Docstoc

Projekt_EU_Eurocat_UMK_Toru馹19-09-2003

Document Sample
Projekt_EU_Eurocat_UMK_Toru馹19-09-2003 Powered By Docstoc
					 European Commission project EUROCAT:
  European Catchments Changes and their Impact on the Coast
 Case Study VISCAT:
   The Vistula River Catchment and the Baltic Sea Coastal Zone

       Kowalewski M., Jędrasik J., Ołdakowski B.,
University of Gdansk, Institute of Oceanography

Impact of the Vistula River waters on
the Gulf of Gdańsk during 1994-2002

 The ecohydrodynamic model of the Baltic Sea
The ecohydrodynamic model of the Baltic Sea

                               Meteorological Data:
                               Model UMPL (ICM)


            River                                            Solar
                               3D Hydrodynamic
           Inflows                                          Radiation
                                    Model
            Data                                             Model


           Atmos-               Production and
           pheric               Destruction of
                                Organic Matter
          Deposition           Model (ProDeMo)



  A 3D coupled hydrodynamic – ecological model: ProDeMo (Production and
  Destruction of Organic Material Model) has been formulated and applied for the
  whole Baltic Sea and the Gulf of Gdańsk.
  The ProDeMo model contains both inflow of matter and energy into the sea
  environment including discharges of rivers and atmospheric deposition.
  Hydrological and biological conditions of the Gulf of Gdańsk influenced by the
  Vistula River are taken into account.
ProDeMo model                                                                                        1 nutrient uptake by phytoplankton,
     The following processes are included in the ProDeMo:
                                                                                                     2 phytoplankton grazing by zooplankton,
        7             17  16       14      Atmosphere
                                                                                                     3 phytoplankton respiration,
                                     23                                                              4 phytoplankton decay,
8                                                                 PHYTOPLANKTON
                                                                                                     5 sedimentation,
     NUTRIENTS                  21        DISSOLVED                 Blue-green algae
                                                             18                                      6 nutrients release from sediment,
          N-NO3                            OXYGEN                   Spring diatoms
                           22                                                                        7atmospheric deposition,
                                      20            19   1          Autumn diatoms
                                                                                                     8 denitrification,
          N-NH4
                           3                                            Dinoflagellate               9 mineralization,
                                                                                                 5
          P-PO4                       DETRITUS                4         Green algae          3       10 zooplankton respiration,
                                           CDETR                                                     11 sedimentation of phosphorus
          Si-SiO4                                                         2         Water
                                           NDETR                                                        adsorbed on particles,
                           7
                                                                  ZOOPLANKTON                        12 detritus sedimentation,
                                           PDETR                                                     13 zooplankton decay
     11                                                      13     Zooplankton
           6                               SiDETR                       C:N:P                        14 nitrogen fixation
                                                         10                                          15 nutrient deposition.

                                                    12                                                   The model also describes processes
                                                                              Sediment                    influenced the dissolved oxygen:
                                                                                    Active           16 reaeration,
                    NSED                         PSED               SiSED
                                                                                    layer
                                                                                                     17 flux to atmosphere due to the over
                    15                      15                     15      Inactive layer
                                                                                                        saturated conditions,
                                                                                                     18 zooplankton respiration,
                                                                                                     19 phytoplankton respiration,
The ProDeMo model describes the nutrients (phosphorus, nitrogen, silicon)
cycles through the food web including water-sediment interactions and                                20 assimilation,
oxygen condition. Five groups of phytoplankton: spring and autumn                                    21 mineralization,
diatoms, dinoflagellates, green algae, blue-green algae as well as                                   22 nitrification,
zooplankton biomass has been considered. Totally, 18 state variables has
                                                                                                     23 denitrification
been included in the model.
                                       How does the model work ?
                                                                Algorithm
               ProDeMo Algorithm                               modification   In order to get the proper agreement between
                                                                              modelled simulations and observed data, three
                                                                              significant procedure steps were made:
                   Model Calibration
                                                                              The calibration procedure has been done by
Adjustment of                Set of the model coefficients                    comparing results of the model with measured
the coefficients
                                                                              nutrient concentrations at stations P1, P110, ZN2
                                                                              for 1994 - 2002 period and the adjustment of the
                                                                              model parameters.
                              Is the agreement with
                                  measurements
          No
                             (1994-1996) acceptable?                          The verification procedure consisted as
                                                                              asessment of behavior of the model. It was
                                                                              subjected to influence of strong atmospheric and
                                         Yes
                                                                              hydrological forceing, different input of nutrient
                                                                              loads. In result the model appeared as stable,
                                                                              internl logical and coherent, does not produces
                               Model verification                  No
                                                                              trends. Its reactions were as expected.
                             Are the model assumptions
                                 defined properly?
                                                                              The verification procedure distinguished from
                                         Yes                                  verification, was objective test how the model
                                                                              results fit the observation data from the stations
                             Model Validation
                                                                              not used for calibration and verification in period
                       Assessment of the model results based                  1994-2002.
                             on data from 1998-2000
                                                                              Obtaining evidences permit to consider this model
                                                                              as reliable tool for studding the coastal processes
                                                                              in the Gulf of Gdańsk.
                          Model as a reliable tool
                       Applications for the environmental
                       studies and management of the
                       coastal waters in the Gulf of Gdańsk
         Monitoring stations at the southern Baltic
The hydrodynamic model
      is based on the POM                                                      Baltic Sea
(Princeton Ocean Model). The
 numerical application of the                                                 grid step: 5 NM
  model has been embedded
      on two nested grids:               Gulf of Gdańsk
 1 NM for the Gulf of Gdańsk        R4    grid step: 1 NM
   in 5 NM for the Baltic Sea.                                       P1
    Calculations in those two
    areas are parallel and the
 exchange of information on                       ZN4                P116
   the common border takes
                                                 P104
  place on each time step. All
                                          P101
       the model variables                                    P110
  calculated on the border of               NP
                                                                          K
one area serve as a boundary                            ZN2
 condition for the other area.     Gdańsk               Vistula
   A “sigma” transformation
 approach was applied in the
 model, making it possible to
  divide the vertical profile in
      each point of the sea,
                                                                                           P140
   irrespectively of its depth,                                                       P5     P63
into equal number of layers. It                                                     P39
  enabled better mapping of
the bottom boundary layer as
 well as simplified numerical
       calculation scheme.
                    Validation of the model – station P1
               1994    1995   1996   1997   1998   1999   2000   2001   2002
             0.12
                                                                   NO3_OBS




 NO3[gm ]
-3
             0.08                                                  NO3_MOD
                                                                 R=0.800
             0.04
             0.00
             0.06
                                                                    NH4_OBS
 NH4[gm ]
-3




             0.04                                                   NH4_MOD
                                                                  R=-0.037

             0.02

             0.00

             0.40
 Ntot[gm ]




             0.30
-3




             0.20                                                    Ntot_OBS
             0.10                                                    Ntot_MOD
                                                                   R=0.480
             0.00

             0.04
                                                                    PO 4_OBS
 PO4[gm ]




             0.03
-3




                                                                    PO 4_MOD
                                                                     R=0.713
             0.02
             0.01
             0.00
                    Validation of the model – station P1
             0.04




 Ptot[gm ]
             0.03




-3
             0.02                                                     Ptot_OBS
             0.01                                                     Ptot_MOD
                                                                      R=0.434
             0.00
 SiO4[gm ]   0.50
             0.40
-3




             0.30
                                                                      SiO4_OBS
             0.20
                                                                      SiO4_MOD
             0.10                                                      R=0.269
             0.00

             17.0                                                      O2_OBS
 O2[gm ]
-3




                                                                       O2_MOD
             14.0                                                      R=0.852

             11.0
              8.0

             24.0
 Tw[ C]




             16.0
o




                                                                       Tw_OBS
              8.0                                                      Tw_MOD
                                                                       R=0.976
              0.0
             8.00
             7.50
  S[psu]




             7.00                                                       S_OBS
             6.50                                                       S_MOD
                                                                        R=0.503
             6.00
                1994   1995   1996   1997   1998   1999   2000   2001 2002
   Distributions of N-NO3 and P-PO4 in crossection through the Gulf of
Gdańsk from mouth of the Vistula River to the station P1 at 4th March 1995
                       0
                                                                                                           0

                    -2 0
                                                                                                        -2 0
 D e p th [m ]




                    -4 0




                                                                                       D e p th [m ]
                                                                                                        -4 0

                    -6 0
                                                                                                        -6 0

                    -8 0                                              N O 3 [g m 3 ]                                                                     P O 4 [g m 3 ]
                                                                                                        -8 0

                   -1 0 0
                                o b s e rv e d                               0 .6                                   o b s e rv e d                              0 .1 2
                                                                                                       -1 0 0

                            0       10      20    30      40     50          0 .5                                                                               0 .1 0
                                                                                                                0      10      20     30     40     50
                                          D is ta n c e [k m ]               0 .4                                                                               0 .0 8
                                                                                                                             D is ta n c e [k m ]
                            0        10     20     30     40     50
                        0                                                    0 .3                               0      10      20     30     40     50
                                                                                                                                                                0 .0 6
                                                                                                           0
                                                                             0 .2
                     -2 0                                                                                                                                       0 .0 4
                                                                                                        -2 0
                                                                             0 .1
                                                                                                                                                                0 .0 2
   D e p th [m ]




                     -4 0
                                                                                       D e p th [m ]
                                                                             0 .0                       -4 0
                                                                                                                                                                0 .0 0

                     -6 0
                                                                                                        -6 0

                     -8 0
                                                                                                        -8 0

                   -1 0 0                                                                                           m o d e lle d
                                 m o d e lle d                                                         -1 0 0
                      Observed and modelled vertical distribution of the variable states
                                during winter and summer seasons in 2001

                                -3                                         N-NH [g m-3]
                                                                               4
                                                                                                                                   N-Ntot [g m -3]                                                 P-PO4 [g m ]
                                                                                                                                                                                                               -3
                                                                                                                                                                                                                                                                  P-Ptot [g m ]
                                                                                                                                                                                                                                                                               -3
                      N-NO3 [g m ]
                                                                   0.00     0.03    0.06    0.09                             0.0     0.1     0.2      0.3    0.4                            0.00        0.10             0.20                               0.0        0.1              0.2
               0.00    0.05   0.10   0.15
                                                                 -10                       OBS                         -10                                                         -10                                                                -10
             -10                      obs
                                                                                                                                                                                                                    OB S                                                            OB S
                                                                                           MOD                                                                                                                      MOD                                                             MOD
                                      m od
                                                                                    09.02.2001                                                                                                                 09.02.2001                                                      09.02.2001
             -30
                                 09.02.2001                      -30                                                   -30                                                         -30                                                                -30




                                                                                                                                                                    Depth [m]




                                                                                                                                                                                                                                   Depth [m]
                                              Depth [m]




                                                                                                    Depth [m]
Depth [m]




             -50                                                 -50                                                   -50                                                         -50                                                                -50


             -70                                                 -70                                                   -70                                                         -70                                                                -70
                                                                                                                                        OBS
             -90                                                 -90                                                   -90              MOD                                        -90                                                                -90
                                                                                                                                   09.02.2001
            -110                                             -110                                                 -110                                                          -110                                                           -110


                                -3                                                                                                                                                                                                                                                 -3
                      N-NO3 [g m ]                                                     -3                                                                                                                           -3                                             P-Ptot [g m ]
                                                                           N-NH4 [g m ]                                              N-Ntot [g m-3]                                                   P-PO4 [g m ]
               0.00    0.05   0.10   0.15                                                                                                                                                                                                                    0.0             0.1              0.2
                                                                    0.00     0.03   0.06    0.09                              0.0      0.1      0.2    0.3    0.4                              0.00        0.10             0.20
             -10                                                                                                                                                                                                                                       -10                          OB S
                                      obs                         -10                                                   -10                                                                  -10
                                                                                            OB S                                                                                                                     OB S                                                           MOD
                                      m od
                                                                                            MOD                                                                                                                      MOD                                                       21.08.2001
                                 21.08.2001                                                                                                                                                                                                            -30
             -30                                                  -30                  21.08.2001                                                                                            -30                21.08.2001
                                                                                                                        -30




                                                                                                                                                                                                                                          Depth [m]
Depth [m]




                                                                                                                                                                                Depth [m]
                                                     Depth [m]




                                                                                                           Depth [m]




             -50                                                                                                                                                                                                                                       -50
                                                                  -50                                                   -50                                                                  -50

                                                                                                                                                                                                                                                       -70
             -70                                                  -70                                                   -70                                                                  -70
                                                                                                                                           OBS                                                                                                         -90
             -90                                                  -90                                                   -90                MOD                                               -90
                                                                                                                                    21.08.2001
                                                                                                                                                                                                                                                      -110
            -110                                                 -110                                                  -110                                                                 -110
Observed and modelled vertical distribution of the variable states
          during winter and summer seasons in 2001

                                               -3                                                      -3                                           o
                                Si-SiO4 [g m ]                                            O-O2 [g m ]                                           Tw [ C]                                                    -3
                                                                                                                                                                                                    S [g m ]
                          0.0    0.5     1.0     1.5      2.0                        -5      0     5        10   15                      0      5    10       15       20
                                                                                                                                                                                           0.00     4.00  8.00   12.00
                    -10                         OB S
                                                                               -10             OB S                                -10                         OB S                      -10           OB S
                                                MOD                                            MOD                                                             MOD
                                                                                          09.02.2001                                                                                                   MOD
                                           09.02.2001                                                                                                     09.02.2001
                    -30                                                        -30                                                 -30                                                            09.02.2001
                                                                                                                                                                                         -30
 Depth [m]




                                                                  Depth [m]




                                                                                                                      Depth [m]




                                                                                                                                                                            Depth [m]
                    -50                                                        -50                                                 -50
                                                                                                                                                                                         -50

                    -70                                                        -70                                                 -70
                                                                                                                                                                                         -70

                    -90                                                        -90                                                 -90
                                                                                                                                                                                         -90

             -110                                                             -110                                                -110
                                                                                                                                                                                        -110
                                                 -3                                                    -3                                           o                                                      -3
                                 Si-SiO4 [g m ]                                           O-O2 [g m ]                                           Tw [ C]                                             S [g m ]
                           0.0     0.4     0.8      1.2     1.6                      -5      0     5        10   15                      0      5    10       15       20                  0.00     4.00  8.00   12.00

                     -10                                                       -10                                                 -10                                                   -10           OB S
                                                    OB S                                       OB S                                               OB S
                                                    MOD                                        MOD                                                MOD                                                  MOD
                                               21.08.2001                                 21.08.2001                                         21.08.2001                                           21.08.2001
                     -30                                                       -30                                                 -30                                                   -30




                                                                                                                                                                            Depth [m]
        Depth [m]




                                                                  Depth [m]




                                                                                                                      Depth [m]
                     -50                                                       -50                                                 -50                                                   -50


                     -70                                                       -70                                                 -70                                                   -70


                     -90                                                       -90                                                 -90                                                   -90


                    -110                                                      -110                                                -110                                                  -110



The model has properly described the seasonal distribution of nutrients, temperature and dissolved oxygen.
Also the vertical distributions of the modelled parameters follows the observations, however better
agreements have been achieved in the upper layer than in the layer below the halocline (60-70 m).
                                                                               Quality of the ProDeMo model
                                                                       integral square error [Ise]
special coeff. of correlation [Rs]

                                       0.0 0.2                 0.4    0.6        0.8      1.0      1.2      1.4         1.6   1.8      2.0
                                     1.0 SO2 T SiO4               NO
                                                               Ntot 3
                                                                     Ptot                                   excellent
                                     0.9                           PO4                                                                         Correlation coefficient
                                                                                                             good                            versus total quadratic error
                                     0.8                                           NH4
                                                                                                                                    PO4       diagram calculated for all
                                                                                                                                    Ptot        measurements beside
                                     0.7                                                                                            SiO4
                                                                                                                                    O2                  stations:
                                            excellent




                                     0.6                                                                                            T                P1, P110, ZN2
                                                        good




                                                                                                                                    S
                                                                                                                                    NO3               has showed
                                     0.5                                                                                            Ntot     an excellent agreement for
                                                                                  for all variables at z = 0m                       NH4
                                     0.4                                                                                                      salinity, dissolved oxygen
                                                                                                                                                   and very good for
                                                                      integral square error [Ise]                                                 temperature. Other
                                                                                                                                             compared parameters lie in
special coeff. of correlation [Rs]




                                       0.0 0.2 0.4 0.6 0.8 1.0 1.2 1.4 1.6 1.8 2.0 2.2 2.4 2.6                                                 the good range except
                                           S O2T
                                     1.0                                                                          excellent                       nitrate nitrogen as
                                                               Ntot
                                                                                                                                             acceptable and ammonium
                                     0.9                              Ptot PO4
                                                                                                                                              nitrogen low satisfactory.
                                                                       SiO4                                        good
                                     0.8                                                              NO3                       PO4
                                                                                                                                Ptot
                                     0.7                                                                                        SiO4
                                                                                                                                O2
                                           excellent




                                                                                                                  NH4           T
                                     0.6                                                                                        S
                                                        good




                                                                                                                                NO3
                                     0.5                                                                                        Ntot
                                                                            for all variables at whole profiles                 NH4
                                     0.4
       Mean concentrations of the modelled parameters for 15th June 1999

                                                                                                     Dissolved oxygen
         Temperature [°C]                                         Salinity [PSU]                          [g m-3]

        11 13 15 17 19 21 23                                      5   10   15   20   25                8     9     10     11




  N-NO3 [g m-3]                    N-NH4 [g m-3]
                                                                                     P-PO4 [g m-3]           Si-SiO4 [g m-3]
0 0.05 0.1 0.15 0.2 0.25       0    0.005   0.01   0.015   0.02
                                                                                      0.01    0.03         0.1   0.4    0.7    1   1.3
                                                                                                                                                        The strong variation in
    Variation in biomass and structure of phytoplankton                                                                                                 biomass and structure of
    modelled for 15th June 1999                                                                                                                         phytoplankton can be also
                                                                                                                                                        observed in the spatial
                                                                                                                                                        distributions. The highest
 Spring diatoms                           Green algae                               Blue-green algae                      Primary production            primary production rates
biomass [gC m-3]                       biomass [gC m-3]                             biomass [gC m-3]                          [gC m-2d-1]               (mean daily rates for July
0    0.05   0.1    0.15   0.2          0   0.05   0.1   0.15     0.2                0     0.05   0.1   0.15   0.2         0.1         0.3   0.5   0.7
                                                                                                                                                        1999) during the summer are
                                                                                                                                                        observed along the coastal
                                                                                                                                                        waters,      especially      in
                                                                                                                                                        surrounding of river outlets.
                                                                                                                                                         Very       high      primary
                                                                                                                                                        production is observed in
                                                                                                                                                        the western parts of the Gulf
                                                                                                                                                        of Gdańsk and the Gulf of
                                                                                                                                                        Riga      as     the     likely
                                                                                                                                                        consequence of upwelling
                                                                                                                                                        process appearing along the
                                                                                                                                                        coasts.
         Dinoflagellate                                                                                                                                 During the summer the
                                                         Autumn diatoms
       biomass [gC m-3]                                                                                           Zooplankton                           green algae dominates in
                                                        biomass [gC m-3]
                                                                                                               biomass [gC m-3]                         phytoplankton biomass of
      0     0.05    0.1   0.15   0.2
                                                        0      0.05    0.1   0.15   0.2
                                                                                                                    0.1         0.2
                                                                                                                                                        the majority Baltic waters,
                                                                                                                                                        however there are regions
                                                                                                                                                        with       appearance        of
                                                                                                                                                        dinoflagelletes and blue-
                                                                                                                                                        green algae (highest water
                                                                                                                                                        temperature). The autumn
                                                                                                                                                        diatoms appear in the
                                                                                                                                                        regions of upweling even
                                                                                                                                                        during the summer season.
                                                                                                                                                        This phenomena is caused
                                                                                                                                                        by cooler water conditions
                                                                                                                                                        in     upwelling      regions
                                                                                                                                                        favourable      by    autumn
                                                                                                                                                        diatoms.
                                    Annual input of the Vistula River
                                       into the Gulf of Gdańsk

                          6
       0.4     PTOT [10 kg]                                        6
                                                13.2 NTOT [10 kg]


                                                                         The model has been applied to study various
               5.2       5.5    Q [km ]
                                        3                              effects of the Vistula River discharge on the
                                                            136.2      environmental state of the coastal waters:
                                                                       ·
                                                                                  Vistula the second largest river in the
                                        36.3
                                                                       Baltic Sea introduces into the Gulf of Gdańsk

                                                                                 85% of discharged fresh waters
                                                                                 90% of nitrogen compounds
                                                                                 92% of phosphorus compounds
Annual input of the Vistula and other rivers into the Gulf of Gdańsk
                                                                                                   T e m p e ra tu re
                                                                                                         [1 m ]
                                                                                                                                                                      Spreading of the Vistula waters
                                                                                                                                                                           at the Gulf of Gdansk
                                                                                                                                                                       during 11 April – 10 May 2000
                                                              [c m s -1 ]                                                                               [°C ]
    0         5           10       15          20   25                                   5        6        7        8        9        10       11

                      N -N O 3                                                                                 N -N H 4
                          [1 m ]                                                                                  [1 m ]
                                                                                                                                                                        The ProDeMo model has been
                                                                                                                                                                        applied to study the consequences
                                                                                                                                                                        of the hydrodynamics of the Gulf of
                                                                                                                                                                        Gdańsk on the nutrient and
                                                                                                                                                                        phytoplankton distributions.

0           0 .2            0 .4          0 .6         0 .8    [g m -3 ]          0                   0 .0 3            0 .0 6              0 .0 9      [g m -3 ]       During the spring conditions (high
                          P -P O 4                                                                             S i-S iO 4                                               values of nitrogen and phosphorus
                           [1 m ]                                                                                 [1 m ]
                                                                                                                                                                        loads) the influence of the Vistula
                                                                                                                                                                        River waters on the nutrient
                                                                                                                                                                        concentrations reached even the
                                                                                                                                                                        open waters of the Gulf of Gdańsk
                                                                                                                                                                        (towards North the Hel Peninsula).
                                                                 -3                                                                                           -3
0              0 .0 1                 0 .0 2          0 .0 3 [g m ]               0 .1            0 .1 5           0 .2            0 .2 5            0 .3 [g m ]

    P rim a ry p ro d u c tio n                                                   P h y to p la n k to n b io m a s s
                                                                                                                                                                        It has been observed that during
                                                                                                 [1 m ]                                                                 the studied period: 11 April – 10
                                                                                                                                                                        May 2000, the main pathway of the
                                                                                                                                                                        Vistula River water was the North-
                                                                                                                                                                        West direction.


     0 .3          0 .6        0 .9       1 .2      1 .5       [g C m -2 d -1 ]          0 .0 5            0 .1           0 .1 5            0 .2        [g C m -3 ]
                                          The Vistula River waters versus the hel upwelling
                                                                                                                      The model has simulated the
                                                                                                                      special dynamic behaviour of
                                                                                                                      the Gulf of Gdańsk and the Hel
                                                                                                                      upwelling.
                                                                                                                      According to the model results
                                                                                                                      (mean values during the 11
                                   1200
                                                                    upwelling/downwelling                             April – 10 May 2000) the area of
          Ładunek N-NO 3 [t d-1]




                                   900
                                   600                              Wisła                                             the Hel upwelling showed much
                                   300                                                                                higher primary production rate
                                     0
                                                                                                                      caused by additional fluxes of
                                   -300
                                   -600                                                                               nutrients from the bottom layer.
                                   -900                                                                               The comparison between the
                             -1200                                                                                    Vistula River loads of inorganic
                                          1   2   3   4       5        6        7       8       9    10    11    12
                                                                                                                      nitrogen and phosphorus and
                                                                                                                      the upwelling/ downwelling
                                   300                                                                                fluxes shows that
                                                                  upelling/downwelling
Ładunek P-PO 4 [t d-1]




                                   200
                                                                  Wisła
                                                                                                                      during      the    autumn    the
                                   100                                                                                upwelling gave higher loads to
                                     0                                                                                the upper layer than the Vistula
                              -100                                                                                    River. In contradiction,
                              -200                                                                                    during the spring time the
                              -300                                                                                    upwelling      phenomena    was
                                          1   2   3   4   5        6        7       8       9       10    11    12
                                                                                                                      rather week while the Vistula
                                                                                                                      River discharged very high
                                                                                                                      loads      of    nitrogen   and
                                                                                                                      phosphorus.
                          Distribution of phytoplankton at Gdansk Deep
                                  station P1 in period 1994 - 2002


            16

            14      Autumn diatoms
                    Blue-green lgae
            12      Green algae
                    Dinoflagellates
            10      Spring Diatoms
[gC m-2 ]




            8

            6

            4

            2

            0

             1994          1995       1996   1997     1998       1999       2000       2001        2002

   The biomass distribution of the five phytoplankton varies in time following different reactions on the water
   temperature, solar radiation and nutrient availability.

   The vegetation seasons start with the high blooms of diatoms during the spring. During the summer
   dinoflagellates and green algae dominates in the phytoplankton biomass. The blue-green algae are able to
   assimilate the nitrogen from the atmosphere, therefore they can grow even during the nitrogen limitation summer
   conditions. The blue-green algae appearance varies from year to year since they prefer higher water temperature
   and solar radiation.

   During the modelled period quite high biomass of blue-green algae has been calculated in 1994, 1995 and 1999.
   Years, while during 1998 and 2000 they have hardly been observed. Autumn diatoms starts to grow in September
   and they dominate trough whole autumn.
               Sequence of surface distribution
     of phytoplankton biomass, nitrates and phosphates
at the Gulf of Gdansk between February 22 – March 27 1995
                                              The model was also able to
                                              observe the dynamics of the
                                              phytoplankton blooms.
                                              During      the     presented
                                              sequence of phytoplankton,
                                              nitrate     nitrogen      and
                                              phosphate         phosphorus
                                              patterns (22 February – 27
                                              March 1995).
                                              The main direction of the
                                              Vistula River waters flowed
                                              along the coast towards
                                              eastern parts of the Gulf
                                              with one exception (12
                                              March).
                                              The phytoplankton growth
                                              started near the coasts of
                                              Gulf of Gdańsk and than
                                              bloom moved to the open
                                              sea.
                                              The model has also given an
                                              evidence that higher values
                                              of phytoplankton biomass
                                              were observed in the areas
                                              of higher content of nitrate
                                              nitrogen and phosphate
                                              phosphorus originating from
                                              the Vistula River.
                                      Conclusions
Hydrodynamic model
validated using monitoring observations according to
the coastal sea level fluctuations, temporal and spatial distributions of salinity as well as the
water temperature including remote sensing pictures of the sea surface.
In result the model obtained evidences (high statistical evaluation) which permit to consider it
as reliable tool for studding the coastal processes in the Gulf of Gdańsk.

ProDeMo model
calibrated, verified and validated using observed data for 9 years period 1994-2002, showed
that the model has properly described the seasonal distribution of nutrients, temperature and
dissolved oxygen, however near the bottom it was overestimated. Other compared parameters
lie in the good range of quality of model except nitrate nitrogen as acceptable and ammonium
nitrogen low satisfactory. The biomass distributions of the five phytoplankton groups as well as
time and places of their blooms appeared reliable.

Impact of the Vistula River on the Gulf of Gdańsk
From among various effects of the Vistula River discharge on the environmental state of the
coastal waters are:
pathways of the Vistula River waters in the Gulf
temporal and spatial dynamics of nutrients
blooms and seasonal variations of phytoplankton biomass

				
DOCUMENT INFO
Shared By:
Categories:
Tags:
Stats:
views:5
posted:10/17/2011
language:English
pages:19