LASER-ENVI - A LASER spectrometer-based ENVIronmental Gas and Gas-Isotope Facility

Lead Research Organisation: University of Cambridge
Department Name: Earth Sciences

Abstract

Earth is a habitable planet because of the particular mixture and pressure of gases it contains in its atmosphere. These gases are involved in a range of processes across Earth's surface that both consume and produce them, creating 'cycles' that result in a planetary atmosphere that is warm, habitable, and critically for eukaryotic life, contains atmospheric oxygen. Importantly today, the concentration of the gases that keep the planet warm, particularly carbon dioxide (CO2) and methane (CH4) are increasing dramatically, causing anthropogenic global warming. Tracing the sources of these gases, their consumption, and the processes they are involved in across Earth's surface informs our understanding of the functioning of our planet under stress and may help with predicting how various processes that consume and produce these greenhouse gases may change under future rising temperature and sea level.

One of the most powerful tools for tracing the various sources and sinks of gas to the atmosphere is the measurement of the stable isotopic composition of these gases. This analysis has in the past been limited to large sample sizes, and by the ability to preserve samples from the environment to the laboratory. Furthermore the traditional measurement of gas concentration and isotopic composition, via isotope-ratio mass spectrometry - highly powerful technology, but large and energy inefficient. Analytical advancements in the last decade in laser spectroscopy is revolutionising the field of research in the analysis of gas concentration and isotopes, making compact, energy-efficient equipment. Because they are compact, they can be field-deployable, allowing more analyses and avoiding the risks associated with returning samples to the laboratory. The analytical capabilities within the field of laser spectroscopy have accelerated in the past decade, yielding instruments capable of measuring the concentration of key gases, their isotopic composition and, for some gases, the ordering of the isotopes within the gas molecule. This technological development means we are at the forefront of being able to fully resolve the gas cycle across a range of natural environments. Furthermore, the analysis time is orders-of-magnitude shorter than conventional IRMS, allowing far higher throughput of samples.

The UK has the potential to be at the forefront of this technology, with the ability to measure the isotopic composition of various gases. Although there are individual laser spectrometers at Universities throughout the UK, there is no national facility that can measure the full range of concentrations and isotopes of climatologically relevant gases across the diverse range of environments and natural abundances. Given the complexity and interconnectedness the questions being asked, and the need to measure more than one species on individual samples, a dedicated facility with a suite of instruments that may be used in tandem on the same samples is required.

Publications

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