Color class and structure-related observable fluorescence response in arctic macroalgae as coastal underwater lidar substrates

Abstract

In the context of underwater marine biological remote sensing surveys, we consider the fluorescence response of macroalgal and kelp targets to underwater fluorescence laser serial and lidar imaging applications. An investigation of absorption and fluorescence emission via excitation–emission (EEM) spectra of Arctic macroalgal substrates is presented via naturally and artificially generated structural scenarios. Fluorescence was found to increase with algal structure thickness for the kelp Alaria esculenta, both when its output is tested with or without structural modification (increase thickness) of the kelp thallus. Several trials involving other species of all three color classes showed fluorescence output decreased after a thickness increase via layering or structure reconfiguration: a process we suggest is due to fluorescence re-absorption sometimes occurring within and between the rearranged algal structures.