Phytoplankton Bloom and Photosynthetically Active Radiation in Coastal Waters

Churilova, T. Ya.; Суслин, В. В.; Moiseeva, Nataliia; Ефимова, Т. В.

doi:10.1007/s10812-020-00944-0

Cited by 8 publications

(4 citation statements)

References 22 publications

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“…The spectral downwelling irradiance (Ed(λ)) was calculated based on measured (aph(λ)), (aNAP(λ)) and (aCDOM(λ)) 11 . Spectral features of Ed(λ) are characterized by wavelength of the maximum of spectral downwelling irradiance (λmax), calculated as the middle of the wavelength range corresponding to half the value of the maximum irradiance 12 .…”

Section: Methodsmentioning

confidence: 99%

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

Ефимова

Churilova

Skorokhod

et al. 2022

28th International Symposium on Atmospheric and Ocean Optics: Atmospheric Physics

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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.

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Section: Methodsmentioning

confidence: 99%

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

Ефимова

Churilova

Skorokhod

et al. 2022

28th International Symposium on Atmospheric and Ocean Optics: Atmospheric Physics

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“…About 44% of the incident solar radiation within the wavelength range 400-700 nm at the sea surface is photosynthetically active (Churilova et al, 2020). Following previous studies (Brewin et al, 2011;Devred et al, 2011;Roy et al, 2013;Varunan & Shanmugam, 2015), we estimate the total a ph (λ) between 400 and 700 nm using a linear combination of the absorption contributions by different phytoplankton size groups, including the pico-(size: <2 μm), nano-(2-20 μm), and micro-phytoplankton (>20 μm) groups:…”

Section: Bio-optical Modelmentioning

confidence: 99%

“…About 44% of the incident solar radiation within the wavelength range 400–700 nm at the sea surface is photosynthetically active (Churilova et al., 2020). Following previous studies (Brewin et al., 2011; Devred et al., 2011; Roy et al., 2013; Varunan & Shanmugam, 2015), we estimate the total a ph ( λ ) between 400 and 700 nm using a linear combination of the absorption contributions by different phytoplankton size groups, including the pico‐ (size: <2 μm), nano‐ (2–20 μm), and micro‐phytoplankton (>20 μm) groups:

a_{ph} (λ) = P^{*} (λ) C_{P} + N^{*} (λ) C_{N} + M^{*} (λ) C_{M},

where P* ( λ ), N* ( λ ), and M* ( λ ) are the size‐specific absorption coefficients of pico‐, nano‐, and micro‐phytoplankton, respectively; and C P , C N , and C M are the corresponding chlorophyll concentrations, expressed as a function of the total chlorophyll concentration (chl) (Brewin et al., 2017).…”

Section: The Formulation Of the Osa Schemementioning

confidence: 99%

An Improved Ocean Surface Albedo Computational Scheme: Structure and Performance

et al. 2021

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Ocean surface albedo (OSA) is an important factor for the transfer of radiation in the coupled atmosphere‐ocean system. By resolving the spectral variations of the reflective properties for incident direct and diffuse solar radiation, we develop an OSA computational scheme to study the impact of ocean biogeochemistry on the air‐sea boundary condition of solar radiative transfer in the atmosphere. The new scheme is implemented for the General Circulation Model applications of the shortwave rapid radiative transfer model RRTMG_SW, a radiative transfer model used extensively in regional and global models. We show that a number of OSA schemes lead to underestimated results in comparison with in‐situ measurements obtained at a site 25 km east of Virginia Beach. The scheme developed in this study considers multiple influential factors and is robust in terms of the mean absolute percentage error (MAPE) and the root mean square error in comparison with in‐situ measurements. Furthermore, the new simulations are highly consistent with the Clouds and the Earth's Radiant Energy System (CERES) OSA distribution on a global scale. However, the theoretical results show slight differences compared with the CERES OSA under all sky conditions and overestimate the OSA in the subpolar Southern Ocean under clear sky conditions. The assumption of a uniform phase function, which neglects the spatial variability of the optical properties of oceanic particles, is largely responsible for the primary source of uncertainties in an OSA scheme.

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“…In particular, this leads to an incorrect estimate of the phytoplankton biomass, primary production and growth rate of plankton microalgae [27,28]. The aCDM-s(443) values are higher than the aph-s (443) values (2.2 times on average), and the aph-s (443) values are lower than the aph-i (443) (9 times on average) throughout the year, leading to an incorrect result of calculating the relative contribution of phytoplankton and non-algal particles of optically active substances in the medium (CDOM and NAP), and, consequently, to an error in determining the optical properties of waters, in particular transparency, spectral properties of quantum irradiation penetrating into the water column [4,24,29] and photosynthetic potential of microalgae [30][31][32].…”

Section: F I Gmentioning

confidence: 99%

Bio-Optical Characteristics of the Black Sea Coastal Waters near Sevastopol: Assessment of the MODIS and VIIRS Products Accuracy

Skorokhod¹,

Churilova²,

Ефимова³

et al. 2021

PhO

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Purpose. The purpose of the work is to evaluate accuracy of the satellite products for the coastal waters near Sevastopol, generated by the standard algorithms based on the MODIS and VIIRS (installed at the artificial Earth satellites Aqua and Terra, and at Suomi NPP, respectively) data. Methods and Results. In situ sampling was carried out at the station (44°37’26" N and 33°26’05" E) located at a distance of two miles from the Sevastopol Bay. The chlorophyll a concentration was measured by the spectrophotometric method. The spectral light absorption coefficients by optically active components were measured in accordance with the current NASA protocol. The spectroradiometers MODIS and VIIRS Level-2 data with spatial resolution 1 km in nadir around the in situ station (44°37’26"±0°00’32" N and 33°26’05"±0°00’54" E) were used. The satellite products were processed by the SeaDAS 7.5.3 software developed in NASA. The research showed that the standard NASA algorithms being applied to the MODIS and VIIRS data, yielded incorrect values of the optically active components’ content in the Black Sea coastal waters near Sevastopol as compared to the data of in situ measurements in the same region: the satellite-derived “chlorophyll a concentration” was on average 1.6 times lower in spring, and 1.4 times higher in summer; the contribution of phytoplankton to total light absorption at 443 nm was underestimated in 8.7 times; the light absorption by colored detrital matter was overestimated in 2.2 times. Conclusions. The NASA standard algorithms are inapplicable to calculating bio-optical indices in the coastal waters of the Black Sea near Sevastopol since they provide incorrect values of the satellite products (Ca-s, aph-s(443) and aCDM-s(443)). Operative ecological monitoring based on satellite data requires development of a regional algorithm taking into account the seawater optical features in the region and in the coastal zone, in particular.

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Phytoplankton Bloom and Photosynthetically Active Radiation in Coastal Waters

Cited by 8 publications

References 22 publications

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

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

An Improved Ocean Surface Albedo Computational Scheme: Structure and Performance

Bio-Optical Characteristics of the Black Sea Coastal Waters near Sevastopol: Assessment of the MODIS and VIIRS Products Accuracy

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