Mapping a Bloom of the Photosynthetic Ciliate Mesodinium rubrum in an Estuary From Airborne Thematic Mapper Data

In Southampton Water, exceptional blooms of the phototrophic planktonic ciliate Mesodinium rubrum over the summer confer a distinctive red colouration to the surface estuarine water. Visible wavelength radiance data from the high resolution Airborne Thematic Mapper were analysed using a ʹchromaticity transformʹ to map the near-surface concentrations of the photosynthetic ciliate. The derived algorithms have an accuracy of about 400 cells ml-1 in total concentrations of up to 2400 cells ml-1. The errors are mainly associated with the difficulty of sampling sea-truth parameters in an estuary where ship movements can divide the bloom into many patches