LONG TERM CHANGES OF

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LONG TERM CHANGES OF ZOOPLANKTON COMMUNITY OF THE
SEVASTOPOL BAY (1976-2002)
Alexandra Gubanova, Denis Altukhov, Maria
Saburova, Igor Polikarpov, Irina Prusova
Plankton Dept., Institute of Biology of the
Southern Seas, Sevastopol, UKRAINE
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BLACK SEA
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ANALYSED SAMPLES
Number of samples
Station
Period (month)
Year
5
2
VIII-X
1968
22
2
I-XII
1976
18
2
XII I-XI
1979-1980
117
1, 2, 3, 4
III-XII I-IX
1989-1990
9
2
VI-XII I-V
1995-1996
34
2
I-XII
2002
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MAIN FACTORS INFLUENCING BIOTA OF THE SEVASTOPOL
BAY

1. Pollution and eutrophication of the bay caused by
   entry of toxic matter and biogenic elements with
   sewage and terrigenous flow.

1. Worsening of water-exchange between the
   Sevastopol Bay and open sea after building of
   breakwaters in 1978.

1. Considerable strengthening of predators pressure
   as a result of mass expansion of ctenophora
   Mnemiopsis leidyi and Beroe ovata after their
   occasional introduction to the Black Sea.

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LONG-TERM CHANGES OF MESOZOOPLANKTON COMMUNITY
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LONG-TERM CHANGES OF MESOZOOPLANKTON COMMUNITY
Numbers,
100
11
11
13
19
32
17
80
17
24
36
60
15
46
44
62
40
21
48
20
26
22
24
11
0
1976
1979-80
1989-90
1995-96
2002
Years
Meroplankton
Noctiluca scintillans
Others
Total copepods
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LONG-TERM CHANGES OF COPEPODS COMMUNITY SPECIES
COMPOSITION
 
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LONG-TERM CHANGES OF COPEPODS COMMUNITY ABUNDANCE
Numbers, ind./m3
3
12000
10000
8000
6000
4000
2000
0
1976
1979-80
1989-90
1995-96
2002
Years
11
LONG-TERM CHANGES OF COPEPODS COMMUNITY SPECIES
STRUCTURE
9
20
3
8
4
56
1979 - 80
1989 - 90
1976
5
3
15
23
5
1
65
76
7
2002
1995 - 96
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LONG-TERM CHANGES OF COPEPODS COMMUNITY
SEASONAL DYNAMICS
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LONG-TERM CHANGES OF MESOZOOPLANKTON COMMUNITY
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SEASONAL DYNAMICS OF TOTAL NUMBERS OF
MESOZOOPLANKTON AND MNEMIOPSIS LEIDYI IN 2002
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CHANGES OF ABUNDANCE OF ZOOPLANKTON DURING
REPRODUCTION PERIOD OF INVADED CTENOPHORA
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CUMULATIVE GRAPHS OF NUMBERS AND BIOMASS OF
ZOOPLANKTON SPECIES
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CONCLUSIONS

• During the observed period (1976 - 2002)
  mesozooplankton community of the Sevastopol Bay
  was unstable.

• Depression of mesozooplankton of the Sevastopol
  Bay was caused by changes of complex of abiotic
  and biotic environmental parameters due to the
  anthropogenic activity, long-term climatic
  fluctuations and the impact of ctenophores
  Mnemiopsis leidyi and Beroe ovata.
• The most considerable form of anthropogenic
  pressure on the zooplankton community during
  observed period is an occasional introduction of
  predatory species new for the investigated area.

• Since the 2000s, changes of the zooplankton
  community of the Sevastopol Bay became positive
  as a result of improvement of environmental
  conditions and reduction of predatory pressure of
  ctenophore Mnemiopsis leidyi.