A mobile optical coherence microscope for studying aquatic organisms in- and outside the laboratory

High-resolution, three-dimensional imaging of live organisms has largely depended on laboratory-bound microscopes, limiting quantitative analysis of morphology and dynamics to species that survive transport and thrive under lab-controlled conditions. Here we present a mobile optical coherence microscopy (OCM) platform that overcomes this constraint, delivering ∼2.5 µm axial resolution, label-free, volumetric imaging of live aquatic organisms in both laboratory and remote field environments. We demonstrate the platform across a broad range of aquatic organisms from the lab and field, spanning multiple phyla - including cnidarians, poriferans, annelids, arthropods and echinoderms – resolving internal anatomy, tissue boundaries and organismal morphology at micrometer scale without fixation, fluorescent labeling, or specialized sample preparation. High-speed acquisition, with up to 250 kHz A-line rate and 7.7 Hz volume rate, further enabled morphodynamic imaging of live biological processes, including cellular aggregate motility, embryonic cell division, and organ-level peristaltic dynamics in intact, living animals. To demonstrate field deployability, the platform was operated during the EMBL TREC pan-European expedition, enabling on-site, label-free imaging of marine organisms and plankton immediately upon collection. By decoupling high-resolution volumetric imaging from fixed laboratory settings, mobile OCM opens a path toward field-ready quantitative morphological and dynamic phenotyping of aquatic life.