We aim at constraining the co-evolution of life and the environments on early Earth, targeting five milestones through life evolution (between 3.4 Ga – 400 Ma, Billion-Million years) linked with important changes in redox conditions and oxygenation. Identifying the fossils of these times has been limited by (1) morphological simplicity, (2) non-diagnostic organic carbon isotope ratio, (3) difficulty to correlate individual fossils with molecular biomarkers analyzed on bulk rocks, (4) difficulty to correlate fossils with geochemical metabolic/environmental proxies from bulk rocks. To overcome these limitations, we will use a combination of micro- to nanoscale characterizations of fossils. We will develop novel microscale molecular methods: Time-of-Flight Secondary Ion Mass Spectrometry (ToF-SIMS), and microscale Laser-desorption Laser-ionization Mass Spectrometry (µL2MS). Thanks to these innovative techniques we will be able, for the first time, to retrieve molecular information (biomarker and fossil biopolymer composition) on single fossil cells, and to distinguish adjacent cells as well as cell anatomy. These spatially-resolved analyses will identify possible in-lab and weathering contaminations. Complementary nanoscale analytical (spectro)microscopy will be used to analyze anatomy as well as mineral structures informing on post-mortem morphological modifications and biominerals. Metabolic signatures will be investigated using microscale and bulk-rock isotope analyses of organic matter and biominerals. The project builds on the gathered participants’ expertise in the fields of organic and isotope geochemistry, paleontology, nano-mineralogy, mass spectrometry and spectroscopy, and analytical developments. (A) Our selection of samples will allow us to address the effects of diagenetic and metamorphic transformations, as i) all fossils are preserved in quartz, ii) their age gradient is correlated with an increase in organic matter maturity and mineral matrix recrystallization, iii) 412 Ma to 1.6 Ga samples contain comparable microfossils (e.g. cyanobacteria, algae). (B) The 412-410 Ma samples will allow us to build a database of microscale molecular fingerprints on a large diversity of micro-organisms (cyanobacteria, algae, fungi) and specialized cells of macrofossils (plants, animals) correlated with nanoscale anatomical imaging. This will inform on cell structures and compositions in some of the earliest land plants (412-400 Ma) thus constraining the evolution of biopolymers including lignin, which triggered a rise in pO2 (O2 partial pressure). (C) We will compare morphologically identified microfossils and ambiguous morphospecies in 800-700 Ma old rocks with coupled molecular, textural and isotopic criteria. We hope to identify the relative importance of cyanobacteria and micro-algae in the primary photosynthetic production in order to constrain the role of the evolution of algae in the rise of pO2 of the Neoproterozoic Oxygenation Event, which resulted in the evolution of multicellular life. (D) ~1.6 Ga microfossil assemblages, coincident with the earliest eukaryotic fossils, will be characterized to constrain primary production during a period of reduced pO2 using microfossils of increased thermal maturity. (E) Microfossil assemblages of the Great Oxidation Event and its aftermaths between 2.45 and 1.8 Ga, will be studied to constrain metabolisms in environments characterized by important redox and pO2 fluctuations, with a focus on Fe-biomineralization associated with ferruginous conditions characterizing the ocean of this time period. (F) Organic microstructures (2.7 Ga) and enigmatic assemblages of small and large microfossils (3.0-3.4 Ga) will be studied to document primary production, methane and sulfur metabolisms associated with early anoxic and ferruginous environments together with possible early production of O2.

As we head into the future with uncertainty regarding the effects that the emission of greenhouse gas will have on our climate, there is an increasing desire to better understand and model carbon fixation by oceanic phytoplankton – a prominent component of the carbon cycle and Earth’s climate system. There is indeed a pressing need to constrain the response of marine phytoplankton ecosystems and the biological pump to increased sea surface temperatures, surface ocean carbonation and consecutive decreased seawater pH. The overarching objective of this project is to establish an unprecedented bulk response of photosynthetic and calcification efficiency through laboratory culture of a prominent biological group, the coccolithophores, subjected to a series of perturbation experiments mimicking the environmental conditions of our future, present and past oceans (spanning the IPCC2014 RCP conditions to greenhouse conditions of the Cenozoic). This project will seek a mechanistic understanding of the modulation of calcification of their biominerals, using the isotopic composition of the coccoliths as tracers of the dynamics of physiological-relevant reactions enabling intracellular calcification. As such, it will unravel a still elusive link between the chemistry and morphometrics of the coccoliths. Conducting laboratory cultures of coccolithophores will enable constraining the environmental control on their ability to calcify and developing a biologically-grounded understanding of these vital effects with ramifications for the use of the geochemistry of the coccolith in palaeoceanography. For decades, palaeoceanographers have struggled to tackle the biological origin of the sedimentary archive, which is still regarded as a black box-type problem and remains a large source of uncertainty in climate reconstruction. Yet, it is of paramount importance to deconvolve the biological vs. environmental forcing on the geochemistry of sediments. The vital effects have been regarded as the villain in the palaeoceanographic world for more than 60 years. Integrated via modelling, this project will provide a valuable biogeochemical framework for the fate of coccolithophore production in our Anthropocene World, and set the stage to a novel means of fingerprinting fluctuations in temperatures, ambient CO2 concentrations and pH in the past by exploiting the magnitude of the vital effects. The CARCLIM project extends well beyond the proxy development, but aims at a conceptual advance in (palae)oceanography with the establishment of a ground-breaking and multidisciplinary approach that will ultimately serve to augment current understanding of the influence of organic and inorganic carbon fixation by the coccolithophores on ocean chemistry and Earth’s climate.

Improvised explosive devices (IED), also known as roadside bombs are causing increased losses of troops and are also widely used for terrorist attacks too. Such devices use various kinds of explosives and due to the difficulty to detect them they are extremely effective. A large range of detection solutions are being evaluated. Optical spectroscopy techniques have without doubt great potential. Among this panel, we propose to use THz radiation, located between the microwaves and infrared bands. THz Spectroscopy is an excellent alternative completing or even to improve traditional approaches for the detection pyrotechnic compounds. Indeed, THz spectroscopy is characterized by an excellent molecular selectivity, with rotational lines of small polar molecules and/or low frequency vibrational signatures of bigger molecular systems. THz spectroscopy is a breakthrough technique for detection, analysis and quantification of a wide variety of molecular compounds . The potentiality of this technique is considered in the context of the detection of chemical agents involved in military programs. While gases has been studied for a long time in the THz domain for fundamental science, the interaction of the THz radiation with explosives substances has only recently been started to be examined. THz Time Domain Spectroscopy (THz TDS) has removed many technological difficulties to initiate those first studies in this spectral gap. Now, many data are available on these types of compounds. However the data contain substantial discrepancies probably due to various experimental conditions measurements (pure or diluted, the use of matrix or not…). Moreover, the additives can modify and so complicate the recognition of prohibited substance present in a mixture. We can also legitimately question the feasibility of identifying an individual compounds whien its spectrum is not attributed to any isolated spectral lines. Some explosives and their derivatives have significant vapour pressure which can be use for the detection with a high degree of discrimination. However, these relatively heavy compounds are not very volatile, and therefore require very high sensitivity spectrometers, especially as additives further decrease their volatility. Such approaches have great potential, but require an extensive and fundamental study of the spectral signatures. To the best of our knowledge, THz gas phase spectra of the most volatile explosives are not available. The objective of this proposal is to record and fully interpret the THz and Far Infrared spectra of the vapour pressures of some target explosives and /or their derivative compounds. Without doubt, these new data provide information about the potential of this spectral band to detect such substances in the gas phase. So, the industrial partner will propose several approaches towards studies or experimental development at higher TRL levels.