Characteristics of Suspended Matter in the South Ocean in the 20ºE Region Based on the Measurements of Light Volume Scattering Functions

V. I. Mankovsky, E. V. Mankovskaya✉

Marine Hydrophysical Institute of RAS, Sevastopol, Russian Federation

✉ e-mail: emankovskaya@mhi-ras.ru

Abstract

Purpose. The purpose of the work is to present and discuss the results of determining the mass concentration of suspended matter and its organic and mineral fractions by measuring the light volume scattering functions in the South Ocean in the 20ºE meridian region from 37º to 55ºS.

Methods and Results. The measurement data on the light volume scattering function were obtained in the 10^th^ cruise of the R/V “Akademik Vernadsky” in January–February, 1975 at the oceanographic section along the 20ºE meridian from 37º to 55ºS at the stations located 1º apart. The suspended matter composition was calculated based on the results of these measurements. The distribution of mass concentration of the suspended matter (total, organic and mineral) at the section was obtained. The maximum increase in the organic suspension concentration at the section was observed in the area of water rise at 53ºS: Corg = 0.830 mg/l (Ctotal = 1.062 mg/l), that indicates the highest water productivity in this region. Based on the empirical relationship with the organic suspension concentration, the chlorophyll concentration at the section was calculated. The relation between the total mass concentration of suspended matter and the scattering coefficient in surface waters in the form Ctotal = 1.496 s~520~ – 0.0676 (R = 0.95) was established. The features of the organic suspension vertical distribution in the areas of water rise and lowering, and with no signs of water vertical movement were considered.

Conclusions. Measurements of the light volume scattering functions in the South Ocean in the region of 20ºE and 37º–55ºS permitted to obtain the data on mass concentration of the total suspended matter, as well as its organic and mineral fractions. The maximum concentration of organic suspension is located in the vicinity of the average long-term position of the Polar Front, where the mass development of phytoplankton is observed regularly. The features of vertical structure of the suspension organic fraction are directly related to the water vertical dynamics. There is a close relationship between the mass concentration of total suspended matter and the scattering coefficient in the surface waters.

Keywords

light volume scattering function, suspended matter, organic suspended matter, mineral suspended matter, suspended matter concentration, South Ocean

Acknowledgements

The study was carried out within the framework of state assignment of the FRC MHI on themes No. FNNN-2021-0003 and No. FNNN-2021-0005.

Original russian text

Original Russian Text © V. I. Mankovsky, E. V. Mankovskaya, 2023, published in MORSKOY GIDROFIZICHESKIY ZHURNAL, Vol. 39, Iss. 3, pp. 371-383 (2023)

For citation

Mankovsky, V.I. and Mankovskaya, E.V., 2023. Characteristics of Suspended Matter in the South Ocean in the 20ºE Region Based on the Measurements of Light Volume Scattering Functions. Physical Oceanography, 30(3), pp. 343-354. doi:10.29039/1573-160X-2023-3-343-354

DOI

10.29039/1573-160X-2023-3-343-354

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