Measurement of oxygen isotope composition in controlled biological experiments in aquatic environments.
The isotopic composition of oxygen in atmospheric air is linked to the intensity of the low-latitude hydrological cycle and the productivity of the biosphere. For some years now, these properties have been used in paleoclimatology, based on the analysis of fossil air trapped in ice. However, to best interpret these data, it is necessary to quantitatively constrain the oxygen fractionation coefficients of the various biological processes.
Projet Instrumentation Innovante et Transverse 2022-2023
Participants : LSCE, ECOTRON, LIPHY, DT INSU
We propose to develop a controlled, instrumented biological chamber system adapted to the aquatic environment for continuous measurement of oxygen isotopic composition during respiration and photosynthesis. This system will be based (1) firstly on the expertise of LSCE and LIPHY in the development of a new optical spectroscopy instrument, the only one of its kind in the world, enabling continuous measurement of the isotopic composition of oxygen in atmospheric air, (2) secondly on the expertise of Ecotron Montpellier and LSCE in the development and multiplexing of controlled, automated biological chambers in terrestrial environments, (3) thirdly, the expertise of CEREEP-Ecotron Ile de France in the development of biological experiments in a controlled aquatic environment, and (4) finally, the mechanical engineering input of DT INSU in the design of a sealed, instrumented system adaptable to the aquatic system in place at CEREEP-Ecotron Ile-de-France. This development will then be deployed in two phases, the first for testing a controlled chamber in an aquatic environment (Figure 1) and the second for a multiplexed system of 6 aquatic chambers operating in parallel, enabling repeatability of experiments and exploration of different species and experimental conditions.