Primary production in the Southern Baltic in 1985 and 1986 compared with long-term mean seasonal variation

On the basis of long-term investigations, the course of seasonal variations of mean daily primary production and mean chlorophyll-a concentration in the Southern Baltic waters are presented. The mean annual primary production of the Gdańsk Deep, Bornholm Deep and the Gotland Deep amounted to 124.4 gC m-2, 88.8 gC m-2 and 107.2 gC m-2, respectively. The primary production of the Southern Baltic in 1986 was higher than in 1985, and higher than the long-term mean value. The mean annual production for the Southern Baltic in 1986 amounted to 130 gC m-2. On the basis of long-term observations of primary production and chlorophyll-a of the Southern Baltic, certain upward trends in phytoplankton production were observed

Long-term changes in primary production and chlorophyll concentrations in the Southern Baltic

The paper presents results of long-term investigations on primary production and chlorophyll a concentrations at two stations in the Southern Baltic (in the Gdańsk Deep and in the Bornholm Deep). The data show increasing trends in the annual primary production and mean chlorophyll a contents. A mean increase in the annual primary production within the recent years is estimated at 1-2% per year