09:45–10:00 | ABSTRACT 1136
AN IN SITU MULTI-WAVELENGTH EXCITATION FLUOROMETER FOR PHYTOPLANKTON TAXA OBSERVATIONS ON ARGO FLOATS
The rapid expansion of the global BGC-Argo network over the past decade has made single-wavelength fluorometers essential tools for observing chlorophyll-a and phytoplankton biomass. However, phytoplankton community composition remains a critical observational gap on Argo platforms. Multi-wavelength excitation fluorometers (MEFs) provide a promising solution by exploiting taxon-specific fluorescence signatures arising from distinct pigment compositions. Different phytoplankton groups exhibit characteristic excitation spectra linked to their light-harvesting pigments (e.g., chlorophyll-b/c, carotenoids, and phycobiliproteins). By combining multiple excitation wavelengths, MEFs enable the retrieval of major phytoplankton functional groups such as diatoms, dinoflagellates, and cyanobacteria. Although existing commercial MEFs have demonstrated strong capability in coastal and open-ocean applications, they remain unsuitable for global BGC-Argo deployment due to limited pressure tolerance or insufficient sensitivity in oligotrophic environments. Here, we present FluoroTax, a novel 10-band MEF specifically designed for Argo floats, with pressure resistance up to 4000 m and enhanced sensitivity for low-biomass waters. We also introduce recent progress in taxa retrieval algorithms, enabling robust estimation of phytoplankton community composition. This development represents a key step toward closing a major observational gap in the global BGC-Argo system.
Xiaogang Xing, State Key Laboratory of Satellite Ocean Environment Dynamics, Second Institute of Oceanography, [email protected], https://orcid.org/0000-0002-9940-1204
Gaofang Yin, Key Laboratory of Environmental Optics and Technology, Anhui Institute of Optics and Fine Mechanics, Chinese Academy of Sciences, Hefei, [email protected]
