Heterotrophic Bacteria of the Ob River Estuary during Growing Season: Spatial and Temporal Variability

• Published in: Oceanology (Washington. 1965) Vol. 62; no. 3; pp. 369 - 378
• Main Authors: Romanova, N. D., Boltenkova, M. A., Polukhin, A. A., Bezzubova, E. M., Shchuka, S. A.
• Format: Journal Article
• Language: English
• Published: Moscow Pleiades Publishing 01.06.2022; Springer Nature B.V
• Subjects: Abundance; Bacteria; Bacterioplankton; Brackish water; Cells; Chemical analysis; Distribution; Earth and Environmental Science; Earth Sciences; Electron transport; Electron transport chain; Environmental factors; Estuaries; Estuarine dynamics; Fresh water; Growing season; Heterotrophic bacteria; Marine Biology; Nanoplankton; Oceanography; Offshore; River discharge; River flow; Rivers; Runoff; Salinity; Salinity effects; Seawater; Spatial analysis; Spatial distribution; Temporal variations; Water analysis; Ob River; Arctic estuaries; temporal changes; bacterioplankton
• ISSN: 0001-4370; 1531-8508
• DOI: 10.1134/S0001437022030109

Analysis of the distribution of abundance and activity of bacterioplankton in the estuary area of the Ob River in July 2016 and September 2013, as well as environmental factors, made it possible to distinguish between riverine, brackish water, and marine zones. In summer, the abundance of bacterioplankton varied from 2604 ± 436 × 10 3 cells/mL in brackish waters to 468 ± 91 × 10 3 cells/mL in seawater. The average values of bacterial production in waters with a salinity of less than 8 and more than 22 PSU were 17.43 and 4.91 mgC m –3 day –1 , respectively. In autumn, the bacterial abundance decreased towards the sea from 1289 ± 385 × 10 3 cells/mL in freshwaters to 85 ± 37 × 10 3 cells/mL in the offshore part; the value of production decreased by more than an order of magnitude. With an increase in salinity, the proportion of cells with active electron transport chain in the abundance of bacterioplankton decreased from 5.8 to 0.6%. Thus, the distribution of river runoff, marked by salinity, proved to be the main factor affecting the spatial distribution and activity of bacterioplankton. However, the mechanism of such regulation remains unclear.