Biogeochemical Investigations For The Szczecin Lagoon 
In The Period Of The Odra Flood In July/August 1997 
H Westphal 1 & W. Rosenthal 2 
1 Energiewerke Nord GmbH 
Postfach 1125 
17507 Lubmin 
2 GKSS Forschungszentrum 
Max-Planck-Strasse 
21504 Geesthacht 
Abstract 
Within the frame of the GOAP program (Greifswalder Bodden und Oderastuar Austausch 
Prozesse), supported by the German Research Ministry, GKSS together with Instytut Morski 
in Szczecin and Energiewerke Nord in Greifswald executed intensive measurements in the 
Zalew Szczecinski in the period from 22 July until 25 September 1997, covering the Odra 
flood period in July and August 1997. Sensors for hydrological, meteorological and 
biogeochemical parameters were placed on 
1. automatic sampling stations with online data transfer to GKSS 
2. the research vessel Ludwig Prandtl. 
The geography of the area is given in fig. 1. The three automatic operating platforms were 
located in the western lagoon (Kleines Haff), while the ship cruises were mainly made in the 
eastern lagoon (Zalew Wielki). 
Fig 1 : The Odra lagoon was equipped 
with fixed platforms in the western part 
(Kleines Hafl). Ship profiles to 
measure fluxes were mainly done in the 
eastern part (Zalew Wielki) 
From the ship water samples were 
taken to derive concentrations of 
nutrients, chlorophyll-a and pheophytin 
and rates for primary production in the 
water column. In combination with 
ADCP measurements along predefined 
profiles perpendicular to the mean 
current it was possible to determine the fluxes of substances. The fluxes differ at the Odra 
mouth and in the sum of the exits of Zalew Wielki: Swina, Dziwna and German-Polish 
border. Especially the fluxes of dissolved nitrogen and phosphate and also those of 
chlorophyll and pheophytin could be determined. 
vngPMB’-. 
X\ ■ : ... ■ T ,. 
- : ... , SuiääT 
..c-T 
The concentrations of nitrogen were within the orders of magnitude that could be expected 
for the time of the year, whereas the concentrations of phosphate were slightly higher (by a 
factor of 2 to 5) than the several year average. The fluxes were much higher than in the 
several year average due to the large water masses (up to 3000 m 3 /s.)