Comparing fluorescent and differential absorption LiDAR techniques for detecting algal biomass with applications to Arctic substrates

The physical and biological properties of Arctic ice and coastal benthos remain poorly understood due to the difficulty of accessing these substrates in ice-covered waters. A LiDAR system deployed on an autonomous underwater vehicle (AUV) can interrogate these 3D surfaces for physical and biological properties simultaneously. Using our understanding of the absorption, inelastic scattering (fluorescent), and elastic scattering properties of photosynthetic micro- and macro-algae excited by lasers, we present results of in situ tank tests using a two-wavelength (473 nm, 532 nm) prototype to evaluate both fluorosensor and differential absorption (DIAL) approaches using reflectance standards and selected macroalgae as targets.