A simple method for algal species discrimination in East China Sea, using multiple satellite imagery

Abstract

Satellites can help monitor harmful algal blooms in coastal regions. Methods have been developed using different satellite missions. However, it is necessary to develop a simple and useful method for discriminating harmful algal species that could be applied to multi-source satellite remote sensing reflectance spectra ($${R}_{\mathrm{rs}}(\lambda ))$$ R rs ( λ ) ) . In this study, based on the bio-optical model, a backscattering indicator, bbp-index (green), was found to be useful for species identification (Karenia mikimotoi and Prorocentrum donghaiense) combined with the red tide index (RI) in water blooms in the East China Sea (ECS). The MODIS, GOCI, and MERIS data collected between 2004 and 2020 were consistent for bloom discrimination, determining that K. mikimotoi exhibited lower bbp-index (green) values than P. donghaiense. The classification of the blooms is based on the following criteria: $${R}_{\mathrm{rs}}(555)$$ R rs ( 555 ) < 0.014 sr−1 and RI > 2.8 and (1) bbp-index (green) > 1.2 $$\times {10}^{-3}$$ × 10 - 3 , classified as P. donghaiense blooms or (2) bbp-index (green) < 1.2 $$\times {10}^{-3}$$ × 10 - 3 , classified as K. mikimotoi blooms. The inclusion of the RI is necessary to directly detect the bloom area. Local bloom reports have confirmed the effectiveness of the bloom discrimination method. In addition, the advantages and limitations of the proposed method are discussed.

Assessing the Performance and Application of Operational Lagrangian Transport HAB Forecasting Systems

“…Interestingly the HAB risk map aimed at Karenia spp. also indicated high likelihood of a bloom during this event 2 , this could indicate a misidentification of species in this case and work discriminating the two, as has been done for K. mikimotoi and another Prorocentrum species (P. donghaiense) in (Feng et al 2022), might be valuable for future HAB prediction. Finally, we have also demonstrated in section 3.3 that the Lagrangian particle simulations are a tool for tracking the evolution of high biomass blooms of the non-toxic Mesodinium rubrum, prey of Dinophysis spp.…”

“…at the in situ monitoring sites were observed see (Atkinson et al 2021). HAB detection algorithms are being constantly improved to distinguish harmful from non-harmful high chlorophyll blooms (Cannizzaro et al 2008;Tomlinson et al 2009;Sourisseau et al 2016), but there are still considerable challenges in species discrimination (Kurekin et al 2014;Feng et al 2022) and in distinguishing high turbidity from high chlorophyll concentrations of HAB species (Martinez-Vicente et al 2020), this issue, and this will remain a source of error independent of the errors from the Lagrangian model.…”