Ultralow viscosity of carbonate melts at high pressures

Knowledge of the occurrence and mobility of carbonate-rich melts in the Earth's mantle is important for understanding the deep carbon cycle and related geochemical and geophysical processes. However, our understanding of the mobility of carbonate-rich melts remains poor. Here we report viscosities of carbonate melts up to 6.2 GPa using a newly developed technique of ultrafast synchrotron X-ray imaging. These carbonate melts display ultralow viscosities, much lower than previously thought, in the range of 0.006-0.010 Pa s, which are ~2 to 3 orders of magnitude lower than those of basaltic melts in the upper mantle. As a result, the mobility of carbonate melts (defined as the ratio of melt-solid density contrast to melt viscosity) is ~2 to 3 orders of magnitude higher than that of basaltic melts. Such high mobility has significant influence on several magmatic processes, such as fast melt migration and effective melt extraction beneath mid-ocean ridges

Diversity of endophytic fungal and bacterial communities in Ilex paraguariensis grown under field conditions

Fil: Pérez, María Laura. Universidad Nacional del Nordeste. Facultad de Ciencias Agrarias; Argentina.Fil: Pérez, María Laura. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto Botánica del Nordeste; Argentina.Fil: Collavino, Mónica Mariana. Universidad Nacional del Nordeste. Facultad de Ciencias Agrarias; Argentina.Fil: Collavino, Mónica Mariana. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto Botánica del Nordeste; Argentina.Fil: Sansberro, Pedro Alfonso. Universidad Nacional del Nordeste. Facultad de Ciencias Agrarias; Argentina.Fil: Sansberro, Pedro Alfonso. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto Botánica del Nordeste; Argentina.Fil: Mroginski, Luis Amado. Universidad Nacional del Nordeste. Facultad de Ciencias Agrarias; Argentina.Fil: Mroginski, Luis Amado. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto Botánica del Nordeste; Argentina.Fil: Galdeano, Ernestina. Universidad Nacional del Nordeste. Facultad de Ciencias Agrarias; Argentina.Fil: Galdeano, Ernestina. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto Botánica del Nordeste; Argentina.The composition and diversity of the endophytic community associated with yerba mate (Ilex paraguariensis) was investigated using culture-depending methods. Fungi were identified based on their micromorphological characteristics and internal transcribed spacer rDNA sequence analysis; for bacteria 16S rDNA sequence analysis was used. Fungal and bacterial diversity did not show significant differences between organ age. The highest fungal diversity was registered during fall season and the lowest in winter. Bacterial diversity was higher in stems and increased from summer to winter, in contrast with leaves, which decreased. The most frequently isolated fungus was Fusarium, followed by Colletotrichum; they were both present in all the sampling seasons and organ types assayed. Actinobacteria represented 57.5 % of all bacterial isolates. The most dominant bacterial taxa were Curtobacterium and Microbacterium. Other bacteria frequently found were Methylobacterium, Sphingomonas, Herbiconiux and Bacillus. Nitrogen fixation and phosphate solubilization activity, ACC deaminase production and antagonism against plant fungal pathogens were assayed in endophytic bacterial strains. In the case of fungi, strains of Trichoderma, Penicillium and Aspergillus were assayed for antagonism against pathogenic Fusarium sp. All microbial isolates assayed showed at least one growth promoting activity. Strains of Bacillus, Pantoea, Curtobacterium, Methylobacterium, Brevundimonas and Paenibacillus had at least two growth-promoting activities, and Bacillus, Paenibacillus and the three endophytic fungi showed high antagonistic activity against Fusarium sp. In this work we have made a wide study of the culturable endophytic community within yerba mate plants and found that several microbial isolates could be considered as potential inoculants useful for improving yerba mate production