POSTER SESSION 3
15:30–17:30, Wednesday, September 16
Poster Session | 1 | 2 | 3 | 4 | Schedule at a Glance
ABSTRACT 1229 | POSTER 219
FIELD PERFORMANCE AND VALIDATION OF AUTONOMOUS OPTICAL SENSORS FOR PARTICULATE INORGANIC CARBON (PIC)
Observations of particulate carbon from surface to depth are essential for understanding the marine carbon cycle. Compared to traditional, labor-intensive biogeochemical sampling, low-power optical sensors enable high-frequency measurements and expand spatial and temporal coverage. Here, we present two autonomous optical sensor prototypes designed to measure particulate inorganic carbon (PIC) in seawater. Both exploit the birefringence of calcium carbonate (CaCO3), the primary component of PIC, by detecting cross-polarized near-forward light scattering (PolX, m–1) using linear or circular polarizers. Laboratory experiments demonstrate that both prototypes are sensitive to PIC derived from cultured coccolithophores across an oceanic concentration range spanning more than three orders of magnitude (0.1-400 μg C/L), with a detection limit below 0.1 μg C/L. Sensors were calibrated over pressures of 0-200 bar (equivalent to 2000 m depth) and temperatures of 0-25°C. The prototypes were deployed during five research cruises in the North Sea and North Atlantic (2025-2026) in both underway flow-through and profiling modes. PolX signals correlated strongly with PIC concentrations from discrete water samples across surface and deep waters in both open-ocean and coastal environments. However, the PolX-PIC relationship varied with depth and environmental conditions, underscoring the need for in situ calibration. These results demonstrate the feasibility of autonomous, high-resolution in situ PIC measurements, providing critical observations to improve understanding of coccolithophore ecology and their role in the ocean carbon cycle.
Qiming Sun*, Ghent University, [email protected], https://orcid.org/0000-0001-6132-5093
Georges Fournier, EO consultants Inc., [email protected]
Filip Beunis, Liquid Crystals and Photonics Group (LCP), Department of Electronics and Information Systems, Faculty of Engineering and Architecture, Ghent University, [email protected]
Kristiaan Neyts, State Key Laboratory of Displays and Opto-Electronics, Department of Electronic and Computer Engineering, The Hong Kong University of Science and Technology, [email protected]
Chuck Pottsmith, Sequoia Scientific, Inc., [email protected]
Griet Neukermans, Marine Optics and Remote Sensing Group (MarSens), Department of Biology, Faculty of Sciences, Ghent University, [email protected]
Poster Session | 1 | 2 | 3 | 4 | Schedule at a Glance
