Gruz Bay (south-eastern Adriatic) is moderately eutrophicated, mostly
by discharge from the karat river Ombla. Input of inorganic nitrogen m
ight be attributed to enrichment from the open sea during strong and c
ontinuous north winds in winter 1988/89. Annual succession of primary
producers, herbivores and decomposers was defined by seven stages and
induced by specific physical-chemical characteristics. In the period A
pril-August, biological production was mostly due to small size fracti
ons of phytoplankton and zooplankton. Recycling of planktonic biomass
occurred in September, of allochtonous organic matter in February and
March.