Spectral bio-optical properties of the Black Sea coastal waters (near Sevastopol) in summer 2020-2021

Abstract

Spectral bio-optical properties of Black Sea coastal waters (near Sevastopol) with different trophic status were analysed. In summer 2020-2021, the chlorophyll a concentration (Ca) differed by an order between stations, located in the apex of the Sevastopol Bay and at a distance ~2 miles from the Sevastopol Bay. At the station located in the apex of the Sevastopol Bay, effected by river runoff (the most trophic waters), the total particulate light absorption at wavelength 438 nm (aP(438)) increased by an order compared to station located at a distance of ~2miles zone from the Bay. The contribution of the light absorption by non-algal particles to the ap(438) was not depended on water trophic status. With a rise of water trophic status the coefficient of colored dissolved organic matter absorption increased by ~2.2 times, and the coefficient of total non-water absorption (atot(438)) increased by ~4 times. The spectral features of downwelling irradiance depended on the atot(438). The increasing of atot(438) of about 10 times resulted in shift of ~50 nm to the longer wavelength domain of the spectrum.

Light Absorption by Optically Active Components in the Arctic Region (August 2020) and the Possibility of Application to Satellite Products for Water Quality Assessment

“…A negative correlation between non-water total light absorption (phytoplankton, NAP and CDOM) in the surface layer and euphotic zone was revealed (Figure 9). The obtained relationship agreed with those for the Black Sea [76]. This relationship can be used for assessment of the euphotic zone based on the remote sensing data, if the three-band bio-optical algorithm [73] is applied for the Arctic region.…”