Field-portable volatile trapping system for marine and atmospheric research

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Our group examines the production, distribution and biogeochemical cycling of oceanic climate-active gases, including dimethyl sulfide (DMS), and other important volatile organic compounds (VOCs). Our aim is to study the sources and fate of these compounds across the air-sea interface, to better understand global climate feedbacks. Dimethyl sulfide impacts Earth's climate through the production of atmospheric aerosols that block incoming solar radiation. This molecule also plays a considerable role in the transfer of carbon, sulfur and energy across marine trophic levels. We have recently developed a powerful analytical method using mass spectrometry to measure DMS and other VOCs in seawater at ultra-low levels. The method is suitable for detecting these compounds in all marine environments, across many of orders of magnitude in concentration, and has enabled unique applications, which are not possible with other methods. These applications include stable isotope incubations to measure the turnover rates of marine DMS, the detection and characterization of DMS micro-zones within low oxygen waters, and the analysis of trace VOCs in the atmosphere. Our new analytical method is a powerful research tool, with strong potential to open new lines of world-leading research in ocean and atmospheric sciences. However, the required instrumentation is cumbersome, delicate, and expensive, and thus not designed to handle the rigors of sea-going research. In order to maintain long-term performance of this instrument, and to extend the utility of our methods to remote field situations (e.g. helicopter-based Arctic sampling), it is critical that we develop a new strategy for sample collection to decouple field sampling from the lab-based analysis. We are requesting funds to build a fully-automated gas trapping system, which will allow us to take quantitative analysis offline, eliminating the need to bring the mass spectrometer to sea on future expeditions. We propose fabrication of a custom-built Volatile Trapping Manifold a large and expandable array of individually addressable commercial thermal desorption tubes, allowing field-based collection, processing and stabilization of DMS and other VOCs extracted from seawater and/or atmospheric samples, before transport back to the lab for MS analysis. The proposed system will be used to support HQP training, and allow us to greatly extend our field-based sampling capabilities.