Observations from working with a simple mathematical model of light absorption by small particles in the ocean

Abstract

In order to investigate the possibility of using oceanic visual spectrum data (i.e., ocean color) to differentiate between phytoplankton cell types, a simple mathematical model of light absorption was constructed in MATLAB, in order to investigate the effects of depth, cell size, and water on light absorption by a layer of water containing suspended particles. The model takes chlorophyll a absorption data, cell diameter, intracellular and bulk concentrations of chlorophyll a, pure water absorption data, and thickness of water layer as inputs, and outputs the attenuation by absorption of light that shines through a layer of water containing suspended, absorbing cells. Plots of absorptive attenuation were made, varying thickness, cell diameter, and inclusion of water absorption. These plots were qualitatively analyzed. It was found that water greatly dominates absorption, when included. This finding suggests that using visual data may be difficult with ocean water, though scattering effects remain to be accounted for, and thus this problem warrants further study.