In t h~s study we estimated the amount and fate of phytoplankton primary product~on in the coastal zone of the Gulf of Gdansk, Poland, an area exposed to nutnent enrichment from the Vistuld R~v e r and nearby inunlcipal agglomeration The ~n v e s t i g a t~o n s were carned out at 2 sites d u r~n g 5 months in 1993 (February, April, May, August and October). A prolonged bloom pei-iod occurred in the coastal zone, as compared to the open Gulf and the open sea waters. From Aprll until October

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... values of gross primary production in the near-surface layer were in the range 100 to 500 m g C m-" d 1 Phytoplankton net exudate release constituted on average 5 % of the gross prlmai-y production, total exudate release was estimated to be about 2 times h~gher. Bacterial production in the growth season was relatively low (the mean value l y~n g between 5 and 9 % of gloss primary production), nevertheless, the microbial community (bactena and protozoans) u t~l~z e d a large proportion of primary production (from about 50% in April and May to 16'%, in October). Usually direct protozoan grazing on phytoplankton exceeded bacterial uptake of the phytoplankton exudates. In winter, summer and autumn communlty respiration exceeded depth-averaged primary production, ~n d~c a t i n g that external energy sources ( s e d~m e n t resuspension, allochthonous organic matter) play a substantial role in communlty metabol~sm.