Description: The marine ciliate Mesodinium rubrum is famous for its ability to acquire and exploit chloroplasts and other cell organelles from some cryptophyte algal species. We sequenced genomes and transcriptomes of free-swimming Teleaulax amphioxeia, as well as well-fed and starved M. rubrum in order to understand cellular processes upon sequestration under different prey and light conditions. From its prey, the ciliate acquires the ability to photosynthesize as well as the potential to metabolize several essential compounds including lysine, glycan, and vitamins that elucidate its specific prey dependency. M. rubrum does not express photosynthesis-related genes itself, but elicits considerable transcriptional control of the acquired cryptophyte organelles. This control is limited as light-dependent transcriptional changes found in free-swimming T. amphioxeia got lost after sequestration. We found strong transcriptional rewiring of the cryptophyte nucleus upon sequestration, where 35% of the T. amphioxeia genes were significantly differentially expressed within well-fed M. rubrum. Qualitatively, 68% of all genes expressed within well-fed M. rubrum originated from T. amphioxeia. Quantitatively, these genes contributed up to 48% to the global transcriptome in well-fed M. rubrum and down to 11% in starved M. rubrum. This tertiary endosymbiosis system functions for several weeks, when deprived of prey. After this point in time, the ciliate dies if not supplied with fresh prey cells. M. rubrum represents one evolutionary way of acquiring photosystems from its algal prey, and might represent a step on the evolutionary way towards a permanent tertiary endosymbiosis.

Description: In the Pliocene Model Intercomparison Project Phase 2 (PlioMIP2), coupled climate models have been used to simulate an interglacial climate during the mid-Piacenzian warm period (mPWP; 3.264 to 3.025 Ma). Here, we compare the Atlantic Meridional Overturning Circulation (AMOC), poleward ocean heat transport and sea surface warming in the Atlantic simulated with these models. In PlioMIP2, all models simulate an intensified mid-Pliocene AMOC. However, there is no consistent response in the simulated Atlantic ocean heat transport nor in the depth of the Atlantic overturning cell. The models show a large spread in the simulated AMOC maximum, the Atlantic ocean heat transport and the surface warming in the North Atlantic. Although a few models simulate a surface warming of ∼ 8–12 ∘C in the North Atlantic, similar to the reconstruction from Pliocene Research, Interpretation and Synoptic Mapping (PRISM) version 4, most models appear to underestimate this warming. The large model spread and model–data discrepancies in the PlioMIP2 ensemble do not support the hypothesis that an intensification of the AMOC, together with an increase in northward ocean heat transport, is the dominant mechanism for the mid-Pliocene warm climate over the North Atlantic.

Description: In this study, we utilized both ground‐based and space‐borne observations including total electron content (TEC) from Beidou geostationary satellites, two‐dimensional TEC maps from the worldwide dense Global Navigation Satellite System receivers, ionosondes, and in situ electron density (Ne) and electron temperature (Te) from both Swarm and China Seismo‐Electromagnetic Satellite satellites, to investigate the low‐latitude ionospheric responses to the annular solar eclipse on 21 June 2020. The decrease in TEC during the eclipse at low latitudes showed a local time dependence with the largest depletions in the noon and afternoon sectors. It was also found that the TEC depletions at different latitudes in the equatorial ionization anomaly (EIA) region over the East Asian sector cannot solely be explained by the solar flux changes associated with the obscuration rate. The differences in TEC reduction between stations can be more than a factor of 2 at latitudes with the same obscuration rate of over 90%. Compared with TEC variations in the Northern Hemisphere, the TEC also underwent a considerable decrease in the EIA region in the conjugate hemisphere without eclipse shadow. Meanwhile, the hmF2 near the magnetic equator increased around the onset of the eclipse, indicating an enhancement of the eastward equatorial electric field. Furthermore, the TEC decrease during the eclipse in the EIA region in both hemispheres lasted for a long period of more than 7 hr after the eclipse, with a TEC depletion of 2–6 TEC units. The Ne from Swarm and China Seismo‐Electromagnetic Satellite satellites showed a complicated variation after the eclipse, whereas no visible change was observed in Te. The enhanced equatorial electric field, neutral wind changes, and the associated plasma transport act together to generate the observed ionospheric effects at low latitudes during the eclipse. Our results also suggest that the eclipse‐induced perturbations of dynamic processes can continue to impact the ionosphere after the eclipse.

Description: Zircon petrochronology from amphibolites and retrogressed eclogites from the basement of the Western Tatra Mountains (CentralWestern Carpathians) reveals a complex rock evolution. An island-arc related basaltic amphibolite from Žiarska Valley shows three distinct zircon forming events: igneous zircon growth at ca. 498 Ma (Middle/Late Cambrian) and two phases of amphibolite-facies metamorphism at ca. 470 Ma (Early Ordovician) and at ca. 344 Ma (Early Carboniferous). A retrogressed eclogite from Baranèc Mountain records two zircon forming events: metamorphic zircon growth under eclogite-facies conditions at ca. 367 Ma (Late Devonian) and amphibolite-facies metamorphism at ca. 349 Ma (Early Carboniferous). These data contribute towards understanding and correlating major tectonothermal events that shaped the eastern margin of Gondwana in the Early Palaeozoic and its subsequent Variscan evolution. The metabasites record vestiges of two completely independent oceanic domains preserved within the Central Western Carpathians: (1) An Ediacaran to Cambrian oceanic arc related to the proto-Rheic - Qaidam oceans and metamorphosed to amphibolite-facies in the Early Ordovician subduction of the proto-Rheic - Qaidam arc during the Cenerian orogeny (ca. 470 Ma) and (2) Late Devonian oceanic crust related to a back-arc basin (Pernek-type), formed by the opening of the Paleotethys and metamorphosed to eclogite-facies during Devonian subduction (ca. 367 Ma). The common Variscan and later evolution of these oceanic remnants commenced with amphibolite-facies metamorphic overprinting in the Early Carboniferous (amphibolite: ca. 344Ma; retrogressed eclogite: ca. 349Ma) related to an Early Variscan consolidation and the formation of Pangea. None of the investigated rocks of the Central Western Carpathians show any evidence of being chronologically or palaeogeographically related to the Rheic Ocean, therefore any prolongation of the Rheic suture from the Sudetes into the Alpine-Carpathian realm is highly problematic. Instead, the Southern and Central Alpine Cenerian orogeny can be traced into the CentralWestern Carpathians.

Description: We investigate the effects of the background dipole magnetic field and cold electron number density on the linear and nonlinear growth of whistler-mode chorus waves for a region of relatively small anisotropy (A T ) in Saturn's inner magnetosphere. The linear and nonlinear features of wave growth rate and associated frequency at L = 6 are presented in detail. Although a large anisotropy is generally in favor of linear and nonlinear wave growth, the nonlinear wave growth for a small anisotropy can still be generated. All cases show a small threshold for wave amplitudes ${\tilde{B}}_{\mathrm{th}}$, which compromises the requirement to trigger the nonlinear wave growth, but the comparisons also clearly indicate the important transition process from the linear phase to the nonlinear phase. After checking the variation of the calculation time steps depending on the chosen electron number density N c and background magnetic field B c , respectively, a large N c can promote the nonlinear wave growth, but a large B c works against it. Our results present how these parameters really affect the generations of linear and nonlinear wave growth quantitatively. This could be significant to further understand the monumental importance of whistler-mode chorus waves and the corresponding wave–particle interactions in the planetary magnetosphere.

Description: To expand the newly developed ARM glasses as reference materials for in situ microanalysis of isotope ratios and iron oxidation state by a variety of techniques such as SIMS, LA-MC-ICP-MS and EPMA, we report Li-B-Si-O-Mg-Sr-Nd-Hf-Pb isotope data and Fe2+/ΣFe ratios for these glasses. The data were mainly obtained by TIMS, MC-ICP-MS, IR-MS and wet-chemistry colorimetric techniques. The quality of these data was cross-checked by comparing different techniques or by comparing the results from different laboratories using the same technique. All three glasses appear to be homogeneous with respect to the investigated isotope ratios (except for B in ARM-3) and Fe2+/ΣFe ratios at the scale of sampling volume and level of the analytical precision of each technique. The homogeneity of Li-B-O-Nd-Pb isotope ratios at the microscale (30–120 μm) was estimated using LA-MC-ICP-MS and SIMS techniques. We also present new EPMA major element data obtained using three different instruments for the glasses. The determination of reference values for the major elements and their uncertainties at the 95% confidence level closely followed ISO guidelines and the Certification Protocol of the International Association of Geoanalysts. The ARM glasses may be particularly useful as reference materials for in situ isotope ratio analysis.

Description: In the current global environmental problems, reducing CO2 emissions is an important goal and guide for countries all over the world in developing environmental and economic policies. It has become a global consensus to jointly promote greenhouse gas emission reduction. From 1970 to 2004, CO2 emissions increased yearly, accounting for 76% of the total emissions in 2004. According to the prediction of the International Energy Agency (IEA), the total global CO2 emission reached a record of 30 billion tons in 2010. In 2005, the Intergovernmental Panel on Climate Change (IPCC) specially recommended Carbon Capture and Storage (CCS) technology to achieve significant emission reduction of greenhouse gases. In 2007, the World Wide Fund for Nature (WWF) identified CCS as one of the six ways to deal with global climate change. The global climate conference in Cancun in 2010 incorporated CCS into the Clean Development Mechanism (CDM). The United States, Canada, the European Union, and other countries have taken CCS as an important part of future energy strategies and carbon emission reduction strategies and have formulated corresponding technology research plans that include Research and Development (R&D) and project demonstration. The NET-Zero Emissions (NZE) scenario proposed by the IEA for 2050 puts global CO2 capture at 1.7 gigatonnes per year in 2030 and 7.6 gigatonnes per year in 2050. Presently, CCS is a hot topic all around the world.