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POSEIDON-363
7-25 March 2008
Oceanography group cruise report
G.I.Shapiro, D.L.Aleynik, D.Soloviev
Aims and objectives.
The aims of the group were:
- Collect oceanographic water column data (temperature, salinity, oxygen, current
velocities) and remotely sensed data ( Sea Surface Temperature and
Chlorophyll- a concentration) for the study of the water column processes on the
western and north-western shelves of the Black Sea.
- Collect water samples for the geochemistry and biochemistry group and for the
Institute of Oceanology (Varna).
- Operate Fast Rate Repetition Fluorometer (FRRF) and pass the data to the
biochemistry group
Constitution and duties.
The group consisted of Prof Georgy Shapiro (group leader, University of Plymouth, UK), Dr
Dmitry Aleynik (University of Plymouth, UK), Mr Dmitry Soloviev ( Marine Hydrophysical
Institute, Ukraine). The duties were shared as follows
- G.Shapiro – group supervision, night time watch sampling (from 20:00 to 8:00),
operational data analysis and interpretation, communication with IFM-
GEOMAR, safety and risk assessment within the group.
- D.Aleynik – day time watch sampling ( from 8:00 to 20:00), provisional data
processing, setting up and maintenance of FRRF.
- D.Soloviev – receiving and full processing of the remotely sensed satellite
information (SST and Chl-a), night time watch sampling (together with
G.Shapiro, from 20:00 to 8:00), assistance in measuring water transparency
conducted by Odessa Branch of the Institute of Biology of Southern Seas group.
Equipment and data collection methodology.
The hydrographic data were collected using a rosette-CTD package equipped with 11 Hydro-
Bios (Apparategebau, Germany) type bottles. The rosette also contained a Fast Rate Repetition
Fluorometer mounted in place of the 12th
bottle. The pressure, temperature and conductivity data
were acquired using a Seabird SBE-9/11plus CTD profiler. The current velocity was measured
by a ship mounted Acoustic Doppler Current Profiler (ADCP) model RDI WH600. ADCP
acquisition kit was configured to receive data from the ADCP and the ship navigation system
NMEA. The ship velocity data (VTG signal) was not transmitted to the ADCP kit via NMEA, so
the ADCP recorded uncorrected velocities ( a combination of the ship and water current
velocities). The actual current velocities will be obtained through further processing of the
recorded acoustic signal in the home institution (University of Plymouth). Both ADCP and CTD
devices were kindly provided by the IFM-GEOMAR (Kiel, Germany), and were calibrated
following IFM-GEOMAR protocol before the cruise. The high resolution (1.1x 1.1 km pixel
size) satellite imagery of sea surface temperature and Chl-a was provided by the support team
from the Marine Hydrophysical Institute (MHI, Ukraine) using the level-2 data from MODIS
AQUA satellite distributed by Oceancolor, NASA. These data were transmitted to the ship as
raw binary data via mobile INTERNET from the MHI server when working close to the coastal
mobile transmitting stations. When the ship was further off-shore, the raw satellite images were
transmitted from MHI via the ship’s email system. Weather data were obtained from the standard
ship weather station.
Data collection was carried out on a 24 hours/ 7 days a week basis. The details of the stations
taken by the oceanography group are shown in the Table 1 below.
Provisional results.
The North-western shelf of the Black Sea experiences thermal heating and freshwater input from
rivers during the spring months. The latter affects the salinity distribution and can be detected far
offshore (up to 100 km from the coast). The temperature, salinity and density distribution over
the whole study region were comparable with the typical early-spring values. Preliminary
analysis shows a strong cold coastal jet flowing southward along the western coast of Romania
and Bulgaria (Fig.1 and Fig2.). The ADCP data acquisition system was configured to record
uncorrected speed of water relative to the moving vessel, so that actual current velocities will be
obtained after in-lab processing using the software scripts developed in UoP.
Fig.1. Sea Surface Temperature Distribution before the cruise ( 02 February 2008)
Fig.2. Sea Surface Temperature Distribution in the middle of the cruise ( 13 March 2008)
The jet was evolving during the cruise and generated a multi-frontal structure of coastal and shelf
water masses. Stratification in the area was variable, from well mixed waters on some stations to
well stratified and dynamically active waters further off-shore.
On the first survey off Cape Kaliakra carried out in early March, the surface temperature was
6.83°C and salinity 17.49 psu.at the coastal station (28°31.03’E 43°21.59’N, st. 101_2) There
was a smooth thermocline and the temperature difference between the surface and the near
bottom layer was 0.4°C. On the off- shore side of the area (st. 109, 29° 16.96'E 43° 5.02 'N) the
surface temperature increased to 7.75°C. We clearly see that the temperature stratifications have
increased. The minimal temperature in the Cold Intermediate Layer (CIL) was observed there at
depth 64 m (6.78°C). See Figs.3,4
The second survey near Kaliakra was made on 23-24 March 2008. At the coastal station (28°
31.03'E 43° 21.60'N, st. 193) the surface temperature was 7.95°C and salinity 17.80 psu. The
thermocline had two inversion layers at 15 and 25 m with T=8.05 and 7.97 °C and the
temperature difference between the surface and the near bottom layer was 0.15°C. On the off-
shore side of the section (29° 21.19'E 43° 2.18 'N, st. 205_1) the surface temperature increased to
8.25°C. The temperature stratifications have increased. The minimal temperature in the CIL was
observed there at depth 49 m (7.68°C). See Figs 5,6.
35
30
25
20
15
10
5
7.80 7.85 7.90 7.95 8.00 8.05
17.50 17.55 17.60 17.65 17.70 17.75 17.80 17.85 17.90 17.95 18.00 18.05 18.10 18.15
6.9 7.0 7.1 7.2 7.3 7.4 7.5 7.6 7.7 7.8 7.9 8.0 8.1 8.2
13.60 13.65 13.70 13.75 13.80 13.85 13.90 13.95 14.00 14.05
P3630193s0s1s2s3s4bin1.cnv
De
pth
[s
alt
wa
ter
, m
]
T emperature [IT S -90, deg C]
O x y gen, S B E 43 [m l/l ]
S al ini ty [P S U]
Deriv ed Dens ity [s igma-theta, K g/m^3]
500
450
400
350
300
250
200
150
100
50
0
7.7 7.8 7.9 8.0 8.1 8.2 8.3 8.4 8.5 8.6 8.7 8.8 8.9
18.0 18.5 19.0 19.5 20.0 20.5 21.0 21.5 22.0
0 1 2 3 4 5 6 7
14.0 14.5 15.0 15.5 16.0 16.5 17.0
P3630205s0s1s2s3s4bin1.cnv
De
pth
[s
alt
wa
ter
, m
]
T emperature [IT S -90, deg C]
O x y gen, S B E 43 [m l/l ]
S al ini ty [P S U]
Deriv ed Dens ity [s igma-theta, K g/m ^3]
Fig.5 Fig.6
The third Kaliakra section was in 15-20 miles to north off the position of the 1st and the 2
nd
surveys in 24 March. At the coastal station (28° 43.20'E 43° 27.98'N st. 211) the surface
temperature was 8.32°C and salinity 17.78 psu. The thermocline had only one inversion layer at
20 m with T=8.27. The temperature difference between the surface and the near bottom layer
was 0.37°C. The CIL was located at depths 30-35 m with 7.90 °C. On the off- shore side of the
section (29° 27.47'E 43° 11.54'N, st. 206) the surface temperature increased to 8.40°C. The
minimal temperature in the CIL was observed there at depth 49 m (7.59°C).See Figs 7, 8.
30
25
20
15
10
5
6.80 6.85 6.90 6.95 7.00 7.05 7.10 7.15 7.20
17.50 17.55 17.60 17.65 17.70 17.75 17.80 17.85
5.5 6.0 6.5 7.0 7.5
13.65 13.70 13.75 13.80 13.85 13.90
P3630101_02s0s1s2s3s4bin1.cnv
De
pth
[s
alt
wa
ter
, m
]
T emperature [IT S -90, deg C]
O x y gen, S B E 43 [m l/l ]
S al ini ty [P S U]
Deriv ed Dens ity [s igma-theta, K g/m^3]
500
450
400
350
300
250
200
150
100
50
0
6.75 7.00 7.25 7.50 7.75 8.00 8.25 8.50 8.75
18.5 19.0 19.5 20.0 20.5 21.0 21.5 22.0
0 1 2 3 4 5 6 7
14.0 14.5 15.0 15.5 16.0 16.5 17.0
P3630109_1s0s1s2s3s4bin1.cnv
De
pth
[s
alt
wa
ter
, m
]
T emperature [IT S -90, deg C]
O x y gen, S B E 43 [m l/l ]
S al ini ty [P S U]
Deriv ed Dens ity [s igma-theta, K g/m^3]
Fig.3. Fig.4
60
50
40
30
20
10
0
7.90 7.95 8.00 8.05 8.10 8.15 8.20 8.25 8.30
17.70 17.75 17.80 17.85 17.90 17.95 18.00 18.05 18.10
6.4 6.5 6.6 6.7 6.8 6.9 7.0 7.1 7.2 7.3 7.4 7.5 7.6
13.70 13.75 13.80 13.85 13.90 13.95 14.00 14.05
P3630211s0s1s2s3s4bin1.cnv
De
pth
[s
alt
wa
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, m
]
T emperature [IT S -90, deg C]
O x y gen, S B E 43 [m l/l ]
S al ini ty [P S U]
Deriv ed Dens ity [s igma-theta, K g/m^3]
500
450
400
350
300
250
200
150
100
50
0
7.6 7.7 7.8 7.9 8.0 8.1 8.2 8.3 8.4 8.5 8.6 8.7 8.8 8.9
18.0 18.5 19.0 19.5 20.0 20.5 21.0 21.5 22.0
0 1 2 3 4 5 6 7
14.0 14.5 15.0 15.5 16.0 16.5 17.0
P3630206s0s1s2s3s4bin1.cnv
De
pth
[s
alt
wa
ter
, m
]
T emperature [IT S -90, deg C]
O x y gen, S B E 43 [m l/l ]
S al ini ty [P S U]
Deriv ed Dens ity [s igma-theta, K g/m^3]
Fig.7. Fig.8.
The vertical structure of temperature at the area of Zernov’s Phyllophora Field (Polygon Phy)
was characterised with the very deep development of the upper homogenous layer. It varies from
12 m to 23 m at a number of stations. The temperature at the surface and in this layer was very
low: 5.2°C at st.138 (31° 44.15'E 45° 54.28'N) and 5.02 at st. 142 (30° 51.78'E 45° 44.04'N).
The temperature difference between the surface and the near bottom layer was 0.6-0.8°C. The
salinity of the surface and subsurface layers decreased toward the coast from 17.85 psu at st. 138
to 16.25 psu at st 142, which were close to Dnistro Lyman. See Figs 9,10
25.0
22.5
20.0
17.5
15.0
12.5
10.0
7.5
5.0
2.5
4.5 4.6 4.7 4.8 4.9 5.0 5.1 5.2
17.65 17.70 17.75 17.80 17.85 17.90 17.95 18.00 18.05 18.10 18.15
6.25 6.50 6.75 7.00 7.25 7.50 7.75 8.00
13.95 14.00 14.05 14.10 14.15 14.20 14.25 14.30 14.35 14.40
P3630138s0s1s2s3s4bin1.cnv
De
pth
[s
alt
wa
ter
, m
]
T emperature [IT S -90, deg C]
O x y gen, S B E 43 [m l/l ]
S al ini ty [P S U]
Deriv ed Dens ity [s igma-theta, K g/m^3]
30
25
20
15
10
5
0
4.3 4.4 4.5 4.6 4.7 4.8 4.9 5.0 5.1
16.25 16.50 16.75 17.00 17.25 17.50 17.75 18.00
7.0 7.1 7.2 7.3 7.4 7.5 7.6 7.7 7.8 7.9 8.0 8.1
13.00 13.25 13.50 13.75 14.00 14.25
P3630142s0s1s2s3s4bin1.cnv
De
pth
[s
alt
wa
ter
, m
]
T emperature [IT S -90, deg C]
O x y gen, S B E 43 [m l/l ]
S al ini ty [P S U]
Deriv ed Dens ity [s igma-theta, K g/m^3]
Fig.9 Fig.10
Two cross-sections from Dnistro river Lyman shows the step-like structure in the vertical
temperature profiles in its upper parts both on off-shore and in-shore stations. At the coastal
station (30° 39.46'E 45° 51.04'N, st. 150) the surface temperature was 5.1°C and salinity 15.96
psu. The thermocline has one inversion layer at 12 m with T=4.96°C. The temperature difference
between the surface and the near bottom layer was 0.5°C. The minimal temperature was
observed at depths 16 m with 4.48°C. On the off-shore side of the section (31° 17.55'E 45° 1.00
'N, st. 158) the surface temperature increased to 7.8°C, salinity – to 17.75 psu. The minimal
temperature (in the CIL) was observed near sea bottom at depths 58 m (6.76°C). See Figs 11,12
22.5
20.0
17.5
15.0
12.5
10.0
7.5
5.0
2.5
4.50 4.55 4.60 4.65 4.70 4.75 4.80 4.85 4.90 4.95 5.00 5.05 5.10
16.00 16.25 16.50 16.75 17.00 17.25 17.50 17.75 18.00
7.75 8.00 8.25 8.50 8.75 9.00
12.50 12.75 13.00 13.25 13.50 13.75 14.00 14.25
P3630150s0s1s2s3s4bin1.cnvD
ep
th [
sa
lt w
ate
r,
m]
T emperature [IT S -90, deg C]
O x y gen, S B E 43 [m l/l ]
S al ini ty [P S U]
Deriv ed Dens ity [s igma-theta, K g/m^3]
60
50
40
30
20
10
0
6.8 6.9 7.0 7.1 7.2 7.3 7.4 7.5 7.6 7.7 7.8
17.75 17.80 17.85 17.90 17.95 18.00 18.05 18.10 18.15
7.0 7.1 7.2 7.3 7.4 7.5 7.6 7.7 7.8
13.70 13.75 13.80 13.85 13.90 13.95 14.00 14.05 14.10 14.15 14.20
P3630158s0s1s2s3s4bin1.cnv
De
pth
[s
alt
wa
ter
, m
]
T emperature [IT S -90, deg C]
O x y gen, S B E 43 [m l/l ]
S al ini ty [P S U]
Deriv ed Dens ity [s igma-theta, K g/m^3]
Fig.11 Fig.12
More developed profiles of temperature were observed at stations in Bulgarian waters. On VA3
(28° 23.88'E 43° 8.24 'N, st. 192) the surface temperature increased to 7.9°C, salinity – to 17.75
psu. Ta depts. 12-30 m there was positive inversion of temperature 8.07°C. The minimum
temperature was 7.83°C at depths 33 m. The temperature difference between the surface and the
near bottom layer (58 m, 7.86°C) was 0.04°C. The low saline (17.6 psu) sub-surface layer was
observed at depths 5-11 m., see Fig 13.
60
50
40
30
20
10
0
7.85 7.90 7.95 8.00 8.05
17.60 17.65 17.70 17.75 17.80 17.85 17.90 17.95 18.00 18.05 18.10 18.15
6.00 6.25 6.50 6.75 7.00 7.25 7.50
13.65 13.70 13.75 13.80 13.85 13.90 13.95 14.00 14.05 14.10
P3630192s0s1s2s3s4bin1.cnv
De
pth
[s
alt
wa
ter
, m
]
T emperature [IT S -90, deg C]
O x y gen, S B E 43 [m l/l ]
S al ini ty [P S U]
Deriv ed Dens ity [s igma-theta, K g/m^3]
Fig.13
The stability of the water mass and its dynamics can be inferred indirectly from comparing the
downcasts ( which are normally used to describe the water column properties) and the upcast ,
which was conducted immediately after the downcast. Examples of stable und evolving
situations are shown in Figs.14, 15 for stations No 120 and 183. Further analysis of the
hydrophysical situation is being carried out at the University of Plymouth.
Fig.14 Fig.15
