Improving Harmful algal blooms (HABs) detection is crucial because massive bloom events are likely to increase in the future due to global warming and eutrophication. Remote sensing has proved useful to detect HABs, however discriminating the causative bloom species is challenging due to a lack of knowledge on the optical properties of HAB-forming species: from about 300 harmful species, only a modicum has been documented so far. We investigate the possibility of improving HAB detection using a three-step approach: 1) measurement of phytoplankton inherent optical properties (IOPs) from laboratory cultures, 2) development of specific inversion algorithm using radiative transfer (RT), and 3) detection using high resolution satellite observation. We applied this analytical approach to Lingulodinium polyedra, a dinoflagellate causing seawater discoloration worldwide. While L. polyedra has been extensively studied over the past years, its optical properties are poorly documented. Here, its IOPs were characterized from laboratory culture, in terms of attenuation, absorption, and scattering. The contribution of the particulate, phytoplankton, detrital, and dissolved constituents was measured. The characterization of the scattering properties included the measurement of the volume scattering function. The IOPs were used to parameterize a generic RT model, and develop a specific inversion algorithm. The algorithm was then applied to field and satellite reflectance data acquired during a coastal red tide to retrieve L. polyedra cell number, as well as Chl a and POC concentration.
Primary Presenter: Pierre Gernez, Nantes University (pierre.gernez@univ-nantes.fr)
Authors:
Pierre Gernez, Nantes University (pierre.gernez@univ-nantes.fr)
Rüdiger Röttgers, Hereon (ruediger.roettgers@hereon.de)
Maria Laura Zoffoli, Consiglio Nazionale delle Ricerche, Istituto di Scienze Marine (CNR-ISMAR) (laura.zoffoli@artov.ismar.cnr.it)
Thomas Lacour, Ifremer (Thomas.Lacour@ifremer.fr)
Victor Pochic, Nantes University (Victor.Pochic@univ-nantes.fr)
Michael Retho, Ifremer (Michael.Retho@ifremer.fr)
Martin Hieronymi, Hereon (Martin.Hieronymi@hereon.de)
Amália Sacilotto Detoni, Consejo Superior de Investigaciones Científicas, Instituto de Ciencias Marinas de Andalucía (CSIC/ICMAN) (amalia.detoni@csic.es)
Tristan Harmel, Magellium (tristan.harmel@magellium.fr)
Remote sensing of Lingulodinium polyedra harmful algal blooms: from laboratory optical measurements to satellite observation
Category
Scientific Sessions > SS102 Inland and Coastal Aquatic Ecosystems Monitoring from In Situ and Satellite Radiometric Measurements
Description
Time: 10:45 AM
Date: 9/6/2023
Room: Sala Menorca A