The capabilities of chemical composition nanoscale mapping are of utmost importance for the advance of microelectronics, power storage, cellular biology, 2D and quantum materials, sensors, photovoltaics, etc. Molecular distribution can be precisely analyzed with secondary ion mass spectrometry (SIMS). MeV-SIMS is a version of this technique capable of detecting high-mass molecules exceeding 1 kDa with primary ions of MeV energies used for molecular desorption. Regardless of the type of SIMS, there are limitations, with the most important ones being low ionization yields between 0.1% and 10% and the matrix effect. They negatively affect the detection limits and almost entirely prevent quantitative analysis. The objective of the project is to overcome these limitations by implementing approaches for ionization enhancement and matrix-effect reduction. The hypothesis is that the main process crucial for achieving this is proton transfer. Changes in the ionization potential as a consequence of the introduction of proton-donor or acceptor organic matrices will be evaluated and cluster secondary ion formation during recombination of the analyte and the matrix will be studied. The formation of these cluster ions via electronic excitations occurring during sputtering will be the basis for the explanation of the recombination mechanisms. Our findings will be implemented in the field of innovative nano-imaging of the chemical composition of organic and biological samples. The research will be conducted on a ToF-SIMS instrument coupled with a state-of-the-art MeV accelerator, while testing different approaches for the deposition of solid and gaseous matrices. The combination of the candidate’s knowledge of the chemical aspects of the ionization and matrix effect, the supervisor’s experience in the field of MeV-SIMS and ion-beam analysis, and the excellent equipment at the facility will be the basis for the successful implementation of this interdisciplinary project.

Human CO2 emissions are critically poisoning the earth's climate. However, sedimentation by marine primary producers contributes greatly to carbon sequestration, with coccolithophores, unicellular marine algae with cell envelopes composed of CaCO3, being the key contributors. Nevertheless, the extent of the biogeochemical impact of coccolithophores is largely unknown. They have a dual life cycle and can grow as both haploids and diploids, but past research has focused mainly on the diploid phase. Moreover, knowledge of coccolithophores is almost exclusively limited to a single species that is distributed worldwide, and can form blooms visible from space. However, this species is peculiar in many biological aspects and does not calcify in the haploid phase, therefore we need to develop more model organisms to represent impact of coccolithophores on the carbon cycle. In this action, my objective is to understand how the physiological acclimations of the coccolithophore life cycle phases allow them to inhabit different ecological niches. I will implement a multidisciplinary approach to investigate two levels of complexity: how environmental factors influence physiology and which genes contribute to distinct genetic programs. To this end, I will work on a widespread coccolithophore species that calcifies at both life cycle phases. I will characterize for the first time how photosynthesis (light-driven CO2 fixation) and photoprotection (dissipation of excess energy) differ between the two phases, and determine which environmental conditions trigger ploidy transitions. To investigate the underlying genetic factors, I will then sequence the genome and, in both phases, the transcriptome. Overall, the ambition of the Cocco-Next project is to provide important insights into the interplay between life cycles, ecological niches, and biological CO2 sequestration and beyond, create novel, interconnected and open datasets that will be invaluable to the oceanographic community.