International Journal of Marine Science 2014, Vol.4, No.42, 1-11
3
the density of benthos was calculated from the number
of animals found per sediment interval of a TV-MUC
core (9.5 cm diameter or 70.8 cm
2
) or an ITU core (7
cm diameter or 38.5 cm
2
) and extrapolated to m
2
of
seafloor area. Sediment sections were preserved in
75 % alcohol, which is known to conserve
morphological structures of fauna without distortion.
To avoid damaging the calcareous taxa we did no
prior fixation in formalin. Sediment samples were
washed with distilled water through sieves with mesh
sizes of 1 mm and 63 μm. The fraction that retained in
the sieves was stained with Rose Bengal solution, a
dye traditionally used to separate living and dead or
decaying organisms (Bernhard, 2000; Bernhard et al.,
2006; Danovaro et al., 2010; Grego et al., 2013) and
sorted in water under a binocular microscope for „live‟
(stained) organisms. We extracted only those
specimens that stained intensely with Rose Bengal and
that showed no signs of morphological damage. All
isolated macro- and meiobenthos was counted and
identified to higher taxa level. All protozoa and
metazoa fauna larger than 63 μm were categorized as
meiobenthos.
Figure 1 Benthic stations in the Istanbul Strait's (Bosporus)
outlet area of the Black Sea (April, 2010)
Notes: triangle: pore water and meiobenthic stations; circle:
meiobenthic stations
Table 1 Water depths and coordinates of meiobenthos stations in the Bosporus outlet area of the Black Sea („
Maria S. Merian
‟ cruise
15/1. 2010)
Station
Pangaea event label
Date
Time [UTC]
Position
Depth [m]
Gear
Latitude
Longitude
285
MSM15/285-1
17.04.2010
05:00
41°25.21' N 29°11.29' E
97.2
TV-MUC
243
MSM15/243-1
15.04.2010
7:01
41°28.92' N 29°15.06' E
153.6
TV-MUC
224
MSM15/224-1
14.04.2010
22:10
41°29.59' N 29°15.74' E
199.9
TV-MUC
333
MSM15/333-1
18.04.2010
18:56
41°29.63' N 29°15.80' E
200
TV-MUC
332
MSM15/332-1
18.04.2010
17:54
41°29.94' N 29°16.11' E
253.6
TV-MUC
203
MSM15/203-1
13.04.2010
20:10
41°29.94' N 29°16.13' E
252.4
GC ITUC
204
MSM15/204-1
13.04.2010
20:24
41°29.94' N 29°16.13' E
252.4
GC ITUC
261
MSM15/262-1*
16.04.2010
3:17
41°30.13' N
29°16.34' E
295.7
TV-MUC
263
MSM15/263-1
16.04.2010
3:17
41°29.92' N 29°16.12' E
247.7
TV-MUC
Notes: *Light microscopy (LM) observation of alive fauna
To reveal the presence of living fauna in the deeper
and potentially anoxic sediments of the Bosporus
outflow area, unfixed sediment samples from 296 m
water depth were studied. The sediment (Station 262)
was transferred to a Petri dish (90 mm diameter)
immediately after sampling and analyzed visually
using light microscopy. These observations of living
benthic fauna were conducted in bottom sediment
without subjecting it to mechanical and physical
effects i.e. washing through sieves or use of thermal
and electrical appliances. Active movements of some
organisms were filmed with a video camera (Canon
DIGITAL IXUS 90 IS Camera).
2.2 Geochemical analyzes
Dissolved oxygen, salinity and temperature of the
water
column
were
measured
with
a
conductivity-temperature-depth
(CTD)
probe,
equipped with an oxygen sensor (SeaBird Electronics).
The oxygen concentration was calibrated against
Winkler titration (Winkler 1888). A total of 59 CTD
casts were performed in the Bosporus outlet area
between 12 and 18 April 2010. Of these, 10 CTD casts
were performed to map the oxygen distribution along
a 4 km long transect crossing the sediment sampling
stations. Oxygen concentrations were measured from
the surface down to 5 m above the sea floor. Oxygen
