The three-dimensional structures and processes of the global oceans are badly constrained since submarine environments are difficult to access. However, documenting the subsurface oceans is fundamental for societies: (i) the oceans are warming and getting more acidic, with consequences on ecosystems and fisheries, (ii) coastal hazards often find their roots in the deep ocean, (iii) the future climate notably depends on internal processes in the oceans, (iv) industrial activities (notably offshore oil and gas exploitation) could strongly impact this environment and require new survey strategies. OCEAN-IDs aimed to proof the concept of measuring multiple dissolved gases and isotopic ratios from seawater using our state-of-the-art laser spectrometer technology combined with our novel patent-pending sample extraction methods and real-time data visualisation, in order to improve process understanding and to support end-users from the industry and from the academic world at work off-shore. OCEAN-IDs was a Proof of Concept follow-up of the ERC Advanced Grant ICE&LASERS (PI: Jérôme Chappellaz) where similar laser technologies were developed and implemented for glaciological applications notably in Antarctica and where first tests in a marine environment proved that the technology could largely benefit to the oceanographic community.
One of the key innovations proposed in the frame of OCEAN-IDs consisted in verifying that an interband cascade laser (ICL) adapted to our laser spectrometer technology could provide the required performances for simultaneous measurements of the ethane/methane ratio and of the 13C/12C isotopic ratio of methane inside dissolved gases in the oceans, two signals helping to constrain the origin and fate of hydrocarbons in seawater. At the moment, the market does not include any instrument able to conduct such measurements simultaneously, in-situ and with the required level of sensitivity and reproducibility. Through the OCEAN-IDs project, we could conduct intensive laboratory design and tests of a prototype instrument including an ICL laser, and we could prove that suitable performances could be reached with our technology once the ICL laser is embedded. Calibrations in the laboratory indicated that the performances would be of real value for potential end-users, either from the industry or from the academic world, thus preparing the market for a new generation of product.
Another task of OCEAN-IDs focused on evaluating possible biases which could affect the measurement of the D/H isotopic ratio of water, based on our technology. Such a signal measured in-situ in the global oceans would help better constraining several physical processes at work, related with ocean circulation, air/sea exchanges and ice shelf/glacier/sea ice/ocean interactions. Our team indeed revealed the existency of significant fractionation effects on water isotopes related with membrane permeation at the inlet of the instrument, requiring an important additional calibration work before considering deployment in seawater.
In addition to the ERC Proof of Concept, the fast-track incubator SATT-Linksium of Grenoble, France, supported us to develop contacts with companies involved in the market of in-situ measurements in the oceans. These contacts proved to be much promising. At the time of writing these lines, discussions are under way with them to consider licencing the pending patent and know-how associated with our technology, and possibly to bring to market the industrial evolution of our laboratory prototypes.
