Small Photosynthetic Flagellates of the White Sea: Seasonal Dynamics and Their Role in Plankton and Ice Communities
- PDF / 647,627 Bytes
- 6 Pages / 612 x 792 pts (letter) Page_size
- 14 Downloads / 180 Views
ARCH ARTICLE
Small Photosynthetic Flagellates of the White Sea: Seasonal Dynamics and Their Role in Plankton and Ice Communities E. R. Nikishovaa, I. G. Radchenkob, and T. A. Belevicha,b,* a
Department of General Ecology and Hydrobiology, Faculty of Biology, Moscow State University, Moscow, 119234 Russia b Belozersky Institute of Physicochemical Biology, Moscow State University, Moscow, 119992 Russia *e-mail: [email protected] Received May 25, 2020; revised June 27, 2020; accepted July 7, 2020
Abstract—Abundance and biomass of small photosynthetic flagellates (SPF; 3–10 μm), chlorophyll a concentration, and the contribution of SPF to total phytoplankton biomass at different stages of seasonal succession in ice and in surface water were studied in Kandalaksha Bay of the White Sea in September 2016 and February and July 2017. In summer, SPF biomass in the photic layer averaged 38.36 ± 9.77 mg C/m3, 2.22 ± 1.43 mg C/m3 in autumn, 2.6 ± 1.72 mg C/m3 in under-ice water, and 14.79 ± 11.25 mg C/m3 in ice. The contribution of SPF to total phytoplankton biomass depended on the season and ranged from 29 to 95%; the contribution of SPF to sympagic communities averaged 66%. The size structure of photosynthetic f lagellates varied by seasons. Flagellates with a cell size of 6–10 μm dominated in summer plankton and in the ice. Flagellates with a cell size of 3–6 μm prevailed in autumn and in the under-ice water. The obtained data of SPF abundance showed higher values of the total phytoplankton biomass of the White Sea in the autumn– winter period compared with the estimates obtained previously. Applying the method of epifluorescence microscopy confirmed the idea that photosynthetic flagellates were the main producers in the winter period as well as in the summer when the biomass of planktonic algae with cell size exceeding 10 μm is low. Keywords: small flagellates, season dynamic, cryoflora, phytoplankton, picophytoplankton, Kandalaksha Bay DOI: 10.3103/S0096392520030062
INTRODUCTION Phototrophic flagellates are the most important component of phytoplankton and ice flora in marine ecosystems; they include representatives of almost all classes of algae, except diatoms [1, 2]. Small phototrophic flagellates (SPF; 3–10 μm) often dominate in the sub-Arctic and Arctic seas [2, 3]. However, assessing the abundance of small-size algae requires the use of special methods that differ from traditional approaches accepted in phytoplankton studies, and defining their taxonomic affiliation is possible only on the basis of molecular methods. This is due to the destruction of delicate cells during fixation of samples as well as the difficulties in identifying small cells under a light microscope. Accordingly, the underestimation of the SPF abundance under the generally accepted methods of processing the phytoplankton and ice samples leads to underestimating the algae total biomass. Despite the importance of small-size algae, the information on the SPF of the sub-Arctic White Sea and the seas of the Russian Arctic is extremely scarce.
Data Loading...
