Optical properties of microphytobenthic biofilms (MPBOM): Biomass retrieval implication

Microphytobenthos Optical Model (MPBOM) provides the optical properties, absorption coefficient and refractive index, of a laboratory simulated microphytobenthic biofilm using the reflectance measurements derived from HySpex laboratory images, with the final aim of estimating photosynthetically active biomass. The high correlation between this biomass, expressed in chlorophyll a (mg Chl a m−2) and the absorption coefficient at the corresponding absorption wavelength of Chl a (673 nm) made possible the estimation of biomass for any absorption coefficient calculated from reflectance measurements of any other data set. The latter was validated for an independent data set which performed an acceptable estimation of biomass in comparison with the biomass measured by HPLC (R2=0.93). Finally, this model is designed to be applied to hyperspectral images, like airborne or satellite, in order to map biomass in the field.

Research Highlights► MPBOM: Microphytobenthos Optical Model, providing the inherent spectral properties. ► Inherent reflectance, having a very low contribution to the apparent reflectance. ► Measured reflectance spectra depend highly on absorption level and the substrate. ► Calculated absorption coefficient (α) is a linear function of absorbing pigments.► Linear regression between α673 nm and known biomass (HPLC): mg Chl a m−2=96α673 nm.