ISSN 10630740, Russian Journal of Marine Biology, 2015, Vol. 41, No. 3, pp. 194–202. © Pleiades Publishing, Ltd., 2015.
Original Russian Text © D.V. Tikhonenkov, I.V. Burkovsky, Yu.A. Mazei, 2015, published in Biologiya Morya.
Deepsea zones (deeper than 200 m) occupy more
than 90% of the World Ocean area but remain one of
the least studied habitats on the planet . Data
about the protozoans living here is extremely scanty
[18, 34]. The deepsea zones are characterized by high
pressure, the absence of light, low concentrations of
nutrients, low seasonal fluctuations of water tempera
ture and density, and are inhabited by a specific fauna
of multicellular organisms . On the one hand, ear
lier taxonomic studies of deepwater protozoans
revealed a significant number of species that are widely
distributed in surface waters as well [10, 11, 19, 25]. On
the other hand, deepwater barophilic species were
found that are unable to grow at normal pressure .
Moreover, Hausmannet al.  showed that 40% of
the protozoan morphospecies that are found in the
deepwater zones of the eastern Mediterranean Sea
cannot be assigned to species that are known from sur
Among the works that are known to us, there are
none in which a comparative analysis of heterotrophic
flagellate communities of the sublittoral and bathyal
zones has been made. Different types of bottom sedi
ments and loose surface sediments significantly differ
in the grain size and the degree of sediment grain size
sorting, which may influence the structures of proto
zoan communities; however, data on the composition
of these communities are lacking.
The purpose of the present research was to study
the species diversity and community structure of free
living benthic heterotrophic flagellates that inhabit
different biotopes in the deepwater zones of the Kara
Sea. As of the present, there have been no data on the
deepsea benthic heterotrophic flagellates of the Arc
tic. Our previous studies in the White, Barents, and
Kara seas were mainly concerned with the flagellates
of the coastal and shelf zones [2–4, 6, 13, 32].
MATERIALS AND METHODS
Material was collected in the course of the 54th
cruise of the R/V
tember 2007. Samples were collected in the area of the
Yamal transect, the Novaya Zemlya Trough, the St.
Anna Trough, and at the transition to the seabed of the
Kara Sea (Fig. 1).
For the study of heterotrophic flagellate communi
ties, samples were taken with an Okean1 grab (the
upper 0.5cm layer of bottom sediments was ana
lyzed). At stations with soft bottom sediments,
Niemisto corers were used to investigate the nearbot
FreeLiving Heterotrophic Flagellates of the Sublittoral
and Bathyal Zones of the Kara Sea
D. V. Tikhonenkov
, I. V. Burkovsky
, and Yu. A. Mazei
Papanin Institute for the Biology of Inland Waters, Russian Academy of Sciences, Borok, 152742 Russia
Moscow State University, Moscow, 119899 Russia
Penza State Pedagogical University, ul. Lermontova 37, Penza, 440026 Russia
Received February 5, 2015
—The first data are presented on the species diversity and community structure of deepsea benthic
heterotrophic flagellates in the Arctic (the Kara Sea). Thirtythree species and forms of heterotrophic flagel
lates were found, with kinetoplastids, stramenopiles, apusomonadids, and choanoflagellates being predomi
nant. The species diversity of the studied region was characterized by a high betadiversity and a low alpha
diversity, which is indicative of a substantially higher potential species richness of flagellates in the Kara Sea.
The total number of species of flagellates decreased with increasing depth (from 15 to 554 m); peculiar fea
tures of the species composition of deepsea flagellates were not revealed. However, the flagellate communi
ties within two different biotopes (the upper layer of the bottom sediments and the loose, flocculent layer on
the surface of sediments together with nearbottom suspended matter) had similar taxonomic and trophic
structures, but differed in the ratio of species with different feeding strategies. Attached or freeswimming
flagellates were predominant in the loose surfacelayer, whereas rapidly gliding species that are able to actively
search for and capture food predominated in the bottom sediments.
: heterotrophic flagellates, community structure, sublittoral, bathyal, Kara Sea