Pico- and nanoplankton
Despite the fact that the Sea of Azov has a long-term record of hydrobiological research, the current state of phytoplankton community of the Sea of Azov remains insufficiently studied. For many decades, phytoplankton studies were reduced to the research on the quantitative and qualitative characteristics of algae over 20 μm. Microalgae under 20 μm – ultraphytoplankton, which can be further categorized into pico- (0.2–2 μm) and nanoplankton (from 2–10 to 20 μm), escaped the attention of researchers. Notably, these microorganisms may compose up to 59-69% of primary production and total phytoplankton biomass. (Azam et al., 1983).
Once collected from the surface profile, the samples of phytoplankton of pico- and nano-fractions are fixed by a glutaraldehyde solution. The samples are processed using epifluorescence microscope after filtration to black membrane filters and fluorochrome colouring. The indicated method also allows obtaining data on the total number of bacterioplankton cells (Sukhanova, 1983; Makarevich, Druzhkov, 1989).
Results from 178 pico- and nanoplankton samples (including bacteria) from the Sea of Azov have been added to the database. Results from 3 samples from the Black Sea were also added. . There was no data available from the Caspian Sea for pico- and nanoplankton (Figure 1 è Table 1).
|Sea of Azov|
|Total by seas||10||21||8||24||6||41||29||0||29||13||0||0||181|