Changes in micro-algal pigment content and optical absorption cross section with growth irradiance, detected by hyperspectral radiometric analyses

Micro-algae are one of the most reactive group of photosynthetic organisms regarding pigment composition. Indeed, cells adjust their pigment pool as a physiological response to the extremely variable light environment they inhabit. Thus, because of pigment dynamics and functions, the estimation of absorption properties of these organisms is primordial to assess micro-algae photosynthetic capabilities. However, optical properties are often estimated by spectrophotometry, either in vitro after an extractive procedure which modifies pigment optical properties, or in vivo on suspended cells in water which increases the scattering phenomenon. To overcome these limitations, and to asses in vivo cell optical properties, the current study outlines a method based on reflectance measurement by hyperspectral radiometry.