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Jędrasik J., Kowalewski M., Ołdakowski B., University of Gdansk, Institute of Oceanography Impact of the Vistula River waters on the G ulf of G dańsk during 1994-2002. European Commission project EUROCAT : European Catchments Changes and their Impact on the Coast Case Study VISCAT :
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Jędrasik J., Kowalewski M., Ołdakowski B.,University of Gdansk, Institute ofOceanographyImpact of the Vistula River waters on the Gulf of Gdańsk during 1994-2002
European Commission project EUROCAT:
European Catchments Changes and their Impact on the Coast
The Vistula River Catchment and the Baltic Sea Coastal Zone
1. The ecohydrodynamic model of the Baltic Sea
2. Impact of the Vistula River on the Gulf of Gdańsk - examples
1 nutrient uptake
3 phytoplank. resp.
4 phytoplank. decay
6 nutr. release f. sed
10 zooplankt. resp.
11 sed.of P ads. on particles,
12 detritus sed.
13 zooplankt. decay
14 nitrogen fixation
15 nutrient deposition
processes influen. dissolved oxygen
17 flux to atmo. due to over saturation
18 zooplankt. resp.
19 phytoplank. resp.
based at stations P1, P110, ZN2 for 1994- 2002 period
as asessment of behavior of the model
test how the model results fit the observation data
The hydrodynamic model is based on the POM (Princeton Ocean Model).
The numerical application of the model has been embedded on two nested grids:
1 NM for
the Gulf of Gdańsk
in 5 NM for
A “sigma” transformation for 18 layers are used.
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
An excellent agreement for salinity,
Other compared parameters lie
in the good range
except nitrate nitrogen as acceptable and ammonium nitrogen low satisfactory.
The vegetation seasons start with the high blooms of diatoms during the spring.
During the summer dinoflagellates and green algae dominates.
The blue-green algae are able to assimilate the nitrogen from the atmosphere. Their appearance varies from year to year since they prefer higher water temperature and solar radiation.
Autumn diatoms starts to grow in September and they dominate trough whole autumn.
Vistula the second largest river of the Baltic Sea
introduces into the Gulf of Gdańsk
85% of discharged fresh waters
90% of nitrogen compounds
(it takes part 15% of N
in the Baltic)
23% is retained at the Gulf
92% of phosphorus compounds
(it takes part 20% of P
in the Baltic)
34% is retained at the Gulf
Distributions of N-NO3 and P-PO4 in crossection through the Gulf of Gdańskfrom mouth of the Vistula River to the station P1at 4th March 1995
The hydrodynamics influences
on the nutrient and phytoplankton distributions.
During the spring season influence of the Vistula River waters on the nutrient concentrations are even at the open waters of the Gulf of Gdańsk.
11 April – 10 May 2000, the main pathway of the Vistula River water - the North-West direction.
Sequence of surface distribution of phytoplankton biomass, nitrates and phosphates at the Gulf of Gdansk between February 22 – March 27 1995
using monitoringdatafor 9 years period 1994-2002, resulted in 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.
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.Conclusions
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