International Journal of Marine Science 2014, Vol.4, No.42, 1-11
5
protozoa can inhabit Black Sea sediments in areas that
were previously thought to be devoid of higher life.
The indigenous eukaryotic fauna observed active in
the fresh, not sieved sediment samples were recorded
on video (Supplementary material). As these
sediments were rather liquid black fine sediment and
had a strong smell of the hydrogen sulfide and the
overlying water column was anoxic and sulfidic
during our sampling (Figure 2, Figure 3), the presence
of these indigenous organisms in the sediments
provides evidence that some eukaryotes can live under
anoxic/sulfidic conditions in the Black Sea at 296 m
water depth.
Analyses of the sediment samples yield a
characteristic fauna of benthic organisms and we have
identified six to seven higher level taxa: Gromiida,
Ciliophora, Foraminifera (soft-shelled), Nematoda,
Kinorhyncha, Harpacticoida and one unknown
specimen in two cores from Stations 296 m.
In the muddy sediments at a 252 m water depth
(Station 203 and 204), we found a large number of the
macrobenthic oligochaetes
Tubificoides
sp. (body
length 5~7 mm). Presence of these macrobenthic
oligochaetes in high density and actively moving will
lead to a strong bioturbation of the sediment on other
studied habitats (Figure 5).
In the same sediment sample three macrobenthic
polychaetes species
Aricidea
sp. and
Capitellidae
g.
sp. and
Vigtorniella zaikai
were identified (Figure 6).
Figure 5
Tubificoides sp
(Oligochaeta) in the seafloor
sediments of Station 224 and Station 263
4.1 Microscopic observations of alive Protozoa
Observations with the microscope showed active
movement and changes in the body shape of both
Ciliophora species detected in the sediments (Figures
7 and 8). The two different morphotypes of ciliates
showed different motion activity. Ciliophora gen. sp. 1
changed its location in the Petri dish, slowly rotating
around its axis, keeping the form of the body (Figure 7.
A-E). In contrast, Ciliophora gen. sp. 2 was actively
moving along the bottom of the Petri dish inside the
silt and detritus particles, changing body length and
diameter, but also the shape of the body (Figure 8
A-K). Significant changes in ciliates body shape
impeded the process of its identification.
Figure 6
Aricidea
sp. (A) and
Vigtorniella zaikai
(B) in the
seafloor sediments of Station 224-1 and Station 263: A – B –
general view of individual polychaetes. C - D – possible
endosymbiontes in different parts of the body of
Aricides
. E-
endosymbiontes in the body of
Vigtorniella
Figure 7 Movements of Ciliophora species, A–E: Ciliophora
gen. sp. 1 (Station 262)
Figure 8 Movements of Ciliophora species. A–K: Ciliophora
gen. sp. 2 (Station 262)
