Anomalous Optical Properties of the Black Sea in July 2012 and Relationship with the Concentration of Mineral Suspension in the Water

Korchemkina E. N. , Lee M. E.

In May—July 2012 a massive bloom of algae Emiliania huxleyi (coccolithophores) was observed in the Black Sea, inducing an increase in the upwelling radiance due to light scattering on the mineral particles, produced by algae cells. Such a strong increase of the brightness of the sea led to the fact that the automatic program of satellite data processing recognized the bloom area as clouds, showing the need for contact measurements. The aim was to study the biooptical characteristics of seawater during the coccolithophores blooming for further applications to remote sensing. The article discusses the results of field measurements of the spectral reflectance of the sea in July 2012. The measurements recorded reflectance values increased 3—4 times compared with the seasonal average, but the shape of reflectance spectra has remained unchanged. Using a previously developed analytical algorithm, concentrations of phytoplankton pigments and mineral particles (coccoliths) were calculated. Obtained particles concentration was 1.2∙1011 m−3 in average. It is concluded that the observed bloom was one of the most intense in recent years.

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