambiguously identify ancient traces of life in ancient rocks requires laboratory experiments to better constrain the evolution of biomolecules during advanced fossilization processes. Here, we submitted RNA to hydrothermal conditions in the presence of a gel of Al- smectite stoichiometry at 200 °C for 20 days. NMR and STXM-XANES investigations revealed that the organic fraction of the residues is no longer RNA, nor the quite homogeneous aromatic-rich residue obtained in the absence of clays, but rather consists of particles of various chemical composition including amide-rich compounds. Rather than the pure clays obtained in the absence of RNA, electron microscopy (SEM and TEM) and diffraction (XRD) data showed that the mineralogy of the experimental residues includes amorphous silica and aluminosilicates mixed together with nanoscales phosphates and clay minerals. In addition to the influence of clay minerals on the degradation of organic compounds, these results evidence the influence of the presence of organic compounds on the nature of the mineral assemblage, highlighting the importance of fine-scale mineralogical investigations when discussing the nature/origin of organo-mineral microstructures found in ancient rocks.

Janssen, D.J., Rickli, J., Quay, P.D., White, A.E., Nasemann, P., Jaccard, S.L., 2020. Biological control of chromium redox and stable isotope composition in the surface ocean. Global Biogeochemical Cycles 34, e2019GB006397.

https://doi.org/10.1029/2019GB006397 53 While chromium stable isotopes (δ Cr) have received significant attention for their utility as a tracer of oxygen availability in the distant geological past, a mechanistic understanding of modern oceanic controls on Cr and 53 53 δ Cr is still lacking. Here we present total dissolved δ Cr, concentrations of Cr (III) and total dissolved Cr, and net community productivity (NCP) from the North Pacific. Chromium concentrations show surface depletions in waters with elevated NCP, but not in lower productivity waters. Observed Cr deficits correspond well with calculated Cr export derived from NCP and Cr:C ratios of natural phytoplankton and marine particulates.